Journal of High Energy Physics

, 2014:80 | Cite as

Framework for model independent analyses of multiple extra quark scenarios

  • Daniele Barducci
  • Alexander Belyaev
  • Mathieu Buchkremer
  • Giacomo Cacciapaglia
  • Aldo Deandrea
  • Stefania De Curtis
  • Jad Marrouche
  • Stefano Moretti
  • Luca PanizziEmail author
Open Access
Regular Article - Theoretical Physics


In this paper we present an analysis strategy and a dedicated tool to determine the exclusion confidence level for any scenario involving multiple heavy extra quarks with generic decay channels, as predicted in several extensions of the Standard Model. We have created, validated and used a software package, called XQCAT (eXtra Quark Combined Analysis Tool), which is based on publicly available experimental data from direct searches for top partners and from Supersymmetry inspired searches. By means of this code, we recast the limits from CMS on new heavy extra quarks considering a complete set of decay channels. The resulting exclusion confidence levels are presented for some simple scenarios with multiple states and general coupling assumptions. Highlighting the importance of combining multiple topology searches to obtain accurate re-interpretations of the existing searches, we discuss the reach of the SUSY analyses so as to set bounds on new quark resonances. In particular, we report on the re-interpretation of the existing limits on benchmark scenarios with one and multiple pair-produced top partners having non-exclusive couplings to the third Standard Model generation of quarks.


Phenomenological Models Monte Carlo Simulations 


Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.


  1. [1]
    LHC New Physics Working Group collaboration, D. Alves et al., Simplified Models for LHC New Physics Searches, J. Phys. G 39 (2012) 105005 [arXiv:1105.2838] [INSPIRE].ADSCrossRefGoogle Scholar
  2. [2]
    M. Drees, H. Dreiner, D. Schmeier, J. Tattersall and J.S. Kim, CheckMATE: Confronting your Favourite New Physics Model with LHC Data, arXiv:1312.2591 [INSPIRE].
  3. [3]
    S. Kraml et al., SModelS: a tool for interpreting simplified-model results from the LHC and its application to supersymmetry, Eur. Phys. J. C 74 (2014) 2868 [arXiv:1312.4175] [INSPIRE].ADSCrossRefGoogle Scholar
  4. [4]
    M. Papucci, K. Sakurai, A. Weiler and L. Zeune, Fastlim: a fast LHC limit calculator, arXiv:1402.0492 [INSPIRE].
  5. [5]
    B. Holdom, The accidental Higgs, Phys. Rev. D 90 (2014) 015004 [arXiv:1404.6229] [INSPIRE].ADSGoogle Scholar
  6. [6]
    I. Antoniadis, A Possible new dimension at a few TeV, Phys. Lett. B 246 (1990) 377 [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  7. [7]
    C. Csáki, C. Grojean, J. Hubisz, Y. Shirman and J. Terning, Fermions on an interval: Quark and lepton masses without a Higgs, Phys. Rev. D 70 (2004) 015012 [hep-ph/0310355] [INSPIRE].ADSGoogle Scholar
  8. [8]
    G. Cacciapaglia, A. Deandrea and J. Llodra-Perez, A Dark Matter candidate from Lorentz Invariance in 6D, JHEP 03 (2010) 083 [arXiv:0907.4993] [INSPIRE].ADSCrossRefGoogle Scholar
  9. [9]
    Y. Grossman and M. Neubert, Neutrino masses and mixings in nonfactorizable geometry, Phys. Lett. B 474 (2000) 361 [hep-ph/9912408] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  10. [10]
    N. Arkani-Hamed et al., The Minimal moose for a little Higgs, JHEP 08 (2002) 021 [hep-ph/0206020] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  11. [11]
    D.B. Kaplan and H. Georgi, SU(2) × U(1) Breaking by Vacuum Misalignment, Phys. Lett. B 136 (1984) 183 [INSPIRE].ADSCrossRefGoogle Scholar
  12. [12]
    D.B. Kaplan, Flavor at SSC energies: A New mechanism for dynamically generated fermion masses, Nucl. Phys. B 365 (1991) 259 [INSPIRE].ADSCrossRefGoogle Scholar
  13. [13]
    K. Agashe, R. Contino and A. Pomarol, The Minimal composite Higgs model, Nucl. Phys. B 719 (2005) 165 [hep-ph/0412089] [INSPIRE].ADSCrossRefGoogle Scholar
  14. [14]
    R. Contino, L. Da Rold and A. Pomarol, Light custodians in natural composite Higgs models, Phys. Rev. D 75 (2007) 055014 [hep-ph/0612048] [INSPIRE].ADSGoogle Scholar
  15. [15]
    G.F. Giudice, C. Grojean, A. Pomarol and R. Rattazzi, The Strongly-Interacting Light Higgs, JHEP 06 (2007) 045 [hep-ph/0703164] [INSPIRE].ADSCrossRefGoogle Scholar
  16. [16]
    Y. Hosotani, Dynamical Mass Generation by Compact Extra Dimensions, Phys. Lett. B 126 (1983) 309 [INSPIRE].ADSCrossRefGoogle Scholar
  17. [17]
    D. Choudhury, T.M.P. Tait and C.E.M. Wagner, Beautiful mirrors and precision electroweak data, Phys. Rev. D 65 (2002) 053002 [hep-ph/0109097] [INSPIRE].ADSGoogle Scholar
  18. [18]
    G. Panico, E. Ponton, J. Santiago and M. Serone, Dark Matter and Electroweak Symmetry Breaking in Models with Warped Extra Dimensions, Phys. Rev. D 77 (2008) 115012 [arXiv:0801.1645] [INSPIRE].ADSGoogle Scholar
  19. [19]
    K. Agashe, R. Contino, L. Da Rold and A. Pomarol, A Custodial symmetry for \( Zb\overline{b} \), Phys. Lett. B 641 (2006) 62 [hep-ph/0605341] [INSPIRE].ADSCrossRefGoogle Scholar
  20. [20]
    R.S. Chivukula, R. Foadi and E.H. Simmons, Patterns of Custodial Isospin Violation from a Composite Top, Phys. Rev. D 84 (2011) 035026 [arXiv:1105.5437] [INSPIRE].ADSGoogle Scholar
  21. [21]
    C. Anastasiou, E. Furlan and J. Santiago, Realistic Composite Higgs Models, Phys. Rev. D 79 (2009) 075003 [arXiv:0901.2117] [INSPIRE].ADSGoogle Scholar
  22. [22]
    D. Marzocca, M. Serone and J. Shu, General Composite Higgs Models, JHEP 08 (2012) 013 [arXiv:1205.0770] [INSPIRE].ADSCrossRefGoogle Scholar
  23. [23]
    A. De Simone, O. Matsedonskyi, R. Rattazzi and A. Wulzer, A First Top Partner Hunters Guide, JHEP 04 (2013) 004 [arXiv:1211.5663] [INSPIRE].CrossRefGoogle Scholar
  24. [24]
    F. del Aguila, M. Pérez-Victoria and J. Santiago, Observable contributions of new exotic quarks to quark mixing, JHEP 09 (2000) 011 [hep-ph/0007316] [INSPIRE].CrossRefGoogle Scholar
  25. [25]
    J.A. Aguilar-Saavedra, Pair production of heavy Q = 2/3 singlets at LHC, Phys. Lett. B 625 (2005) 234 [Erratum ibid. B 633 (2006) 792] [hep-ph/0506187] [INSPIRE].
  26. [26]
    J.A. Aguilar-Saavedra, Identifying top partners at LHC, JHEP 11 (2009) 030 [arXiv:0907.3155] [INSPIRE].ADSCrossRefGoogle Scholar
  27. [27]
    G. Cacciapaglia, A. Deandrea, D. Harada and Y. Okada, Bounds and Decays of New Heavy Vector-like Top Partners, JHEP 11 (2010) 159 [arXiv:1007.2933] [INSPIRE].ADSCrossRefGoogle Scholar
  28. [28]
    S.A.R. Ellis, R.M. Godbole, S. Gopalakrishna and J.D. Wells, Survey of vector-like fermion extensions of the Standard Model and their phenomenological implications, JHEP 09 (2014) 130 [arXiv:1404.4398] [INSPIRE].ADSCrossRefGoogle Scholar
  29. [29]
    A. Atre et al., Model-Independent Searches for New Quarks at the LHC, JHEP 08 (2011) 080 [arXiv:1102.1987] [INSPIRE].ADSCrossRefGoogle Scholar
  30. [30]
    G. Cacciapaglia et al., Heavy Vector-like Top Partners at the LHC and flavour constraints, JHEP 03 (2012) 070 [arXiv:1108.6329] [INSPIRE].ADSCrossRefGoogle Scholar
  31. [31]
    A.L. Read, Presentation of search results: The CL(s) technique, J. Phys. G 28 (2002) 2693 [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  32. [32]
    A.L. Read, Modified frequentist analysis of search results (the CL s method), CERN-OPEN-2000-205.
  33. [33]
    M. Buchkremer, G. Cacciapaglia, A. Deandrea and L. Panizzi, Model Independent Framework for Searches of Top Partners, Nucl. Phys. B 876 (2013) 376 [arXiv:1305.4172] [INSPIRE].ADSCrossRefGoogle Scholar
  34. [34]
    CMS collaboration, Inclusive search for a vector-like T quark with charge \( \frac{2}{3} \) in pp collisions at \( \sqrt{s}=8 \) TeV, Phys. Lett. B 729 (2014) 149 [arXiv:1311.7667] [INSPIRE].ADSGoogle Scholar
  35. [35]
    CMS collaboration, Search for supersymmetry in final states with missing transverse energy and 0, 1, 2, or at least 3 b-quark jets in 7 TeV pp collisions using the variable alphaT, JHEP 01 (2013) 077 [arXiv:1210.8115] [INSPIRE].ADSGoogle Scholar
  36. [36]
    CMS collaboration, Search for supersymmetry in final states with a single lepton, b-quark jets and missing transverse energy in proton-proton collisions at \( \sqrt{s}=7 \) TeV, Phys. Rev. D 87 (2013) 052006 [arXiv:1211.3143] [INSPIRE].ADSGoogle Scholar
  37. [37]
    CMS collaboration, Search for new physics in events with opposite-sign leptons, jets and missing transverse energy in pp collisions at \( \sqrt{s}=7 \) TeV, Phys. Lett. B 718 (2013) 815 [arXiv:1206.3949] [INSPIRE].ADSGoogle Scholar
  38. [38]
    CMS collaboration, Search for new physics in events with same-sign dileptons and b-tagged jets in pp collisions at \( \sqrt{s}=7 \) TeV, JHEP 08 (2012) 110 [arXiv:1205.3933] [INSPIRE].ADSGoogle Scholar
  39. [39]
    CMS collaboration, Search for supersymmetry in hadronic final states with missing transverse energy using the variables α T and b-quark multiplicity in pp collisions at \( \sqrt{s}=8 \) TeV, Eur. Phys. J. C 73 (2013) 2568 [arXiv:1303.2985] [INSPIRE].ADSGoogle Scholar
  40. [40]
    CMS collaboration, Search for new physics in events with same-sign dileptons and b jets in pp collisions at \( \sqrt{s}=8 \) TeV, JHEP 03 (2013) 037 [Erratum ibid. 1307 (2013) 041] [arXiv:1212.6194] [INSPIRE].
  41. [41]
    M. Buchkremer and A. Schmidt, Long-lived heavy quarks: a review, Adv. High Energy Phys. 2013 (2013) 690254 [arXiv:1210.6369] [INSPIRE].CrossRefGoogle Scholar
  42. [42]
    M. Perelstein and J. Shao, T-Quarks at the Large Hadron Collider: 2010-12, Phys. Lett. B 704 (2011) 510 [arXiv:1103.3014] [INSPIRE].ADSCrossRefGoogle Scholar
  43. [43]
    O. Matsedonskyi, G. Panico and A. Wulzer, Light Top Partners for a Light Composite Higgs, JHEP 01 (2013) 164 [arXiv:1204.6333] [INSPIRE].ADSCrossRefGoogle Scholar
  44. [44]
    J. Alwall, M. Herquet, F. Maltoni, O. Mattelaer and T. Stelzer, MadGraph 5: Going Beyond, JHEP 06 (2011) 128 [arXiv:1106.0522] [INSPIRE].ADSCrossRefGoogle Scholar
  45. [45]
    P. Meade and M. Reece, BRIDGE: Branching ratio inquiry/decay generated events, hep-ph/0703031 [INSPIRE].
  46. [46]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 Physics and Manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].ADSCrossRefGoogle Scholar
  47. [47]
    S. Ovyn, X. Rouby and V. Lemaitre, DELPHES, a framework for fast simulation of a generic collider experiment, arXiv:0903.2225 [INSPIRE].
  48. [48]
    O. Buchmueller et al., The CMSSM and NUHM1 in Light of 7 TeV LHC, B sμ + μ and XENON100 Data, Eur. Phys. J. C 72 (2012) 2243 [arXiv:1207.7315] [INSPIRE].ADSCrossRefGoogle Scholar
  49. [49]
    O. Buchmueller and J. Marrouche, Universal mass limits on gluino and third-generation squarks in the context of Natural-like SUSY spectra, Int. J. Mod. Phys. A 29 (2014) 1450032 [arXiv:1304.2185] [INSPIRE].ADSCrossRefGoogle Scholar
  50. [50]
    Inclusive search for a vector-like T quark by CMSAdditional material,
  51. [51]
    CMS collaboration, Search for top-quark partners with charge 5/3 in the same-sign dilepton final state, Phys. Rev. Lett. 112 (2014) 171801 [arXiv:1312.2391] [INSPIRE].ADSCrossRefGoogle Scholar
  52. [52]
    CMS Collaboration, Search for Vector-Like bPair Production with Multilepton Final States in pp collisions at \( \sqrt{s}=8 \) TeV, CMS-PAS-B2G-13-003.
  53. [53]
    ATLAS collaboration, Search for heavy top-like quarks decaying to a Higgs boson and a top quark in the lepton plus jets final state in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, ATLAS-CONF-2013-018 (2013).
  54. [54]
    ATLAS collaboration, Search for anomalous production of events with same-sign dileptons and b jets in 14.3 fb −1 of pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, ATLAS-CONF-2013-051 (2013).
  55. [55]
    ATLAS collaboration, Search for pair production of heavy top-like quarks decaying to a high-p T W boson and a b quark in the lepton plus jets final state in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, ATLAS-CONF-2013-060 (2013).
  56. [56]
    ATLAS collaboration, Search for pair production of new heavy quarks that decay to a Z boson and a third generation quark in pp collisions at \( \sqrt{\mathbf{s}}=\mathbf{8} \) TeV with the ATLAS detector, ATLAS-CONF-2013-056 (2013).
  57. [57]
    D. Barducci et al., Towards model-independent approach to the analysis of interference effects in pair production of new heavy quarks, JHEP 07 (2014) 142 [arXiv:1311.3977] [INSPIRE].ADSCrossRefGoogle Scholar
  58. [58]
    G. Cacciapaglia, A. Deandrea and S. De Curtis, Nearby resonances beyond the Breit-Wigner approximation, Phys. Lett. B 682 (2009) 43 [arXiv:0906.3417] [INSPIRE].ADSCrossRefGoogle Scholar
  59. [59]
    M. Cacciari, M. Czakon, M. Mangano, A. Mitov and P. Nason, Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation, Phys. Lett. B 710 (2012) 612 [arXiv:1111.5869] [INSPIRE].ADSCrossRefGoogle Scholar
  60. [60]
    N.D. Christensen and C. Duhr, FeynRules - Feynman rules made easy, Comput. Phys. Commun. 180 (2009) 1614 [arXiv:0806.4194] [INSPIRE].ADSCrossRefGoogle Scholar
  61. [61]
    M. Buchkremer, G. Cacciapaglia, A. Deandrea and L. Panizzi, VLQ FeynRules model,
  62. [62]
    M. Bondarenko et al., High Energy Physics Model Database: Towards decoding of the underlying theory, in G. Brooijmans et al., Les Houches 2011: Physics at TeV Colliders New Physics Working Group Report, arXiv:1203.1488, pg. 218,
  63. [63]
    G. Brooijmans et al., Les Houches 2013: Physics at TeV Colliders: New Physics Working Group Report, arXiv:1405.1617 [INSPIRE].
  64. [64]
    ATLAS collaboration, Search for exotic same-sign dilepton signatures (bquark, T 5/3 and four top quarks production) in 4.7/fb of pp collisions at \( \sqrt{s}=7 \) TeV with the ATLAS detector, J. Phys. Conf. S. 452 (2013) 012047.ADSCrossRefGoogle Scholar
  65. [65]
    R. Contino, T. Kramer, M. Son and R. Sundrum, Warped/composite phenomenology simplified, JHEP 05 (2007) 074 [hep-ph/0612180] [INSPIRE].ADSCrossRefGoogle Scholar
  66. [66]
    Y. Hosotani, K. Oda, T. Ohnuma and Y. Sakamura, Dynamical Electroweak Symmetry Breaking in SO(5) × U(1) Gauge-Higgs Unification with Top and Bottom Quarks, Phys. Rev. D 78 (2008) 096002 [Erratum ibid. D 79 (2009) 079902] [arXiv:0806.0480] [INSPIRE].
  67. [67]
    A. Alves, E. Ramirez Barreto, D.A. Camargo and A.G. Dias, A Model with Chiral Quarks of Electric Charges −4/3 and 5/3, JHEP 07 (2013) 129 [arXiv:1306.1275] [INSPIRE].ADSCrossRefGoogle Scholar
  68. [68]
    A. Carmona, M. Chala and J. Santiago, New Higgs Production Mechanism in Composite Higgs Models, JHEP 07 (2012) 049 [arXiv:1205.2378] [INSPIRE].ADSCrossRefGoogle Scholar
  69. [69]
    A. Atre, M. Chala and J. Santiago, Searches for New Vector Like Quarks: Higgs Channels, JHEP 05 (2013) 099 [arXiv:1302.0270] [INSPIRE].ADSCrossRefGoogle Scholar
  70. [70]
    A. Atre, M. Carena, T. Han and J. Santiago, Heavy Quarks Above the Top at the Tevatron, Phys. Rev. D 79 (2009) 054018 [arXiv:0806.3966] [INSPIRE].ADSGoogle Scholar
  71. [71]
    ATLAS collaboration, Search for a heavy top-quark partner in final states with two leptons with the ATLAS detector at the LHC, JHEP 11 (2012) 094 [arXiv:1209.4186] [INSPIRE].ADSGoogle Scholar
  72. [72]
    D. Shephard, A two-dimensional interpolation function for irregularly-spaced data, in proceedings of 23 rd National Conference ACM (1968) 517-523.Google Scholar

Copyright information

© The Author(s) 2014

Authors and Affiliations

  • Daniele Barducci
    • 1
    • 2
  • Alexander Belyaev
    • 1
    • 2
  • Mathieu Buchkremer
    • 3
  • Giacomo Cacciapaglia
    • 4
    • 5
    • 6
  • Aldo Deandrea
    • 4
    • 5
    • 6
  • Stefania De Curtis
    • 7
  • Jad Marrouche
    • 8
  • Stefano Moretti
    • 1
    • 2
  • Luca Panizzi
    • 1
    • 2
    Email author
  1. 1.School of Physics and AstronomyUniversity of SouthamptonSouthamptonU.K.
  2. 2.Particle Physics DepartmentRutherford Appleton LaboratoryDidcotU.K.
  3. 3.Centre for Cosmology, Particle Physics and Phenomenology (CP3)Université catholique de LouvainLouvain-la-NeuveBelgium
  4. 4.Université de LyonLyonFrance
  5. 5.Université Lyon 1VilleurbanneFrance
  6. 6.CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de LyonVilleurbanne CedexFrance
  7. 7.INFN, Sezione di FirenzeSesto FiorentinoItaly
  8. 8.Physics DepartmentCERNGeneva 23Switzerland

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