Inelastic heavy quark and quarkonium ultra-incoherent photoproduction in ultra-peripheral collisions

The inelastic heavy quark and quarkonium photoproduction through the ultra-incoherent photon channel in ultra-peripheral collisions is studied. Considering the ultra-relativistic hadrons as a beam of freely moving elementary constituents, the inclusive photoproduction cross sections for charm quark, bottom quark, $J/\psi$, and $\mathrm{{\rm Y}}\left(1S\right)$ are calculated by using the incoherent photon spectrum from the individual quarks in the nucleus. Comparing with the predictions of the coherent photon channel in the literatures, it is shown that the ultra-incoherent photon channel provides non-negligible contributions to the heavy quarks and heavy quarkonia photoproduction in ultra-peripheral collisions.

Figure 1

The UPCs in the parton level under ultra-relativistic condition. $a$ denotes the charged parton (quark) in nuclear $A,b$ is the parton (quark or gluon) in nuclear $B,a^{\prime }$ is the scattered parton $a,c$ is the final particle in which we are interested, and $X^{\prime }$ is the residue of $b$ after scattering with the photon.