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Soft-Dielectron Excess in Proton-Proton Collisions at s=13 TeVстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 15 сентября 2021 г.
- Авторы: ALICE C., Malinina L.
- Журнал: Physical Review Letters
- Том: 127
- Номер: 4
- Год издания: 2021
- Издательство: American Physical Society
- Местоположение издательства: United States
- Первая страница: 042302
- DOI: 10.1103/physrevlett.127.042302
- Аннотация: A measurement of dielectron production in proton-proton (pp) collisions at s=13\sqrt{s} = 13s=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 invariant mass meem_{\rm ee}mee and pair transverse momentum pT,eep_{\rm T,ee}pT,ee that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of meem_{\rm ee}mee, pT,eep_{\rm T,ee}pT,ee, and event multiplicity dNch/dη{\rm d} N_{\rm ch}/{\rm d} \etadNch/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π0\eta/\pi^0η/π0 ratio in pp and proton-nucleus (p-A) 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<0.60.15<m_{\rm ee}<0.60.15<mee<0.6 GeV/c2c^2c2 and for pT,ee<0.4p_{\rm T,ee} < 0.4pT,ee<0.4 GeV/ccc indicates an enhancement of soft dielectrons, reminiscent of the 'anomalous' soft-photon and -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)1.61\pm 0.13\,(\rm{stat.})\pm 0.17\,(\rm{syst., data}) \pm 0.34\,(\rm{syst., cocktail})1.61±0.13(stat.)±0.17(syst.,data)±0.34(syst.,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in meem_{\rm ee}mee and pT,eep_{\rm T,ee}pT,ee are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.
- Добавил в систему: Малинина Людмила Владимировна