Search for the rare decay of the W boson into a pion and a photon in proton-proton collisions at s=13TeV
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
A search is performed for the rare decay W± → π±γ in proton-proton collisions at √s = 13 TeV. Data
corresponding to an integrated luminosity of 137 fb−1 were collected during 2016 to 2018 with the CMS
detector. This analysis exploits a novel search strategy based on W boson production in top quark pair
events. An inclusive search for the W± → π±γ decay is not optimal at the LHC because of the high
trigger thresholds. Instead, a trigger selection is exploited in which the W boson originating from one of
the top quarks is used to tag the event in a leptonic decay. The W boson emerging from the other top
quark is used to search for the W± → π±γ signature. Such decays are characterized by an isolated
track pointing to a large energy deposit, and by an isolated photon of large transverse momentum.
The presence of b quark jets reduces the background from the hadronization of light-flavor quarks and
gluons. The W± → π±γ decay is not observed. An upper exclusion limit is set to this branching fraction,
corresponding to 1.50 × 10−5 at 95% confidence level, whereas the expected upper exclusion limit is
0.85+0.52
−0.29 × 10−5.
corresponding to an integrated luminosity of 137 fb−1 were collected during 2016 to 2018 with the CMS
detector. This analysis exploits a novel search strategy based on W boson production in top quark pair
events. An inclusive search for the W± → π±γ decay is not optimal at the LHC because of the high
trigger thresholds. Instead, a trigger selection is exploited in which the W boson originating from one of
the top quarks is used to tag the event in a leptonic decay. The W boson emerging from the other top
quark is used to search for the W± → π±γ signature. Such decays are characterized by an isolated
track pointing to a large energy deposit, and by an isolated photon of large transverse momentum.
The presence of b quark jets reduces the background from the hadronization of light-flavor quarks and
gluons. The W± → π±γ decay is not observed. An upper exclusion limit is set to this branching fraction,
corresponding to 1.50 × 10−5 at 95% confidence level, whereas the expected upper exclusion limit is
0.85+0.52
−0.29 × 10−5.
Date Issued
2021-08
Date Acceptance
2021-05-25
Citation
Physics Letters B, 2021, 819, pp.1-24
ISSN
0370-2693
Publisher
Elsevier BV
Start Page
1
End Page
24
Journal / Book Title
Physics Letters B
Volume
819
Copyright Statement
© 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP3.
SCOAP3.
License URL
Identifier
https://www.sciencedirect.com/science/article/pii/S037026932100349X?via%3Dihub
Subjects
hep-ex
hep-ex
Nuclear & Particles Physics
0105 Mathematical Physics
0201 Astronomical and Space Sciences
0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
Publication Status
Published
Article Number
136409
Date Publish Online
2021-05-28