XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects

Production of three isolated photons in the high-energy factorization approach

Not scheduled

20m

Virtual (Stony Brook, NY)

Recorded Flash Talk QCD with Heavy Flavors and Hadronic Final States Recorded Flash Talk

Speaker

Vladimir Saleev (Samara National Research University)

Description

We study production of three isolated photons at the energy of Large Hadron Collider [1] in the Parton Reggeization Approach [2,3], which is based on high-energy factorization, Lipatov effective theory [4] and new unintegrated PDFs, obtained in modified multi-Regge kinematics approximation for QCD scattering amplitudes [5]. It is shown that data from ATLAS Collaboration can be described after merging of LO and NLO in strong coupling constant contributions, which are going via partonic subprocesses, $Q+\overline{Q}\to 3\gamma$ and $Q+R\to 3\gamma +q$, where $R$ is the Reggeized gluon and $Q(\overline{Q})$ is the Reggeized quark (antiquark). We found that contribution of subprocess $Q+\overline{Q}\to 3\gamma +g$ is very small. We demonstrate also agreement between calculation with analytical amplitudes obtained via Feynman rules of the Lipatov effective theory and calculation using Monte-Carlo generator Katie [6].

[1] ATLAS Collaboration, Measurement of the production cross section of three isolated photons in pp-collisions at √s=8TeV using the ATLAS detector. Phys. Lett. B781 (2018) 55-76
[2] A.V. Karpishkov, M.A. Nefedov and V.A. Saleev, $B\overline{B}$ angular correlations at the LHC in parton Reggeization approach merged with higher-order matrix elements, Phys. Rev. D96 (2017) no.9, 096019.
[3] M. Nefedov and V. Saleev, Diphoton production at the Tevatron and the LHC in the NLO approximation of the parton Reggeization approach, Phys. Rev. D 92 (2015) no.9, 094033.
[4] L.N. Lipatov, Gauge invariant effective action for high-energy processes in QCD, Nucl. Phys. B452 (1995), 369-400
[5] M.A. Nefedov and V.A. Saleev, High-Energy Factorization for Drell-Yan process in $pp$ and $p\overline{p}$ collisions with new Unintegrated PDFs, Phys. Rev. D102 (2020), 114018
[6] A. van Hameren, KaTie : For parton-level event generation with $k_T$-dependent initial states,
Comput. Phys. Commun. 224 (2018), 371-380

Presentation materials

Saleev_3gamma.pdf