scholarly journals Search for top squark pair production in the dielectron channel

1998 ◽  
Vol 57 (1) ◽  
pp. 589-593 ◽  
Author(s):  
S. Abachi ◽  
B. Abbott ◽  
M. Abolins ◽  
B. S. Acharya ◽  
I. Adam ◽  
...  
Author(s):  
S. Chatrchyan ◽  
◽  
V. Khachatryan ◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
...  

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.


1995 ◽  
Vol 10 (29) ◽  
pp. 4241-4264 ◽  
Author(s):  
JORGE L. LOPEZ ◽  
D.V. NANOPOULOS ◽  
A. ZICHICHI

We consider the experimental predictions of two one-parameter no-scale SU (5)× U (1) supergravity models with string-inspired moduli and dilaton seeds of supersymmetry breaking. These predictions have been considerably sharpened with the new information on the top-quark mass from the Tevatron, and the actual measurement of the B(b→sγ) branching ratio from CLEO. In particular, the sign of the Higgs mixing parameter μ is fixed. A more precise measurement of the top-quark mass above (below) ≈160 GeV would disfavor the dilaton (moduli) scenario. Similarly a measurement of the lightest Higgs-boson mass above 90 GeV (below 100 GeV) would disfavor the dilaton (moduli) scenario. At the Tevatron with 100 pb−1, the reach into parameter space is significant only in the dilaton scenario [Formula: see text] via the trilepton and top-squark signals. At LEPII the dilaton scenario could be probed up to the kinematical limit via chargino and top-squark pair production, and the discovery of the lightest Higgs boson is guaranteed. In the moduli scenario, only selectron pair production looks promising. We also calculate the supersymmetric contribution to the anomalous magnetic moment of the muon.


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