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.

Sirunyan A.M., Tumasyan A., Adam W., Bergauer T., Dragicevic M., Ero J., et al. (2021). Search for the rare decay of the W boson into a pion and a photon in proton-proton collisions at √s = 13 TeV. PHYSICS LETTERS. SECTION B, 819, 1-24 [10.1016/j.physletb.2021.136409].

Search for the rare decay of the W boson into a pion and a photon in proton-proton collisions at √s = 13 TeV

Battilana C.;Bonacorsi D.;Borgonovi L.;Braibant-Giacomelli S.;Castro A.;Cuffiani M.;Diotalevi T.;Fanfani A.;Fontanesi E.;Giommi L.;Guiducci L.;Iemmi F.;Primavera F.;Rovelli T.;Siroli G. P.;
2021

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.
2021
Sirunyan A.M., Tumasyan A., Adam W., Bergauer T., Dragicevic M., Ero J., et al. (2021). Search for the rare decay of the W boson into a pion and a photon in proton-proton collisions at √s = 13 TeV. PHYSICS LETTERS. SECTION B, 819, 1-24 [10.1016/j.physletb.2021.136409].
Sirunyan A.M.; Tumasyan A.; Adam W.; Bergauer T.; Dragicevic M.; Ero J.; Escalante Del Valle A.; Fruhwirth R.; Jeitler M.; Krammer N.; Lechner L.; Lik...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/852621
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