Search for Admixture of Scalar Top in the t$$\bar{t}$$ Lepton+Jets Final State at √s= 1.96 TeV

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 2007

DOI:https://doi.org/10.2172/921978· OSTI ID:921978

Park, Su-Jung ^[1]

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1. Univ. of Rochester, NY (United States)

A search for pair production of scalar top (stop) quarks has been performed in the lepton+jets channel in ~ 1 fb^-1 of data at the D0 experiment. Kinematic differences between $$\bar{t}$$₁$$\tilde{t}$$₁ and the dominant t$$\bar{t}$$ process are used to separate the two reactions. For stop-quark masses of 145-175 GeV, and chargino masses of 105-135 GeV, to which the stop quarks decay ($$\tilde{t}$$₁ → $$\tilde{X}$$₁⁺b), we obtain upper limits on the $$\tilde{t}$$₁$$\bar{t}$$₁ cross section at 95% confidence, that are a factor of ~ 7-12 larger than expected from the Minimal Supersymmetric Standard Model (MSSM), as calculated in a next-to-leading-order (NLO) approximation in quantum chromodynamics (QCD).

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 921978
• Report Number(s): FERMILAB-THESIS--2007-45
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
APPROXIMATIONS
CROSS SECTIONS
DECAY
Experiment-HEP
PAIR PRODUCTION
QUANTUM CHROMODYNAMICS
QUARKS
SCALARS
STANDARD MODEL