Elsevier

Physics Letters B

Volume 715, Issues 1–3, 29 August 2012, Pages 44-60
Physics Letters B

Search for scalar top quark pair production in natural gauge mediated supersymmetry models with the ATLAS detector in pp collisions at s=7TeV

https://doi.org/10.1016/j.physletb.2012.07.010Get rights and content
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Abstract

The results of a search for pair production of the lighter scalar partners of top quarks (t˜1) in 2.05 fb−1 of pp collisions at s=7 TeV using the ATLAS experiment at the LHC are reported. Scalar top quarks are searched for in events with two same flavour opposite-sign leptons (e,μ) with invariant mass consistent with the Z boson mass, large missing transverse momentum and jets in the final state. At least one of the jets is identified as originating from a b-quark. No excess over Standard Model expectations is found. The results are interpreted in the framework of R-parity conserving, gauge mediated Supersymmetry breaking ‘natural’ scenarios, where the neutralino (χ˜10) is the next-to-lightest supersymmetric particle. Scalar top quark masses up to 310 GeV are excluded for 115GeV<mχ˜10<230GeV at 95% confidence level, reaching an exclusion of mt˜1<330GeV for mχ˜10=190GeV. Scalar top quark masses below 240 GeV are excluded for all values of mχ˜10>mZ.

Cited by (0)

© CERN for the benefit of the ATLAS Collaboration.

E-mail address: [email protected].

a

Also at Laboratorio de Instrumentacao e Fisica Experimental de Particulas – LIP, Lisboa, Portugal.

b

Also at Faculdade de Ciencias and CFNUL, Universidade de Lisboa, Lisboa, Portugal.

c

Also at Particle Physics Department, Rutherford Appleton Laboratory, Didcot, United Kingdom.

d

Also at TRIUMF, Vancouver, BC, Canada.

e

Also at Department of Physics, California State University, Fresno, CA, United States.

f

Also at Novosibirsk State University, Novosibirsk, Russia.

g

Also at Fermilab, Batavia, IL, United States.

h

Also at Department of Physics, University of Coimbra, Coimbra, Portugal.

i

Also at Università di Napoli Parthenope, Napoli, Italy.

j

Also at Institute of Particle Physics (IPP), Canada.

k

Also at Department of Physics, Middle East Technical University, Ankara, Turkey.

l

Also at Louisiana Tech University, Ruston, LA, United States.

m

Also at Department of Physics and Astronomy, University College London, London, United Kingdom.

n

Also at Group of Particle Physics, University of Montreal, Montreal, QC, Canada.

o

Also at Department of Physics, University of Cape Town, Cape Town, South Africa.

p

Also at Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan.

q

Also at Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany.

r

Also at Manhattan College, New York, NY, United States.

s

Also at School of Physics, Shandong University, Shandong, China.

t

Also at CPPM, Aix-Marseille Université and CNRS/IN2P3, Marseille, France.

u

Also at School of Physics and Engineering, Sun Yat-sen University, Guanzhou, China.

v

Also at Academia Sinica Grid Computing, Institute of Physics, Academia Sinica, Taipei, Taiwan.

w

Also at Dipartimento di Fisica, Università La Sapienza, Roma, Italy.

x

Also at DSM/IRFU (Institut de Recherches sur les Lois Fondamentales de lʼUnivers), CEA Saclay (Commissariat a lʼEnergie Atomique), Gif-sur-Yvette, France.

y

Also at Section de Physique, Université de Genève, Geneva, Switzerland.

z

Also at Departamento de Fisica, Universidade de Minho, Braga, Portugal.

aa

Also at Department of Physics and Astronomy, University of South Carolina, Columbia, SC, United States.

ab

Also at Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Budapest, Hungary.

ac

Also at California Institute of Technology, Pasadena, CA, United States.

ad

Also at Institute of Physics, Jagiellonian University, Krakow, Poland.

ae

Also at LAL, Univ. Paris-Sud and CNRS/IN2P3, Orsay, France.

af

Also at Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom.

ag

Also at Department of Physics, Oxford University, Oxford, United Kingdom.

ah

Also at Institute of Physics, Academia Sinica, Taipei, Taiwan.

ai

Also at Department of Physics, The University of Michigan, Ann Arbor, MI, United States.

Deceased.