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arXiv · 2403.17039

Exclusive Bremsstrahlung of One and Two Photons in Proton-Proton Collisions

Piotr Lebiedowicz·Antoni Szczurek·Otto Nachtmann
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Abstract

We discuss the diffractive bremsstrahlung of a single photon in the $pp \to pp γ$ reaction at LHC energies and at forward photon rapidities. We compare the results for our standard approach, based on QFT and the tensor-Pomeron model, with two versions of soft-photon approximations, SPA1 and SPA2, where the radiative amplitudes contain only the leading terms proportional to $ω^{-1}$ (the inverse of the photon energy). SPA1, which does not have the correct energy-momentum relations, performs surprisingly well in the kinematic range considered, namely at very forward photon rapidities and $0.02 < ξ_{1,2} < 0.1$, the relative energy loss of the protons, corresponding to small values of the photon transverse momentum. Azimuthal correlations between outgoing particles are presented. We discuss also the role of the $p p \to p p π^0$ background for single photon production. We discuss also the possibility of a measurement of the $pp \to pp γγ$ reaction. Our predictions can be verified by ATLAS-LHCf combined experiments.

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Piotr Lebiedowicz, Antoni Szczurek, Otto Nachtmann. 2024-03-25. Exclusive Bremsstrahlung of One and Two Photons in Proton-Proton Collisions. https://arxiv.org/abs/2403.17039

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