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

ATLAS Publications; T.M. Carter; R.Y. Gonzalez Andana; A. Hasib; M.P. Heath; S. Palazzo; V.A. Parrish; E.P. Takeva; N. Themistokleous; E.M. Villhauer; E. Zaid

doi:10.1103/PhysRevLett.131.151802

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

ATLAS Publications
, T.M. Carter
, R.Y. Gonzalez Andana
, A. Hasib
, M.P. Heath
, S. Palazzo
, V.A. Parrish
, E.P. Takeva
, N. Themistokleous
, E.M. Villhauer
, E. Zaid

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

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 aτ. The dataset corresponds to an integrated luminosity of 1.44 nb−1 of LHC Pb+Pb collisions at √sNN=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 μττ=1.03+0.06−0.05 assuming the standard model value for aτ. To measure aτ, 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 aτ is −0.057<aτ<0.024.

Original language	English
Article number	151802
Pages (from-to)	1-23
Number of pages	23
Journal	Physical Review Letters
Volume	131
Issue number	15
DOIs	https://doi.org/10.1103/PhysRevLett.131.151802
Publication status	Published - 12 Oct 2023

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10.1103/PhysRevLett.131.151802Licence: Creative Commons: Attribution (CC-BY)

http://arxiv.org/abs/2204.13478

Upgrade of the ATLAS detector at the LHC (2023-26)
Clark, P. (Principal Investigator)
1/04/23 → 31/03/26
Project: Research
Experimental Particle Physics at the University of Edinburgh
Leonidopoulos, C. (Principal Investigator)
1/04/23 → 30/09/25
Project: Research
Experimental Particle Physics at the University of Edinburgh
Leonidopoulos, C. (Principal Investigator)
1/10/22 → 30/09/25
Project: Research

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ATLAS Publications, Carter, T. M., Gonzalez Andana, R. Y., Hasib, A., Heath, M. P., Palazzo, S., Parrish, V. A., Takeva, E. P., Themistokleous, N., Villhauer, E. M., & Zaid, E. (2023). Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector. Physical Review Letters, 131(15), 1-23. Article 151802. https://doi.org/10.1103/PhysRevLett.131.151802

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

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 aτ. The dataset corresponds to an integrated luminosity of 1.44 nb−1 of LHC Pb+Pb collisions at √sNN=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 μττ=1.03+0.06−0.05 assuming the standard model value for aτ. To measure aτ, 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 aτ is −0.057",

author = "\{ATLAS Publications\} and Clark, \{Philip James\} and Sinead Farrington and Yanyan Gao and Christos Leonidopoulos and Martin, \{Victoria Jane\} and Liza Mijovic and Benjamin Wynne and Sara Alderweireldt and T.M. Carter and \{Gonzalez Andana\}, R.Y. and A. Hasib and M.P. Heath and S. Palazzo and V.A. Parrish and E.P. Takeva and N. Themistokleous and E.M. Villhauer and E. Zaid",

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ATLAS Publications, Carter, TM, Gonzalez Andana, RY, Hasib, A, Heath, MP, Palazzo, S, Parrish, VA, Takeva, EP, Themistokleous, N, Villhauer, EM & Zaid, E 2023, 'Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector', Physical Review Letters, vol. 131, no. 15, 151802, pp. 1-23. https://doi.org/10.1103/PhysRevLett.131.151802

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AU - ATLAS Publications

AU - Clark, Philip James

AU - Farrington, Sinead

AU - Gao, Yanyan

AU - Leonidopoulos, Christos

AU - Martin, Victoria Jane

AU - Mijovic, Liza

AU - Wynne, Benjamin

AU - Alderweireldt, Sara

AU - Carter, T.M.

AU - Gonzalez Andana, R.Y.

AU - Hasib, A.

AU - Heath, M.P.

AU - Palazzo, S.

AU - Parrish, V.A.

AU - Takeva, E.P.

AU - Themistokleous, N.

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AU - Zaid, E.

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N2 - 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 aτ. The dataset corresponds to an integrated luminosity of 1.44 nb−1 of LHC Pb+Pb collisions at √sNN=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 μττ=1.03+0.06−0.05 assuming the standard model value for aτ. To measure aτ, 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 aτ is −0.057

AB - 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 aτ. The dataset corresponds to an integrated luminosity of 1.44 nb−1 of LHC Pb+Pb collisions at √sNN=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 μττ=1.03+0.06−0.05 assuming the standard model value for aτ. To measure aτ, 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 aτ is −0.057

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DO - 10.1103/PhysRevLett.131.151802

M3 - Article

SN - 0031-9007

VL - 131

SP - 1

EP - 23

JO - Physical Review Letters

JF - Physical Review Letters

IS - 15

M1 - 151802

ER -

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

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Projects

Upgrade of the ATLAS detector at the LHC (2023-26)

Experimental Particle Physics at the University of Edinburgh

Experimental Particle Physics at the University of Edinburgh

Cite this