Backward timelike Compton scattering to decipher the photon content of the nucleon

Autor: Bernard Pire, Kirill M. Semenov-Tian-Shansky, Alisa A. Shaikhutdinova, Lech Szymanowski
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: European Physical Journal C: Particles and Fields, Vol 82, Iss 7, Pp 1-18 (2022)
Druh dokumentu: article
ISSN: 1434-6052
DOI: 10.1140/epjc/s10052-022-10587-4
Popis: Abstract The exclusive photoproduction off nucleon of a large invariant mass lepton pair in the backward region specified by the small Mandelstam variable $$-u$$ - u is discussed in the framework of collinear QCD factorization. The amplitude is factorized in terms of photon-to-nucleon Transition Distribution Amplitudes (TDAs). These new non-perturbative objects, complementary to the “photon-inside-the-nucleon PDF”, lead to a tomographic picture of the nucleon’s photon content after Fourier transforming to the impact parameter space. This allows to address the question of where in the transverse plane the nucleon emits a photon. A simplistic model-estimate of photon-to-nucleon TDAs is used to estimate the magnitude of the corresponding cross sections. The background due to the electromagnetic Bethe–Heitler process is shown to be negligible in the kinematical regime of interest.
Databáze: Directory of Open Access Journals
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