Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV
Evidence for the light-by-light scattering process, γγ→γγ, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390μb−1 recorded by the CMS experiment at the L...
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| Format: | Article |
| Language: | English |
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Elsevier BV
2020
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| Online Access: | https://hdl.handle.net/1721.1/125327 |
| _version_ | 1826200516808409088 |
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| author | CMS Collaboration |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics CMS Collaboration |
| author_sort | CMS Collaboration |
| collection | MIT |
| description | Evidence for the light-by-light scattering process, γγ→γγ, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390μb−1 recorded by the CMS experiment at the LHC. Light-by-light scattering processes are selected in events with two photons exclusively produced, each with transverse energy ETγ>2GeV, pseudorapidity |ηγ|<2.4, diphoton invariant mass mγγ>5GeV, diphoton transverse momentum pTγγ<1GeV, and diphoton acoplanarity below 0.01. After all selection criteria are applied, 14 events are observed, compared to expectations of 9.0±0.9(theo) events for the signal and 4.0±1.2(stat) for the background processes. The excess observed in data relative to the background-only expectation corresponds to a significance of 3.7 standard deviations, and has properties consistent with those expected for the light-by-light scattering signal. The measured fiducial light-by-light scattering cross section, σfid(γγ→γγ)=120±46(stat)±28(syst)±12(theo)nb, is consistent with the standard model prediction. The mγγ distribution is used to set new exclusion limits on the production of pseudoscalar axion-like particles, via the (Figure presented.) process, in the mass range (Figure presented.). |
| first_indexed | 2024-09-23T11:37:41Z |
| format | Article |
| id | mit-1721.1/125327 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:37:41Z |
| publishDate | 2020 |
| publisher | Elsevier BV |
| record_format | dspace |
| spelling | mit-1721.1/1253272022-10-01T04:54:41Z Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV CMS Collaboration Massachusetts Institute of Technology. Department of Physics Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Massachusetts Institute of Technology. Laboratory for Nuclear Science Evidence for the light-by-light scattering process, γγ→γγ, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390μb−1 recorded by the CMS experiment at the LHC. Light-by-light scattering processes are selected in events with two photons exclusively produced, each with transverse energy ETγ>2GeV, pseudorapidity |ηγ|<2.4, diphoton invariant mass mγγ>5GeV, diphoton transverse momentum pTγγ<1GeV, and diphoton acoplanarity below 0.01. After all selection criteria are applied, 14 events are observed, compared to expectations of 9.0±0.9(theo) events for the signal and 4.0±1.2(stat) for the background processes. The excess observed in data relative to the background-only expectation corresponds to a significance of 3.7 standard deviations, and has properties consistent with those expected for the light-by-light scattering signal. The measured fiducial light-by-light scattering cross section, σfid(γγ→γγ)=120±46(stat)±28(syst)±12(theo)nb, is consistent with the standard model prediction. The mγγ distribution is used to set new exclusion limits on the production of pseudoscalar axion-like particles, via the (Figure presented.) process, in the mass range (Figure presented.). 2020-05-19T20:30:51Z 2020-05-19T20:30:51Z 2019-08 2019-07 2020-03-03T18:52:05Z Article http://purl.org/eprint/type/JournalArticle 0370-2693 https://hdl.handle.net/1721.1/125327 CMS Collaboration (Sirunyan, A.M. et al). "Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV." Physics Letters B 797 (October 2019): 134826 © 2019 The Author(s) en http://dx.doi.org/10.1016/J.PHYSLETB.2019.134826 Physics Letters B Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf Elsevier BV Elsevier |
| spellingShingle | CMS Collaboration Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV |
| title | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV |
| title_full | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV |
| title_fullStr | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV |
| title_full_unstemmed | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV |
| title_short | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at √ s NN = 5.02 TeV |
| title_sort | evidence for light by light scattering and searches for axion like particles in ultraperipheral pbpb collisions at √ s nn 5 02 tev |
| url | https://hdl.handle.net/1721.1/125327 |
| work_keys_str_mv | AT cmscollaboration evidenceforlightbylightscatteringandsearchesforaxionlikeparticlesinultraperipheralpbpbcollisionsatsnn502tev |