arXiv subjects

E. Ya. Paryev

Publications and source records attributed to E. Ya. Paryev.

At least 19 recordsLinked to original sources

arXiv2026

On the nature of fully-charmed four-quark exotic state $X(6900)$ from its photoproduction off nuclei

The possibility to study the nature of fully-charmed tetraquark state $X(6900)$ from its inclusive photoproduction off nuclei near the kinematic threshold is investigated within the collision model based on the nuclear spectral function. The model accounts for $X(6900)$ production in direct photon--nucleon interactions as well as three different scenarios for its internal structure: compact tetraquark, molecule of the two hidden-charm $J/ψ$ and $ψ(3770)$ mesons and the mixture of both of them. We calculate within these scenarios the absolute and relative excitation functions on $^{12}$C and $^{184}$W nuclei at near-threshold photon energies of 30--40 GeV, the absolute momentum differential cross sections and ratios of them for the $X(6900)$ meson production off these target nuclei at laboratory polar angles of 0$^{\circ}$--5$^{\circ}$ and for photon energy of 35 GeV as well as the A-dependences of its transparency ratios at photon energy of 35 GeV. We show that these observables reveal a definite sensitivity to the $X(6900)$ intrinsic structure. Therefore, they might be useful for the determination of this structure from the comparison of them with the experimental data from the future experiments at the upcoming experimental facilities, such as the planned electron-ion colliders in the United States and China.

hep-ph↗

arXiv2026

Absorption of 1$P$-wave heavy charmonium $χ_{c1}(1P)$ in nuclei

We study the inclusive heavy charmonium $χ_{c1}(1P)$ photoproduction from nuclei near the kinematic threshold within the collision model, based on the nuclear spectral function, for incoherent direct photon--nucleon charmonium creation processes. The model accounts for the final $χ_{c1}(1P)$ absorption in nuclear medium, target nucleon binding and Fermi motion. We calculate the absolute and relative excitation functions on $^{12}$C and $^{184}$W target nuclei at near-threshold photon beam energies of 8.25--16.0 GeV, the absolute momentum differential cross sections and ratios of them for its production off these target nuclei at laboratory polar angles of 0$^{\circ}$--10$^{\circ}$ and for photon energy of 13 GeV as well as the A-dependences of the transparency ratios for the $χ_{c1}(1P)$ at photon energy of 13 GeV within the different scenarios for its absorption cross section in nuclei. We demonstrate that the absolute and relative observables considered reveal distinct sensitivity to these scenarios. Therefore, they might be useful for the determination of this cross section from the comparison of them with the experimental data from the future experiments at the upgraded up to 22 GeV CEBAF facility, which is of crucial importance in understanding of charmonium production and suppression in high-energy heavy--ion collisions in a search for the quark-gluon plasma.

nucl-th↗

arXiv2026

Insights into the exotic charged states $Z_b(10610)$ and $Z_b(10650)$ from their photoproduction off nuclei

The possibility to study the nature of the famous charged bottomonium-like states $Z_b(10610)$ and $Z_b(10650)$, which is by far the best known, from their inclusive photoproduction off nuclei near the kinematic threshold is investigated within the collision model based on the nuclear spectral function. The model accounts for $Z_b(10610)^{\pm}$ and $Z_b(10650)^{\pm}$ production in direct photon--nucleon interactions as well as four different scenarios for their intrinsic configurations: compact tetraquarks, molecules of the two open-beauty mesons and two mixtures of both of them for each of $Z_b$ state. We calculate within these scenarios the absolute and relative excitation functions on $^{12}$C and $^{184}$W nuclei at photon energies of 61--90 GeV, the absolute momentum differential cross sections and ratios of them for their production off these target nuclei at laboratory polar angles of 0$^{\circ}$--5$^{\circ}$ and for photon energy of 75 GeV as well as the A-dependences of the transparency ratios for the $Z_b(10610)^{\pm}$ mesons at photon energy of 75 GeV. We show that the absolute and relative observables considered reveal distinct sensitivity to the $Z_b(10610)^{\pm}$ and $Z_b(10650)^{\pm}$ internal structures. Therefore, they might be useful for the determination of these structures from the comparison of them with the experimental data from the future high-precision experiments at the upcoming experimental facilities, such as the planned high-luminosity electron-ion colliders in the United States and China.

hep-ph↗

arXiv2025

Photon-induced production of the exotic charged charmonium-like state $Z_c(3900)$ off nuclear targets and its internal structure

In this paper, we investigate the possibility to study the famous charged charmonium-like state $Z_c(3900)$ production off nuclear targets and its properties in inclusive photon-induced reactions near the kinematic threshold within the collision model based on the nuclear spectral function. The model accounts for its charged components $Z_c(3900)^{\pm}$ production in direct photon-nucleon interactions as well as three different popular scenarios for their internal structures: compact tetraquarks, molecules of the two open-charm mesons and mixtures of both of them. We calculate the absolute and relative excitation functions for production of $Z_c(3900)^{\pm}$ mesons on $^{12}$C and $^{184}$W target nuclei at initial photon energies of 9.0-17.5 GeV, the absolute momentum differential cross sections and their ratios for the $Z_c(3900)^{\pm}$ production off these target nuclei at laboratory polar angles of 0$^{\circ}$-10$^{\circ}$ and at photon energy of 14 GeV as well as the A-dependences of the ratios of the total cross sections for $Z_c(3900)^{\pm}$ production at photon energy of 14 GeV within the adopted scenarios for the $Z_c(3900)^{\pm}$ internal structures. We demonstrate that the absolute and relative observables considered show a certain sensitivity to the $Z_c(3900)^{\pm}$ internal structures which are by far the best known. Hence, they might be useful for the determination of these structures -- the issue which has attracted much attention in the hadron physics community -- from the comparison of them with the experimental data from the future high-precision experiments at the CEBAF facility.

hep-ph↗

arXiv2025

Absorption of $ψ(2S)$ mesons in nuclei

In the present work we explore the inclusive $ψ(2S)$ meson photoproduction from nuclei near the kinematic threshold within the collision model, based on the nuclear spectral function, for incoherent direct photon--nucleon charmonium creation processes. The model takes into account the final $ψ(2S)$ absorption, target nucleon binding and Fermi motion. We calculate the absolute and relative excitation functions for production of $ψ(2S)$ mesons on $^{12}$C and $^{184}$W target nuclei at near-threshold photon beam energies of 8.0--16.4 GeV, the absolute momentum differential cross sections for their production off these target nuclei at laboratory polar angles of 0$^{\circ}$--10$^{\circ}$, the momentum dependence of the ratio of these cross sections as well as the A-dependences of the ratios (transparency ratios) of the total cross cross sections for $ψ(2S)$ production at photon energy of 13 GeV within the different scenarios for the $ψ(2S)N$ absorption cross section. We also calculate the A-dependence of the ratio of $ψ(2S)$ and $J/ψ$ photoproduction transparency ratios at photon energies around of 11.5 GeV within the adopted scenarios for this cross section. We demonstrate that both the absolute and relative observables considered reveal a definite sensitivity to these scenarios. Therefore, the measurement of such observables in future experiments at the upgraded up to 22 GeV CEBAF facility in the near-threshold energy region might shed light both on the $ψ(2S)N$ absorption cross section and on its part associated with the nondiagonal process $ψ(2S)+N \to J/ψ+N$ at finite momenta, which are of crucial importance in understanding of charmonium production and suppression in high-energy nucleus--nucleus collisions in a search for the quark-gluon plasma.

nucl-th↗

arXiv2024

An alternative way to decipher the nature of the doubly charmed tetraquark $T_{cc}(3875)^+$: its antiparticle $T_{{\bar c}{\bar c}}(3875)^-$ photoproduction off nuclei near threshold

We study the inclusive photoproduction of $T_{{\bar c}{\bar c}}(3875)^-$ mesons (which are the antiparticles of the doubly charmed tetraquarks $T_{cc}(3875)^+$ discovered recently by the LHCb Collaboration) from nuclei in the near-threshold energy region within the nuclear spectral function approach by considering incoherent direct ($γp(n) \to D^+(D^0){T_{{\bar c}{\bar c}}(3875)^-}Λ^+_c$) photon--nucleon $T_{{\bar c}{\bar c}}(3875)^-$ creation processes as well as five possible different scenarios for their internal structure with the main goal of clarifying the possibility to decipher this structure (and, hence, that of $T_{cc}(3875)^+$) in photoproduction via integral and differential observables. We calculate the absolute and relative excitation functions for $T_{{\bar c}{\bar c}}(3875)^-$ production off $^{12}$C and $^{184}$W target nuclei at near-threshold photon beam energies of 30--38 GeV, the absolute differential cross sections for their production off these target nuclei at laboratory polar angles of 0$^{\circ}$--10$^{\circ}$ as well as the A and momentum dependences of the relative (transparency ratios) cross sections for $T_{{\bar c}{\bar c}}(3875)^-$ production at photon energy of 35 GeV within the adopted scenarios for the $T_{{\bar c}{\bar c}}(3875)^-$ meson intrinsic structure. We demonstrate that the absolute and relative observables considered show a certain sensitivity to these scenarios. Therefore, the measurement of such observables in future experiments at the proposed high-luminosity electron-ion colliders EIC and EicC in the US and China in the near-threshold energy region might shed light on the $T_{cc}(3875)^+$ internal structure.

hep-ph↗

arXiv2024

Probing the structure of $X(3872)$ in photoproduction

We study the production of $X(3872)$ mesons in photon-induced nuclear reactions near the threshold within the collision model based on the nuclear spectral function. The model accounts for direct photon-nucleon $X(3872)$ production processes as well as five different scenarios for their internal structure. We calculate the absolute and relative excitation functions for $X(3872)$ production off $^{12}$C and $^{184}$W target nuclei at near-threshold incident photon energies of 8--16 GeV, the absolute differential cross sections for their production off these target nuclei at laboratory angles of 0$^{\circ}$--10$^{\circ}$ and for incident photon energy of 13 GeV as well as the A dependences of the relative (transparency ratios) cross sections for $X(3872)$ production from $γA$ collisions at photon energies around 13 GeV within the adopted scenarios for the $X(3872)$ meson internal structure. We show that the absolute and relative observables considered reveal distinct sensitivity to these scenarios. Therefore, the measurement of such observables in a dedicated experiment at the CEBAF facility in the near-threshold energy range will allow us to get valuable information on the $X(3872)$ inner structure.

hep-ph↗

arXiv2023

Probing the hidden-bottom pentaquark resonances in photonuclear bottomonium production near threshold: differential observables

We study the near-threshold $Υ(1S)$ meson photoproduction from protons and nuclei by considering incoherent direct non-resonant ($γp \to {Υ(1S)}p$, $γn \to {Υ(1S)}n$) and two-step resonant ($γp \to P^+_{bi} \to {Υ(1S)}p$, $γn \to P^0_{bi} \to {Υ(1S)}n$, $i=1$, 2, 3; $P^{+,0}_{b1}=P^{+,0}_{b}(11080)$, $P^{+,0}_{b2}=P^{+,0}_{b}(11125)$, $P^{+,0}_{b3}=P^{+,0}_{b}(11130)$) bottomonium production processes with the main goal of clarifying the possibility to observe the non-strange hidden-bottom pentaquark states $P^{+,0}_{bi}$ in this production via differential observables. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of $Υ(1S)$ mesons on protons, on carbon and tungsten target nuclei at near-threshold incident photon beam energies by assuming the spin-parity assignments of the hypothetical hidden-bottom resonances $P^{+,0}_{b}(11080)$, $P^{+,0}_{b}(11125)$ and $P^{+,0}_{b}(11130)$ as $J^P=(1/2)^-$, $J^P=(1/2)^-$ and $J^P=(3/2)^-$ within four different realistic choices for the branching ratios of their decays to the $Υ(1S)p$ and $Υ(1S)n$ modes (0.125, 0.25, 0.5 and 1\%) as well as for two options for the background contribution. We demonstrate that the measurements of these combined observables on proton and nuclear targets in the near-threshold energy region in future experiments at the planned high-luminosity electron-ion colliders EIC and EicC in the US and China should provide evidence for the existence of the above hidden-bottom pentaquark resonances as well as clarify their decay rates.

hep-ph↗

arXiv2023

On the possibility of testing the two-peak structure of the LHCb hidden-charm strange pentaquark $P_{cs}(4459)^0$ in near-threshold antikaon-induced charmonium production on protons and nuclei

Accounting for the LHCb observation that the reported hidden-charm strange pentaquark $P_{cs}(4459)^0$ can split into two substructures, $P_{cs}(4455)^0$ and $P_{cs}(4468)^0$, with a mass difference of 13 MeV as well as the newly observed hidden-charm pentaquark resonance $P_{cs}(4338)^0$ with strangeness, we study within the double-peak scenario for the $P_{cs}(4459)^0$ state the near-threshold $J/ψ$ meson production from protons and nuclei by considering incoherent direct non-resonant (${K^-}p \to {J/ψ}Λ$) and two-step resonant (${K^-}p \to P_{csi}^0 \to {J/ψ}Λ$, $i=1$, 2, 3; $P_{cs1}^{0}=P_{cs}(4338)^0$, $P_{cs2}^{0}=P_{cs}(4455)^0$, $P_{cs3}^{0}=P_{cs}(4468)^0$) charmonium production processes with the main goal of clarifying the possibility to observe within this scenario both above two substructures contributing to the $P_{cs}(4459)^0$ state and the $P_{cs}(4338)^0$ resonance in this production. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of $J/ψ$ mesons on protons as well as on carbon and tungsten target nuclei at near-threshold incident antikaon beam momenta by assuming the spin-parity assignments of the hidden-charm resonances $P_{cs}(4338)^0$, $P_{cs}(4455)^0$ and $P_{cs}(4468)^0$ as $J^P=(1/2)^-$, $J^P=(1/2)^-$ and $J^P=(3/2)^-$ within four different realistic choices for the branching ratios of their decays to the ${J/ψ}Λ$ mode (0.125, 0.25, 0.5 and 1\%) as well as for two options for the branching fraction of their decays to the $K^-p$ channel (0.01 and 0.001\%). We show that these combined observables reveal clear sensitivity to these scenarios. Hence, they may be an important tool to provide further evidence for the existence of the above strange hidden-charm pentaquark resonances.

hep-ph↗

arXiv2023

Testing the $ϕ$-nuclear potential in pion-induced $ϕ$ meson production on nuclei near threshold

The near-threshold pion-induced $ϕ$ production off nuclei has been studied in the kinematical conditions of the HADES experiment using a collision model based on the nuclear spectral function. Starting from the elementary reaction ${π^-}p \to ϕn$, absolute differential and integral cross sections for the production of $ϕ$ mesons off a light carbon and a heavy tungsten target have been calculated and compared to the recently reported experimental cross sections. The absolute cross section values are shown to be sensitive to the effective nuclear scalar $ϕ$ and neutron potentials while the transparency ratio is governed by the $ϕN$ absorption cross section. The experimental data are found to be consistent with an attractive $ϕ$-nucleus potential of $\approx$ -(50--100) MeV at normal nuclear matter density $ρ_0$ and an effective $ϕN$ absorption cross section of $\approx$ 12--25 mb. The extracted $ϕ$-nucleus potential is deeper than previous theoretical and experimental findings as well as those obtained in the present work within the ($tρ$) approximation with accounting for Pauli correlations from the spin-averaged $ϕ$-$p$ scattering length reported in a recent ALICE experiment.

nucl-ex↗

arXiv2022

Towards clarifying the possibility of observation of the LHCb hidden-charm pentaquarks $P_{c}^+(4312)$, $P_{c}^+(4337)$, $P_{c}^+(4440)$ and $P_{c}^+(4457)$ in near-threshold charmonium photoproduction off protons and nuclei

We study the near-threshold $J/ψ$ meson photoproduction from protons and nuclei by considering incoherent direct non-resonant ($γp \to {J/ψ}p$, $γn \to {J/ψ}n$) and two-step resonant ($γp \to P_{ci}^+ \to {J/ψ}p$, $γn \to P_{ci}^0 \to {J/ψ}n$, $i=1$, 2, 3, 4; $P_{c1}^{+,0}=P_c^{+,0}(4312)$, $P_{c2}^{+,0}=P_c^{+,0}(4337)$, $P_{c3}^{+,0}=P_c^{+,0}(4440)$, $P_{c4}^{+,0}=P_c^{+,0}(4457)$) charmonium production processes. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of $J/ψ$ mesons on protons as well as, using the nuclear spectral function approach, on carbon and tungsten target nuclei at near-threshold incident photon energies by assuming the spin-parity assignments of the hidden-charm resonances $P_{c}^{+,0}(4312)$, $P_{c}^{+,0}(4337)$, $P_{c}^{+,0}(4440)$ and $P_{c}^{+,0}(4457)$ as $J^P=(1/2)^-$, $J^P=(1/2)^-$, $J^P=(1/2)^-$ and $J^P=(3/2)^-$ within three different realistic scenarios for the branching ratios of their decays to the ${J/ψ}p$ and ${J/ψ}n$ modes (0.25, 0.5 and 1%). We show that will be very hard to measure the $P_{ci}^+$ pentaquark states through the scan of the $J/ψ$ total photoproduction cross section on a proton target in the near-threshold energy region around the resonant photon energies of 9.44, 9.554, 10.04 and 10.12 GeV if these branching ratios $\sim$ 1% and less. We also demonstrate that at these photon beam energies the $J/ψ$ energy and momentum combined distributions considered reveal distinct sensitivity to the above scenarios, respectively, at "low" $J/ψ$ total energies and momenta, which implies that they may be an important tool to provide further evidence for the existence of the pentaquark $P_{ci}^+$ and $P_{ci}^0$ resonances.

hep-ph↗

arXiv2022

Regarding the possibility to observe the LHCb hidden-charm strange pentaquark $P_{cs}(4459)^0$ in antikaon-induced $J/ψ$ meson production on protons and nuclei near the $J/ψ$$Λ$ production threshold

We study the near-threshold $J/ψ$ meson production on protons and nuclei by considering incoherent direct non-resonant $K^-p \to {J/ψ}Λ$ and two-step resonant ${K^-}p \to P_{cs}(4459)^0 \to {J/ψ}Λ$ charmonium production processes. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of $J/ψ$ mesons off protons as well as off carbon and tungsten target nuclei at near-threshold incident antikaon energies by considering these elementary production channels as well as by assuming the spin-parity assignment of the hidden-charm resonance $P_{cs}(4459)^0$ with strangeness as $J^P=(3/2)^-$ within six different scenarios for the branching ratio $Br[P_{cs}(4459)^0 \to {J/ψ}Λ]$ of the decay $P_{cs}(4459)^0 \to {J/ψ}Λ$. We show that the combined observables considered reveal definite sensitivity to these scenarios, which means that they may be an important tool to provide further evidence for the existence of the pentaquark $P_{cs}(4459)^0$ resonance and to get valuable information on its decay rate to the ${J/ψ}Λ$ final state. Their measurements could be performed in the future at the J-PARC Hadron Experimental Facility.

hep-ph↗

arXiv2021

Momentum dependence of near-threshold photoproduction of $Ξ^-$ hyperons off nuclei and their properties in the nuclear medium

We study the near-threshold inclusive photoproduction of $Ξ^-$ hyperons off $^{12}$C and $^{184}$W target nuclei within a first-collision model relying on the nuclear spectral function and including incoherent $Ξ^-$ production in direct elementary $γp \to K^+{K^+}Ξ^-$ and $γn \to K^+{K^0}Ξ^-$ processes. The model takes into account the impact of the nuclear effective scalar $K^+$, $K^0$, $Ξ^-$ and their Coulomb potentials on these processes as well as the absorption of final $Ξ^-$ hyperons in nuclear matter, the binding of intranuclear nucleons and their Fermi motion. We calculate the absolute differential cross sections and their ratios for the production of $Ξ^-$ hyperons off these nuclei at laboratory polar angles $\le$ 45$^{\circ}$ by photons with energies of 2.5 and 3.0 GeV, with and without imposing the phase space constraints on the $Ξ^-$ emission angle in the respective $γp$ center-of-mass system. We also calculate the momentum dependence of the transparency ratio for $Ξ^-$ hyperons for the $^{184}$W/$^{12}$C combination at these photon energies. We show that the $Ξ^-$ momentum distributions (absolute and relative) at the adopted initial photon energies possess, contrary to the transparency ratio for $Ξ^-$ hyperons, a definite sensitivity to the considered changes in the scalar $Ξ^-$ nuclear mean-field potential at saturation density $ρ_0$ in the low-momentum range of 0.1--0.8 GeV/c. Therefore, the precise measurements of these distributions in a dedicated experiment at the CEBAF facility will provide valuable information on the $Ξ^-$ in-medium properties, which will be supplementary to that inferred from studying of the ($K^-$,$K^+$) reactions at initial momenta of 1.6--1.8 GeV/c.

nucl-th↗

arXiv2021

Medium effects in antikaon-induced $Ξ^-$ hyperon production on nuclei near threshold

We study the antikaon-induced inclusive cascade $Ξ^-$ hyperon production from $^{12}$C and $^{184}$W target nuclei near threshold within a nuclear spectral function approach. The approach describes incoherent direct $Ξ^-$ hyperon production in elementary ${K^-}p \to {K^+}Ξ^-$ and ${K^-}n \to {K^0}Ξ^-$ processes as well as takes into account the influence of the scalar nuclear $K^-$, $K^+$, $K^0$, $Ξ^-$ and their Coulomb potentials on these processes. We calculate the absolute differential and total cross sections for the production of $Ξ^-$ hyperons off these nuclei at laboratory angles $\le$ 45$^{\circ}$ by $K^-$ mesons with momenta of 1.0 and 1.3 GeV/c, which are close to the threshold momentum (1.05 GeV/c) for $Ξ^-$ hyperon production on the free target nucleon at rest. We also calculate the momentum dependence of the transparency ratio for the $^{184}$W/$^{12}$C combination for $Ξ^-$ hyperons at these $K^-$ beam momenta. We show that the $Ξ^-$ differential and total (absolute and relative) production cross sections at the considered initial momenta reveal a distinct sensitivity to the variations in the scalar $Ξ^-$ nuclear potential at saturation density $ρ_0$, studied in the paper, in the low-momentum region of 0.1--0.6 GeV/c. We also demonstrate that for the subthreshold $K^-$ meson momentum of 1.0 GeV/c there is a strong sensitivity of the transparency ratio for $Ξ^-$ hyperons to the considered changes in the $Ξ^-$ nuclear potential at all outgoing $Ξ^-$ momenta as well. Therefore, the measurement of these absolute and relative observables in a dedicated experiment at the J-PARC will provide valuable information on the $Ξ^-$ in-medium properties, which will be complementary to that deduced from the study of the inclusive ($K^-$,$K^+$) reactions at incident momenta of 1.6--1.8 GeV/c in the $Ξ^-$ bound and quasi-free regions.

nucl-th↗

arXiv2021

Antikaon-induced $K_1(1270)^+$ meson production on nuclei near threshold

We study the inclusive strange axial-vector meson $K_1(1270)^+$ production in ${K^-}A$ reactions at near-threshold laboratory incident antikaon momenta within a nuclear spectral function approach, which describes incoherent direct $K_1(1270)^+$ meson production in $K^-$ meson--proton ${K^-}p \to {K_1(1270)^+}Ξ^-$ production processes and accounts for three different options for its in-medium mass shift (or for its effective scalar potential) at central density $ρ_0$. We calculate the absolute differential and total cross sections for the production of $K_1(1270)^+$ mesons on $^{12}$C and $^{184}$W target nuclei at laboratory angles of 0$^{\circ}$--45$^{\circ}$ by $K^-$ mesons with momenta of 2.5, 2.8 and 3.5 GeV/c, which are close to the threshold momentum ($\approx$ 2.95 GeV/c) for $K_1(1270)^+$ meson production off the free target proton at rest. The intrinsic properties of carbon and tungsten target nuclei have been described in terms of their spectral functions, which take into account the momenta of target protons and the energies of their separation from the considered nuclei. We show that the differential and total (absolute and relative) $K_1(1270)^+$ antikaon-induced production cross sections at initial momenta not far from threshold -- at momenta $\sim$ 2.8--3.5 GeV/c, at which there is yet no strong drop in their strength, reveal a distinct sensitivity to changes in the in-medium shift of the $K_1(1270)^+$ mass, studied in the paper, both in the $K_1(1270)^+$ meson low-momentum (0.1--1.0 GeV/c) and in its full-momentum ranges. This would permit evaluating this shift. Experimental data necessary for this aim can be obtained in a dedicated experiment at the J-PARC Hadron Experimental Facility.

nucl-th↗

arXiv2020

Near-threshold $K^*(892)^+$ meson production in the interaction of $π^-$ mesons with nuclei

We study the inclusive strange vector meson $K^*(892)^+$ production in ${π^-}A$ reactions at near-threshold laboratory incident pion momenta of 1.4--2.0 GeV/c within a nuclear spectral function approach. The approach accounts for incoherent primary $π^-$ meson--proton ${π^-}p \to {K^*(892)^+}Σ^-$ production processes as well as the influence of the scalar $K^*(892)^+$--nucleus potential (or the $K^*(892)^+$ in-medium mass shift) on these processes. We calculate the absolute differential and total cross sections for the production of $K^*(892)^+$ mesons off carbon and tungsten nuclei at laboratory angles of 0$^{\circ}$--45$^{\circ}$ and at these momenta within five scenarios for the above shift. We show that the $K^*(892)^+$ momentum distributions and their excitation functions (absolute and relative) possess a high sensitivity to changes in the in-medium $K^*(892)^+$ mass shift in the low-momentum region of 0.1--0.6 GeV/c. Therefore, the measurement of such observables in a dedicated experiment at the GSI pion beam facility in the near-threshold momentum domain will allow to get valuable information on the $K^*(892)^+$ in-medium properties.

nucl-th↗

arXiv2020

Study of a possibility of observation of hidden-bottom pentaquark resonances in bottomonium photoproduction on protons and nuclei near threshold

We study the $Υ(1S)$ meson photoproduction on protons and nuclei at the near-threshold center-of-mass energies below 11.4 GeV (or at the corresponding photon laboratory energies $E_γ$ below 68.8 GeV). We calculate the absolute excitation functions for the non-resonant and resonant photoproduction of $Υ(1S)$ mesons off protons at incident photon laboratory energies of 63--68 GeV by accounting for direct ($γp \to {Υ(1S)}p$) and two-step ($γp \to P^+_b(11080,11125,11130) \to {Υ(1S)}p$) $Υ(1S)$ production channels within different scenarios for the non-resonant total cross section of elementary reaction $γp \to {Υ(1S)}p$ and for branching ratios of the decays $P^+_b(11080,11125,11130) \to {Υ(1S)}p$. We also calculate an analogous functions for photoproduction of $Υ(1S)$ mesons on $^{12}$C and $^{208}$Pb target nuclei in the near-threshold center-of-mass beam energy region of 9.0--11.4 GeV by considering respective incoherent direct ($γN \to {Υ(1S)}N$) and two-step ($γp \to P^+_b(11080,11125,11130) \to {Υ(1S)}p$, $γn \to P^0_b(11080,11125,11130) \to {Υ(1S)}n$) $Υ(1S)$ production processes within a nuclear spectral function approach. We show that a detailed scan of the $Υ(1S)$ total photoproduction cross section on a proton and nuclear targets in the near-threshold energy region in future high-precision experiments at the proposed high-luminosity electron-ion colliders EIC and EicC in the U.S. and China should give a definite result for or against the existence of the non-strange hidden-bottom pentaquark states $P_{bi}^+$ and $P_{bi}^0$ ($i=$1, 2, 3) as well as clarify their decay rates.

nucl-th↗

arXiv2020

The possibility to study in-medium modification of $J/ψ$ mesons from their photoproduction on nuclei near threshold in the case of presence of the LHCb pentaquark states $P^+_c$ in this photoproduction

We study the $J/ψ$ photoproduction from nuclei in the near-threshold beam energy region of $E_γ$=5--11 GeV within the nuclear spectral function approach by considering incoherent direct ($γN \to {J/ψ}N$) and two-step ($γp \to P^+_c(4312)$, $P^+_c(4312) \to {J/ψ}p$; $γp \to P^+_c(4440)$, $P^+_c(4440) \to {J/ψ}p$; $γp \to P^+_c(4457)$, $P^+_c(4457) \to {J/ψ}p$) $J/ψ$ production processes. We calculate the absolute excitation functions for the non-resonant and resonant production of $J/ψ$ mesons off $^{12}$C and $^{208}$Pb target nuclei within the different scenarios for in-medium modification of the directly photoproduced $J/ψ$ mesons and for branching ratios of the decays $P^+_c(4312) \to {J/ψ}p$, $P^+_c(4440) \to {J/ψ}p$ and $P^+_c(4457) \to {J/ψ}p$. We show that the non-resonant subthreshold $J/ψ$ production in $γA$ reactions reveals some sensitivity to employed in-medium modification scenarios for $J/ψ$ mesons, which is not masked by the resonantly produced $J/ψ$ mesons, only if above branching ratios are less than 5\%. We also demonstrate that if these branching ratios more than 5\% then the presence of the $P^+_c(4312)$, $P^+_c(4440)$ and $P^+_c(4457)$ resonances in $J/ψ$ photoproduction on nuclei produces above threshold additional enhancements in the behavior of the total $J/ψ$ creation cross section on nuclei, which could be also studied in the future JLab experiments at the CEBAF facility to provide both further evidence for their existence and valuable information on their nature.

nucl-th↗