Publication: Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at sNN=5.02TeV
Дата
2019
Авторы
Sirunyan, A. M.
Tumasyan, A.
Adam, W.
Ambrogi, F.
Matveev, V.
Chadeeva, M.
Parygin, P.
Philippov, D.
Polikarpov, S.
Popova, E.
Journal Title
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Volume Title
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Аннотация
© 2019 The Author(s)Evidence for the light-by-light scattering process, γγ→γγ, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390μb−1 recorded by the CMS experiment at the LHC. Light-by-light scattering processes are selected in events with two photons exclusively produced, each with transverse energy ET γ>2GeV, pseudorapidity |ηγ|<2.4, diphoton invariant mass mγγ>5GeV, diphoton transverse momentum pT γγ<1GeV, and diphoton acoplanarity below 0.01. After all selection criteria are applied, 14 events are observed, compared to expectations of 9.0±0.9(theo) events for the signal and 4.0±1.2(stat) for the background processes. The excess observed in data relative to the background-only expectation corresponds to a significance of 3.7 standard deviations, and has properties consistent with those expected for the light-by-light scattering signal. The measured fiducial light-by-light scattering cross section, σfid(γγ→γγ)=120±46(stat)±28(syst)±12(theo)nb, is consistent with the standard model prediction. The mγγ distribution is used to set new exclusion limits on the production of pseudoscalar axion-like particles, via the (Figure presented.) process, in the mass range (Figure presented.).
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Цитирование
Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at sNN=5.02TeV / Sirunyan, A.M. [et al.] // Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 2019. - 797. - 10.1016/j.physletb.2019.134826
URI
https://www.doi.org/10.1016/j.physletb.2019.134826
https://www.scopus.com/record/display.uri?eid=2-s2.0-85070721104&origin=resultslist
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https://openrepository.mephi.ru/handle/123456789/18546
https://www.scopus.com/record/display.uri?eid=2-s2.0-85070721104&origin=resultslist
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000488071200025
https://openrepository.mephi.ru/handle/123456789/18546