Elsevier

Physics Letters B

Volume 819, 10 August 2021, 136412
Physics Letters B

Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at s=13 TeV with the ATLAS detector

https://doi.org/10.1016/j.physletb.2021.136412Get rights and content
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Abstract

A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass m<30 GeV is presented. The analysis is performed using 139 fb−1 of proton–proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the Hγ process is found with a significance of 3.2 over the background-only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal-strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ=1.5±0.5. The Higgs boson production cross-section times the Hγ branching ratio for m<30 GeV is determined to be 8.72.7+2.8 fb.

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 CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France.

g

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

h

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

i

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

j

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

k

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

l

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

m

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

n

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

o

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

p

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

q

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

r

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

s

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

t

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

u

Also at Giresun University, Faculty of Engineering, Giresun, Turkey.

v

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

w

Also at Hellenic Open University, Patras, Greece.

x

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

y

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

z

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

aa

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

ab

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

ac

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

ad

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

ae

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

af

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

ag

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

ah

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

ai

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

aj

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

ak

Also at TRIUMF, Vancouver BC, Canada.

al

Also at Universita di Napoli Parthenope, Napoli, Italy.

am

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

Deceased.

E-mail address: [email protected].