scholarly journals Searches for pair production of charginos and top squarks in final states with two oppositely charged leptons at CMS experiment

2020 ◽  
Vol 1586 ◽  
pp. 012011
Author(s):  
B Chazin
2021 ◽  
Vol 81 (1) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

AbstractA search is presented for supersymmetric partners of the top quark (top squarks) in final states with two oppositely charged leptons (electrons or muons), jets identified as originating from $${\text {b}}$$ b quarks, and missing transverse momentum. The search uses data from proton-proton collisions at $$\sqrt{s}=13\,\text {TeV} $$ s = 13 TeV collected with the CMS detector, corresponding to an integrated luminosity of 137$$\,{\text {fb}}^{-1}$$ fb - 1 . Hypothetical signal events are efficiently separated from the dominant top quark pair production background with requirements on the significance of the missing transverse momentum and on transverse mass variables. No significant deviation is observed from the expected background. Exclusion limits are set in the context of simplified supersymmetric models with pair-produced lightest top squarks. For top squarks decaying exclusively to a top quark and a lightest neutralino, lower limits are placed at $$95\%$$ 95 % confidence level on the masses of the top squark and the neutralino up to 925 and 450$$\,\text {GeV}$$ GeV , respectively. If the decay proceeds via an intermediate chargino, the corresponding lower limits on the mass of the lightest top squark are set up to 850$$\,\text {GeV}$$ GeV for neutralino masses below 420$$\,\text {GeV}$$ GeV . For top squarks undergoing a cascade decay through charginos and sleptons, the mass limits reach up to 1.4$$\,\text {TeV}$$ TeV and 900$$\,\text {GeV}$$ GeV respectively for the top squark and the lightest neutralino.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  

Abstract The results of a search for new phenomena in final states with b-jets and missing transverse momentum using 139 fb−1 of proton-proton data collected at a centre-of-mass energy $$ \sqrt{s} $$ s = 13 TeV by the ATLAS detector at the LHC are reported. The analysis targets final states produced by the decay of a pair-produced supersymmetric bottom squark into a bottom quark and a stable neutralino. The analysis also seeks evidence for models of pair production of dark matter particles produced through the decay of a generic scalar or pseudoscalar mediator state in association with a pair of bottom quarks, and models of pair production of scalar third-generation down-type leptoquarks. No significant excess of events over the Standard Model background expectation is observed in any of the signal regions considered by the analysis. Bottom squark masses below 1270 GeV are excluded at 95% confidence level if the neutralino is massless. In the case of nearly mass-degenerate bottom squarks and neutralinos, the use of dedicated secondary-vertex identification techniques permits the exclusion of bottom squarks with masses up to 660 GeV for mass splittings between the squark and the neutralino of 10 GeV. These limits extend substantially beyond the regions of parameter space excluded by similar ATLAS searches performed previously.


2017 ◽  
Vol 768 ◽  
pp. 137-162 ◽  
Author(s):  
V. Khachatryan ◽  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
E. Asilar ◽  
...  

2005 ◽  
Vol 20 (14) ◽  
pp. 3177-3179
Author(s):  
◽  
TOBIAS GOLLING

A measurement of the [Formula: see text] production cross-section at [Formula: see text] with the DØ detector at the Fermilab Tevatron, based on the application of a multivariate topological method is presented. The integrated luminosity corresponds to 143.9 pb-1 in the μ+jets and 141.2 pb-1 in the e+jets channel. The preliminary cross-section is measured to be [Formula: see text].


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