Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root 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 5.02 TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390 μb−1 recorded by the CMS experiment...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English English English |
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Elsevier B.V.
2019
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| Online Access: | http://irep.iium.edu.my/79918/ http://irep.iium.edu.my/79918/1/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_article.pdf http://irep.iium.edu.my/79918/2/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_scopus.pdf http://irep.iium.edu.my/79918/3/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_wos.pdf |
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| author | Sirunyan, A. M. Tumasyan, A. R. Adam, Wolfgang Ambrogi, Federico Asilar, Ece Md. Ali, Mohd. Adli |
| author_facet | Sirunyan, A. M. Tumasyan, A. R. Adam, Wolfgang Ambrogi, Federico Asilar, Ece Md. Ali, Mohd. Adli |
| author_sort | Sirunyan, A. M. |
| building | IIUM Repository |
| collection | Online Access |
| 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 is reported. The analysis is conducted using a
data sample corresponding to an integrated luminosity of 390 μb−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 Eγ
T > 2 GeV, pseudorapidity |ηγ | < 2.4, diphoton invariant mass
mγγ > 5 GeV, diphoton transverse momentum pγγ
T < 1 GeV, 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 γγ → a → γγ process, in the mass range
ma = 5–90 GeV. |
| first_indexed | 2025-11-14T17:47:44Z |
| format | Article |
| id | iium-79918 |
| institution | International Islamic University Malaysia |
| institution_category | Local University |
| language | English English English |
| last_indexed | 2025-11-14T17:47:44Z |
| publishDate | 2019 |
| publisher | Elsevier B.V. |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | iium-799182020-07-02T00:38:33Z http://irep.iium.edu.my/79918/ Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV Sirunyan, A. M. Tumasyan, A. R. Adam, Wolfgang Ambrogi, Federico Asilar, Ece Md. Ali, Mohd. Adli Q Science (General) QC Physics 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 is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390 μb−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 Eγ T > 2 GeV, pseudorapidity |ηγ | < 2.4, diphoton invariant mass mγγ > 5 GeV, diphoton transverse momentum pγγ T < 1 GeV, 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 γγ → a → γγ process, in the mass range ma = 5–90 GeV. Elsevier B.V. 2019-10-10 Article PeerReviewed application/pdf en http://irep.iium.edu.my/79918/1/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_article.pdf application/pdf en http://irep.iium.edu.my/79918/2/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_scopus.pdf application/pdf en http://irep.iium.edu.my/79918/3/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_wos.pdf Sirunyan, A. M. and Tumasyan, A. R. and Adam, Wolfgang and Ambrogi, Federico and Asilar, Ece and Md. Ali, Mohd. Adli (2019) Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 797. pp. 1-27. ISSN 0370-2693 https://reader.elsevier.com/reader/sd/pii/S0370269319305404?token=3BE7E0865E5FAF0C801C3561F5E29768DF48D367C91A54827330B124824D8E54D9C94FA8EB38960549CC143E75E45C66 10.1016/j.physletb.2019.134826 |
| spellingShingle | Q Science (General) QC Physics Sirunyan, A. M. Tumasyan, A. R. Adam, Wolfgang Ambrogi, Federico Asilar, Ece Md. Ali, Mohd. Adli Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV |
| title | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV |
| title_full | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV |
| title_fullStr | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root 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 root s(NN)=5.02 TeV |
| title_short | Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV |
| title_sort | evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral pbpb collisions at root s(nn)=5.02 tev |
| topic | Q Science (General) QC Physics |
| url | http://irep.iium.edu.my/79918/ http://irep.iium.edu.my/79918/ http://irep.iium.edu.my/79918/ http://irep.iium.edu.my/79918/1/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_article.pdf http://irep.iium.edu.my/79918/2/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_scopus.pdf http://irep.iium.edu.my/79918/3/79918_Evidence%20for%20light-by-light%20scattering%20and%20searches_wos.pdf |