Conveners
Parallel Session 5.2: Initial State Physics and Approach to Equilibrium (III)
- Zhangbu Xu (Brookhaven National Laboratory)
W and Z bosons are short lived and do not participate in the strong interaction. Thus their production yields, observed via dilepton decay channels in proton-lead and lead-lead collisions, provide direct tests of both binary collision scaling and the nuclear modification of parton distribution functions (nPDF). Proton-lead collisions further provide a relatively clean environment for...
W and Z bosons are massive weakly interacting probes; insensitive to the strong interaction, they are clean observables of the initial state of heavy-ion collisions. Despite their low production rates, their relatively clean signatures in the leptonic decay channels allow their study in heavy-ion collisions at the LHC. Their measurement in p--Pb and Pb--Pb collisions provides constraints on...
Our understanding of proton structure and of nuclear interactions at high energy would be advanced significantly with the definitive discovery of the gluon saturation regime. Forward particle production in hadron collisions at RHIC probes gluons at small x where gluon density is high and expected to reach the saturation regime. Until today the golden channel at RHIC to observe strong hints of...
We review the recent results from the event-by-event NLO pQCD + saturation + viscous hydrodynamics (EbyE NLO EKRT) model [1,2,3], where we perform a simultaneous analysis of LHC and RHIC bulk observables to systematically constrain the temperature dependence of the QCD matter shear viscosity-to-entropy ratio eta/s(T), and to test the initial state computation. In particular, we study the...
Exclusive vector meson production can be used to directly probe the gluon density of a hadron. Measuring the cross section differentially in transverse momentum transfer makes it possible to determine the transverse density profile (via coherent diffraction) and density fluctuations (incoherent diffraction) of the target hadron. This knowledge about the geometric fluctuations of the proton is...
