We study theΥ(1S)meson photoproduction on protons and nuclei at near-threshold center-of-mass energies below 11.4 GeV(or at the corresponding photon laboratory energies Eγbelow 68.8 GeV).We calculate the absolute ex...We study theΥ(1S)meson photoproduction on protons and nuclei at near-threshold center-of-mass energies below 11.4 GeV(or at the corresponding photon laboratory energies Eγbelow 68.8 GeV).We calculate the absolute excitation functions for the nonresonant and resonant photoproduction ofΥ(1S)mesons off protons at incident photon laboratory energies of 63-68 GeV by considering direct(γp→Υ(1S)p)and two-step(γp→P^+b(11080)→Υ(1S)p,γp→P^+b(11125)→Υ(1S)p,γp→P^+b(11130)→Υ(1S)p)Υ(1S)production channels within different scenarios for the nonresonant total cross section of the elementary reactionγp→Υ(1S)p and for branching ratios of the decays P^+b(11080)→Υ(1S)p,P^+b(11125)→Υ(1S)p,and P^+b(11130)→Υ(1S)p.We also calculate an analogous function for the photoproduction ofΥ(1S)mesons on the 12C and 208Pb target nuclei in the near-threshold center-of-mass beam energy region of 9.0-11.4 GeV by considering the respective incoherent direct(γN→Υ(1S)N)and two-step(γp→P^+b(11080)→Υ(1S)p,γp→P^+b(11125)→Υ(1S)p,γp→P^+b(11130)→Υ(1S)p andγn→P^0b(11080)→Υ(1S)n,γn→P^0b(11125)→Υ(1S)n,γn→P^0b(11130)→Υ(1S)n)Υ(1S))production processes using a nuclear spectral function approach.We demonstrate that a detailed scan of theΥ(1S)total photoproduction cross section on 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 US and China should provide a definite result for or against the existence of the nonstrange hidden-bottom pentaquark statesP^+bi and P^0bi(i=1,2,3)as well as clarify their decay rates.展开更多
We study the inclusive production of strange vector K^∗(892)^+ mesons in π−A reactions at near-threshold laboratory incident pion momenta of 1.4-2.0 GeV/c via a nuclear spectral function approach.The approach account...We study the inclusive production of strange vector K^∗(892)^+ mesons in π−A reactions at near-threshold laboratory incident pion momenta of 1.4-2.0 GeV/c via a nuclear spectral function approach.The approach accounts for incoherent primary π−meson-proton π−p→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 from carbon and tungsten nuclei at laboratory angles of 0∘-45∘and at the aforementioned momenta in five scenarios for the aforenoted 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 us to get valuable information on the K^∗(892)^+ in-medium properties.展开更多
We study the near-threshold pion-induced production ofφmesons off nuclei in the kinematical conditions of the HADES experiment,recently performed at GSI.The calculations have been performed within a collision model b...We study the near-threshold pion-induced production ofφmesons off nuclei in the kinematical conditions of the HADES experiment,recently performed at GSI.The calculations have been performed within a collision model based on the nuclear spectral function.The model accounts for both the primaryπ^-meson–protonπ^-p→φn and the secondary pion–nucleonπN→φNφproduction processes as well as the effects of the nuclearφand nucleon mean-field potentials.We find that the primary reaction channelπ^-p→φn dominates in theφproduction off 12C and^（184）W target nuclei in the HADES acceptance window at incident pion momentum of 1.7 Ge V/c.We calculate the momentum dependence of the absolute and relative（transparency ratio）φmeson yields from the above direct channel.The calculations have been performed for this initial pion momentum allowing for different options for theφN absorption cross sectionσ（φN ）and different scenarios for the in-medium mass shifts of theφmeson and secondary neutron,produced together withφin this channel.We demonstrate that the transparency ratio for theφmesons has,contrary to the absolute cross sections,an insignificant sensitivity to theφmeson and secondary neutron in-medium mass shifts atφmomenta studied in the HADES experiment.On the other hand,we show that there are measurable changes in the transparency ratio due to theφN absorption cross section,which means that such a relative observable can be useful to help determine this cross section from the data taken in the HADES experiment.展开更多
文摘We study theΥ(1S)meson photoproduction on protons and nuclei at near-threshold center-of-mass energies below 11.4 GeV(or at the corresponding photon laboratory energies Eγbelow 68.8 GeV).We calculate the absolute excitation functions for the nonresonant and resonant photoproduction ofΥ(1S)mesons off protons at incident photon laboratory energies of 63-68 GeV by considering direct(γp→Υ(1S)p)and two-step(γp→P^+b(11080)→Υ(1S)p,γp→P^+b(11125)→Υ(1S)p,γp→P^+b(11130)→Υ(1S)p)Υ(1S)production channels within different scenarios for the nonresonant total cross section of the elementary reactionγp→Υ(1S)p and for branching ratios of the decays P^+b(11080)→Υ(1S)p,P^+b(11125)→Υ(1S)p,and P^+b(11130)→Υ(1S)p.We also calculate an analogous function for the photoproduction ofΥ(1S)mesons on the 12C and 208Pb target nuclei in the near-threshold center-of-mass beam energy region of 9.0-11.4 GeV by considering the respective incoherent direct(γN→Υ(1S)N)and two-step(γp→P^+b(11080)→Υ(1S)p,γp→P^+b(11125)→Υ(1S)p,γp→P^+b(11130)→Υ(1S)p andγn→P^0b(11080)→Υ(1S)n,γn→P^0b(11125)→Υ(1S)n,γn→P^0b(11130)→Υ(1S)n)Υ(1S))production processes using a nuclear spectral function approach.We demonstrate that a detailed scan of theΥ(1S)total photoproduction cross section on 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 US and China should provide a definite result for or against the existence of the nonstrange hidden-bottom pentaquark statesP^+bi and P^0bi(i=1,2,3)as well as clarify their decay rates.
文摘We study the inclusive production of strange vector K^∗(892)^+ mesons in π−A reactions at near-threshold laboratory incident pion momenta of 1.4-2.0 GeV/c via a nuclear spectral function approach.The approach accounts for incoherent primary π−meson-proton π−p→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 from carbon and tungsten nuclei at laboratory angles of 0∘-45∘and at the aforementioned momenta in five scenarios for the aforenoted 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 us to get valuable information on the K^∗(892)^+ in-medium properties.
文摘We study the near-threshold pion-induced production ofφmesons off nuclei in the kinematical conditions of the HADES experiment,recently performed at GSI.The calculations have been performed within a collision model based on the nuclear spectral function.The model accounts for both the primaryπ^-meson–protonπ^-p→φn and the secondary pion–nucleonπN→φNφproduction processes as well as the effects of the nuclearφand nucleon mean-field potentials.We find that the primary reaction channelπ^-p→φn dominates in theφproduction off 12C and^（184）W target nuclei in the HADES acceptance window at incident pion momentum of 1.7 Ge V/c.We calculate the momentum dependence of the absolute and relative（transparency ratio）φmeson yields from the above direct channel.The calculations have been performed for this initial pion momentum allowing for different options for theφN absorption cross sectionσ（φN ）and different scenarios for the in-medium mass shifts of theφmeson and secondary neutron,produced together withφin this channel.We demonstrate that the transparency ratio for theφmesons has,contrary to the absolute cross sections,an insignificant sensitivity to theφmeson and secondary neutron in-medium mass shifts atφmomenta studied in the HADES experiment.On the other hand,we show that there are measurable changes in the transparency ratio due to theφN absorption cross section,which means that such a relative observable can be useful to help determine this cross section from the data taken in the HADES experiment.
