Elsevier

Physics Letters B

Volume 830, 10 July 2022, 137106
Physics Letters B

A search for an unexpected asymmetry in the production of e+μ and eμ+ pairs in proton–proton collisions recorded by the ATLAS detector at s=13 TeV

https://doi.org/10.1016/j.physletb.2022.137106Get rights and content
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Abstract

This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for e+μ and eμ+ pairs to constrain physics processes beyond the Standard Model. It uses 139fb1 of proton–proton collision data recorded at s=13 TeV at the LHC. Targeting sources of new physics which prefer final states containing e+μ to eμ+, the search contains two broad signal regions which are used to provide model-independent constraints on the ratio of cross sections at the 2% level. The search also has two special selections targeting supersymmetric models and leptoquark signatures. Observations using one of these selections are able to exclude, at 95% confidence level, singly produced smuons with masses up to 640 GeV in a model in which the only other light sparticle is a neutralino when the R-parity-violating coupling λ231 is close to unity. Observations using the other selection exclude scalar leptoquarks with masses below 1880 GeV when g1Reu=g1Rμc=1, at 95% confidence level. The limit on the coupling reduces to g1Reu=g1Rμc=0.46 for a mass of 1420 GeV.

Cited by (0)

a

Also at Borough of Manhattan Community College, City University of New York, New York NY; United States of America.

b

Also at Bruno Kessler Foundation, Trento; Italy.

c

Also at Center for High Energy Physics, Peking University; China.

d

Also at Centro Studi e Ricerche Enrico Fermi; Italy.

e

Also at CERN, Geneva; Switzerland.

f

Also at Département de Physique Nucléaire et Corpusculaire, Université de Genève, Genève; Switzerland.

g

Also at Departament de Fisica de la Universitat Autonoma de Barcelona, Barcelona; Spain.

h

Also at Department of Financial and Management Engineering, University of the Aegean, Chios; Greece.

i

Also at Department of Physics and Astronomy, Michigan State University, East Lansing MI; United States of America.

j

Also at Department of Physics and Astronomy, University of Louisville, Louisville, KY; United States of America.

k

Also at Department of Physics, Ben Gurion University of the Negev, Beer Sheva; Israel.

l

Also at Department of Physics, California State University, East Bay; United States of America.

m

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

n

Also at Department of Physics, California State University, Sacramento; United States of America.

o

Also at Department of Physics, King's College London, London; United Kingdom.

p

Also at Department of Physics, St. Petersburg State Polytechnical University, St. Petersburg; Russia.

q

Also at Department of Physics, University of Fribourg, Fribourg; Switzerland.

r

Also at Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow; Russia.

s

Also at Faculty of Physics, Sofia University, ‘St. Kliment Ohridski’, Sofia; Bulgaria.

t

Also at Graduate School of Science, Osaka University, Osaka; Japan.

u

Also at Hellenic Open University, Patras; Greece.

v

Also at Institucio Catalana de Recerca i Estudis Avancats, ICREA, Barcelona; Spain.

w

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

x

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

y

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

z

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

aa

Also at Institute of Theoretical Physics, Ilia State University, Tbilisi; Georgia.

ab

Also at Instituto de Fisica Teorica, IFT-UAM/CSIC, Madrid; Spain.

ac

Also at Istanbul University, Dept. of Physics, Istanbul; Turkey.

ad

Also at Joint Institute for Nuclear Research, Dubna; Russia.

ae

Also at Moscow Institute of Physics and Technology State University, Dolgoprudny; Russia.

af

Also at National Research Nuclear University MEPhI, Moscow; Russia.

ag

Also at Physics Department, An-Najah National University, Nablus; Palestine.

ah

Also at Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg; Germany.

ai

Also at The City College of New York, New York NY; United States of America.

aj

Also at TRIUMF, Vancouver BC; Canada.

ak

Also at Università di Napoli Parthenope, Napoli; Italy.

al

Also at University of Chinese Academy of Sciences (UCAS), Beijing; China.

am

Also at Yeditepe University, Physics Department, Istanbul; Turkey.

Deceased.

E-mail address: [email protected].