Light stop searches at the LHC in events with two<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>b</mml:mi></mml:math>jets and missing energy

Bornhauser, Sascha; Drees, Manuel; Grab, S.; Kim, Jong Soo

doi:10.1103/physrevd.83.035008

Cited by 45 publications

(39 citation statements)

References 82 publications

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“…We also assume that the mass difference between the stop and the LSP is substantially larger than the top quark mass. Otherwise the signal will strongly overlap with the SM backgrounds, which would need some different search strategies [20][21][22][23][24].…”

Section: Jhep07(2012)110mentioning

confidence: 99%

Stop the top background of the stop search

Bai

Cheng

Gallicchio

et al. 2012

J. High Energ. Phys.

113

110

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Abstract:The main background for the supersymmetric stop direct production search comes from Standard Model tt events. For the single-lepton search channel, we introduce a few kinematic variables to further suppress this background by focusing on its dileptonic and semileptonic topologies. All are defined to have end points in the background, but not signal distributions. They can substantially improve the stop signal significance and mass reach when combined with traditional kinematic variables such as the total missing transverse energy. Among them, our variable M W T 2 has the best overall performance because it uses all available kinematic information, including the on-shell mass of both W 's. We see 20%-30% improvement on the discovery significance and estimate that the 8 TeV LHC run with 20 fb −1 of data would be able to reach an exclusion limit of 650-700 GeV for direct stop production, as long as the stop decays dominantly to the top quark and a light stable neutralino. Most of the mass range required for the supersymmetric solution of the naturalness problem in the standard scenario can be covered.

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Section: Jhep07(2012)110mentioning

confidence: 99%

Stop the top background of the stop search

Bai

Cheng

Gallicchio

et al. 2012

J. High Energ. Phys.

113

110

View full text Add to dashboard Cite

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“…They proceed through both off-shell top quark and W boson exchange (or sbottom, sleptons, sneutrino, charginos), only off-shell top quark (or sbottom, charginos), and via on-shell top quark respectively. In the region of nearly degenerate NLSP stop and LSP neutralino masses that we are interested in, the last two tree level channels are both kinematically forbidden, so that the loop-induced NLSP stop two-body decay into a charm quark and a neutralino is generally considered to be the dominant decay mode [16][17][18][19]22]. Experimentally, at a hadron collider, for a given ∆M , the NLSP stop decay products from the 4-body channel (including leptons) are much softer and thus harder to detect compared to the 2-body channel, and have not been searched so far.…”

Section: Production and Decay Modes Of Nlsp Stopmentioning

confidence: 99%

“…Motivated by these considerations in this paper we pursue a model-independent analysis of the NLSP stop scenario. The search for NLSP stop, especially in the region of nearly degenerate stop and LSP neutralino masses, is challenging and has been implemented by both LEP and Tevatron [12][13][14][15], assuming the loop-induced NLSP stop two-body decay into a charm quark and a neutralino is dominant [16][17][18][19]. The NLSP stop mass limit is Mt 1 > 100 GeV from LEP-II and Mt 1 > 180 GeV from CDF Run-II.…”

Section: Introductionmentioning

confidence: 99%

Impact of LHC searches on NLSP top squark and gluino mass

Shafi

2012

J. High Energ. Phys.

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Abstract:We explore the implications of 7 TeV LHC searches for a scenario in which one of the stops is the next-to-lightest supersymmetric particle (NLSP). The NLSP stop (t 1 ) is assumed to decay exclusively into neutralino and charm quark. We consider processes where the stops are pair produced together with a hard QCD jet. We also consider stop quarks from gluino decays,g → tt * 1 +tt 1 . We show that the monojet ATLAS and CMS searches corresponding to 1 fb −1 of integrated luminosity are sensitive to stop masses of up to 160 GeV, with the 20% neutralino-stop coannihilation region essentially ruled out for Mt 1 140 GeV. The region Mt 1 130 GeV is excluded with even relatively larger mass difference, Mt 1 −Mχ0 1 ∼ 40 GeV, by the multi-jets search. The b-jet and same-sign dilepton searches are sensitive to a heavier gluino because they only pick up gluino pair production events followed by top quarks decaying into b-jets and same-sign dileptons, respectively. We find that the LHC data places a lower limit on the gluino mass in this scenario of about 600 GeV (700 GeV) from b-jets (same-sign dileptons) searches.

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“…In this neutralino mass range the production of colored particles is the most promising. References [123][124][125] studied the stop coannihilation region, not only by direct stop production but also by gluino production, where direct stop productions constrain light stops (m~t 1 ≲ 400 GeV); for heavier stops gluino, the production seems to be more promising. On the other hand, the region where neutralino annihilation is mediated by squarks is directly constrained by limits on squarks masses.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Dark matter protohalos in a nine parameter MSSM and implications for direct and indirect detection

2015

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Dark matter protohalos in a nine parameter MSSM and implications for direct and indirect detection Diamanti, R.; Cabrera Catalan, M.E.; Ando, S. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 24 Mar 2019Dark matter protohalos in a nine parameter MSSM and implications for direct and indirect detection We study how the kinetic decoupling of dark matter within a minimal supersymmetric extension of the standard model, by adopting nine independent parameters (MSSM-9), could improve our knowledge of the properties of the dark matter protohalos. We show that the most probable neutralino mass regions, which satisfy the relic density and the Higgs mass constraints, are those with the lightest supersymmetric neutralino mass around 1 TeV and 3 TeV, corresponding to Higgsino-like and winolike neutralino, respectively. The kinetic decoupling temperature in the MSSM-9 scenario leads to a most probable protohalo mass in a range of M ph ∼ 10 −12 -10 −7 M ⊙ . The part of the region closer to ∼2 TeV gives also important contributions from the neutralino-stau coannihilation, reducing the effective annihilation rate in the early Universe. We also study how the size of the smallest dark matter substructures correlates to experimental signatures, such as the spin-dependent and spin-independent scattering cross sections, relevant for direct detection of dark matter. Improvements on the spin-independent sensitivity might reduce the most probable range of the protohalo mass between ∼10 −9 M ⊙ and ∼10 −7 M ⊙ , while the expected spindependent sensitivity provides weaker constraints. We show how the boost of the luminosity due to dark matter annihilation increases, depending on the protohalo mass. In the Higgsino case, the protohalo mass is lower than the canonical value often used in the literature (∼10 −6 M ⊙ ), while hσvi does not deviate from hσvi ∼ 10 −26 cm 3 s −1 ; there is no significant enhancement of the luminosity. On the contrary, in the wino case, the protohalo mass is even lighter, and hσvi is two orders of magnitude larger; as its consequence, we see a substantial enhancement of the luminosity.

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Light stop searches at the LHC in events with twobjets and missing energy

Cited by 45 publications

References 82 publications

Stop the top background of the stop search

Stop the top background of the stop search

Impact of LHC searches on NLSP top squark and gluino mass

Dark matter protohalos in a nine parameter MSSM and implications for direct and indirect detection

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