Find Paper, Faster
Example：10.1021/acsami.1c06204 or Chem. Rev., 2007, 107, 2411-2502
Photoproductions of dileptons, photons, and light vector mesons inp−p,p−Pb, andPb−Pbcollisions at Large Hadron Collider energies
Physical Review D  (IF5.296),  Pub Date : 2021-10-20, DOI: 10.1103/physrevd.104.074023
Zhi-Lei Ma, Zhun Lu, Jia-Qing Zhu, Li Zhang

The photoproduction of large ${p}_{T}$ dileptons, photons, and light vector mesons in $p\text{−}p$, $p\text{−}\mathrm{Pb}$, and $\mathrm{Pb}\text{−}\mathrm{Pb}$ collisions at LHC energies is studied, where the fragmentation processes and the ultra-incoherent photon channel are included. An exact treatment is developed for photoproduction processes in heavy ion collisions, which recovers the equivalent photon approximation (EPA) in the limit ${Q}^{2}\to 0$ and can avoid double counting effectively. The full kinematical relations are also achieved. We present the results as the distributions in ${Q}^{2}$, ${p}_{T}$, and ${y}_{r}$, and the total cross sections are also estimated. The numerical results indicate that the contribution of photoproduction processes is evident in the large ${p}_{T}$ and ${y}_{r}$ regions and starts to play a fundamental role in $p\text{−}\mathrm{Pb}$ collisions. The ultra-incoherent photon emission is an important channel of photoproduction processes, which can provide the meaningful contributions. EPA is only applicable in small $y$ and ${Q}^{2}$ domains and is very sensitive to the values of ${y}_{\mathrm{max}}$ and ${Q}_{\mathrm{max}}^{2}$. The EPA errors appear when $y>0.29$ and ${Q}^{2}>0.1\text{\hspace{0.17em}}\text{\hspace{0.17em}}{\mathrm{GeV}}^{2}$ and are rather serious in $p\text{−}\mathrm{Pb}$ and $\mathrm{Pb}\text{−}\mathrm{Pb}$ collisions. When dealing with widely kinematical regions, the exact treatment needs to be adopted.