arXiv subjects

Marat Siddikov

Publications and source records attributed to Marat Siddikov.

At least 19 recordsLinked to original sources

arXiv2026

Production of quarkonium pairs via the fragmentation mechanism

In this manuscript, we analyze the contribution of fragmentation mechanisms to the inclusive hadroproduction of heavy quarkonium pairs, taking into account both single- and double-hadron (dihadron) fragmentation channels. To estimate the contribution of the latter mechanism, we construct a microscopic perturbative model of the dihadron fragmentation function, which is valid in the limit of large invariant masses of the heavy quarkonium pair. Using the Color Glass Condensate framework to evaluate the $Q\bar{Q}$ production amplitude, we find that in LHC kinematics, the single fragmentation of heavy quarks into quarkonium is only a minor correction, whereas dihadron fragmentation can provide a sizable contribution, on par with the contributions of single- and double-parton scattering.

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arXiv2026

Constraints on the odderon amplitude in the CGC framework

In this manuscript we analyzed the elastic $pp$ and $p\bar{p}$ cross-section in the Color Glass Condensate framework, treating them as a dilute-dense system, and derived the phenomenological constraints (upper bounds) on the odderon-mediated part of the dipole scattering amplitude $\mathcal{O}(Y,\,\boldsymbol{r},\,\boldsymbol{b})$. For our analysis we used the experimental data available from TOTEM-D0 and ISR collaborations and construct an observable defined as a combination of the cross-sections which allows us to suppress possible uncertainties associated with charge-parity even part of the amplitude. We analyzed two phenomenological parametrizations of odderons and demonstrated that after minor adjustments to the global normalization, they can describe the experimental data reasonably well, although due to large experimental uncertainties the odderon amplitude remains loosely constrained. Our results indicate that existing data provide limited sensitivity to the odderon and emphasize the need for improved precision and complementary observables.

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arXiv2025

Exclusive photoproduction of $χ_{c}γ$ pairs

In this manuscript we study the exclusive photoproduction of $χ_{c}γ$ pairs in the collinear factorization framework. We found the coefficient functions for all possible spins and helicity projections of $χ_{c}$ mesons and final-state photons in the leading order in the strong coupling $α_{s}$. In our analysis we focused on the contribution of the leading twist chiral even GPDs, and found that for all spin states of $χ_{c}$ the suggested process is determined by the behavior of the gluon GPDs $H_{g}$ in the ERBL kinematics. Using the phenomenological parametrizations of the GPDs from the literature, we estimated numerically the photoproduction cross-sections and the expected counting rates in the kinematics of middle-energy photoproduction experiments that could be realized at the Electron-Ion Collider. We observed that the $χ_{c1}$, $χ_{c2}$ mesons are produced predominantly with the same polarization as the incoming photon, and the expected counting rates of $χ_{c1}γ$ and $χ_{c2}γ$ pairs are sufficiently large for their experimental study. We also analyzed the angular distribution of $χ_{c}$ mesons in electroproduction experiments, and noticed that for some helicity components there are sizable angular asymmetries, which can be used as complementary observables for experimental study. Finally, we estimated the role of this process as a potential background to $χ_{c}$ photoproduction, which has been recently suggested as a tool for studies of odderons. We found that the contribution of $χ_{c}γ$ (with undetected photon) is on par with expected contributions of odderons and Primakoff mechanisms in the kinematics of small momentum transfer $|t|\lesssim1$ GeV$^{2}$, but becomes negligible at larger $|t|$.

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arXiv2024

Inclusive photoproduction of charmonia-bottomonia pairs

In this preprint we analyze the inclusive photoproduction of heavy charmonia-bottomonia pairs in the Color Glass Condensate framework and demonstrate that the cross-section of the process is sensitive to dipole and quadrupole forward scattering amplitudes (2- and 4-point correlators of Wilson lines). Using the phenomenological parametrizations of these amplitudes, we estimate numerically the production cross-sections in the kinematics of the forthcoming Electron Ion Collider and the ultraperipheral collisions at LHC. We found that the contribution controlled by the quadrupole amplitude is dominant, and for this reason, the suggested channel can be used as a gateway for studies of this nonperturbative object.

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arXiv2023

Exclusive photoproduction of open heavy flavor meson pairs

In this paper we argue that exclusive photoproduction of $D$-meson pairs can be used as a complementary tool for studies of the generalized parton distributions of the target. We analyzed the photoproduction of the pseudoscalar-vector pairs with net zero electric charge (e.g. $D^{\pm}D^{*\mp}$, $D^{0}\overline{D}^{*0}$, $D_{s}^{+}D_{s}^{*-}$) and found that it allows to study the chiral even GPDs in ERBL region. A unique feature of the suggested process is contribution of the gluon and just one of the light quark flavors. We made numerical estimates in the kinematics of the future Electron Ion Collider and found that numerically the production cross-section is reasonably large for experimental studies, thus justifying its viability as a complementary probe of GPDs.

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arXiv2023

Exclusive photoproduction of $D$-meson pairs with large invariant mass

In this paper we analyze the exclusive photoproduction of the $D$-meson pairs with large invariant mass. We perform evaluations in the collinear factorization framework and in the leading order of the strong coupling $α_{s}$, expressing the cross-section in terms of generalized parton distributions (GPDs) of different parton flavors in the proton. We focus on the photoproduction of the pseudoscalar-vector pairs, like e.g. $D^{\pm}D^{*\mp}$, $D^{0}\overline{D}^{*0}$, $D_{s}^{+}D_{s}^{*-}$, which gets the dominant contribution from the chiral even GPDs of the target, and estimate the cross-section in the kinematics of the future Electron Ion Collider (EIC). In all channels the amplitude of the process obtains comparable contributions from gluons and only one of the light quark flavors. This finding signals that the process potentially could be used to single out the contributions of the individual chiral even GPDs of light flavors. We found that the process is mostly sensitive to the behavior of GPDs in the so-called Efremov-Radyushkin-Brodsky-Lepage (ERBL) region. Numerically, the cross-section of the process is sufficiently large for experimental studies and thus can be used as a complementary probe for studies of the partons GPDs.

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arXiv2023

Quarkonia pair production as a tool for study of gluon GPDs

In these proceedings we present our results on the exclusive photoproduction of $J/ψ\,η_{c}$ pairs in the collinear factorization framework. We argue that the process might be used as a complementary channel for studying the generalized parton distributions (GPDs) of gluons. We provide numerical estimates for the cross-section in the kinematics of the future Electron Ion Collider.

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arXiv2023

Exclusive production of quarkonia pairs in collinear factorization framework

In this paper we analyze the exclusive photoproduction of heavy quarkonia pairs in the collinear factorization framework. We evaluate the amplitude of the process for $J/ψ\,-η_{c}$ quarkonia pair in the leading order of the strong coupling $α_{s},$ and express it in terms of generalized parton distributions (GPDs) of gluons in the proton. We made numerical estimates in the kinematics of the Electron Ion Collider, and found that in the photoproduction regime, when the virtuality of the photon is much smaller than the quarkonia mass, the cross-section of the process is sufficiently large for experimental studies. We demonstrate that the study of this channel can complement existing studies of gluon GPDs from other channels.

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arXiv2022

Exclusive photoproduction of $B_{c}^{\pm}$ and bottomonia pairs

In this paper we analyze the photoproduction of heavy quarkonia pairs which include $b$-quarks, such as $B_{c}^{+}B_{c}^{-}$-mesons or charmonium-bottomonium pairs. Compared to charmonia pair production, these channels get contributions only from some subsets of diagrams, and thus allow for a better theoretical understanding of different production mechanisms. In contrast to the production of hidden-flavor quarkonia, for the production of $B_{c}$-meson pairs there are no restrictions on internal quantum numbers in the suggested mechanisms. Using the Color Glass Condensate approach, we estimated numerically the production cross-sections in the kinematics of the forthcoming Electron-Proton collider and in the kinematics of ultraperipheral collisions at LHC. We found that the production of $J/ψ\,η_{c}$ and $B_{c}^{+}B_{c}^{-}$ meson pairs are the most promising channels for studies of quarkonia pair production.

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arXiv2022

Exclusive photoproduction of heavy quarkonia pairs

In this paper we study the high energy exclusive photoproduction of heavy quarkonia pairs in the leading order of the strong coupling constant $α_{s}$. In the suggested mechanism the quarkonia pairs are produced with opposite charge parities, and have predominantly oppositely directed transverse momenta. Using the Color Glass Condensate approach, we estimated numerically the production cross-sections in the kinematics of the forthcoming electron-proton colliders, as well as proton-ion colliders in ultraperipheral collisions. We found that the cross-sections are within the reach of planned experiments and can be measured with reasonable precision. The suggested mechanism has significantly larger cross-section than that of the same $C$-parity quarkonia pair production.

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arXiv2021

Electroproduction of $D$- and $B$-mesons in high-multiplicity $ep$ collisions

In this paper we study the electroproduction of open heavy flavor $D$- and $B$-mesons in the kinematics of future $ep$ colliders, such as the Electron Ion Collider (EIC), the Large Hadron electron Collider (LHeC) and the Future Circular Collider (FCC-he). We study in detail the dependence of the cross-sections on multiplicity of co-produced hadrons, in view of its possible sensitivity to contributions from multipomeron contributions, and discuss different observables which might be used for its study. According to our theoretical expectations, in $ep$ collisions the multipomeron contributions are small in the EIC kinematics, although they might be sizable at LHeC and FCC-he. We also provide theoretical predictions for the production cross-sections of heavy mesons in the kinematics of all the above-mentioned $ep$ colliders.

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arXiv2021

Strangeness production in high-multiplicity events

In this paper we analyze in detail the production of strangeness in proton-proton collisions in the kinematics of large transverse momenta $p_{T}$ of produced hadrons. Using the color dipole framework, we estimated the production cross-sections for kaons, and demonstrated that the shapes of the $p_{T}$-dependence are in agreement with available experimental data. We also analyzed the self-normalized yields of strange hadrons as a function of multiplicity of co-produced hadrons, and found that the predictions are in agreement with the faster-than-linear growth seen in experimental data. Our description is largely parameter-free and complements our previous studies dedicated to the explanation of multiplicity enhancement of quarkonia, as well as $D$- and $B$-mesons.

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arXiv2020

Multiplicity dependence of $χ_{c}$ and $χ_{b}$ meson production

In this paper we analyze in detail the production of the $χ_{c}$ and $χ_{b}$ mesons in $pp$ collisions. Using the color dipole framework, we estimated the cross-sections in the kinematics of ongoing and forthcoming experiments, and found that our estimates are in reasonable agreement with currently available experimental data. We also analyzed the dependence on multiplicity of co-produced hadrons and found that it is significantly milder than that of $S$-wave quarkonia. We expect that the experimental confirmation of this result could constitute an important test of our understanding of multiplicity enhancement mechanisms in the production of different quarkonia states.

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arXiv2020

Single diffractive production of open heavy flavor mesons

In this paper we discuss the single diffractive production of open heavy flavor mesons and non-prompt charmonia in $pp$ collisions. Using the color dipole approach, we found that the single diffractive production constitutes 0.5-2 per cent of the inclusive production of the same mesons. In Tevatron kinematics our theoretical results are in reasonable agreement with the available experimental data. In LHC kinematics we found that the cross-section is sufficiently large and could be accessed experimentally. We also analyzed the dependence on multiplicity of co-produced hadrons and found that it is significantly slower than that of inclusive production of the same heavy mesons.

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arXiv2020

Production mechanisms of open-heavy flavor mesons

In this paper we discuss different mechanisms of open-heavy flavor meson production. Using the color dipole framework, we analyze in detail the contributions of the conventional two-pomeron fusion and the three-pomeron fusion correction. In a parameter-free way we found that the three-pomeron mechanism is significant for $D$-meson production in the small-$p_{T}$ kinematics, although it is less important at large $p_{T}$, as well as for $B$-mesons. The inclusion of the three-pomeron mechanism significantly improves the agreement of theoretical predictions with experimental data in the small-$p_{T}$ kinematics. We also consider the non-prompt charmonia production, and demonstrate that the theoretical results are in reasonable agreement with experimental data. Finally, we compare the theoretical predictions for the dependence on multiplicity of co-produced hadrons to experimental data recently measured by the ALICE collaboration. We found that, contrary to naive expectations, the contribution of the three-pomeron mechanism has only a mild effect on the self-normalized observables in the range of multiplicities studied at ALICE, and for this reason the two-pomeron fusion mechanism can describe reasonably well the experimentally observed multiplicity dependence.

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arXiv2019

Multiplicity distributions as probes of quarkonia production mechanisms

In this paper we demonstrate that the vigorously growing multiplicity distributions measured by STAR and ALICE present a strong evidence in favor of multigluon fusion mechanisms of the quarkonia production in CGC approach. We analyze the contribution of 3-gluon fusion mechanism and demonstrate that it gives a sizeable contribution to quarkonia yields, as well as predicts correctly the multiplicity distributions for $J/ψ$ at RHIC and LHC. We also make predictions for other quarkonia states, such as $ψ(2S)$ and $Υ(1S)$, and find that the multiplicity dependence of these states should be comparable to similar dependence for $J/ψ$. Finally, we discuss an experimental setup in which very strong multiplicity dependence could be observed. This observation would be a strong evidence in favor of CGC approach.

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arXiv2019

Generalized Parton Distributions from charged current meson production

In this paper we prove that the simultaneous study of both $ρ$- and $π$-meson production by charged currents in Bjorken kinematics allows for a very clean extraction of the leading twist Generalized Parton Distributions of the target, with inherent control of the contribution of higher-twist corrections. Also, it might provide target-independent constraints on the distribution amplitudes of the produced mesons. We expect that such processes might be studied either in neutrino-induced or in electron-induced processes. According to our numerical estimates, the cross-sections of these processes are within the reach of JLab and EIC experiments.

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arXiv2018

$J/ψ$ production in hadron scattering: three-pomeron contribution

In this paper we discuss the inclusive $J/ψ$ production in proton-proton collisions from fusion of three pomerons. We demonstrate that this mechanism gets dominant contribution from the region which can be theoretically described by CGC/Saturation approach. Numerically, it gives a substantial contribution to the $J/ψ$ production, and is able to describe the experimentally observable shapes of the rapidity, momenta and multiplicity distributions. The latter fact provides a natural explanation of the experimentally observed enhancement of multiplicity distribution in $J/ψ$ production.

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