Deeply virtual Compton scattering in the tensor-pomeron approach

Lebiedowicz, Piotr; Nachtmann, Otto; Szczurek, Antoni

doi:10.1016/j.physletb.2022.137497

Cited by 4 publications

(12 citation statements)

References 64 publications

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“…From Fig. 3 of [40] we see that the cross section σ Here W 2 has to be included in GeV. Our estimate gives a cross section falling roughly as 1/W 2 with a size of order 0.3 nb/GeV for W 2 = 40 GeV.…”

Section: Discussionmentioning

confidence: 72%

“…energy W 2 such that the t-channel exchanges dominate. In [40] we have studied this reaction in the tensor-pomeron-approach and we obtained a good description of the data for large c.m. energies and small Bjorken x values.…”

Section: A Photoproduction Contributionsmentioning

confidence: 99%

“…In the tensor pomeron model the pomeron-and reggeon-γγ vertices have two coupling functions; see (A5). By comparing the tensor-pomeron model and the experimental data on real Compton scattering from FNAL and on DVCS obtained by the H1 and ZEUS Collaborations at HERA we fixed in [40] these coupling functions. In our calculations we shall use the FIT 2 parametrization from [40] [see (A10) in Appendix A].…”

Section: A Photoproduction Contributionsmentioning

confidence: 99%

“…In addition to the γ − P-fusion process we shall also estimate the subleading γ − f 2R -fusion process. The Ansätze for the relevant vertices for real and virtual photons are discussed in [23,26,40]. The Q 2 and t dependencies of the coupling functions in the pomeron/reggeon-photon-photon vertices must be determined from a comparison to experimental data.…”

Section: Introductionmentioning

confidence: 99%

“…The Q 2 and t dependencies of the coupling functions in the pomeron/reggeon-photon-photon vertices must be determined from a comparison to experimental data. We shall use the parametrizations obtained in [40] from a comparison of the tensor-pomeron model to the elastic γp-scattering data from FNAL and to the deeply virtual Compton scattering (DVCS) data measured at HERA. The CEP of photons via the γ − P-fusion process can be expected to populate preferentially the midrapidity region as was discussed earlier in [41] within another approach.…”

Section: Introductionmentioning

confidence: 99%

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Central exclusive diffractive production of single photon in high-energy proton-proton collisions within the tensor-pomeron approach

Lebiedowicz¹,

Nachtmann²,

Szczurek³

2023

Preprint

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We discuss central-exclusive production (CEP) of photons via different fusion processes in the reaction pp → ppγ at high energies, available at RHIC and LHC, within the tensor-pomeron model. We consider two types of processes, the photoproduction contribution via the photonpomeron and photon-reggeon fusion reactions, and the purely diffractive contribution via the reggeon-pomeron and odderon-pomeron fusion reactions. We present predictions for the measurements of photons at midrapidity, |y| < 2.5, and at relatively low transverse momentum, 0.1 GeV < k ⊥ < 1 GeV. To check the main results of our study the measurement of the outgoing protons is not necessary. This is of relevance, e.g., for the present version of the ALICE detector at the LHC. Several differential distributions, for instance, in y, k ⊥ and ω, the rapidity, the absolute value of the transverse momentum, and the energy of the photon, respectively, are presented. We show that the photoproduction is an important process in the kinematic region specified above. There it gives a much larger cross section than diffractive bremsstrahlung. This is remarkable as the CEP cross section is of order α 3 em whereas the bremsstrahlung one is only of order α em . On the other hand, the soft-photon bremsstrahlung where the basic pp → pp reaction is due to strong interaction diffraction is more important than CEP in the forward rapidity range, |y| > 4, and/or at very low k ⊥ . We leave it as a challenge for the planned ALICE 3 experiment at the LHC to study these two contributions to soft photon production in pp collisions. This could shed new light on the so called "soft photon puzzle" in hadron-hadron collisions.

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Section: Discussionmentioning

confidence: 72%

Section: A Photoproduction Contributionsmentioning

confidence: 99%