Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/196290 |
Resumo: | Measurements of inclusive and direct photon production at midrapidity in pp collisions at √ s = 2.76 and 8 TeV are presented by the ALICE experiment at the LHC. The results are reported in transverse momentum ranges of 0.4 < pT < 10 GeV/c and 0.3 < pT < 16 GeV/c, respectively. Photons are detected with the electromagnetic calorimeter (EMCal) and via reconstruction of e+e− pairs from conversions in the ALICE detector material using the central tracking system. For the final measurement of the inclusive photon spectra the results are combined in the overlapping pT interval of both methods. Direct photon spectra, or their upper limits at 90% C.L. are extracted using the direct photon excess ratio Rγ , which quantifies the ratio of inclusive photons over decay photons generated with a decay-photon simulation. An additional hybrid method, combining photons reconstructed from conversions with those identified in the EMCal, is used for the combination of the direct photon excess ratio Rγ , as well as the extraction of direct photon spectra or their upper limits. While no significant signal of direct photons is seen over the full pT range, Rγ for pT > 7 GeV/c is at least one σ above unity and consistent with expectations from next-to-leading order pQCD calculations. |
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Acharya, ShreyasiGay Ducati, Maria BeatrizPereira, Luis GustavoPezzi, Rafael PerettiALICE Collaboration2019-06-26T02:35:06Z20190556-2813http://hdl.handle.net/10183/196290001092241Measurements of inclusive and direct photon production at midrapidity in pp collisions at √ s = 2.76 and 8 TeV are presented by the ALICE experiment at the LHC. The results are reported in transverse momentum ranges of 0.4 < pT < 10 GeV/c and 0.3 < pT < 16 GeV/c, respectively. Photons are detected with the electromagnetic calorimeter (EMCal) and via reconstruction of e+e− pairs from conversions in the ALICE detector material using the central tracking system. For the final measurement of the inclusive photon spectra the results are combined in the overlapping pT interval of both methods. Direct photon spectra, or their upper limits at 90% C.L. are extracted using the direct photon excess ratio Rγ , which quantifies the ratio of inclusive photons over decay photons generated with a decay-photon simulation. An additional hybrid method, combining photons reconstructed from conversions with those identified in the EMCal, is used for the combination of the direct photon excess ratio Rγ , as well as the extraction of direct photon spectra or their upper limits. While no significant signal of direct photons is seen over the full pT range, Rγ for pT > 7 GeV/c is at least one σ above unity and consistent with expectations from next-to-leading order pQCD calculations.application/pdfengPhysical review. C, Nuclear physics. Melville. Vol. 99, no. 2 (Feb. 2019), 024912, 19 p.Colisões proton-protonAceleradores de partículasProdução de fótonsDirect photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 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:UFRGSTEXT001092241.pdf.txt001092241.pdf.txtExtracted Texttext/plain103161http://www.lume.ufrgs.br/bitstream/10183/196290/2/001092241.pdf.txt658a3b0877793b6a0a061a9ae6d11aedMD52ORIGINAL001092241.pdfTexto completo (inglês)application/pdf813944http://www.lume.ufrgs.br/bitstream/10183/196290/1/001092241.pdf0da6bd6dd94fd095635e162808fd8133MD5110183/1962902023-11-12 04:24:28.725382oai:www.lume.ufrgs.br:10183/196290Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-11-12T06:24:28Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV |
title |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV |
spellingShingle |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV Acharya, Shreyasi Colisões proton-proton Aceleradores de partículas Produção de fótons |
title_short |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV |
title_full |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV |
title_fullStr |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV |
title_full_unstemmed |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 TeV |
title_sort |
Direct photon production at low transverse momentum in proton-proton collisions at √s = 2.76 and 8 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 Produção de fótons |
topic |
Colisões proton-proton Aceleradores de partículas Produção de fótons |
description |
Measurements of inclusive and direct photon production at midrapidity in pp collisions at √ s = 2.76 and 8 TeV are presented by the ALICE experiment at the LHC. The results are reported in transverse momentum ranges of 0.4 < pT < 10 GeV/c and 0.3 < pT < 16 GeV/c, respectively. Photons are detected with the electromagnetic calorimeter (EMCal) and via reconstruction of e+e− pairs from conversions in the ALICE detector material using the central tracking system. For the final measurement of the inclusive photon spectra the results are combined in the overlapping pT interval of both methods. Direct photon spectra, or their upper limits at 90% C.L. are extracted using the direct photon excess ratio Rγ , which quantifies the ratio of inclusive photons over decay photons generated with a decay-photon simulation. An additional hybrid method, combining photons reconstructed from conversions with those identified in the EMCal, is used for the combination of the direct photon excess ratio Rγ , as well as the extraction of direct photon spectra or their upper limits. While no significant signal of direct photons is seen over the full pT range, Rγ for pT > 7 GeV/c is at least one σ above unity and consistent with expectations from next-to-leading order pQCD calculations. |
publishDate |
2019 |
dc.date.accessioned.fl_str_mv |
2019-06-26T02:35:06Z |
dc.date.issued.fl_str_mv |
2019 |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
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publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/196290 |
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0556-2813 |
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001092241 |
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http://hdl.handle.net/10183/196290 |
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eng |
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eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Physical review. C, Nuclear physics. Melville. Vol. 99, no. 2 (Feb. 2019), 024912, 19 p. |
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info:eu-repo/semantics/openAccess |
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openAccess |
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