First Measurement of the $Z\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ Angular Coefficients in the Forward Region of $pp$ Collisions at $\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}$

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First Measurement of the $Z \to μ^{+} μ^{-}$ Angular Coefficients in the Forward Region of $p p$ Collisions at $\sqrt{s} = 13 TeV$

R. Aaij et al. (LHCb Collaboration)

Phys. Rev. Lett. 129, 091801 – Published 24 August 2022

Abstract

The first study of the angular distribution of $μ^{+} μ^{-}$ pairs produced in the forward rapidity region via the Drell-Yan reaction $p p \to γ^{*} / Z + X \to ℓ^{+} ℓ^{-} + X$ is presented, using data collected with the LHCb detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of $5.1 {fb}^{- 1}$ . The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the $Z$ -boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton.

Received 7 March 2022
Accepted 13 July 2022

DOI:https://doi.org/10.1103/PhysRevLett.129.091801

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