Abstract
Multiple analyses from ATLAS and CMS collaborations, including searches for ttH production, supersymmetric particles and vector-like quarks, observed excesses in the same-sign dilepton channel containing b-jets and missing transverse energy in the LHC Run 1 data. In the context of little Higgs theories with T parity, we explain these excesses using vector-like T-odd quarks decaying into a top quark, a W boson and the lightest T-odd particle (LTP). For heavy vector-like quarks, decay topologies containing the LTP have not been searched for at the LHC. The bounds on the masses of the T-odd quarks can be estimated in a simplified model approach by adapting the search limits for top/bottom squarks in supersymmetry. Assuming a realistic decay branching fraction, a benchmark with a 750 GeV T-odd b′ quark is proposed. We also comment on the possibility to fit excesses in different analyses in a common framework.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
P. Huang, A. Ismail, I. Low and C.E.M. Wagner, Same-sign dilepton excesses and light top squarks, Phys. Rev. D 92 (2015) 075035 [arXiv:1507.01601] [INSPIRE].
ATLAS collaboration, Search for supersymmetry at \( \sqrt{s}=8 \) TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector, JHEP 06 (2014) 035 [arXiv:1404.2500] [INSPIRE].
ATLAS collaboration, Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, JHEP 10 (2015) 150 [arXiv:1504.04605] [INSPIRE].
ATLAS collaboration, Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector, Phys. Lett. B 749 (2015) 519 [arXiv:1506.05988] [INSPIRE].
CMS collaboration, Search for the standard model Higgs boson produced in association with top quarks in multilepton final states, CMS-PAS-HIG-13-020, CERN, Geneva Switzerland (2013).
CMS collaboration, Search for the associated production of the Higgs boson with a top-quark pair, JHEP 09 (2014) 087 [Erratum ibid. 10 (2014) 106] [arXiv:1408.1682] [INSPIRE].
CMS collaboration, Search for new physics in events with same-sign dileptons and jets in pp collisions at \( \sqrt{s}=8 \) TeV, JHEP 01 (2014) 163 [Erratum ibid. 01 (2015) 014] [arXiv:1311.6736] [INSPIRE].
ATLAS collaboration, Measurement of the \( t\overline{t}W \) and \( t\overline{t}Z \) production cross sections in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, JHEP 11 (2015) 172 [arXiv:1509.05276] [INSPIRE].
CMS collaboration, Observation of top quark pairs produced in association with a vector boson in pp collisions at \( \sqrt{s}=8 \) TeV, JHEP 01 (2016) 096 [arXiv:1510.01131] [INSPIRE].
H.-C. Cheng, K.T. Matchev and M. Schmaltz, Bosonic supersymmetry? Getting fooled at the CERN LHC, Phys. Rev. D 66 (2002) 056006 [hep-ph/0205314] [INSPIRE].
L.-T. Wang and I. Yavin, A review of spin determination at the LHC, Int. J. Mod. Phys. A 23 (2008) 4647 [arXiv:0802.2726] [INSPIRE].
H.-C. Cheng and I. Low, TeV symmetry and the little hierarchy problem, JHEP 09 (2003) 051 [hep-ph/0308199] [INSPIRE].
S.P. Martin, A supersymmetry primer, Adv. Ser. Direct. High Energy Phys. 21 (2010) 1 [hep-ph/9709356] [INSPIRE].
T. Appelquist, H.-C. Cheng and B.A. Dobrescu, Bounds on universal extra dimensions, Phys. Rev. D 64 (2001) 035002 [hep-ph/0012100] [INSPIRE].
H.-C. Cheng, K.T. Matchev and M. Schmaltz, Radiative corrections to Kaluza-Klein masses, Phys. Rev. D 66 (2002) 036005 [hep-ph/0204342] [INSPIRE].
H.-C. Cheng, K.T. Matchev and M. Schmaltz, Bosonic supersymmetry? Getting fooled at the CERN LHC, Phys. Rev. D 66 (2002) 056006 [hep-ph/0205314] [INSPIRE].
R. Barbieri and A. Strumia, What is the limit on the Higgs mass?, Phys. Lett. B 462 (1999) 144 [hep-ph/9905281] [INSPIRE].
Z. Han and W. Skiba, Effective theory analysis of precision electroweak data, Phys. Rev. D 71 (2005) 075009 [hep-ph/0412166] [INSPIRE].
A. Falkowski and F. Riva, Model-independent precision constraints on dimension-6 operators, JHEP 02 (2015) 039 [arXiv:1411.0669] [INSPIRE].
L. Randall and R. Sundrum, A large mass hierarchy from a small extra dimension, Phys. Rev. Lett. 83 (1999) 3370 [hep-ph/9905221] [INSPIRE].
K. Agashe, A. Falkowski, I. Low and G. Servant, KK parity in warped extra dimension, JHEP 04 (2008) 027 [arXiv:0712.2455] [INSPIRE].
N. Arkani-Hamed, A.G. Cohen and H. Georgi, Electroweak symmetry breaking from dimensional deconstruction, Phys. Lett. B 513 (2001) 232 [hep-ph/0105239] [INSPIRE].
N. Arkani-Hamed et al., The minimal moose for a little Higgs, JHEP 08 (2002) 021 [hep-ph/0206020] [INSPIRE].
N. Arkani-Hamed, A.G. Cohen, E. Katz and A.E. Nelson, The littlest Higgs, JHEP 07 (2002) 034 [hep-ph/0206021] [INSPIRE].
H.-C. Cheng and I. Low, Little hierarchy, little Higgses and a little symmetry, JHEP 08 (2004) 061 [hep-ph/0405243] [INSPIRE].
I. Low, T parity and the littlest Higgs, JHEP 10 (2004) 067 [hep-ph/0409025] [INSPIRE].
K. Agashe and G. Servant, Warped unification, proton stability and dark matter, Phys. Rev. Lett. 93 (2004) 231805 [hep-ph/0403143] [INSPIRE].
LHC New Physics Working Group collaboration, D. Alves, Simplified models for LHC new physics searches, J. Phys. G 39 (2012) 105005 [arXiv:1105.2838] [INSPIRE].
A. Anandakrishnan, J.H. Collins, M. Farina, E. Kuflik and M. Perelstein, Odd top partners at the LHC, arXiv:1506.05130 [INSPIRE].
L.-T. Wang and I. Yavin, Spin measurements in cascade decays at the LHC, JHEP 04 (2007) 032 [hep-ph/0605296] [INSPIRE].
H.-C. Cheng, I. Low and L.-T. Wang, Top partners in little Higgs theories with T-parity, Phys. Rev. D 74 (2006) 055001 [hep-ph/0510225] [INSPIRE].
J. Hubisz, P. Meade, A. Noble and M. Perelstein, Electroweak precision constraints on the littlest Higgs model with T parity, JHEP 01 (2006) 135 [hep-ph/0506042] [INSPIRE].
A. Belyaev, C.-R. Chen, K. Tobe and C.P. Yuan, Phenomenology of littlest Higgs model with T parity: including effects of T-odd fermions, Phys. Rev. D 74 (2006) 115020 [hep-ph/0609179] [INSPIRE].
M. Carena, J. Hubisz, M. Perelstein and P. Verdier, Collider signature of T-quarks, Phys. Rev. D 75 (2007) 091701 [hep-ph/0610156] [INSPIRE].
D. Choudhury and D.K. Ghosh, LHC signals of T-odd heavy quarks in the littlest Higgs model, JHEP 08 (2007) 084 [hep-ph/0612299] [INSPIRE].
G. Cacciapaglia, S.R. Choudhury, A. Deandrea, N. Gaur and M. Klasen, Dileptonic signatures of T-odd quarks at the LHC, JHEP 03 (2010) 059 [arXiv:0911.4630] [INSPIRE].
M. Perelstein and J. Shao, T-odd quarks at the Large Hadron Collider: 2010–2012, Phys. Lett. B 704 (2011) 510 [arXiv:1103.3014] [INSPIRE].
ATLAS collaboration, ATLAS run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider, Eur. Phys. J. C 75 (2015) 510 [arXiv:1506.08616] [INSPIRE].
I. Low, Polarized charginos (and top quarks) in scalar top quark decays, Phys. Rev. D 88 (2013) 095018 [arXiv:1304.0491] [INSPIRE].
CMS collaboration, Search for supersymmetry in pp collisions at \( \sqrt{s}=8 \) TeV in events with three leptons and at least one b-tagged jet, CMS-PAS-SUS-13-008, CERN, Geneva Switzerland (2013).
M. Krämer et al., Supersymmetry production cross sections in pp collisions at \( \sqrt{s}=7 \) TeV, arXiv:1206.2892 [INSPIRE].
C. Borschensky et al., Squark and gluino production cross sections in pp collisions at \( \sqrt{s}=13 \) , 14, 33 and 100 TeV, Eur. Phys. J. C 74 (2014) 3174 [arXiv:1407.5066] [INSPIRE].
S. Moch and P. Uwer, Heavy-quark pair production at two loops in QCD, Nucl. Phys. Proc. Suppl. 183 (2008) 75 [arXiv:0807.2794] [INSPIRE].
U. Langenfeld, S. Moch and P. Uwer, New results for \( t\overline{t} \) production at hadron colliders, arXiv:0907.2527 [INSPIRE].
J. Alwall et al., MadGraph/MadEvent v4: the new web generation, JHEP 09 (2007) 028 [arXiv:0706.2334] [INSPIRE].
T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 physics and manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].
DELPHES 3 collaboration, J. de Favereau et al., DELPHES 3, a modular framework for fast simulation of a generic collider experiment, JHEP 02 (2014) 057 [arXiv:1307.6346] [INSPIRE].
Dilepton final state webpage, https://twiki.cern.ch/twiki/bin/view/CMSPublic/Hig13020TWiki#Dilepton final state.
ATLAS collaboration, Search for supersymmetry at \( \sqrt{s}=13 \) TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector, ATLAS-CONF-2015-078, CERN, Geneva Switzerland (2015).
CMS collaboration, Search for SUSY in same-sign dilepton events at \( \sqrt{s}=13 \) TeV, CMS-PAS-SUS-15-008, CERN, Geneva Switzerland (2015).
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.
Author information
Authors and Affiliations
Corresponding author
Additional information
ArXiv ePrint: 1511.01452
Rights and permissions
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Chen, CR., Cheng, HC. & Low, I. Same-sign dilepton excesses and vector-like quarks. J. High Energ. Phys. 2016, 98 (2016). https://doi.org/10.1007/JHEP03(2016)098
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP03(2016)098