Next-to-leading-order time-like rho electromagnetic form factors in factorization

Ya-Lan Zhang; Si-Yu Wang; Chao Wang; Zhen-Jun Xiao; Ya Li

doi:10.1140/epjc/s10052-025-13979-4

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2025) 85: 312
https://doi.org/10.1140/epjc/s10052-025-13979-4

Regular Article - Theoretical Physics

Next-to-leading-order time-like rho electromagnetic form factors in $k_{T}$ ${k_{\textrm{T}}}$ factorization

Ya-Lan Zhang¹, Si-Yu Wang¹, Chao Wang¹, Zhen-Jun Xiao² and Ya Li³^a

¹ Faculty of Mathematics and Physics, Huaiyin Institute of Technology, 223200, Huaian, Jiangsu, People’s Republic of China
² Department of Physics and Institute of Theoretical Physics, Nanjing Normal University, 210023, Nanjing, Jiangsu, People’s Republic of China
³ Department of Physics, College of Sciences, Nanjing Agricultural University, 210095, Nanjing, Jiangsu, People’s Republic of China

^a liyakelly@163.com

Received: 9 January 2025
Accepted: 19 February 2025
Published online: 17 March 2025

Abstract

We calculate the time-like $ρ$ $\rho$ electromagnetic (EM) form factor in the $k_{T}$ $$k_T$$ factorization formalism by including the next-to-leading-order (NLO) corrections of the leading-twist and sub-leading twist contributions. It’s observed that the NLO correction to the magnitude of the LO leading-twist form factor is lower than $30 %$ $30\%$ at large invariant mass squared $Q^{2} > 30 {GeV}^{2}$ $Q^2 > 30 \,\text {GeV}^2$ . It is found that the $ρ$ $\rho$ meson EM form factor is dominated by twist-3 contribution instead of by twist-2 one because of the end-point enhancement. The theoretical predictions of the moduli of three helicity amplitudes and total cross section are analyzed at $\sqrt{s} = 10.58$ $\sqrt{s}=10.58$ GeV, which are consistent with measurements from BABAR Collaboration.

© The Author(s) 2025

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