Production of vector mesons in pentaquark state resonance channel in p-A ultraperipheral collisions

Ultraperipheral collisions(UPCs) of protons and nuclei are important for the study of the photoproduction of vector mesons and exotic states.The photoproduction of vector mesons in the pentaquark resonance channel in p-Au UPCs at the Relative Heavy Ion Collider(RHIC) and p-Pb UPCs at the Large Hadron Collider(LHC) is investigated by employing the STARlight package.The cross sections of vector mesons via the pentaquark state resonance channel are obtained using the effective Lagrangian method.The pseudo-rapidity and rapidity distributions of J/Ψ and γ(1 S) are given for p-Au UPCs at the RHIC and p-PbUPCs at the LHC.It is found that the RHIC is a better platform for discovering pentaquark states than the LHC.Moreover,Pb(11080) is easier to identify than PC(4312) because the background of γ(1 S) is weaker than that of J/Ψ in the t-channel at the RHIC.

Spin asymmetry and dipole moments inτ-pair production with ultraperipheral heavy ion collisions

The anomalous magnetic(MDM)and electric(EDM)dipole moments of theτlepton serve as crucial indicators of new physics beyond the standard model.Leveraging azimuthal angular asymmetry as a novel tool in ultraperipheral collisions(UPCs),we attain unparalleled precision in the study of these key properties.Driven by the highly linear polarization of coherent photons,this method uniquely enables both the MDM and EDM to contribute to the cos 2φangular distribution in similar magnitudes.Importantly,our approach substantially narrows the parameter space,excluding more than half of it compared to expected UPC-based measurements reliant solely on the total cross-section.This method not only provides improved constraints but also minimizes the need for additional theoretical assumptions,and offers a novel avenue to probe the EDM effects.

Production of bottomonium-like Zb states in e-h and ultraperipheral h-h collisions

The photoproduction of the bottomonium-like states Zb(10610) and Zb(10650) via γ p scattering is studied within an effective Lagrangian approach and the vector-meson-dominance model. The Regge model is employed to calculate the photoproduction of Zb states via the t-channel with π exchange. The numerical results show that the values of the total cross-sections of Zb(10610) and Zb(10650) can reach 0.09 nb and 0.02 nb, respectively,near the center-of-mass energy of 22 GeV. Experimental measurements and studies of the photoproduction of Zb states near the energy region around W ■ 22 GeV are suggested. Moreover, with the help of eSTARlight and STARlight programs, we have obtained the cross-sections and numbers of events for Zb(10610) production in electron-ion collisions(EIC) and ultraperipheral collisions(UPCs). The results show that a considerable number of Zb(10610)events can be produced in the relevant experiments on EICs and UPCs. We have also calculated the rates and kinematic distributions for γp → Zbn in ep and pA collisions via EICs and UPCs. The results will provide an important reference for the RHIC, LHC, EIC-US, LHeC, and FCC experiments in searching for bottomonium-like Zb states.