{"title":"$J/\\psi$ yield enhancement at very low transverse momentum in Pb-Pb collisions at $\\sqrt{s_\\mathrm{NN}} = \\mathrm{5.02 \\,TeV}$ with ALICE","authors":"Zhuo Zhou","doi":"10.22323/1.320.0028","DOIUrl":null,"url":null,"abstract":"A large excess in the yield of $\\mathrm{J/\\psi}$ at very low transverse momentum (${p}_\\mathrm{T}<\\mathrm{300 MeV/}c$) and forward rapidity (2.5$<y<$4.0) was recently reported by $\\mathrm{ALICE}$ using the LHC Run-1 data, in Pb-Pb collisions at $\\sqrt{s_\\mathrm{NN}} = \\mathrm{2.76 \\,TeV}$. This is suggestive of coherent $\\mathrm{J/\\psi}$ photo-production, similar to measurements in ultra-peripheral collisions (UPC), where the nuclei only interact electromagnetically.\r\n\r\nDuring the LHC Run-2, the measurement of the very low ${p}_\\mathrm{T}$ $\\mathrm{J/\\psi}$ at mid-rapidity (-0.9$<y<$0.9) in the di-electron decay channel was possible thanks to the large sample of recorded Pb-Pb collisions. The central barrel detectors provide a good momentum resolution, and make the measurement sensitive to the key characteristics of $\\mathrm{J/\\psi}$ coherent photo-production, like the corresponding transverse momentum spectrum.\r\n\r\nIn this talk, it will focus on the $\\mathrm{J/\\psi}$ production in the very low-${p}_\\mathrm{T}$ range in peripheral Pb-Pb collisions at $\\sqrt{s_\\mathrm{NN}} = 5.02 \\,TeV$. The ${p}_\\mathrm{T}$ spectrum shape for coherent production will be shown and compared to UPC measurements.","PeriodicalId":104537,"journal":{"name":"Proceedings of 12th International Workshop on High-pT Physics in the RHIC/LHC Era — PoS(High-pT2017)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2019-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of 12th International Workshop on High-pT Physics in the RHIC/LHC Era — PoS(High-pT2017)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.22323/1.320.0028","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
A large excess in the yield of $\mathrm{J/\psi}$ at very low transverse momentum (${p}_\mathrm{T}<\mathrm{300 MeV/}c$) and forward rapidity (2.5$