arXiv subjects

M. A. Nefedov

Publications and source records attributed to M. A. Nefedov.

9 recordsLinked to original sources

arXiv2025

New evidence for the rapidity evolution in Mueller-Navelet dijet production: BFKL, Sudakov, and RG-invariance

We study the effects of matching of the high-energy resummation based on the BFKL equation with initial state radiation effects, taken into account within the framework of high-energy factorization, in the production of Mueller-Navelet dijets. We use RG-invariant solution of the NLO BFKL equation built out of eigenfunctions perturbatively constructed up to NLO to avoid the need for a special renormalization scale setting. We demonstrate that various data sets from the FNAL Tevatron and CERN LHC can be described in this way and both, the NLL BFKL resummation and initial state radiation effects of the high-energy factorization, are crucial for the uniform description of the data across all values of the rapidity difference between the jets. The behavior of angular distributions and ratios of angular coefficients with increasing rapidity separation between the jets provides clear evidence for the BFKL dynamics at the FNAL Tevatron and CERN LHC.

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arXiv2016

Dijet azimuthal decorrelations at the LHC in the parton Reggeization approach

We study inclusive dijet azimuthal decorrelations in proton-proton collisions at the CERN LHC invoking the hypothesis of parton Reggeization in t-channel exchanges at high energies. In the parton Reggeization approach, the main contribution to the azimuthal angle difference between the two most energetic jets is due to the Reggeon-Reggeon-Particle-Particle scattering, when the fusion of two Reggeized gluons into a pair of Yang-Mills gluons dominates. Using a high-energy factorization scheme with the Kimber-Martin-Ryskin unintegrated parton distribution functions and the Fadin-Lipatov effective vertices we obtain good agreement of our calculations with recent measurements by the ATLAS and CMS Collaborations at the CERN LHC.

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arXiv2016

$ψ(2S)$ and $Υ(3S)$ hadroproduction in the parton Reggeization approach: Yield, polarization, and the role of fragmentation

The hadroproduction of the radially excited heavy-quarkonium states $ψ(2S)$ and $Υ(3S)$ at high energies is studied in the parton reggeization approach and the factorization formalism of nonrelativistic QCD at lowest order in the strong-coupling constant $α_s$ and the relative heavy-quark velocity $v$. A satisfactory description of the $ψ(2S)$ transverse-momentum ($p_T$) distributions measured by ATLAS, CMS, and LHCb at center-of-mass energy $\sqrt{S}=7$ TeV is obtained using the color-octet long-distance matrix elements (LDMEs) extracted from CDF data at $\sqrt{S}=1.96$ TeV. The importance of the fragmentation mechanism and the scale evolution of the fragmentation functions in the upper $p_T$ range, beyond 30 GeV, is demonstrated. The $Υ(3S)$ $p_T$ distributions measured by CDF at $\sqrt{S}=1.8$ TeV and by LHCb at $\sqrt{S}=7$ TeV and forward rapidities are well described using LDMEs fitted to ATLAS data at $\sqrt{S}=7$ TeV. Comparisons of polarization measurements by CDF and CMS at large $p_T$ values with our predictions consolidate the familiar problem in the $ψ(2S)$ case, but yield reasonable agreement in the $Υ(3S)$ case.

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arXiv2016

DbarD and DD pair production at the LHCb in the parton Reggeization approach

We study the inclusive DbarD and DD pair production in proton-proton collisions at the LHC at lead- ing order of the parton Reggeization approach endowed with universal scale-depended fragmen- tation functions for c-quark to D-meson and for gluon to D-meson transitions. We have described DbarD and DD distributions in azimuthal angle, as well as transverse momentum, rapidity distance, and invariant mass measured in the region of large rapidity 2 < y < 4 by the LHCb Collabora- tion at the LHC without free parameters. We have used Reggeized amplitudes for the processes RR - gg and RR - c barc which are obtained accordingly to Feynman rules of the L.N. Lipatov effective theory of Reggeized partons, and Kimber-Martin-Ryskin model for unintegrated gluon distribution function in a proton with Martin-Stirling-Thorne-Watt collinear parton distributions as inputs.

hep-ph↗

arXiv2016

Prompt-photon plus jet photoproduction with ZEUS at DESY HERA in the parton Reggeization approach

We study the photoproduction of isolated prompt photons associated with hadron jets in the framework of the parton Reggeization approach. The main improvements with respect to previous studies in the k_T-factorization framework include the application of the Reggeized-quark formalism, the generation of exactly gauge-invariant amplitudes with off-shell initial-state quarks, and the exact treatment of the gamma+R -> gamma+g box contribution with off-shell initial-state gluons. In this proceedings, the new data set, published recently by ZEUS collaboration is analyzed, were the distributions in photon and jet rapidity, transverse energy, azimuthal angle between photon and jet and proton momentum fraction are presented for different values of measured photon momentum fraction x_gamma <0.7, 0.8 and x_gamma>0.8$. The good agreement of measured distributions with our predictions is observed for the direct-dominating part of the data set. The comparison with the previous calculations in k_T-factorization, role of nonfactorizable higher-order and hadronization corrections is discussed.

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arXiv2014

Prompt-photon plus jet associated photoproduction at HERA in the parton Reggeization approach

We study the photoproduction of isolated prompt photons associated with hadron jets in the framework of the parton Reggeization approach. The cross section distributions in the transverse energies and pseudorapidities of the prompt photon and the jet as well as the azimuthal decorrelation variables measured by the H1 and ZEUS collaborations at DESY HERA are nicely described by our predictions. The main improvements with respect to previous studies in the $k_T$-factorization framework include the application of the Reggeized-quark formalism, the generation of exactly gauge-invariant amplitudes with off-shell initial-state quarks, and the exact treatment of the $γR\to γg$ box contribution with off-shell initial-state gluons.

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arXiv2013

Heavy quarkonium production in the Regge limit of QCD: from Tevatron to LHC

Heavy quarkonium production in the framework of the non-relativistic quantum chromodynamics and leading order of the parton Reggeization approach at the Tevatron and LHC is discussed. In this note, we compare our predictions for the bottomonium production at the LHC due to the color-singlet approximation of the non-relativistic quantum chromodynamics with CMS and LHCb data. It is found, that in the production of Upsilon(1S) states, the color-singlet mechanism is dominating, whereas to describe the data for the inclusive Upsilon(2S) and Upsilon(3S) production, the color- octet contributions should be taken into account.

hep-ph↗

arXiv2012

Drell-Yan lepton pair production at high energies in the Parton Reggeization Approach

According to extensive theoretical studies of the high energy limit of QCD, inelastic interactions are dominated by the multi-Regge final states. The appropriate gauge-invariant objects, which simultaneously incorporate the transverse momentum degrees of freedom, are Reggeized gluons, quarks and antiquarks. In the present communication we extend parton Reggeization approach to Drell-Yan production of massive lepton pairs. The basic ingredient is a process of Reggeized quark-antiquark annihilation, which is described by the Reggeon-Reggeon-photon effective vertex. We calculate transverse-momentum and invariant-mass distributions of Drell-Yan lepton pairs measured at the CERN SPS, FNAL Tevatron and CERN LHC in the different ranges of energy and rapidity. We focus on angular distributions of Drell-Yan leptons in different kinematical ranges. The obtained results are compared with the existing data and a good agreement is found. The predictions for future experiments for Drell-Yan lepton pair production at the CERN LHC have been made.

hep-ph↗

arXiv2012

Prompt J/psi production in the Regge limit of QCD: From Tevatron to LHC

We study prompt J/psi-meson hadroproduction invoking the hypothesis of gluon Reggeization in t-channel exchanges at high energy and the factorization formalism of nonrelativistic quantum chromodynamics at the leading order in the strong-coupling constant alpha_s and the relative velocity of quarks v. The transverse-momentum distribution of direct and prompt J/psi-meson production measured at the Fermilab Tevatron fitted to obtain the nonperturbative long-distance matrix elements, which are used to predict prompt J/psi production spectra at the CERN LHC. At the numerical calculation, we adopt the Kimber-Martin-Ryskin and Blumlein prescriptions to derive unintegrated gluon distribution function of the proton from their collinear counterpart, for which we use the Martin-Roberts-Stirling-Thorne set. Without adjusting any free parameters, we find good agreement with measurements by the ATLAS, CMS and LHCb Collaborations at the LHC at the hadronic c.m. energy sqrt S=7 TeV.

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