Publication: Soft-Dielectron Excess in Proton-Proton Collisions at s =13 TeV
Дата
2021
Авторы
Acharya, S.
Adamova, D.
Adler, A.
Adolfsson, J.
Belyaev, V.
Bogdanov, A.
Bolozdynya, A.
Borissov, A.
Grigoriev, V.
Kaplin, V.
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Аннотация
© 2021 CERN. A measurement of dielectron production in proton-proton (pp) collisions at s=13 TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass mee and pair transverse momentum pT,ee that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of mee, pT,ee, and event multiplicity dNch/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π0 ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15<mee<0.6 GeV/c2 and for pT,ee<0.4 GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous"soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61±0.13(stat)±0.17(syst,data)±0.34(syst,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in mee and pT,ee are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.
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Soft-Dielectron Excess in Proton-Proton Collisions at s =13 TeV / Acharya, S. [et al.] // Physical Review Letters. - 2021. - 127. - № 4. - 10.1103/PhysRevLett.127.042302
URI
https://www.doi.org/10.1103/PhysRevLett.127.042302
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https://openrepository.mephi.ru/handle/123456789/24448
https://www.scopus.com/record/display.uri?eid=2-s2.0-85111541130&origin=resultslist
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000677559400008
https://openrepository.mephi.ru/handle/123456789/24448