Abstract
The centrality dependencies of the inclusive neutral pion and prompt photon nuclear modification factors for p+Pb collisions at the LHC are studied using a spatially dependent set of nuclear PDFs, EPS09s. The calculations are performed at mid- and forward rapidities searching for an observable which would optimally probe the spatial dependence of the nuclear PDFs. In addition, we discuss to which x values of the nucleus the different observables are sensitive.
Highlights
In the framework of collinear factorization [1, 2], the cross section for producing a hard parton k in a nuclear collision can be calculated as dσAB→k+X =fiA(x1, Q2) ⊗ fjB(x2, Q2) ⊗ dσij→k+X + O(1/Q2), (1)i,j,X where fiA(x, Q2)s are the nuclear parton distribution functions describing the number distributions of parton i at given values of momentum fraction x and scale Q for nucleus A
In Ref. [9] we addressed this problem by developing a model framework for spatially dependent nuclear parton distribution functions (nPDFs) which is described
Centrality dependent nuclear modification factor Incorporating the spatially dependent nPDFs into the factorization formula (1) and multiplying this with the nuclear overlap function gives the yield of hard partons k corresponding to a specific impact parameter b in a collision of nuclei A and B as follows: dN AB→k+X (b) = d2s TA(s1) TB(s2)
Summary
It has been observed that the nPDFs, if they exist, are modified with respect to the free proton PDFs [3, 4, 5, 6]. This modification can be made explicit by decomposing the nPDFs as fiA(x, Q2) = RiA(x, Q2) fiN (x, Q2),. More predictions for p+Pb collisions at the LHC with other approaches can be found from compilation [10]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have