Production ofη′from thermal gluon fusion

Abstract

We study the production of η ′ from hadronizing thermal gluons using recently proposed η ′ − g − g effective vertex. The η ′ yield is found to be sensitive to the initial condition. At RHIC and LHC, the enhancement is large enough to be easily detected.

Probing gluons in nuclei: The case ofη′

“…We also note that the momenta involved in this process is not so soft compared to Λ QCD or the pion mass since the η ′ mass is almost 1 GeV. Recently, these interesting features of the ggη ′ vertex were exploited to calculate the η ′ production from a hadronizing quark-gluon plasma [6]. In that study, a Boltzmann equation was used to evolve the η ′ density towards the hadronization time in heavy ion collisions.…”

η′ production in nucleus-nucleus collisions as a probe of chiral dynamics

“…The obvious theoretical background to the effects examined here are other mechanisms of η ′ production. Indeed, I interpreted the production as a kind of coalescence at hadronization, neglecting kinetic production and in-medium modification of the sort examined in [20]. To what extent this is a good approximation is highly dependent on how hadronization actually occurs.…”

“…To do this, one must treat Eq. 1 as a kernel for thermal gluons to coalesce into η ′ at hadronization, thereby neglecting the loss term [20]. Because I am interested in an estimate, I shall make some simplifying assumptions such as neglecting mass and coupling temperature dependence computed carefully in [20].…”

“…Of course, coalescence should happen around hadronization temperature the turnoff seen on the lattice at higher temperature should not, naively, impact on the η ′ abundance. However, if the "in-QGP" production mechanism argued for in [48,49] is applicable to the η ′ , this particle becomes a very important probe of chiral susceptibility, althoguh in this case the loss term [20] becomes important.…”

“…This was used in [19,20] to propose the η ′ as a probe of the double spin asymmetry in the parton distribution function, since the above expressions would have lead to a finite difference ∆σ ggη ′ = dσ ++ − dσ +− = 0 where dσ ++ denotes the cross section where both protons have their spins parallel to their momenta while dσ +− denotes the cross section when one proton has its spin anti-parallel to its momentum. The difference would be directly dependent on the polarized part of the parton distribution function ∆G given the usual deep inelastic scattering cross-sections…”