The European Physical Journal C

, 74:2835

Measurement of \({\Upsilon } \) production in \({{\mathrm {p}}} {{\mathrm {p}}} \) collisions at \({\sqrt{s}} =2.76{\mathrm {\,TeV}} \)

Authors

  • R. Aaij
    • Nikhef National Institute for Subatomic Physics
  • B. Adeva
    • Universidad de Santiago de Compostela
  • M. Adinolfi
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • A. Affolder
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • Z. Ajaltouni
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • J. Albrecht
    • Fakultät PhysikTechnische Universität Dortmund
  • F. Alessio
    • European Organization for Nuclear Research (CERN)
  • M. Alexander
    • School of Physics and AstronomyUniversity of Glasgow
  • S. Ali
    • Nikhef National Institute for Subatomic Physics
  • G. Alkhazov
    • Petersburg Nuclear Physics Institute (PNPI)
  • P. Alvarez Cartelle
    • Universidad de Santiago de Compostela
  • A. A. AlvesJr
    • Sezione INFN di Roma La Sapienza
  • S. Amato
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • S. Amerio
    • Sezione INFN di Padova
  • Y. Amhis
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • L. Anderlini
    • Sezione INFN di Firenze
  • J. Anderson
    • Physik-Institut, Universität Zürich
  • R. Andreassen
    • University of Cincinnati
  • M. Andreotti
    • Sezione INFN di Ferrara
  • J. E. Andrews
    • University of Maryland
  • R. B. Appleby
    • School of Physics and AstronomyUniversity of Manchester
  • O. Aquines Gutierrez
    • Max-Planck-Institut für Kernphysik (MPIK)
  • F. Archilli
    • European Organization for Nuclear Research (CERN)
  • A. Artamonov
    • Institute for High Energy Physics (IHEP)
  • M. Artuso
    • Syracuse University
  • E. Aslanides
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • G. Auriemma
    • Sezione INFN di Roma La Sapienza
  • M. Baalouch
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • S. Bachmann
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • J. J. Back
    • Department of PhysicsUniversity of Warwick
  • A. Badalov
    • Universitat de Barcelona
  • V. Balagura
    • Institute of Theoretical and Experimental Physics (ITEP)
  • W. Baldini
    • Sezione INFN di Ferrara
  • R. J. Barlow
    • School of Physics and AstronomyUniversity of Manchester
  • C. Barschel
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • S. Barsuk
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • W. Barter
    • Cavendish LaboratoryUniversity of Cambridge
  • V. Batozskaya
    • National Center for Nuclear Research (NCBJ)
  • Th. Bauer
    • Nikhef National Institute for Subatomic Physics
  • A. Bay
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • J. Beddow
    • School of Physics and AstronomyUniversity of Glasgow
  • F. Bedeschi
    • Sezione INFN di Pisa
  • I. Bediaga
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • S. Belogurov
    • Institute of Theoretical and Experimental Physics (ITEP)
  • K. Belous
    • Institute for High Energy Physics (IHEP)
  • I. Belyaev
    • Institute of Theoretical and Experimental Physics (ITEP)
  • E. Ben-Haim
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • G. Bencivenni
    • Laboratori Nazionali dell’INFN di Frascati
  • S. Benson
    • School of Physics and AstronomyUniversity of Edinburgh
  • J. Benton
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • A. Berezhnoy
    • Institute of Nuclear PhysicsMoscow State University (SINP MSU)
  • R. Bernet
    • Physik-Institut, Universität Zürich
  • M.-O. Bettler
    • Cavendish LaboratoryUniversity of Cambridge
  • M. van Beuzekom
    • Nikhef National Institute for Subatomic Physics
  • A. Bien
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • S. Bifani
    • University of Birmingham
  • T. Bird
    • School of Physics and AstronomyUniversity of Manchester
  • A. Bizzeti
    • Sezione INFN di Firenze
  • P. M. Bjørnstad
    • School of Physics and AstronomyUniversity of Manchester
  • T. Blake
    • Department of PhysicsUniversity of Warwick
  • F. Blanc
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • J. Blouw
    • Max-Planck-Institut für Kernphysik (MPIK)
  • S. Blusk
    • Syracuse University
  • V. Bocci
    • Sezione INFN di Roma La Sapienza
  • A. Bondar
    • Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University
  • N. Bondar
    • Petersburg Nuclear Physics Institute (PNPI)
  • W. Bonivento
    • Sezione INFN di Cagliari
    • European Organization for Nuclear Research (CERN)
  • S. Borghi
    • School of Physics and AstronomyUniversity of Manchester
  • A. Borgia
    • Syracuse University
  • M. Borsato
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • T. J. V. Bowcock
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • E. Bowen
    • Physik-Institut, Universität Zürich
  • C. Bozzi
    • Sezione INFN di Ferrara
  • T. Brambach
    • Fakultät PhysikTechnische Universität Dortmund
  • J. van den Brand
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • J. Bressieux
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • D. Brett
    • School of Physics and AstronomyUniversity of Manchester
  • M. Britsch
    • Max-Planck-Institut für Kernphysik (MPIK)
  • T. Britton
    • Syracuse University
  • N. H. Brook
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • H. Brown
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • A. Bursche
    • Physik-Institut, Universität Zürich
  • G. Busetto
    • Sezione INFN di Padova
  • J. Buytaert
    • European Organization for Nuclear Research (CERN)
  • S. Cadeddu
    • Sezione INFN di Cagliari
  • R. Calabrese
    • Sezione INFN di Ferrara
  • O. Callot
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • M. Calvi
    • Sezione INFN di Milano Bicocca
  • M. Calvo Gomez
    • Universitat de Barcelona
  • A. Camboni
    • Universitat de Barcelona
  • P. Campana
    • Laboratori Nazionali dell’INFN di Frascati
    • European Organization for Nuclear Research (CERN)
  • D. Campora Perez
    • European Organization for Nuclear Research (CERN)
  • A. Carbone
    • Sezione INFN di Bologna
  • G. Carboni
    • Sezione INFN di Roma Tor Vergata
  • R. Cardinale
    • Sezione INFN di Genova
  • A. Cardini
    • Sezione INFN di Cagliari
  • H. Carranza-Mejia
    • School of Physics and AstronomyUniversity of Edinburgh
  • L. Carson
    • School of Physics and AstronomyUniversity of Edinburgh
  • K. Carvalho Akiba
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • G. Casse
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • L. Castillo Garcia
    • European Organization for Nuclear Research (CERN)
  • M. Cattaneo
    • European Organization for Nuclear Research (CERN)
  • Ch. Cauet
    • Fakultät PhysikTechnische Universität Dortmund
  • R. Cenci
    • University of Maryland
  • M. Charles
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • Ph. Charpentier
    • European Organization for Nuclear Research (CERN)
  • S.-F. Cheung
    • Department of PhysicsUniversity of Oxford
  • N. Chiapolini
    • Physik-Institut, Universität Zürich
  • M. Chrzaszcz
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
    • Physik-Institut, Universität Zürich
  • K. Ciba
    • European Organization for Nuclear Research (CERN)
  • X. Cid Vidal
    • European Organization for Nuclear Research (CERN)
  • G. Ciezarek
    • Imperial College London
  • P. E. L. Clarke
    • School of Physics and AstronomyUniversity of Edinburgh
  • M. Clemencic
    • European Organization for Nuclear Research (CERN)
  • H. V. Cliff
    • Cavendish LaboratoryUniversity of Cambridge
  • J. Closier
    • European Organization for Nuclear Research (CERN)
  • C. Coca
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • V. Coco
    • European Organization for Nuclear Research (CERN)
  • J. Cogan
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • E. Cogneras
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • P. Collins
    • European Organization for Nuclear Research (CERN)
  • A. Comerma-Montells
    • Universitat de Barcelona
  • A. Contu
    • Sezione INFN di Cagliari
    • European Organization for Nuclear Research (CERN)
  • A. Cook
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • M. Coombes
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • S. Coquereau
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • G. Corti
    • European Organization for Nuclear Research (CERN)
  • I. Counts
    • Massachusetts Institute of Technology
  • B. Couturier
    • European Organization for Nuclear Research (CERN)
  • G. A. Cowan
    • School of Physics and AstronomyUniversity of Edinburgh
  • D. C. Craik
    • Department of PhysicsUniversity of Warwick
  • M. Cruz Torres
    • Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
  • S. Cunliffe
    • Imperial College London
  • R. Currie
    • School of Physics and AstronomyUniversity of Edinburgh
  • C. D’Ambrosio
    • European Organization for Nuclear Research (CERN)
  • J. Dalseno
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • P. David
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • P. N. Y. David
    • Nikhef National Institute for Subatomic Physics
  • A. Davis
    • University of Cincinnati
  • I. De Bonis
    • LAPP, Université de Savoie, CNRS/IN2P3
  • K. De Bruyn
    • Nikhef National Institute for Subatomic Physics
  • S. De Capua
    • School of Physics and AstronomyUniversity of Manchester
  • M. De Cian
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • J. M. De Miranda
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • L. De Paula
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • W. De Silva
    • University of Cincinnati
  • P. De Simone
    • Laboratori Nazionali dell’INFN di Frascati
  • D. Decamp
    • LAPP, Université de Savoie, CNRS/IN2P3
  • M. Deckenhoff
    • Fakultät PhysikTechnische Universität Dortmund
  • L. Del Buono
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • N. Déléage
    • LAPP, Université de Savoie, CNRS/IN2P3
  • D. Derkach
    • Department of PhysicsUniversity of Oxford
  • O. Deschamps
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • F. Dettori
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • A. Di Canto
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • H. Dijkstra
    • European Organization for Nuclear Research (CERN)
  • S. Donleavy
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • F. Dordei
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • M. Dorigo
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • P. Dorosz
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
  • A. Dosil Suárez
    • Universidad de Santiago de Compostela
  • D. Dossett
    • Department of PhysicsUniversity of Warwick
  • A. Dovbnya
    • NSC Kharkiv Institute of Physics and Technology (NSC KIPT)
  • F. Dupertuis
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • P. Durante
    • European Organization for Nuclear Research (CERN)
  • R. Dzhelyadin
    • Institute for High Energy Physics (IHEP)
  • A. Dziurda
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
  • A. Dzyuba
    • Petersburg Nuclear Physics Institute (PNPI)
  • S. Easo
    • STFC Rutherford Appleton Laboratory
  • U. Egede
    • Imperial College London
  • V. Egorychev
    • Institute of Theoretical and Experimental Physics (ITEP)
  • S. Eidelman
    • Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University
  • S. Eisenhardt
    • School of Physics and AstronomyUniversity of Edinburgh
  • U. Eitschberger
    • Fakultät PhysikTechnische Universität Dortmund
  • R. Ekelhof
    • Fakultät PhysikTechnische Universität Dortmund
  • L. Eklund
    • European Organization for Nuclear Research (CERN)
    • School of Physics and AstronomyUniversity of Glasgow
  • I. El Rifai
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • Ch. Elsasser
    • Physik-Institut, Universität Zürich
  • S. Esen
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • A. Falabella
    • Sezione INFN di Ferrara
  • C. Färber
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • C. Farinelli
    • Nikhef National Institute for Subatomic Physics
  • S. Farry
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • D. Ferguson
    • School of Physics and AstronomyUniversity of Edinburgh
  • V. Fernandez Albor
    • Universidad de Santiago de Compostela
  • F. Ferreira Rodrigues
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • M. Ferro-Luzzi
    • European Organization for Nuclear Research (CERN)
  • S. Filippov
    • Institute for Nuclear Research of the Russian Academy of Sciences (INR RAN)
  • M. Fiore
    • Sezione INFN di Ferrara
  • M. Fiorini
    • Sezione INFN di Ferrara
  • C. Fitzpatrick
    • European Organization for Nuclear Research (CERN)
  • M. Fontana
    • Max-Planck-Institut für Kernphysik (MPIK)
  • F. Fontanelli
    • Sezione INFN di Genova
  • R. Forty
    • European Organization for Nuclear Research (CERN)
  • O. Francisco
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • M. Frank
    • European Organization for Nuclear Research (CERN)
  • C. Frei
    • European Organization for Nuclear Research (CERN)
  • M. Frosini
    • Sezione INFN di Firenze
    • European Organization for Nuclear Research (CERN)
  • J. Fu
    • Sezione INFN di Milano
  • E. Furfaro
    • Sezione INFN di Roma Tor Vergata
  • A. Gallas Torreira
    • Universidad de Santiago de Compostela
  • D. Galli
    • Sezione INFN di Bologna
  • M. Gandelman
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • P. Gandini
    • Syracuse University
  • Y. Gao
    • Center for High Energy PhysicsTsinghua University
  • J. Garofoli
    • Syracuse University
  • J. Garra Tico
    • Cavendish LaboratoryUniversity of Cambridge
  • L. Garrido
    • Universitat de Barcelona
  • C. Gaspar
    • European Organization for Nuclear Research (CERN)
  • R. Gauld
    • Department of PhysicsUniversity of Oxford
  • E. Gersabeck
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • M. Gersabeck
    • School of Physics and AstronomyUniversity of Manchester
  • T. Gershon
    • Department of PhysicsUniversity of Warwick
  • Ph. Ghez
    • LAPP, Université de Savoie, CNRS/IN2P3
  • A. Gianelle
    • Sezione INFN di Padova
  • S. Giani’
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • V. Gibson
    • Cavendish LaboratoryUniversity of Cambridge
  • L. Giubega
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • V. V. Gligorov
    • European Organization for Nuclear Research (CERN)
  • C. Göbel
    • Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
  • D. Golubkov
    • Institute of Theoretical and Experimental Physics (ITEP)
  • A. Golutvin
    • Institute of Theoretical and Experimental Physics (ITEP)
    • European Organization for Nuclear Research (CERN)
    • Imperial College London
  • A. Gomes
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • H. Gordon
    • European Organization for Nuclear Research (CERN)
  • M. Grabalosa Gándara
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • R. Graciani Diaz
    • Universitat de Barcelona
  • L. A. Granado Cardoso
    • European Organization for Nuclear Research (CERN)
  • E. Graugés
    • Universitat de Barcelona
  • G. Graziani
    • Sezione INFN di Firenze
  • A. Grecu
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • E. Greening
    • Department of PhysicsUniversity of Oxford
  • S. Gregson
    • Cavendish LaboratoryUniversity of Cambridge
  • P. Griffith
    • University of Birmingham
  • L. Grillo
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • O. Grünberg
    • Institut für PhysikUniversität Rostock
  • B. Gui
    • Syracuse University
  • E. Gushchin
    • Institute for Nuclear Research of the Russian Academy of Sciences (INR RAN)
  • Yu. Guz
    • Institute for High Energy Physics (IHEP)
    • European Organization for Nuclear Research (CERN)
  • T. Gys
    • European Organization for Nuclear Research (CERN)
  • C. Hadjivasiliou
    • Syracuse University
  • G. Haefeli
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • C. Haen
    • European Organization for Nuclear Research (CERN)
  • T. W. Hafkenscheid
    • KVI, University of Groningen
  • S. C. Haines
    • Cavendish LaboratoryUniversity of Cambridge
  • S. Hall
    • Imperial College London
  • B. Hamilton
    • University of Maryland
  • T. Hampson
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • S. Hansmann-Menzemer
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • N. Harnew
    • Department of PhysicsUniversity of Oxford
  • S. T. Harnew
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • J. Harrison
    • School of Physics and AstronomyUniversity of Manchester
  • T. Hartmann
    • Institut für PhysikUniversität Rostock
  • J. He
    • European Organization for Nuclear Research (CERN)
  • T. Head
    • European Organization for Nuclear Research (CERN)
  • V. Heijne
    • Nikhef National Institute for Subatomic Physics
  • K. Hennessy
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • P. Henrard
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • L. Henry
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • J. A. Hernando Morata
    • Universidad de Santiago de Compostela
  • E. van Herwijnen
    • European Organization for Nuclear Research (CERN)
  • M. Heß
    • Institut für PhysikUniversität Rostock
  • A. Hicheur
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • D. Hill
    • Department of PhysicsUniversity of Oxford
  • M. Hoballah
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • C. Hombach
    • School of Physics and AstronomyUniversity of Manchester
  • W. Hulsbergen
    • Nikhef National Institute for Subatomic Physics
  • P. Hunt
    • Department of PhysicsUniversity of Oxford
  • N. Hussain
    • Department of PhysicsUniversity of Oxford
  • D. Hutchcroft
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • D. Hynds
    • School of Physics and AstronomyUniversity of Glasgow
  • V. Iakovenko
    • Institute for Nuclear Research of the National Academy of Sciences (KINR)
  • M. Idzik
    • Faculty of Physics and Applied Computer ScienceAGH, University of Science and Technology
  • P. Ilten
    • Massachusetts Institute of Technology
  • R. Jacobsson
    • European Organization for Nuclear Research (CERN)
  • A. Jaeger
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • E. Jans
    • Nikhef National Institute for Subatomic Physics
  • P. Jaton
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • A. Jawahery
    • University of Maryland
  • F. Jing
    • Center for High Energy PhysicsTsinghua University
  • M. John
    • Department of PhysicsUniversity of Oxford
  • D. Johnson
    • Department of PhysicsUniversity of Oxford
  • C. R. Jones
    • Cavendish LaboratoryUniversity of Cambridge
  • C. Joram
    • European Organization for Nuclear Research (CERN)
  • B. Jost
    • European Organization for Nuclear Research (CERN)
  • N. Jurik
    • Syracuse University
  • M. Kaballo
    • Fakultät PhysikTechnische Universität Dortmund
  • S. Kandybei
    • NSC Kharkiv Institute of Physics and Technology (NSC KIPT)
  • W. Kanso
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • M. Karacson
    • European Organization for Nuclear Research (CERN)
  • T. M. Karbach
    • European Organization for Nuclear Research (CERN)
  • M. Kelsey
    • Syracuse University
  • I. R. Kenyon
    • University of Birmingham
  • T. Ketel
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • B. Khanji
    • Sezione INFN di Milano Bicocca
  • C. Khurewathanakul
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • S. Klaver
    • School of Physics and AstronomyUniversity of Manchester
  • O. Kochebina
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • I. Komarov
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • R. F. Koopman
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • P. Koppenburg
    • Nikhef National Institute for Subatomic Physics
  • M. Korolev
    • Institute of Nuclear PhysicsMoscow State University (SINP MSU)
  • A. Kozlinskiy
    • Nikhef National Institute for Subatomic Physics
  • L. Kravchuk
    • Institute for Nuclear Research of the Russian Academy of Sciences (INR RAN)
  • K. Kreplin
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • M. Kreps
    • Department of PhysicsUniversity of Warwick
  • G. Krocker
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • P. Krokovny
    • Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University
  • F. Kruse
    • Fakultät PhysikTechnische Universität Dortmund
  • M. Kucharczyk
    • Sezione INFN di Milano Bicocca
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
    • European Organization for Nuclear Research (CERN)
  • V. Kudryavtsev
    • Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University
  • K. Kurek
    • National Center for Nuclear Research (NCBJ)
  • T. Kvaratskheliya
    • Institute of Theoretical and Experimental Physics (ITEP)
    • European Organization for Nuclear Research (CERN)
  • V. N. La Thi
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • D. Lacarrere
    • European Organization for Nuclear Research (CERN)
  • G. Lafferty
    • School of Physics and AstronomyUniversity of Manchester
  • A. Lai
    • Sezione INFN di Cagliari
  • D. Lambert
    • School of Physics and AstronomyUniversity of Edinburgh
  • R. W. Lambert
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • E. Lanciotti
    • European Organization for Nuclear Research (CERN)
  • G. Lanfranchi
    • Laboratori Nazionali dell’INFN di Frascati
  • C. Langenbruch
    • European Organization for Nuclear Research (CERN)
  • T. Latham
    • Department of PhysicsUniversity of Warwick
  • C. Lazzeroni
    • University of Birmingham
  • R. Le Gac
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • J. van Leerdam
    • Nikhef National Institute for Subatomic Physics
  • J.-P. Lees
    • LAPP, Université de Savoie, CNRS/IN2P3
  • R. Lefèvre
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • A. Leflat
    • Institute of Nuclear PhysicsMoscow State University (SINP MSU)
  • J. Lefrançois
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • S. Leo
    • Sezione INFN di Pisa
  • O. Leroy
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • T. Lesiak
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
  • B. Leverington
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • Y. Li
    • Center for High Energy PhysicsTsinghua University
  • M. Liles
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • R. Lindner
    • European Organization for Nuclear Research (CERN)
  • C. Linn
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • F. Lionetto
    • Physik-Institut, Universität Zürich
  • B. Liu
    • Sezione INFN di Cagliari
  • G. Liu
    • European Organization for Nuclear Research (CERN)
  • S. Lohn
    • European Organization for Nuclear Research (CERN)
  • I. Longstaff
    • School of Physics and AstronomyUniversity of Glasgow
  • J. H. Lopes
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • N. Lopez-March
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • P. Lowdon
    • Physik-Institut, Universität Zürich
  • H. Lu
    • Center for High Energy PhysicsTsinghua University
  • D. Lucchesi
    • Sezione INFN di Padova
  • J. Luisier
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • H. Luo
    • School of Physics and AstronomyUniversity of Edinburgh
  • E. Luppi
    • Sezione INFN di Ferrara
  • O. Lupton
    • Department of PhysicsUniversity of Oxford
  • F. Machefert
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • I. V. Machikhiliyan
    • Institute of Theoretical and Experimental Physics (ITEP)
  • F. Maciuc
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • O. Maev
    • Petersburg Nuclear Physics Institute (PNPI)
    • European Organization for Nuclear Research (CERN)
  • S. Malde
    • Department of PhysicsUniversity of Oxford
  • G. Manca
    • Sezione INFN di Cagliari
  • G. Mancinelli
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • M. Manzali
    • Sezione INFN di Ferrara
  • J. Maratas
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • U. Marconi
    • Sezione INFN di Bologna
  • P. Marino
    • Sezione INFN di Pisa
  • R. Märki
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • J. Marks
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • G. Martellotti
    • Sezione INFN di Roma La Sapienza
  • A. Martens
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • A. Martín Sánchez
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • M. Martinelli
    • Nikhef National Institute for Subatomic Physics
  • D. Martinez Santos
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • F. Martinez Vidal
    • Instituto de Fisica Corpuscular (IFIC)Universitat de Valencia-CSIC
  • D. Martins Tostes
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • A. Massafferri
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • R. Matev
    • European Organization for Nuclear Research (CERN)
  • Z. Mathe
    • European Organization for Nuclear Research (CERN)
  • C. Matteuzzi
    • Sezione INFN di Milano Bicocca
  • A. Mazurov
    • Sezione INFN di Ferrara
    • European Organization for Nuclear Research (CERN)
  • M. McCann
    • Imperial College London
  • J. McCarthy
    • University of Birmingham
  • A. McNab
    • School of Physics and AstronomyUniversity of Manchester
  • R. McNulty
    • School of PhysicsUniversity College Dublin
  • B. McSkelly
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • B. Meadows
    • Department of PhysicsUniversity of Oxford
    • University of Cincinnati
  • F. Meier
    • Fakultät PhysikTechnische Universität Dortmund
  • M. Meissner
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • M. Merk
    • Nikhef National Institute for Subatomic Physics
  • D. A. Milanes
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • M.-N. Minard
    • LAPP, Université de Savoie, CNRS/IN2P3
  • J. Molina Rodriguez
    • Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
  • S. Monteil
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • D. Moran
    • School of Physics and AstronomyUniversity of Manchester
  • M. Morandin
    • Sezione INFN di Padova
  • P. Morawski
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
  • A. Mordà
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • M. J. Morello
    • Sezione INFN di Pisa
  • R. Mountain
    • Syracuse University
  • F. Muheim
    • School of Physics and AstronomyUniversity of Edinburgh
  • K. Müller
    • Physik-Institut, Universität Zürich
  • R. Muresan
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • B. Muryn
    • Faculty of Physics and Applied Computer ScienceAGH, University of Science and Technology
  • B. Muster
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • P. Naik
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • T. Nakada
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • R. Nandakumar
    • STFC Rutherford Appleton Laboratory
  • I. Nasteva
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • M. Needham
    • School of Physics and AstronomyUniversity of Edinburgh
  • N. Neri
    • Sezione INFN di Milano
  • S. Neubert
    • European Organization for Nuclear Research (CERN)
  • N. Neufeld
    • European Organization for Nuclear Research (CERN)
  • A. D. Nguyen
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • T. D. Nguyen
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • C. Nguyen-Mau
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • M. Nicol
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • V. Niess
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • R. Niet
    • Fakultät PhysikTechnische Universität Dortmund
  • N. Nikitin
    • Institute of Nuclear PhysicsMoscow State University (SINP MSU)
  • T. Nikodem
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • A. Novoselov
    • Institute for High Energy Physics (IHEP)
  • A. Oblakowska-Mucha
    • Faculty of Physics and Applied Computer ScienceAGH, University of Science and Technology
  • V. Obraztsov
    • Institute for High Energy Physics (IHEP)
  • S. Oggero
    • Nikhef National Institute for Subatomic Physics
  • S. Ogilvy
    • School of Physics and AstronomyUniversity of Glasgow
  • O. Okhrimenko
    • Institute for Nuclear Research of the National Academy of Sciences (KINR)
  • R. Oldeman
    • Sezione INFN di Cagliari
  • G. Onderwater
    • KVI, University of Groningen
  • M. Orlandea
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • J. M. Otalora Goicochea
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • P. Owen
    • Imperial College London
  • A. Oyanguren
    • Universitat de Barcelona
  • B. K. Pal
    • Syracuse University
  • A. Palano
    • Sezione INFN di Bari
  • F. Palombo
    • Sezione INFN di Milano
  • M. Palutan
    • Laboratori Nazionali dell’INFN di Frascati
  • J. Panman
    • European Organization for Nuclear Research (CERN)
  • A. Papanestis
    • European Organization for Nuclear Research (CERN)
    • STFC Rutherford Appleton Laboratory
  • M. Pappagallo
    • School of Physics and AstronomyUniversity of Glasgow
  • L. Pappalardo
    • Sezione INFN di Ferrara
  • C. Parkes
    • School of Physics and AstronomyUniversity of Manchester
  • C. J. Parkinson
    • Fakultät PhysikTechnische Universität Dortmund
  • G. Passaleva
    • Sezione INFN di Firenze
  • G. D. Patel
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • M. Patel
    • Imperial College London
  • C. Patrignani
    • Sezione INFN di Genova
  • C. Pavel-Nicorescu
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • A. Pazos Alvarez
    • Universidad de Santiago de Compostela
  • A. Pearce
    • School of Physics and AstronomyUniversity of Manchester
  • A. Pellegrino
    • Nikhef National Institute for Subatomic Physics
  • G. Penso
    • Sezione INFN di Roma La Sapienza
  • M. Pepe Altarelli
    • European Organization for Nuclear Research (CERN)
  • S. Perazzini
    • Sezione INFN di Bologna
  • E. Perez Trigo
    • Universidad de Santiago de Compostela
  • P. Perret
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • M. Perrin-Terrin
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • L. Pescatore
    • University of Birmingham
  • E. Pesen
    • Celal Bayar University
  • G. Pessina
    • Sezione INFN di Milano Bicocca
  • K. Petridis
    • Imperial College London
  • A. Petrolini
    • Sezione INFN di Genova
  • E. Picatoste Olloqui
    • Universitat de Barcelona
  • B. Pietrzyk
    • LAPP, Université de Savoie, CNRS/IN2P3
  • T. Pilař
    • Department of PhysicsUniversity of Warwick
  • D. Pinci
    • Sezione INFN di Roma La Sapienza
  • A. Pistone
    • Sezione INFN di Genova
  • S. Playfer
    • School of Physics and AstronomyUniversity of Edinburgh
  • M. Plo Casasus
    • Universidad de Santiago de Compostela
  • F. Polci
    • LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3
  • G. Polok
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
  • A. Poluektov
    • Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University
    • Department of PhysicsUniversity of Warwick
  • E. Polycarpo
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • A. Popov
    • Institute for High Energy Physics (IHEP)
  • D. Popov
    • Max-Planck-Institut für Kernphysik (MPIK)
  • B. Popovici
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • C. Potterat
    • Universitat de Barcelona
  • A. Powell
    • Department of PhysicsUniversity of Oxford
  • J. Prisciandaro
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • A. Pritchard
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • C. Prouve
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • V. Pugatch
    • Institute for Nuclear Research of the National Academy of Sciences (KINR)
  • A. Puig Navarro
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • G. Punzi
    • Sezione INFN di Pisa
  • W. Qian
    • LAPP, Université de Savoie, CNRS/IN2P3
  • B. Rachwal
    • Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
  • J. H. Rademacker
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • B. Rakotomiaramanana
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • M. Rama
    • Laboratori Nazionali dell’INFN di Frascati
  • M. S. Rangel
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • I. Raniuk
    • NSC Kharkiv Institute of Physics and Technology (NSC KIPT)
  • N. Rauschmayr
    • European Organization for Nuclear Research (CERN)
  • G. Raven
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • S. Redford
    • Department of PhysicsUniversity of Oxford
  • S. Reichert
    • School of Physics and AstronomyUniversity of Manchester
  • M. M. Reid
    • Department of PhysicsUniversity of Warwick
  • A. C. dos Reis
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • S. Ricciardi
    • STFC Rutherford Appleton Laboratory
  • A. Richards
    • Imperial College London
  • K. Rinnert
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • V. Rives Molina
    • Universitat de Barcelona
  • D. A. Roa Romero
    • Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC
  • P. Robbe
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • D. A. Roberts
    • University of Maryland
  • A. B. Rodrigues
    • Centro Brasileiro de Pesquisas Físicas (CBPF)
  • E. Rodrigues
    • School of Physics and AstronomyUniversity of Manchester
  • P. Rodriguez Perez
    • Universidad de Santiago de Compostela
  • S. Roiser
    • European Organization for Nuclear Research (CERN)
  • V. Romanovsky
    • Institute for High Energy Physics (IHEP)
  • A. Romero Vidal
    • Universidad de Santiago de Compostela
  • M. Rotondo
    • Sezione INFN di Padova
  • J. Rouvinet
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • T. Ruf
    • European Organization for Nuclear Research (CERN)
  • F. Ruffini
    • Sezione INFN di Pisa
  • H. Ruiz
    • Universitat de Barcelona
  • P. Ruiz Valls
    • Universitat de Barcelona
  • G. Sabatino
    • Sezione INFN di Roma La Sapienza
  • J. J. Saborido Silva
    • Universidad de Santiago de Compostela
  • N. Sagidova
    • Petersburg Nuclear Physics Institute (PNPI)
  • P. Sail
    • School of Physics and AstronomyUniversity of Glasgow
  • B. Saitta
    • Sezione INFN di Cagliari
  • V. Salustino Guimaraes
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • B. Sanmartin Sedes
    • Universidad de Santiago de Compostela
  • R. Santacesaria
    • Sezione INFN di Roma La Sapienza
  • C. Santamarina Rios
    • Universidad de Santiago de Compostela
  • E. Santovetti
    • Sezione INFN di Roma Tor Vergata
  • M. Sapunov
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • A. Sarti
    • Laboratori Nazionali dell’INFN di Frascati
  • C. Satriano
    • Sezione INFN di Roma La Sapienza
  • A. Satta
    • Sezione INFN di Roma Tor Vergata
  • M. Savrie
    • Sezione INFN di Ferrara
  • D. Savrina
    • Institute of Theoretical and Experimental Physics (ITEP)
    • Institute of Nuclear PhysicsMoscow State University (SINP MSU)
  • M. Schiller
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • H. Schindler
    • European Organization for Nuclear Research (CERN)
  • M. Schlupp
    • Fakultät PhysikTechnische Universität Dortmund
  • M. Schmelling
    • Max-Planck-Institut für Kernphysik (MPIK)
  • B. Schmidt
    • European Organization for Nuclear Research (CERN)
  • O. Schneider
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • A. Schopper
    • European Organization for Nuclear Research (CERN)
  • M.-H. Schune
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • R. Schwemmer
    • European Organization for Nuclear Research (CERN)
  • B. Sciascia
    • Laboratori Nazionali dell’INFN di Frascati
  • A. Sciubba
    • Sezione INFN di Roma La Sapienza
  • M. Seco
    • Universidad de Santiago de Compostela
  • A. Semennikov
    • Institute of Theoretical and Experimental Physics (ITEP)
  • K. Senderowska
    • Faculty of Physics and Applied Computer ScienceAGH, University of Science and Technology
  • I. Sepp
    • Imperial College London
  • N. Serra
    • Physik-Institut, Universität Zürich
  • J. Serrano
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • P. Seyfert
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • M. Shapkin
    • Institute for High Energy Physics (IHEP)
  • I. Shapoval
    • Sezione INFN di Ferrara
    • NSC Kharkiv Institute of Physics and Technology (NSC KIPT)
  • Y. Shcheglov
    • Petersburg Nuclear Physics Institute (PNPI)
  • T. Shears
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • L. Shekhtman
    • Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University
  • O. Shevchenko
    • NSC Kharkiv Institute of Physics and Technology (NSC KIPT)
  • V. Shevchenko
    • National Research Centre Kurchatov Institute
  • A. Shires
    • Fakultät PhysikTechnische Universität Dortmund
  • R. Silva Coutinho
    • Department of PhysicsUniversity of Warwick
  • G. Simi
    • Sezione INFN di Padova
  • M. Sirendi
    • Cavendish LaboratoryUniversity of Cambridge
  • N. Skidmore
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • T. Skwarnicki
    • Syracuse University
  • N. A. Smith
    • Oliver Lodge LaboratoryUniversity of Liverpool
  • E. Smith
    • STFC Rutherford Appleton Laboratory
    • Department of PhysicsUniversity of Oxford
  • E. Smith
    • Imperial College London
  • J. Smith
    • Cavendish LaboratoryUniversity of Cambridge
  • M. Smith
    • School of Physics and AstronomyUniversity of Manchester
  • H. Snoek
    • Nikhef National Institute for Subatomic Physics
  • M. D. Sokoloff
    • University of Cincinnati
  • F. J. P. Soler
    • School of Physics and AstronomyUniversity of Glasgow
  • F. Soomro
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • D. Souza
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • B. Souza De Paula
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • B. Spaan
    • Fakultät PhysikTechnische Universität Dortmund
  • A. Sparkes
    • School of Physics and AstronomyUniversity of Edinburgh
  • F. Spinella
    • Sezione INFN di Pisa
  • P. Spradlin
    • School of Physics and AstronomyUniversity of Glasgow
  • F. Stagni
    • European Organization for Nuclear Research (CERN)
  • S. Stahl
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • O. Steinkamp
    • Physik-Institut, Universität Zürich
  • S. Stevenson
    • Department of PhysicsUniversity of Oxford
  • S. Stoica
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • S. Stone
    • Syracuse University
  • B. Storaci
    • Physik-Institut, Universität Zürich
  • S. Stracka
    • Sezione INFN di Pisa
    • European Organization for Nuclear Research (CERN)
  • M. Straticiuc
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • U. Straumann
    • Physik-Institut, Universität Zürich
  • R. Stroili
    • Sezione INFN di Padova
  • V. K. Subbiah
    • European Organization for Nuclear Research (CERN)
  • L. Sun
    • University of Cincinnati
  • W. Sutcliffe
    • Imperial College London
  • S. Swientek
    • Fakultät PhysikTechnische Universität Dortmund
  • V. Syropoulos
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • M. Szczekowski
    • National Center for Nuclear Research (NCBJ)
  • P. Szczypka
    • European Organization for Nuclear Research (CERN)
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • D. Szilard
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • T. Szumlak
    • Faculty of Physics and Applied Computer ScienceAGH, University of Science and Technology
  • S. T’Jampens
    • LAPP, Université de Savoie, CNRS/IN2P3
  • M. Teklishyn
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • G. Tellarini
    • Sezione INFN di Ferrara
  • E. Teodorescu
    • Horia Hulubei National Institute of Physics and Nuclear Engineering
  • F. Teubert
    • European Organization for Nuclear Research (CERN)
  • C. Thomas
    • Department of PhysicsUniversity of Oxford
  • E. Thomas
    • European Organization for Nuclear Research (CERN)
  • J. van Tilburg
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • V. Tisserand
    • LAPP, Université de Savoie, CNRS/IN2P3
  • M. Tobin
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • S. Tolk
    • Nikhef National Institute for Subatomic Physics and VU University Amsterdam
  • L. Tomassetti
    • Sezione INFN di Ferrara
  • D. Tonelli
    • European Organization for Nuclear Research (CERN)
  • S. Topp-Joergensen
    • Department of PhysicsUniversity of Oxford
  • N. Torr
    • Department of PhysicsUniversity of Oxford
  • E. Tournefier
    • LAPP, Université de Savoie, CNRS/IN2P3
    • Imperial College London
  • S. Tourneur
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • M. T. Tran
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • M. Tresch
    • Physik-Institut, Universität Zürich
  • A. Tsaregorodtsev
    • CPPM, Aix-Marseille Université, CNRS/IN2P3
  • P. Tsopelas
    • Nikhef National Institute for Subatomic Physics
  • N. Tuning
    • Nikhef National Institute for Subatomic Physics
  • M. Ubeda Garcia
    • European Organization for Nuclear Research (CERN)
  • A. Ukleja
    • National Center for Nuclear Research (NCBJ)
  • A. Ustyuzhanin
    • National Research Centre Kurchatov Institute
  • U. Uwer
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • V. Vagnoni
    • Sezione INFN di Bologna
  • G. Valenti
    • Sezione INFN di Bologna
  • A. Vallier
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • R. Vazquez Gomez
    • Laboratori Nazionali dell’INFN di Frascati
  • P. Vazquez Regueiro
    • Universidad de Santiago de Compostela
  • C. Vázquez Sierra
    • Universidad de Santiago de Compostela
  • S. Vecchi
    • Sezione INFN di Ferrara
  • J. J. Velthuis
    • H.H. Wills Physics LaboratoryUniversity of Bristol
  • M. Veltri
    • Sezione INFN di Firenze
  • G. Veneziano
    • Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • M. Vesterinen
    • Physikalisches InstitutRuprecht-Karls-Universität Heidelberg
  • B. Viaud
    • LAL, Université Paris-Sud, CNRS/IN2P3
  • D. Vieira
    • Universidade Federal do Rio de Janeiro (UFRJ)
  • X. Vilasis-Cardona
    • Universitat de Barcelona
  • A. Vollhardt
    • Physik-Institut, Universität Zürich
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    • H.H. Wills Physics LaboratoryUniversity of Bristol
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    • Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University
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    • Nikhef National Institute for Subatomic Physics
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    • Massachusetts Institute of Technology
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    • European Organization for Nuclear Research (CERN)
Open AccessRegular Article - Experimental Physics

DOI: 10.1140/epjc/s10052-014-2835-1

Cite this article as:
Aaij, R., Adeva, B., Adinolfi, M. et al. Eur. Phys. J. C (2014) 74: 2835. doi:10.1140/epjc/s10052-014-2835-1

Abstract

The production of \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of \(3.3{\mathrm{\,pb}^{-1}} \) collected in proton–proton collisions at a centre-of-mass energy of \(\sqrt{s}=2.76\) TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the \({\Upsilon } \) transverse momentum and rapidity, over the ranges \(p_\mathrm{T}<15\) GeV/\(c\) and \(2.0<y<4.5\). The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be
$$\begin{aligned}&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (1\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (1\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 1.111 \pm 0.043 \pm 0.044\mathrm{\,nb}, \\&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (2\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (2\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 0.264 \pm 0.023 \pm 0.011\mathrm{\,nb}, \\&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (3\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (3\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 0.159 \pm 0.020 \pm 0.007\mathrm{\,nb}, \end{aligned}$$
where the first uncertainty is statistical and the second systematic.

1 Introduction

Studies of the production of heavy quark-antiquark bound systems, such as the \({{{\mathrm {b}}} {\overline{{{\mathrm {b}}}}}} \) states \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) (indicated generically as \({\Upsilon } \) in the following) in hadron-hadron interactions probe the dynamics of the colliding partons and provide a unique insight into quantum chromodynamics (QCD). The total production cross-sections and spin configurations of these heavy quarkonium states are currently not reproduced by the theoretical models. These include the colour singlet model [15], recently improved by adding higher-order contributions [6, 7], the colour-evaporation model [8], and the non-perturbative colour octet mechanism [911], which is investigated in the framework of non-relativistic QCD. The first complete next-to-leading order calculation of \({\Upsilon } \) production properties [12], based on the non-relativistic QCD factorisation scheme, provides a good description of the measured differential cross-sections at large transverse momentum, \(p_\mathrm{T} \), but overestimates the data at low \(p_\mathrm{T} \).

The production of \({\Upsilon } \) mesons in proton–proton (\({{\mathrm {p}}} {{\mathrm {p}}} \)) collisions occurs either directly in parton scattering or via feed-down from the decay of heavier prompt bottomonium states, like \({\upchi } _{{{\mathrm {b}}}}\) [1316], or higher-mass \({\Upsilon } \) states. The latter source complicates the theoretical description of bottomonium production [17, 18].

The Large Hadron Collider provides a unique possibility to study bottomonium and charmonium hadroproduction in \({{\mathrm {p}}} {{\mathrm {p}}} \) interactions at different collision energies and discriminate between various theoretical approaches. This study presents the first measurement of the inclusive production cross-sections of the three considered \({\Upsilon } \) mesons in \({{\mathrm {p}}} {{\mathrm {p}}} \) collisions at a centre-of-mass energy of \({\sqrt{s}} =2.76{\mathrm {\,TeV}} \). The measurements are performed as functions of the \({\Upsilon } \) transverse momentum and rapidity, \(y\), separately in six bins of \(p_\mathrm{T} \) in the range \(p_\mathrm{T} <15{{\mathrm {\,GeV\!/}c}} \) and five bins of \(y\) in the range \(2.0<y<4.5\). The results are reported as products of the cross-sections and the branching fractions of \({\Upsilon } \) mesons into the dimuon final state. This analysis is complementary to those performed by the ATLAS [19], CMS [20] and LHCb [21, 22] collaborations and allows studies of the \({\Upsilon } \) production cross-section at forward rapidities as a function of the centre-of-mass energy.

2 Detector and data sample

The LHCb detector [23] is a single-arm forward spectrometer covering the pseudorapidity range \(2<\eta <5\), designed for the study of particles containing \({{\mathrm {b}}} \) or \({{\mathrm {c}}} \) quarks. The detector includes a high-precision tracking system consisting of a silicon-strip vertex detector surrounding the \({{\mathrm {p}}} {{\mathrm {p}}} \) interaction region, a large-area silicon-strip detector located upstream of a dipole magnet with a bending power of about \(4\mathrm{\,Tm}\), and three stations of silicon-strip detectors and straw drift tubes placed downstream. The combined tracking system provides a momentum measurement with relative uncertainty that varies from 0.4 % at 5\({{\mathrm {\,GeV\!/}c}} \) to 0.6 % at 100\({{\mathrm {\,GeV\!/}c}} \), and impact parameter resolution of 20\({\,\upmu \mathrm m} \) for tracks with large transverse momentum. Different types of charged hadrons are distinguished by information from two ring-imaging Cherenkov detectors [24]. Photon, electron and hadron candidates are identified by a calorimeter system consisting of scintillating-pad and preshower detectors, an electromagnetic calorimeter and a hadronic calorimeter. Muons are identified by a system composed of alternating layers of iron and multiwire proportional chambers [25].

The analysis is carried out using a sample of data corresponding to an integrated luminosity of \(3.3{\mathrm{\,pb}^{-1}} \) collected in \({{\mathrm {p}}} {{\mathrm {p}}} \) collisions at \({\sqrt{s}} =2.76{\mathrm {\,TeV}} \). Events of interest are preselected by a trigger consisting of a hardware stage, based on information from the calorimeter and muon systems, followed by a software stage, which applies a full event reconstruction. The presence of two muon candidates with the product of their \(p_\mathrm{T} \) larger than 1.68 \((\)GeV\(/c)^{2}\) is required in the hardware trigger. At the software stage, the events are required to contain two well reconstructed tracks with hits in the muon system, having total and transverse momenta greater than \(6\) and \(0.5{{\mathrm {\,GeV\!/}c}} \), respectively. The selected muon candidates are further required to originate from a common vertex and have an invariant mass larger than \(4.7{{\mathrm {\,GeV\!/}c^2}} \).

To determine the acceptance, reconstruction and trigger efficiencies, fully simulated signal samples are reweighted to reproduce the multiplicity distributions for reconstructed primary vertices, tracks and hits in the detector observed in the data. The simulation is performed using the LHCb configuration [26] of the Pythia 6.4 event generator [27]. Here, decays of hadronic particles are described by EvtGen [28] in which final-state photons are generated using Photos [29]. The interaction of the generated particles with the detector and its response are implemented using the Geant4 toolkit [30, 31] as described in Ref. [32].

3 Signal selection and cross-section determination

The selection strategy used in the previous LHCb studies on \({\Upsilon } \) production [21, 22] is applied here. It includes selection criteria that ensure good quality track and vertex reconstruction. In addition, the muon candidates are required to have \(p>10{{\mathrm {\,GeV\!/}c}} \) and \(p_\mathrm{T} >1{{\mathrm {\,GeV\!/}c}} \). To further reduce background contamination, a set of additional requirements is employed in this analysis. It consists of tightened criteria on track quality [33], muon identification [34] and a good quality of a global fit of the dimuon vertex with a primary vertex constraint [35].

The invariant mass distribution of the selected \({{\Upsilon } \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \) candidates is shown in Fig. 1 for the full kinematic range. The distribution is described by a function similar to the one used in the previous studies on \({\Upsilon } \) production [21, 22]. It models the signal component using the sum of three Crystal Ball functions [36], one for each of the \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) signals, and includes an exponential component to account for combinatorial background. The position and width of the Crystal Ball function describing the \({{\Upsilon } (1\mathrm {S})} \) meson are allowed to vary, while the mass differences between \({\Upsilon } \) states are fixed to their known values [37] along with parameters describing the radiative tail, as determined from simulation studies. The widths of the \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) peaks are constrained to the value of the width of the \({{\Upsilon } (1\mathrm {S})} \) signal scaled by the ratio of their masses to the \({{\Upsilon } (1\mathrm {S})} \) mass. In total, five parameters are extracted from the fit for the signal component: the yields of \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) states, the \({{\Upsilon } (1\mathrm {S})} \) mass resolution and its peak position. The latter is found to be consistent with the known mass of the \({{\Upsilon } (1\mathrm {S})} \) meson [37], while reasonable agreement is observed between the data and simulation for the \({{\Upsilon } (1\mathrm {S})} \) mass resolution.
https://static-content.springer.com/image/art%3A10.1140%2Fepjc%2Fs10052-014-2835-1/MediaObjects/10052_2014_2835_Fig1_HTML.gif
Fig. 1

Invariant mass distribution of selected \({{\Upsilon } \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \) candidates with \(p_\mathrm{T} <15{{\mathrm {\,GeV\!/}c}} \) and \(2.0<y<4.5\). The result of the fit described in the text is illustrated with a red solid line, while the signal and background components are shown with magenta dotted and blue dashed lines, respectively. The three peaks correspond to the \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) mesons (from left to right)

The \({\Upsilon } \) production cross-sections are measured separately in six bins of \(p_\mathrm{T} \) and five bins of \(y\) since the limited amount of data does not allow a measurement of double differential cross-sections. For a given \(p_\mathrm{T} \) or \(y\) bin, the differential cross-section for the inclusive \({\Upsilon } \) production of the three different states decaying into the dimuon final state is determined as
$$\begin{aligned} \dfrac{ {\mathrm {d}}\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {\Upsilon } {\mathrm {X}} \right) }{\mathrm {d}p_\mathrm{T}}&\times \mathcal {B}\left( {{\Upsilon } \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) = \dfrac{ N^{\mathrm {corr}}_{{\Upsilon }}}{{\mathcal {L}} \times \Delta p_\mathrm{T}} \;,\end{aligned}$$
(1a)
$$\begin{aligned} \dfrac{ {\mathrm {d}}\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {\Upsilon } {\mathrm {X}}\right) }{\mathrm {d}y}&\times \mathcal {B}\left( {{\Upsilon } \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) = \dfrac{ N^{\mathrm {corr}}_{{\Upsilon }}}{{\mathcal {L}} \times \Delta y } \;, \end{aligned}$$
(1b)
where \(N^{\mathrm {corr}}_{{\Upsilon }}\) is the efficiency-corrected yield of \({{\Upsilon } \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \) decays, \({\mathcal {L}} \) stands for the integrated luminosity and \(\Delta p_\mathrm{T} \,(\Delta y)\) denotes the \(p_\mathrm{T} \,(y)\) bin size. For the mass fits in individual \(p_\mathrm{T} \) and \(y\) bins, the \({{\Upsilon } (1\mathrm {S})} \) peak position is fixed to the value obtained from the fit for the full kinematic range, while the \({{\Upsilon } (1\mathrm {S})} \) mass resolution is parameterised with a function of \(p_\mathrm{T} \) and \(y\) using simulation. The total observed signal yields and their statistical uncertainties for \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) mesons obtained by summation over \(p_\mathrm{T} \,(y)\) bins are \(1139\pm 37\,(1145\pm 37)\), \(271\pm 20\,(270\pm 20)\) and \(158\pm 16\,(156\pm 16)\), respectively. These results are in good agreement with the total signal yields obtained from the fit to the reconstructed dimuon invariant mass for the full kinematic range.
Based on the mass fit results in individual bins, the efficiency-corrected yield for each kinematic region is determined as
$$\begin{aligned} N^{\mathrm {corr}}_{{\Upsilon }} = \sum _{i} \dfrac{ w^{{\Upsilon }}_{i} }{ \varepsilon ^{\mathrm {tot}}_{i}}, \end{aligned}$$
(2)
where \(w^{{\Upsilon }}_{i}\) is a signal weight factor, \(\varepsilon ^{\mathrm {tot}}_{i}\) is the total signal event efficiency and the sum runs over all candidates \(i\). The \(w^{{\Upsilon }}_{i}\) factor accounts for the background subtraction and is obtained from the fit using the sPlot technique [38]. The total signal event efficiency is calculated for each \({{\Upsilon } \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \) candidate as
$$\begin{aligned} \varepsilon ^{\mathrm {tot}} = \varepsilon ^{\mathrm {acc}} \times \varepsilon ^{\mathrm {rec}} \times \varepsilon ^{\mathrm {trg}} \times \varepsilon ^{{\upmu } {\mathrm {ID}}}, \end{aligned}$$
(3)
where \(\varepsilon ^{\mathrm {acc}}\) is the detector acceptance, \(\varepsilon ^{\mathrm {rec}}\) is the reconstruction and selection efficiency, \(\varepsilon ^{\mathrm {trg}}\) is the trigger efficiency and \(\varepsilon ^{{\upmu } {\mathrm {ID}}}\) is the efficiency of muon identification. The efficiencies \(\varepsilon ^{\mathrm {acc}}\), \(\varepsilon ^{\mathrm {rec}}\) and \(\varepsilon ^{\mathrm {trg}}\) are determined using simulation and further corrected using data-driven techniques to account for small differences in muon reconstruction efficiency between data and simulation [33, 34, 39]. The efficiency \(\varepsilon ^{{\upmu } {\mathrm {ID}}}\) is measured directly from data using a tag-and-probe method on a large sample of \({{{\mathrm {J}}/{\uppsi }}} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-} \) decays. The total efficiency-corrected signal yields obtained by summation over \(p_\mathrm{T} \,(y)\) bins for \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) mesons are \(3678\pm 144\,(3684\pm 143)\), \(875\pm 76\,(869\pm 75)\) and \(527\pm 65\,(515\pm 64)\), respectively.

The integrated luminosity of the data sample is estimated with the beam-gas imaging method [4044]. It is based on the beam currents and the measurements of the angles, offsets and transverse profiles of the two colliding bunches, which is achieved by reconstructing beam-gas interaction vertices.

4 Systematic uncertainties

Previous LHCb studies of \({\Upsilon } \) production [21, 22] showed that the signal efficiency depends on the initial polarisation of \({\Upsilon } \) mesons. This property was measured in \({{\mathrm {p}}} {{\mathrm {p}}} \) collisions at \({\sqrt{s}} =7{\mathrm {\,TeV}} \) by the CMS collaboration at central rapidities and large \(p_\mathrm{T} \) and was found to be small [45]. Polarisation of other vector quarkonium states, such as \({{{\mathrm {J}}/{\uppsi }}} \) and \({\uppsi } {\mathrm {(2S)}}\) mesons was studied in \({{\mathrm {p}}} {{\mathrm {p}}} \) collisions at \({\sqrt{s}} =7{\mathrm {\,TeV}} \) by the LHCb [46, 47] and ALICE [48] collaborations and was also found to be small. This analysis is performed assuming zero polarisation of \({\Upsilon } \) mesons and no corresponding systematic uncertainty is assigned.
Table 1

Relative systematic uncertainties (in \(\%\)) affecting the \({\Upsilon } \) production cross-section measurements in the full kinematic region. The total uncertainties are obtained by adding the individual effects in quadrature

Source

\({{\Upsilon } (1\mathrm {S})} \)

\({{\Upsilon } (2\mathrm {S})} \)

\({{\Upsilon } (3\mathrm {S})} \)

Luminosity

2.3

2.3

2.3

Fit model and range

0.5

1.0

2.3

Data-simulation agreement

   Radiative tails

1.0

1.0

1.0

   Multiplicity reweighting

0.6

0.4

2.0

   Efficiency corrections

0.7

1.0

1.0

   Track reconstruction

\(2\times 0.4\)

\(2\times 0.4\)

\(2\times 0.4\)

   Selection variables

1.0

1.0

1.0

   Trigger

2.0

2.0

2.0

Total

3.6

3.7

4.7

The systematic uncertainties affecting the \({\Upsilon } \) cross-section measurements presented in this paper are summarised in Table 1. These uncertainties are strongly correlated between bins. The largest contribution arises from the absolute luminosity scale, which is determined with a 2.3 % uncertainty. It is dominated by the vertex resolution of beam-gas interactions and detector alignment [44].

The influence of the signal extraction technique is studied by varying the fit range and the signal and background parameterisations used in the fit model. The fits are also performed with floating mass and resolution of the \({{\Upsilon } (1\mathrm {S})} \) peak and without constraints for the \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) masses. The spread of the extracted signal yields between these scenarios is taken as the corresponding systematic uncertainty. It ranges from 0.4 to 33 % for different \(p_\mathrm{T} \,(y)\) bins and amounts to 0.5, 1.0 and 2.3 % for the \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) cross-section measurements in the full kinematic region, respectively.

The possible mismodeling of bremsstrahlung simulation for the radiative tail and its effect on the signal shape was addressed in the previous LHCb analysis [22]. It leads to an additional uncertainty of 1.0 %.

Several systematic uncertainties are related to the determination of the total efficiency components in Eq. (3). The detector acceptance, reconstruction and selection efficiencies are determined using simulated samples. These are corrected using an iterative procedure to match the multiplicity distributions for reconstructed primary vertices, tracks and hits in the detector with those observed in data. The systematic uncertainty associated with this reweighting procedure is assessed by varying the number of iterative steps. It ranges from 0.4 to 4.8 % for different \(p_\mathrm{T} \,(y)\) bins and is found to be 0.6, 0.4 and 2.0 % for the \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) cross-section measurements in the full kinematic region, respectively.

The \(\varepsilon ^{\mathrm {rec}}\) efficiency is corrected using data-driven techniques for a small difference in the muon reconstruction efficiency between data and simulation [33, 34]. The \(\varepsilon ^{{\upmu } {\mathrm {ID}}}\) efficiency is determined from data using alternative methods, based on a tag-and-probe approach on a large sample of \({{{\mathrm {J}}/{\uppsi }}} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-} \) decays. The difference between these methods is taken as the corresponding systematic uncertainty. It is combined with the uncertainties associated with the correction factors discussed above and propagated to the \({\Upsilon } \) cross-section measurements using 400 pseudo-experiments. The resulting uncertainty ranges from 1.0 to 13 % for different \(p_\mathrm{T} \,(y)\) bins and amounts to 0.7, 1.0 and 1.0 % for the \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) cross-section measurements in the full kinematic region, respectively.

To account for differences between the actual tracking efficiency and that estimated with simulation using data-driven techniques [33, 39], a systematic uncertainty of 0.4 % is assigned per track.

Good agreement between the data and reweighted simulation is observed for all selection variables used in this analysis, in particular for the \({\chi ^2} \) of the dimuon vertex fit and the \({\chi ^2} \) of the global fit [35]. The discrepancies do not exceed 1.0 %, which is conservatively taken as a systematic uncertainty to account for the disagreement between the data and simulation.

The systematic uncertainty associated with the trigger requirements is assessed by studying the performance of the dimuon trigger, described in Sect. 2, for events selected using the single muon high-\(p_\mathrm{T} \) trigger [49]. The fractions of signal \({{\Upsilon } (1\mathrm {S})} \) events selected using both trigger requirements are compared for the data and simulation in bins of dimuon \(p_\mathrm{T} \), and a systematic uncertainty of 2.0 % is assigned.
https://static-content.springer.com/image/art%3A10.1140%2Fepjc%2Fs10052-014-2835-1/MediaObjects/10052_2014_2835_Fig2_HTML.gif
Fig. 2

Differential cross-sections for \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) mesons times dimuon branching fractions as functions of \(p_\mathrm{T} \) (left) and \(y\) (right). The inner error bars indicate the statistical uncertainty, while the outer error bars indicate the sum of statistical and systematic uncertainties in quadrature. The next-to-leading order non-relativistic QCD predictions [18] are shown by the solid yellow band

Table 2

Cross-sections for \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) mesons times dimuon branching fractions (in  nb) in bins of \(p_\mathrm{T} \) and \(y\) without normalisation to the bin sizes. The first uncertainty is statistical and the second is systematic

\(p_\mathrm{T} \,\left[ \!{{\mathrm {\,GeV\!/}c}} \right] \)

\({{{\Upsilon } (1\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \)

\({{{\Upsilon } (2\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \)

\({{{\Upsilon } (3\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \)

0–2

\(0.257\pm 0.021\pm 0.011\)

\(0.066\pm 0.012\pm 0.007\)

\(0.023\pm 0.007\pm 0.002\)

2–3

\(0.167\pm 0.014\pm 0.007\)

\(0.028\pm 0.007\pm 0.002\)

\(0.024\pm 0.008\pm 0.002\)

3–4

\(0.154\pm 0.016\pm 0.009\)

\(0.038\pm 0.008\pm 0.002\)

\(0.023\pm 0.008\pm 0.001\)

4–6

\(0.277\pm 0.023\pm 0.013\)

\(0.065\pm 0.011\pm 0.003\)

\(0.038\pm 0.010\pm 0.002\)

6–10

\(0.212\pm 0.019\pm 0.008\)

\(0.048\pm 0.010\pm 0.002\)

\(0.033\pm 0.008\pm 0.001\)

10–15

\(0.043\pm 0.008\pm 0.003\)

\(0.020\pm 0.007\pm 0.001\)

\(0.018\pm 0.006\pm 0.002\)

\(y\)

\({{{\Upsilon } (1\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \)

\({{{\Upsilon } (2\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \)

\({{{\Upsilon } (3\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \)

2.0–2.5

\(0.404\pm 0.034\pm 0.022\)

\(0.101\pm 0.019\pm 0.005\)

\(0.061\pm 0.016\pm 0.003\)

2.5–3.0

\(0.321\pm 0.018\pm 0.012\)

\(0.086\pm 0.010\pm 0.004\)

\(0.053\pm 0.008\pm 0.003\)

3.0–3.5

\(0.227\pm 0.013\pm 0.008\)

\(0.050\pm 0.007\pm 0.002\)

\(0.029\pm 0.005\pm 0.001\)

3.5–4.0

\(0.124\pm 0.011\pm 0.005\)

\(0.025\pm 0.005\pm 0.001\)

\(0.007\pm 0.003\pm 0.001\)

4.0–4.5

\(0.035\pm 0.008\pm 0.002\)

\(0.001\pm 0.003\pm 0.001\)

\(0.005\pm 0.004\pm 0.001\)

5 Results

The integrated \({\Upsilon } \) production cross-sections times dimuon branching fractions in the kinematic region \(p_\mathrm{T} <15{{\mathrm {\,GeV\!/}c}} \) and \(2.0<y<4.5\) are measured to be
$$\begin{aligned}&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (1\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (1\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad =1.111 \pm 0.043 \pm 0.044\mathrm{\,nb},\\&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (2\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (2\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 0.264 \pm 0.023 \pm 0.011\mathrm{\,nb},\\&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (3\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (3\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 0.159 \pm 0.020 \pm 0.007\mathrm{\,nb}, \end{aligned}$$
where the first uncertainty is statistical and the second systematic.

The single differential cross-sections times dimuon branching fractions are shown as functions of \(p_\mathrm{T} \) and \(y\) in Fig. 2 and summarised in Table 2. The total uncertainties of the results are dominated by statistical effects in all \(p_\mathrm{T} \) and \(y\) bins. In addition to the data, Fig. 2 reports theoretical predictions, based on the next-to-leading order non-relativistic QCD calculation [18], for the \({\Upsilon } \) differential cross-sections in the kinematic region \(6<p_\mathrm{T} <15{{\mathrm {\,GeV\!/}c}} \) and \(2.0<y<4.5\). The long-distance matrix elements used in the calculations are fitted to CDF [50] and D0 [51] results for \({{\Upsilon } (1\mathrm {S})} \) production in \({{\mathrm {p}}} {\overline{{{\mathrm {p}}}}} \) collisions at \(\sqrt{s}=1.8\) and 1.96\({\mathrm {\,TeV}} \). The predictions include the feed-down contributions from higher excited S-wave and P-wave \({{\mathrm {b}}} {\overline{{{\mathrm {b}}}}} \) states. Good agreement between the data and predictions is found for all three \(\Upsilon \) states. The dependence of the \({\Upsilon } \) cross-sections on \(y\) is found to be more pronounced than at higher collision energies [21, 22], which is in line with theoretical expectations presented for example in Ref. [52].

Figure 3 illustrates the ratios of the \({{\Upsilon } (2\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \), \(\mathcal {R}^{\mathrm {2S/1S}}\), and \({{\Upsilon } (3\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \), \(\mathcal {R}^{\mathrm {3S/1S}}\), cross-sections times dimuon branching fractions as functions of \(p_\mathrm{T} \) and \(y\). Here, most of the systematic uncertainties on the cross-sections cancel, while the statistical uncertainties remain significant. The ratios are found to be in good agreement with the corresponding results obtained in the previous analyses on \({\Upsilon } \) production at \(\sqrt{s}=7\) and \(8{\mathrm {\,TeV}} \) [21, 22]. The measured \(\mathcal {R}^{\mathrm {2S/1S}}\) and \(\mathcal {R}^{\mathrm {3S/1S}}\) are also consistent with theoretical predictions presented in Refs. [5254], where the \({{\Upsilon } (3\mathrm {S})} \) meson is considered as a mixture of normal \({{\mathrm {b}}} {\overline{{{\mathrm {b}}}}} \) and hybrid \({{\mathrm {b}}} {\overline{{{\mathrm {b}}}}} {\mathrm {g}}\) states. Table 3 lists \(\mathcal {R}^{\mathrm {2S/1S}}\) and \(\mathcal {R}^{\mathrm {3S/1S}}\) for each \(p_\mathrm{T} \) and \(y\) bin.
Table 3

Ratios of the \({{\Upsilon } (2\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \) cross-sections times dimuon branching fractions as functions of \(p_\mathrm{T} \) and \(y\). The first uncertainty is statistical and the second is systematic

\(p_\mathrm{T} \,\left[ \!{{\mathrm {\,GeV\!/}c}} \right] \)

\(\mathcal {R}^{\mathrm { 2S/1S}}\)

\(\mathcal {R}^{\mathrm {3S/1S}}\)

0–2

\(0.257\pm 0.053\pm 0.009\)

\(0.090\pm 0.030\pm 0.006\)

2–3

\(0.165\pm 0.044\pm 0.007\)

\(0.141\pm 0.050\pm 0.010\)

3–4

\(0.244\pm 0.056\pm 0.007\)

\(0.148\pm 0.055\pm 0.006\)

4–6

\(0.233\pm 0.043\pm 0.007\)

\(0.138\pm 0.037\pm 0.005\)

6–10

\(0.227\pm 0.051\pm 0.006\)

\(0.157\pm 0.041\pm 0.004\)

10–15

\(0.474\pm 0.179\pm 0.031\)

\(0.413\pm 0.155\pm 0.029\)

\(y\)

  

2.0–2.5

\(0.249\pm 0.051\pm 0.007\)

\(0.152\pm 0.042\pm 0.006\)

2.5–3.0

\(0.266\pm 0.033\pm 0.007\)

\(0.164\pm 0.026\pm 0.007\)

3.0–3.5

\(0.219\pm 0.032\pm 0.004\)

\(0.129\pm 0.025\pm 0.003\)

3.5–4.0

\(0.204\pm 0.046\pm 0.004\)

\(0.060\pm 0.026\pm 0.003\)

https://static-content.springer.com/image/art%3A10.1140%2Fepjc%2Fs10052-014-2835-1/MediaObjects/10052_2014_2835_Fig3_HTML.gif
Fig. 3

Ratios of the \({{\Upsilon } (2\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \) cross-sections times dimuon branching fractions as functions of \(p_\mathrm{T} \) and \(y\). The error bars indicate the total uncertainties of the results obtained by adding statistical and systematic uncertainties in quadrature

To provide a reference for a future LHCb measurement of \({\Upsilon } \) production with \({{\mathrm {p}}} {\mathrm {Pb}}\) collisions at \(\sqrt{s_{NN}}=5\) TeV, the \({\Upsilon } \) cross-sections are measured in the reduced kinematic region \(p_\mathrm{T} <15{{\mathrm {\,GeV\!/}c}} \) and \(2.5<y<4.0\). The corresponding integrated cross-sections times dimuon branching fractions in this kinematic region are
$$\begin{aligned}&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (1\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (1\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 0.670 \pm 0.025 \pm 0.026\mathrm{\,nb},\\&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (2\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (2\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 0.159 \pm 0.013 \pm 0.007\mathrm{\,nb},\\&\upsigma \left( {{\mathrm {p}}} {{\mathrm {p}}} \rightarrow {{\Upsilon } (3\mathrm {S})} {\mathrm {X}} \right) \times {\mathcal{B}}\left( {{{\Upsilon } (3\mathrm {S})} \,{\rightarrow } \,{{\upmu } ^+{\upmu } ^-}} \right) \\&\quad = 0.089 \pm 0.010 \pm 0.004\mathrm{\,nb}. \end{aligned}$$

6 Conclusions

The production of \({{\Upsilon } (1\mathrm {S})} \), \({{\Upsilon } (2\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) mesons is observed for the first time in \({{\mathrm {p}}} {{\mathrm {p}}} \) collisions at a centre-of-mass energy of \(\sqrt{s}=2.76{\mathrm {\,TeV}} \) at forward rapidities with a data sample corresponding to an integrated luminosity of 3.3\({\mathrm{\,pb}^{-1}} \). The \({\Upsilon } \) differential production cross-sections times dimuon branching fractions are measured separately as functions of the \({\Upsilon } \) transverse momentum and rapidity for \(p_\mathrm{T} <15{{\mathrm {\,GeV\!/}c}} \) and \(2.0<y<4.5\). The theoretical predictions, based on the next-to-leading order non-relativistic QCD calculation, provide a good description of the data at large \(p_\mathrm{T} \). The ratios of the \({{\Upsilon } (2\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \) and \({{\Upsilon } (3\mathrm {S})} \) to \({{\Upsilon } (1\mathrm {S})} \) cross-sections times dimuon branching fractions as functions of \(p_\mathrm{T} \) and \(y\) are found to be in agreement with the corresponding results obtained at higher collision energies.

Acknowledgments

We thank G. Bodwin, L. S. Kisslinger, A. K. Likhoded and A. V. Luchinsky for fruitful discussions about bottomonium production. In addition, we are grateful to K.-T. Chao, H. Han and H.-S. Shao for the next-to-leading order non-relativistic QCD predictions for prompt \(\Upsilon \) production at \(\sqrt{s}=2.76{\mathrm {\,TeV}} \). We also express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3 and Region Auvergne (France); BMBF, DFG, HGF and MPG (Germany); SFI (Ireland); INFN (Italy); FOM and NWO (The Netherlands); SCSR (Poland); MEN/IFA (Romania); MinES, Rosatom, RFBR and NRC “Kurchatov Institute” (Russia); MinECo, XuntaGal and GENCAT (Spain); SNSF and SER (Switzerland); NAS Ukraine (Ukraine); STFC (United Kingdom); NSF (USA). We also acknowledge the support received from the ERC under FP7. The Tier1 computing centres are supported by IN2P3 (France), KIT and BMBF (Germany), INFN (Italy), NWO and SURF (The Netherlands), PIC (Spain), GridPP (United Kingdom). We are indebted to the communities behind the multiple open source software packages we depend on. We are also thankful for the computing resources and the access to software R&D tools provided by Yandex LLC (Russia).

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