Soft-dielectron excess in proton-proton collisions at √s=13 TeV
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/235114 |
Resumo: | 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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Acharya, ShreyasiGay Ducati, Maria BeatrizPereira, Luis GustavoPezzi, Rafael PerettiALICE Collaboration2022-02-12T04:53:49Z20210031-9007http://hdl.handle.net/10183/235114001130265A 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.application/pdfengPhysical review letters. Melville. Vol. 127, no. 4 (July 2021), 042302, 13 p.Colisões proton-protonAceleradores de partículasSoft-dielectron excess in proton-proton collisions at √s=13 TeVEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT001130265.pdf.txt001130265.pdf.txtExtracted Texttext/plain69914http://www.lume.ufrgs.br/bitstream/10183/235114/2/001130265.pdf.txt8b3ed81d6b4f63d8654f0a82fbb0cb73MD52ORIGINAL001130265.pdfTexto completo (inglês)application/pdf467913http://www.lume.ufrgs.br/bitstream/10183/235114/1/001130265.pdf3b6f04fa6b4fd965a04adf89d3829e30MD5110183/2351142023-11-12 04:24:51.673475oai:www.lume.ufrgs.br:10183/235114Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-11-12T06:24:51Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV |
title |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV |
spellingShingle |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV Acharya, Shreyasi Colisões proton-proton Aceleradores de partículas |
title_short |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV |
title_full |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV |
title_fullStr |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV |
title_full_unstemmed |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV |
title_sort |
Soft-dielectron excess in proton-proton collisions at √s=13 TeV |
author |
Acharya, Shreyasi |
author_facet |
Acharya, Shreyasi Gay Ducati, Maria Beatriz Pereira, Luis Gustavo Pezzi, Rafael Peretti ALICE Collaboration |
author_role |
author |
author2 |
Gay Ducati, Maria Beatriz Pereira, Luis Gustavo Pezzi, Rafael Peretti ALICE Collaboration |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Acharya, Shreyasi Gay Ducati, Maria Beatriz Pereira, Luis Gustavo Pezzi, Rafael Peretti ALICE Collaboration |
dc.subject.por.fl_str_mv |
Colisões proton-proton Aceleradores de partículas |
topic |
Colisões proton-proton Aceleradores de partículas |
description |
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. |
publishDate |
2021 |
dc.date.issued.fl_str_mv |
2021 |
dc.date.accessioned.fl_str_mv |
2022-02-12T04:53:49Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
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publishedVersion |
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http://hdl.handle.net/10183/235114 |
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0031-9007 |
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001130265 |
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0031-9007 001130265 |
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http://hdl.handle.net/10183/235114 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Physical review letters. Melville. Vol. 127, no. 4 (July 2021), 042302, 13 p. |
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info:eu-repo/semantics/openAccess |
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openAccess |
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