Abstract
Current searches for the light top squark (stop) mostly focus on the decay channels of \( \tilde{t}\to t{\chi}_1^0 \) or \( \tilde{t}\to b{\chi}_1^{\pm}\to bW{\chi}_1^0 \), leading to final states for stop pair productions at the LHC. However, in supersymmetric scenarios with light neutralinos and charginos other than the neutralino lightest supersymmetric particle (LSP), more than one decay mode of the stop could be dominant. While those new decay modes could significantly weaken the current stop search limits at the LHC, they also offer alternative discovery channels for stop searches. In this paper, we studied the scenario with light Higgsino next-to-LSPs (NLSPs) and Bino LSP. The light stop decays primarily via \( {\tilde{t}}_1\to t{\chi}_2^0/{\chi}_3^0 \), with the neutralinos subsequent decaying to a Z boson or a Higgs boson: χ 02 /χ 03 → χ 01 h/Z. Pair production of light stops at the LHC leads to final states of or . We consider three signal regions: one charged lepton (1ℓ), two opposite sign charged leptons (2 OS ℓ) and at least three charged leptons (≥3ℓ). We found that the 1ℓ signal region of channel has the best reach sensitivity for light stop searches. For 14 TeV LHC with 300 fb−1 integrated luminosity, a stop mass up to 900 GeV can be discovered at 5σ significance, or up to 1050 GeV can be excluded at 95% C.L. Combining all three decay channels for 1ℓ signal region extends the reach for about 100−150 GeV. We also studied the stop reach at the 100 TeV pp collider with 3 ab−1 luminosity, with discovery and exclusion reach being 6 TeV and 7 TeV, respectively.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
References
ATLAS collaboration, Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC, Phys. Lett. B 716 (2012) 1 [arXiv:1207.7214] [INSPIRE].
CMS collaboration, Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC, Phys. Lett. B 716 (2012) 30 [arXiv:1207.7235] [INSPIRE].
S. Weinberg, Implications of dynamical symmetry breaking, Phys. Rev. D 13 (1976) 974 [INSPIRE].
ATLAS collaboration, Search for top-squark pair production in final states with one lepton, jets and missing transverse momentum using 36 fb −1 of \( \sqrt{s}=13 \) TeV pp collision data with the ATLAS detector, arXiv:1711.11520 [INSPIRE].
ATLAS collaboration, Search for a scalar partner of the top quark in the jets plus missing transverse momentum final state at \( \sqrt{s}=13 \) TeV with the ATLAS detector, JHEP 12 (2017) 085 [arXiv:1709.04183] [INSPIRE].
ATLAS collaboration, Search for supersymmetry in events with b-tagged jets and missing transverse momentum in pp collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector, JHEP 11 (2017) 195 [arXiv:1708.09266] [INSPIRE].
ATLAS collaboration, Search for direct top squark pair production in final states with two leptons in \( \sqrt{s}=13 \) TeV pp collisions with the ATLAS detector, Eur. Phys. J. C 77 (2017) 898 [arXiv:1708.03247] [INSPIRE].
ATLAS collaboration, Search for supersymmetry in final states with two same-sign or three leptons and jets using 36 fb −1 of \( \sqrt{s}=13 \) TeV pp collision data with the ATLAS detector, JHEP 09 (2017) 084 [arXiv:1706.03731] [INSPIRE].
CMS collaboration, Search for top squark pair production in pp collisions at \( \sqrt{s}=13 \) TeV using single lepton events, JHEP 10 (2017) 019 [arXiv:1706.04402] [INSPIRE].
CMS collaboration, Search for top squarks and dark matter particles in opposite-charge dilepton final states at \( \sqrt{s}=13 \) TeV, Phys. Rev. D 97 (2018) 032009 [arXiv:1711.00752] [INSPIRE].
CMS collaboration, Search for supersymmetry in multijet events with missing transverse momentum in proton-proton collisions at 13 TeV, Phys. Rev. D 96 (2017) 032003 [arXiv:1704.07781] [INSPIRE].
CMS collaboration, Search for new phenomena with the M T 2 variable in the all-hadronic final state produced in proton-proton collisions at \( \sqrt{s}=13 \) TeV, Eur. Phys. J. C 77 (2017) 710 [arXiv:1705.04650] [INSPIRE].
CMS collaboration, Search for supersymmetry in proton-proton collisions at 13 TeV using identified top quarks, Phys. Rev. D 97 (2018) 012007 [arXiv:1710.11188] [INSPIRE].
CMS collaboration, Search for supersymmetry in events with at least one soft lepton, low jet multiplicity and missing transverse momentum in proton-proton collisions at \( \sqrt{s}=13 \) TeV, CMS-PAS-SUS-16-052 (2016).
CMS collaboration, Search for new physics in events with two soft oppositely charged leptons and missing transverse momentum in proton-proton collisions at \( \sqrt{s}=13 \) TeV, arXiv:1801.01846 [INSPIRE].
CMS collaboration, Search for the pair production of third-generation squarks with two-body decays to a bottom or charm quark and a neutralino in proton-proton collisions at \( \sqrt{s}=13 \) TeV, Phys. Lett. B 778 (2018) 263 [arXiv:1707.07274] [INSPIRE].
CMS collaboration, Search for direct production of supersymmetric partners of the top quark in the all-jets final state in proton-proton collisions at \( \sqrt{s}=13 \) TeV, JHEP 10 (2017) 005 [arXiv:1707.03316] [INSPIRE].
ATLAS collaboration, Search for direct top squark pair production in events with a Higgs or Z boson and missing transverse momentum in \( \sqrt{s}=13 \) TeV pp collisions with the ATLAS detector, JHEP 08 (2017) 006 [arXiv:1706.03986] [INSPIRE].
CMS collaboration, Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at \( \sqrt{s}=8 \) TeV, Phys. Lett. B 736 (2014) 371 [arXiv:1405.3886] [INSPIRE].
CMS collaboration, Search for direct top squark pair production with Higgs bosons in the final state in pp collisions at \( \sqrt{s}=8 \) TeV, CMS-PAS-SUS-13-021 (2013).
J. Eckel, S. Su and H. Zhang, Complex decay chains of top and bottom squarks, JHEP 07 (2015) 075 [arXiv:1411.1061] [INSPIRE].
T. Han, S. Su, Y. Wu, B. Zhang and H. Zhang, Sbottom discovery via mixed decays at the LHC, Phys. Rev. D 92 (2015) 115009 [arXiv:1507.04006] [INSPIRE].
M. Chala, A. Delgado, G. Nardini and M. Quirós, A light sneutrino rescues the light stop, JHEP 04 (2017) 097 [arXiv:1702.07359] [INSPIRE].
D. Ghosh, Boosted dibosons from mixed heavy top squarks, Phys. Rev. D 88 (2013) 115013 [arXiv:1308.0320] [INSPIRE].
A. Chakraborty, D.K. Ghosh, D. Ghosh and D. Sengupta, Stop and sbottom search using dileptonic M T 2 variable and boosted top technique at the LHC, JHEP 10 (2013) 122 [arXiv:1303.5776] [INSPIRE].
S.P. Martin, A Supersymmetry primer, Adv. Ser. Direct.High Energy Phys. 21 (2010) 1 [hep-ph/9709356] [INSPIRE].
D.J.H. Chung et al., The soft supersymmetry breaking Lagrangian: theory and applications, Phys. Rept. 407 (2005) 1 [hep-ph/0312378] [INSPIRE].
M. Carena, J.R. Espinosa, M. Quirós and C.E.M. Wagner, Analytical expressions for radiatively corrected Higgs masses and couplings in the MSSM, Phys. Lett. B 355 (1995) 209 [hep-ph/9504316] [INSPIRE].
M. Carena, M. Quirós and C.E.M. Wagner, Effective potential methods and the Higgs mass spectrum in the MSSM, Nucl. Phys. B 461 (1996) 407 [hep-ph/9508343] [INSPIRE].
N.D. Christensen, T. Han and S. Su, MSSM Higgs bosons at The LHC, Phys. Rev. D 85 (2012) 115018 [arXiv:1203.3207] [INSPIRE].
M. Carena, S. Gori, N.R. Shah and C.E.M. Wagner, A 125 GeV SM-like Higgs in the MSSM and the γγ rate, JHEP 03 (2012) 014 [arXiv:1112.3336] [INSPIRE].
T. Han, S. Padhi and S. Su, Electroweakinos in the light of the Higgs boson, Phys. Rev. D 88 (2013) 115010 [arXiv:1309.5966] [INSPIRE].
J. Alwall et al., The automated computation of tree-level and next-to-leading order differential cross sections and their matching to parton shower simulations, JHEP 07 (2014) 079 [arXiv:1405.0301] [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].
T. Junk, Confidence level computation for combining searches with small statistics, Nucl. Instrum. Meth. A 434 (1999) 435 [hep-ex/9902006] [INSPIRE].
J. Anderson et al., Snowmass energy frontier simulations, arXiv:1309.1057 [INSPIRE].
W. Beenakker et al., Supersymmetric top and bottom squark production at hadron colliders, JHEP 08 (2010) 098 [arXiv:1006.4771] [INSPIRE].
A. Broggio et al., Approximate NNLO Predictions for the Stop-Pair Production Cross Section at the LHC, JHEP 07 (2013) 042 [arXiv:1304.2411] [INSPIRE].
C. Borschensky et al., Squark and gluino production cross sections in pp collisions at \( \sqrt{s}=13,14,33 \) and 100TeV, Eur. Phys. J. C 74 (2014) 3174 [arXiv:1407.5066] [INSPIRE].
M. Cacciari et al., Updated predictions for the total production cross sections of top and of heavier quark pairs at the Tevatron and at the LHC, JHEP 09 (2008) 127 [arXiv:0804.2800] [INSPIRE].
A. Bredenstein, A. Denner, S. Dittmaier and S. Pozzorini, NLO QCD corrections to \( pp\to t\overline{t}b\overline{b}+X \) at the LHC, Phys. Rev. Lett. 103 (2009) 012002 [arXiv:0905.0110] [INSPIRE].
W. Beenakker et al., NLO QCD corrections to \( t\overline{t}H \) production in hadron collisions, Nucl. Phys. B 653 (2003) 151 [hep-ph/0211352] [INSPIRE].
J.M. Campbell and R.K. Ellis, \( t\overline{t}{W}^{+-} \) production and decay at NLO, JHEP 07 (2012) 052 [arXiv:1204.5678] [INSPIRE].
A. Lazopoulos, T. McElmurry, K. Melnikov and F. Petriello, Next-to-leading order QCD corrections to \( t\overline{t}Z \) production at the LHC, Phys. Lett. B 666 (2008) 62 [arXiv:0804.2220] [INSPIRE].
C.G. Lester and D.J. Summers, Measuring masses of semiinvisibly decaying particles pair produced at hadron colliders, Phys. Lett. B 463 (1999) 99 [hep-ph/9906349] [INSPIRE].
A. Barr, C. Lester and P. Stephens, m(T 2): the truth behind the glamour, J. Phys. G 29 (2003) 2343 [hep-ph/0304226] [INSPIRE].
H.-C. Cheng and Z. Han, Minimal kinematic constraints and m(T2), JHEP 12 (2008) 063 [arXiv:0810.5178] [INSPIRE].
T. Cohen, R.T. D’Agnolo, M. Hance, H.K. Lou and J.G. Wacker, Boosting stop searches with a 100 TeV proton collider, JHEP 11 (2014) 021 [arXiv:1406.4512] [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].
A. Avetisyan et al., Methods and results for standard model event generation at \( \sqrt{s}=14 \) TeV, 33 TeV and 100 TeV proton colliders (A Snowmass Whitepaper), in the proceedings of the 2013 Community Summer Study on the Future of U.S. Particle Physics: Snowmass on the Mississippi (CSS2013), July 29-August 6, Minneapolis, U.S.A. (2013), arXiv:1308.1636, http://lss.fnal.gov/archive/test-fn/0000/fermilab-fn-0965-t.pdf [INSPIRE].
M. Cacciari, G.P. Salam and G. Soyez, The anti-k t jet clustering algorithm, JHEP 04 (2008) 063 [arXiv:0802.1189] [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: 1802.10532
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, 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 licence, and indicate if changes were made.
The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.
To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Su, S., Zhang, H. Higgs and Z assisted stop searches at hadron colliders. J. High Energ. Phys. 2018, 135 (2018). https://doi.org/10.1007/JHEP05(2018)135
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP05(2018)135