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Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector

Aad, G. ; Åkesson, T.P.A. LU orcid ; Corrigan, E.E. LU ; Doglioni, C. LU ; Ekman, P.A. LU ; Geisen, J. LU orcid ; Hedberg, V. LU ; Jarlskog, G. LU ; Konya, B. LU and Lytken, E. LU orcid , et al. (2023) In Physical Review Letters 131(15).
Abstract
This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44  nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To... (More)
This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44  nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To measure a_{τ}, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a_{τ} is -0.057 (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Magnetic moments, Anomalous magnetic moments, ATLAS detectors, ATLAS experiment, Integrated luminosity, Lead collisions, Lepton pairs, Moment formula, Pair production, Particle tracks, Standard deviation, Charged particles
in
Physical Review Letters
volume
131
issue
15
article number
151802
publisher
American Physical Society
external identifiers
  • pmid:37897746
  • scopus:85185370802
ISSN
1079-7114
DOI
10.1103/PhysRevLett.131.151802
language
English
LU publication?
yes
id
ce1cb9a1-2283-4a9b-abac-c2aec843c767
date added to LUP
2024-01-16 10:16:19
date last changed
2024-03-06 11:30:01
@article{ce1cb9a1-2283-4a9b-abac-c2aec843c767,
  abstract     = {{This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44  nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To measure a_{τ}, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a_{τ} is -0.057}},
  author       = {{Aad, G. and Åkesson, T.P.A. and Corrigan, E.E. and Doglioni, C. and Ekman, P.A. and Geisen, J. and Hedberg, V. and Jarlskog, G. and Konya, B. and Lytken, E. and Mankinen, K.H. and Mjörnmark, J.U. and Mullier, G.A. and Poettgen, R. and Simpson, N.D. and Skorda, E. and Smirnova, O. and Zwalinski, L.}},
  issn         = {{1079-7114}},
  keywords     = {{Magnetic moments; Anomalous magnetic moments; ATLAS detectors; ATLAS experiment; Integrated luminosity; Lead collisions; Lepton pairs; Moment formula; Pair production; Particle tracks; Standard deviation; Charged particles}},
  language     = {{eng}},
  number       = {{15}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review Letters}},
  title        = {{Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector}},
  url          = {{http://dx.doi.org/10.1103/PhysRevLett.131.151802}},
  doi          = {{10.1103/PhysRevLett.131.151802}},
  volume       = {{131}},
  year         = {{2023}},
}