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Observation of light-by-light scattering and search for axion-like particles with the CMS experiment
Evidence for the light-by-light scattering process, γγ → γγ, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV was reported by the CMS Collaboration at the LHC based on a data sample corresponding to an integrated luminosity of 390 µb−1. Light-by-light scatte...
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Lenguaje: | eng |
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SISSA
2021
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Acceso en línea: | https://dx.doi.org/10.22323/1.390.0296 http://cds.cern.ch/record/2790053 |
_version_ | 1780972218574962688 |
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author | Tamási-Böttger, Rebeka Lilla |
author_facet | Tamási-Böttger, Rebeka Lilla |
author_sort | Tamási-Böttger, Rebeka Lilla |
collection | CERN |
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 5.02 TeV was reported by the CMS Collaboration at the LHC based on a data sample corresponding to an integrated luminosity of 390 µb−1. Light-by-light scattering processes were selected from the events in which only two photons are exclusively produced, each with transverse energy E_T^γ > 2 GeV, pseudorapidity | η^(γ )| < 2.4, diphoton invariant mass m^γγ > 5 GeV, diphoton transverse momentum p_T^γγ < 1 GeV, and diphoton acoplanarity below A < 0.01. 14 events were observed after all selection criteria, 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, σ_fid(γγ → γγ) = 120 ± 46 (stat) ± 28 (syst) ± 12 (theo) nb, is consistent with the Standard Model prediction. The m^γγ distribution was used to set constraints on the production of pseudoscalar axion-like particles via the γγ → a → γγ process in the mass range m_a = 5–90 GeV |
id | cern-2790053 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2021 |
publisher | SISSA |
record_format | invenio |
spelling | cern-27900532022-11-17T14:30:02Zdoi:10.22323/1.390.0296http://cds.cern.ch/record/2790053engTamási-Böttger, Rebeka LillaObservation of light-by-light scattering and search for axion-like particles with the CMS experimentParticle Physics - ExperimentEvidence for the light-by-light scattering process, γγ → γγ, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV was reported by the CMS Collaboration at the LHC based on a data sample corresponding to an integrated luminosity of 390 µb−1. Light-by-light scattering processes were selected from the events in which only two photons are exclusively produced, each with transverse energy E_T^γ > 2 GeV, pseudorapidity | η^(γ )| < 2.4, diphoton invariant mass m^γγ > 5 GeV, diphoton transverse momentum p_T^γγ < 1 GeV, and diphoton acoplanarity below A < 0.01. 14 events were observed after all selection criteria, 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, σ_fid(γγ → γγ) = 120 ± 46 (stat) ± 28 (syst) ± 12 (theo) nb, is consistent with the Standard Model prediction. The m^γγ distribution was used to set constraints on the production of pseudoscalar axion-like particles via the γγ → a → γγ process in the mass range m_a = 5–90 GeVSISSAoai:cds.cern.ch:27900532021 |
spellingShingle | Particle Physics - Experiment Tamási-Böttger, Rebeka Lilla Observation of light-by-light scattering and search for axion-like particles with the CMS experiment |
title | Observation of light-by-light scattering and search for axion-like particles with the CMS experiment |
title_full | Observation of light-by-light scattering and search for axion-like particles with the CMS experiment |
title_fullStr | Observation of light-by-light scattering and search for axion-like particles with the CMS experiment |
title_full_unstemmed | Observation of light-by-light scattering and search for axion-like particles with the CMS experiment |
title_short | Observation of light-by-light scattering and search for axion-like particles with the CMS experiment |
title_sort | observation of light-by-light scattering and search for axion-like particles with the cms experiment |
topic | Particle Physics - Experiment |
url | https://dx.doi.org/10.22323/1.390.0296 http://cds.cern.ch/record/2790053 |
work_keys_str_mv | AT tamasibottgerrebekalilla observationoflightbylightscatteringandsearchforaxionlikeparticleswiththecmsexperiment |