Abstract
We propose a new search strategy for heavy top partners at the early stages of the LHC run-II, based on lepton-jet final states. Our results show that final states containing a boosted massive jet and a hard lepton, in addition to a top quark and possibly a forward jet, offer a new window to both detecting and measuring top partners of mass ∼ 2TeV. Our resulting signal significance is comparable or superior to the same sign dilepton channels for top partner masses heavier than roughly 1 TeV. Unlike the di-lepton channel, the selection criteria we propose are sensitive both to 5/3 and 1/3 charge top partners and allow for full reconstruction of the resonance mass peak. Our search strategy utilizes a simplified b-tagging procedure and the Template Overlap Method to tag the massive boosted objects and reject the corresponding backgrounds. In addition, we propose a new, pileup insensitive method, to tag forward jets which characterize our signal events. We consider full effects of pileup contamination at 50 interactions per bunch crossing. We demonstrate that even in the most pessimistic pileup scenarios, the significance we obtain is sufficient to claim a discovery over a wide range of top partner parameters. While we focus on the minimal natural composite Higgs model, the results of this paper can be easily translated into bounds on any heavy partner with a \( t\overline{t}Wj \) final state topology.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
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].
ATLAS collaboration, Search for pair and single production of new heavy quarks that decay to a Z boson and a third-generation quark in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, JHEP 11 (2014) 104 [arXiv:1409.5500] [INSPIRE].
G. Perez, Top quark theory and the new physics searches frontier, Phys. Scripta T 158 (2013) 014008.
C. Grojean, O. Matsedonskyi and G. Panico, Light top partners and precision physics, JHEP 10 (2013) 160 [arXiv:1306.4655] [INSPIRE].
M. Ciuchini, E. Franco, S. Mishima and L. Silvestrini, Electroweak precision observables, new physics and the nature of a 126 GeV Higgs boson, JHEP 08 (2013) 106 [arXiv:1306.4644] [INSPIRE].
A. De Simone, O. Matsedonskyi, R. Rattazzi and A. Wulzer, A first top partner hunter’s guide, JHEP 04 (2013) 004 [arXiv:1211.5663] [INSPIRE].
A. Azatov, M. Salvarezza, M. Son and M. Spannowsky, Boosting top partner searches in composite Higgs models, Phys. Rev. D 89 (2014) 075001 [arXiv:1308.6601] [INSPIRE].
G. Salam and A. Weiler, Collider reach, online (2014).
C. Dennis, M. Karagoz, G. Servant and J. Tseng, Multi-W events at LHC from a warped extra dimension with custodial symmetry, hep-ph/0701158 [INSPIRE].
R. Contino and G. Servant, Discovering the top partners at the LHC using same-sign dilepton final states, JHEP 06 (2008) 026 [arXiv:0801.1679] [INSPIRE].
J. Mrazek and A. Wulzer, A strong sector at the LHC: top partners in same-sign dileptons, Phys. Rev. D 81 (2010) 075006 [arXiv:0909.3977] [INSPIRE].
N.G. Ortiz, J. Ferrando, D. Kar and M. Spannowsky, Reconstructing singly produced top partners in decays to Wb, Phys. Rev. D 90 (2014) 075009 [arXiv:1403.7490] [INSPIRE].
B. Gripaios, T. Müller, M.A. Parker and D. Sutherland, Search strategies for top partners in composite Higgs models, JHEP 08 (2014) 171 [arXiv:1406.5957] [INSPIRE].
S. Gopalakrishna, T. Mandal, S. Mitra and R. Tibrewala, LHC signatures of a vector-like b′, Phys. Rev. D 84 (2011) 055001 [arXiv:1107.4306] [INSPIRE].
L.G. Almeida, O. Erdogan, J. Juknevich, S.J. Lee, G. Perez and G. Sterman, Three-particle templates for a boosted Higgs boson, Phys. Rev. D 85 (2012) 114046 [arXiv:1112.1957] [INSPIRE].
L.G. Almeida, S.J. Lee, G. Perez, G. Sterman and I. Sung, Template overlap method for massive jets, Phys. Rev. D 82 (2010) 054034 [arXiv:1006.2035] [INSPIRE].
M. Backovic, J. Juknevich and G. Perez, Boosting the standard model Higgs signal with the template overlap method, JHEP 07 (2013) 114 [arXiv:1212.2977] [INSPIRE].
M. Backovic, O. Gabizon, J. Juknevich, G. Perez and Y. Soreq, Measuring boosted tops in semi-leptonic \( t\overline{t} \) events for the standard model and beyond, JHEP 04 (2014) 176 [arXiv:1311.2962] [INSPIRE].
K. Agashe, R. Contino and A. Pomarol, The minimal composite Higgs model, Nucl. Phys. B 719 (2005) 165 [hep-ph/0412089] [INSPIRE].
A. Azatov, G. Panico, G. Perez and Y. Soreq, On the flavor structure of natural composite Higgs models & top flavor violation, JHEP 12 (2014) 082 [arXiv:1408.4525] [INSPIRE].
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] [INSPIRE].
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] [INSPIRE].
F. Maltoni and T. Stelzer, MadEvent: automatic event generation with MadGraph, JHEP 02 (2003) 027 [hep-ph/0208156] [INSPIRE].
T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 physics and manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].
J. Pumplin, D.R. Stump, J. Huston, H.L. Lai, P.M. Nadolsky and W.K. Tung, New generation of parton distributions with uncertainties from global QCD analysis, JHEP 07 (2002) 012 [hep-ph/0201195] [INSPIRE].
M.L. Mangano, M. Moretti, F. Piccinini and M. Treccani, Matching matrix elements and shower evolution for top-quark production in hadronic collisions, JHEP 01 (2007) 013 [hep-ph/0611129] [INSPIRE].
M. Cacciari, G.P. Salam and G. Soyez, FastJet user manual, Eur. Phys. J. C 72 (2012) 1896 [arXiv:1111.6097] [INSPIRE].
M. Cacciari, G.P. Salam and G. Soyez, The anti-k t jet clustering algorithm, JHEP 04 (2008) 063 [arXiv:0802.1189] [INSPIRE].
M. Czakon, P. Fiedler and A. Mitov, Total top-quark pair-production cross section at hadron colliders through O(α 4 S ), Phys. Rev. Lett. 110 (2013) 252004 [arXiv:1303.6254] [INSPIRE].
K. Rehermann and B. Tweedie, Efficient identification of boosted semileptonic top quarks at the LHC, JHEP 03 (2011) 059 [arXiv:1007.2221] [INSPIRE].
S.D. Ellis, J. Huston, K. Hatakeyama, P. Loch and M. Tonnesmann, Jets in hadron-hadron collisions, Prog. Part. Nucl. Phys. 60 (2008) 484 [arXiv:0712.2447] [INSPIRE].
A. Abdesselam et al., Boosted objects: a probe of beyond the standard model physics, Eur. Phys. J. C 71 (2011) 1661 [arXiv:1012.5412] [INSPIRE].
G.P. Salam, Towards jetography, Eur. Phys. J. C 67 (2010) 637 [arXiv:0906.1833] [INSPIRE].
P. Nath et al., The hunt for new physics at the Large Hadron Collider, Nucl. Phys. Proc. Suppl. 200-202 (2010) 185 [arXiv:1001.2693] [INSPIRE].
L.G. Almeida, R. Alon and M. Spannowsky, Structure of fat jets at the Tevatron and beyond, Eur. Phys. J. C 72 (2012) 2113 [arXiv:1110.3684] [INSPIRE].
T. Plehn and M. Spannowsky, Top tagging, J. Phys. G 39 (2012) 083001 [arXiv:1112.4441] [INSPIRE].
A. Altheimer et al., Jet substructure at the Tevatron and LHC: new results, new tools, new benchmarks, J. Phys. G 39 (2012) 063001 [arXiv:1201.0008] [INSPIRE].
D.E. Soper and M. Spannowsky, Finding physics signals with shower deconstruction, Phys. Rev. D 84 (2011) 074002 [arXiv:1102.3480] [INSPIRE].
D.E. Soper and M. Spannowsky, Finding top quarks with shower deconstruction, Phys. Rev. D 87 (2013) 054012 [arXiv:1211.3140] [INSPIRE].
M. Jankowiak and A.J. Larkoski, Jet substructure without trees, JHEP 06 (2011) 057 [arXiv:1104.1646] [INSPIRE].
D. Krohn, J. Thaler and L.-T. Wang, Jet trimming, JHEP 02 (2010) 084 [arXiv:0912.1342] [INSPIRE].
S.D. Ellis, C.K. Vermilion and J.R. Walsh, Recombination algorithms and jet substructure: pruning as a tool for heavy particle searches, Phys. Rev. D 81 (2010) 094023 [arXiv:0912.0033] [INSPIRE].
M. Backović and J. Juknevich, TemplateTagger v1.0.0: a template matching tool for jet substructure, Comput. Phys. Commun. 185 (2014) 1322 [arXiv:1212.2978] [INSPIRE].
A. Hook, M. Jankowiak and J.G. Wacker, Jet dipolarity: top tagging with color flow, JHEP 04 (2012) 007 [arXiv:1102.1012] [INSPIRE].
J. Thaler and K. Van Tilburg, Identifying boosted objects with N-subjettiness, JHEP 03 (2011) 015 [arXiv:1011.2268] [INSPIRE].
J. Thaler and K. Van Tilburg, Maximizing boosted top identification by minimizing N-subjettiness, JHEP 02 (2012) 093 [arXiv:1108.2701] [INSPIRE].
J. Thaler and L.-T. Wang, Strategies to identify boosted tops, JHEP 07 (2008) 092 [arXiv:0806.0023] [INSPIRE].
L.G. Almeida, S.J. Lee, G. Perez, G.F. Sterman, I. Sung and J. Virzi, Substructure of high-p T jets at the LHC, Phys. Rev. D 79 (2009) 074017 [arXiv:0807.0234] [INSPIRE].
V. Rentala, W. Shepherd and T.M.P. Tait, Tagging boosted Ws with wavelets, JHEP 08 (2014) 042 [arXiv:1404.1929] [INSPIRE].
J. Cogan, M. Kagan, E. Strauss and A. Schwarztman, Jet-images: computer vision inspired techniques for jet tagging, JHEP 02 (2015) 118 [arXiv:1407.5675] [INSPIRE].
A.J. Larkoski, S. Marzani, G. Soyez and J. Thaler, Soft drop, JHEP 05 (2014) 146 [arXiv:1402.2657] [INSPIRE].
ATLAS collaboration, Tagging and suppression of pileup jets, ATLAS-CONF-2014-018 (2014).
CMS collaboration, Pileup removal algorithms, CMS-PAS-JME-14-001 (2014).
CMS collaboration, Measurement of the t-channel single-top-quark production cross section and of the |V tb | CKM matrix element in pp collisions at \( \sqrt{s}=8 \) TeV, JHEP 06 (2014) 090 [arXiv:1403.7366] [INSPIRE].
M. Capeans et al., ATLAS insertable B-layer technical design report, CERN-LHCC-2010-013 (2010).
R. Barbieri, B. Bellazzini, V.S. Rychkov and A. Varagnolo, The Higgs boson from an extended symmetry, Phys. Rev. D 76 (2007) 115008 [arXiv:0706.0432] [INSPIRE].
C. Delaunay, T. Flacke, J. Gonzalez-Fraile, S.J. Lee, G. Panico and G. Perez, Light non-degenerate composite partners at the LHC, JHEP 02 (2014) 055 [arXiv:1311.2072] [INSPIRE].
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: 1409.0409
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
Backović, M., Flacke, T., Lee, S.J. et al. LHC top partner searches beyond the 2 TeV mass region. J. High Energ. Phys. 2015, 22 (2015). https://doi.org/10.1007/JHEP09(2015)022
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP09(2015)022