Measuring the polarization of boosted hadronic tops



We propose a new technique for measuring the polarization of hadronically decaying boosted top quarks. In particular, we apply a subjet-based technique to events where the decay products of the top are clustered within a single jet. The technique requires neither b-tagging nor W-reconstruction, and does not rely on assumptions about either the top production mechanism or the sources of missing energy in the event. We include results for various new physics scenarios made with different Monte Carlo generators to demonstrate the robustness of the technique.


Jets Beyond Standard Model Heavy Quark Physics 


  1. [1]
    S. Dimopoulos and H. Georgi, Softly Broken Supersymmetry and SU(5), Nucl. Phys. B 193 (1981) 150 [SPIRES].CrossRefADSGoogle Scholar
  2. [2]
    N. Arkani-Hamed, A.G. Cohen and H. Georgi, Electroweak symmetry breaking from dimensional deconstruction, Phys. Lett. B 513 (2001) 232 [hep-ph/0105239] [SPIRES].MathSciNetADSGoogle Scholar
  3. [3]
    K. Agashe, A. Delgado, M.J. May and R. Sundrum, RS1, custodial isospin and precision tests, JHEP 08 (2003) 050 [hep-ph/0308036] [SPIRES].CrossRefADSGoogle Scholar
  4. [4]
    G.L. Kane, G.A. Ladinsky and C.P. Yuan, Using the top quark for testing standard model polarization and CP predictions, Phys. Rev. D 45 (1992) 124 [SPIRES].ADSGoogle Scholar
  5. [5]
    K. Agashe, A. Belyaev, T. Krupovnickas, G. Perez and J. Virzi, LHC signals from warped extra dimensions, Phys. Rev. D 77 (2008) 015003 [hep-ph/0612015] [SPIRES].ADSGoogle Scholar
  6. [6]
    B. Lillie, L. Randall and L.-T. Wang, The Bulk RS KK-gluon at the LHC, JHEP 09 (2007) 074 [hep-ph/0701166] [SPIRES].CrossRefADSGoogle Scholar
  7. [7]
    V. Barger, T. Han and D.G.E. Walker, Top Quark Pairs at High Invariant Mass: A Model-Independent Discriminator of New Physics at the LHC, Phys. Rev. Lett. 100 (2008) 031801 [hep-ph/0612016] [SPIRES].CrossRefADSGoogle Scholar
  8. [8]
    A.L. Fitzpatrick, J. Kaplan, L. Randall and L.-T. Wang, Searching for the Kaluza-Klein Graviton in Bulk RS Models, JHEP 09 (2007) 013 [hep-ph/0701150] [SPIRES].CrossRefMathSciNetADSGoogle Scholar
  9. [9]
    W. Skiba and D. Tucker-Smith, Using jet mass to discover vector quarks at the LHC, Phys. Rev. D 75 (2007) 115010 [hep-ph/0701247] [SPIRES].ADSGoogle Scholar
  10. [10]
    U. Baur and L.H. Orr, High p T Top Quarks at the Large Hadron Collider, Phys. Rev. D 76 (2007) 094012 [arXiv:0707.2066] [SPIRES].ADSGoogle Scholar
  11. [11]
    R. Frederix and F. Maltoni, Top pair invariant mass distribution: a window on new physics, JHEP 01 (2009) 047 [arXiv:0712.2355] [SPIRES].CrossRefADSGoogle Scholar
  12. [12]
    U. Baur and L.H. Orr, Searching for \( t\bar{t} \) Resonances at the Large Hadron Collider, Phys. Rev. D77 (2008) 114001 [arXiv:0803.1160] [SPIRES].ADSGoogle Scholar
  13. [13]
    J. Thaler and L.-T. Wang, Strategies to Identify Boosted Tops, JHEP 07 (2008) 092 [arXiv:0806.0023] [SPIRES].CrossRefADSGoogle Scholar
  14. [14]
    D.E. Kaplan, K. Rehermann, M.D. Schwartz and B. Tweedie, Top Tagging: A Method for Identifying Boosted Hadronically Decaying Top Quarks, Phys. Rev. Lett. 101 (2008) 142001 [arXiv:0806.0848] [SPIRES].CrossRefADSGoogle Scholar
  15. [15]
    L.G. Almeida et al., Substructure of high-p T Jets at the LHC, Phys. Rev. D 79 (2009) 074017 [arXiv:0807.0234] [SPIRES].MathSciNetADSGoogle Scholar
  16. [16]
    L.G. Almeida, S.J. Lee, G. Perez, I. Sung and J. Virzi, Top Jets at the LHC, Phys. Rev. D 79 (2009) 074012 [arXiv:0810.0934] [SPIRES].ADSGoogle Scholar
  17. [17]
    Y. Bai and Z. Han, Top-antitop and Top-top Resonances in the Dilepton Channel at the CERN LHC, JHEP 04 (2009) 056 [arXiv:0809.4487] [SPIRES].CrossRefADSGoogle Scholar
  18. [18]
    CMS collaboration, A cambridge-aachen (c-a) based jet algorithm for boosted top-jet tagging, Tech. Report CMS PAS JME-09-001, CERN Geneva, July 2007.Google Scholar
  19. [19]
    G. Brooijmans, High p t hadronic top quark identification, Tech. Report ATL-COM-PHYS-2008-001, CERN Geneva, February 2008.
  20. [20]
    S.D. Ellis, C.K. Vermilion and J.R. Walsh, Techniques for improved heavy particle searches with jet substructure, Phys. Rev. D 80 (2009) 051501 [arXiv:0903.5081] [SPIRES].ADSGoogle Scholar
  21. [21]
    J. Shelton, Polarized tops from new physics: signals and observables, Phys. Rev. D 79 (2009) 014032 [arXiv:0811.0569] [SPIRES].ADSGoogle Scholar
  22. [22]
    M. Perelstein and A. Weiler, Polarized Tops from Stop Decays at the LHC, JHEP 03 (2009) 141 [arXiv:0811.1024] [SPIRES].CrossRefADSGoogle Scholar
  23. [23]
    L. March, E. Ros, and B. Salvachúa, Search for kaluza-klein excitations of the gluon in models with extra dimensions, Tech. Report ATL-COM-PHYS-2005-032, CERN Geneva, July 2005.
  24. [24]
    S. González de la Hoz, L. March, and E. Ros, Search for hadronic decays of z H and w H in the little higgs model, Tech. Report ATL-COM-PHYS-2005-001, CERN Geneva, 2005.
  25. [25]
    M. Lehmacher, b-Tagging Algorithms and their Performance at ATLAS, arXiv:0809.4896 [SPIRES].
  26. [26]
    M. Cacciari, G. Salam, and G. Soyez, FastJet,
  27. [27]
    F. Maltoni and T. Stelzer, MadEvent: Automatic event generation with MadGraph, JHEP 02 (2003) 027 [hep-ph/0208156] [SPIRES].CrossRefADSGoogle Scholar
  28. [28]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 Physics and Manual, JHEP 05 (2006) 026 [hep-ph/0603175] [SPIRES].CrossRefADSGoogle Scholar
  29. [29]
    M. Bahr et al., Herwing++ Physics and Manual, Eur. Phys. J. C 58 (2008) 639 [arXiv:0803.0883] [SPIRES].CrossRefADSGoogle Scholar
  30. [30]
    M. Cacciari, G.P. Salam and G. Soyez, The anti-k t jet clustering algorithm, JHEP 04 (2008) 063 [arXiv:0802.1189] [SPIRES].CrossRefADSGoogle Scholar
  31. [31]
    M. Jezabek and J.H. Kuhn, Lepton Spectra from Heavy Quark Decay, Nucl. Phys. B 320 (1989) 20 [SPIRES].CrossRefADSGoogle Scholar
  32. [32]
    M. Jezabek, Top quark physics, Nucl. Phys. Proc. Suppl. 37B (1994) 197 [hep-ph/9406411] [SPIRES].CrossRefADSGoogle Scholar
  33. [33]
    A. Brandenburg, Z.G. Si and P. Uwer, QCD-corrected spin analysing power of jets in decays of polarized top quarks, Phys. Lett. B 539 (2002) 235 [hep-ph/0205023] [SPIRES].ADSGoogle Scholar

Copyright information

© SISSA, Trieste, Italy 2010

Authors and Affiliations

  1. 1.Department of PhysicsPrinceton UniversityPrincetonU.S.A.
  2. 2.Department of Physics and AstronomyRutgers UniversityPiscatawayU.S.A.
  3. 3.Department of PhysicsYale UniversityNew HavenU.S.A.

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