Kazuhiro Watanabe: Quarkonium and Open Heavy Flavor productions at collider energies in Small-x formalism
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US/Eastern
Universe
Universe
Description
Heavy quark pair production in high energy proton-nucleus (pA) collisions provides valuable information on the gluon saturation dynamics at small-x of a heavy nucleus. Nowadays, large amounts of data of quarkonium, open heavy flavor, and decay lepton accumulated by RHIC and LHC enable us to examine the calculations in Small-x formalism or Color Glass Condensate (CGC). Essentially, the calculations of heavy quark pair production have been based on the Small-x/CGC framework at leading order (LO) with the running coupling Balitsky-Kovchegov equation (rcBK) which includes a subset of next-to-leading order (NLO) correction. A main difference between pp and pA collisions is the choice of the initial saturation scale in the rcBK equation. The recent theoretical computations have gradually clarified the gluon saturation effect in pA collision by comparing with data on the transverse momentum spectrums and the nuclear modification factors measured at RHIC and LHC. In this talk, we will review the recent studies of heavy quark pair production in the Small-x/CGC framework and discuss the relevant topical issues. Furthermore, we will discuss the Sudakov implementation in Small-x formalism which has received attention in recent years. I will show that the Sudakov effect on top of the saturation effect is indeed indispensable for Upsilon production.
