{"title":"$J/\\psi$ 在极低横向动量下与ALICE在$\\sqrt{s_\\mathrm{NN}} = \\mathrm{5.02 \\,TeV}$的Pb-Pb碰撞的产率增强","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":"{\"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}","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}