Vector boson production in pPb and PbPb collisions at the LHC and its impact on nCTEQ15 PDFs

Abstract

We provide a comprehensive comparison of W ± /Z vector boson production data in pPb and PbPb collisions at the LHC with predictions obtained using the nCTEQ15 PDFs. We identify the measurements which have the largest potential impact on the PDFs, and estimate the effect of including these data using a Bayesian reweighting method. We find this data set can provide information as regards both the nuclear corrections and the heavy flavor (strange quark) PDF components. As for the proton, the parton flavor determination/separation is dependent on nuclear corrections (from heavy target DIS, for example), this information can also help improve the proton PDFs.

Nuclear parton distributions from lepton-nucleus scattering and the impact of an electron-ion collider

“…A major improvement in this respect has been the recent availability of data on hard-scattering cross-sections from proton-lead collisions at the LHC, with processes ranging from jet [23][24][25][26][27] and electroweak boson production [28][29][30][31][32], to heavy quark production [33][34][35][36][37][38][39][40] among several others. Indeed, measurements of hard probes in p+Pb collisions provide useful information to constrain the nPDFs, as was demonstrated by a few recent studies [41,42].…”

Constraints on nuclear parton distributions from dijet photoproduction at the LHC

“…To quantity the power of inclusive dijet photoproduction in Pb-Pb UPCs at the LHC to constrain nPDFs, we use the standard Bayesian reweighting procedure outlined in the literature [37,38,39]. In detail, starting with 2N error sets of nPDFs (N = 16 for nCTEQ15 [5] and N = 20 for EPPS16 [7]), one generates Nrep = 10, 000 replicas labeled by the index k as follows…”

“…In this work, we explore the potential of inclusive dijet photoproduction in Pb-Pb UPCs in the LHC kinematics to provide new constraints on nPDFs. In particular, using the results of our NLO QCD calculations of the cross section of this process [36] as pseudo-data, we study the effect of including these data using the Bayesian reweighting technique [37,38,39] on nCTEQ15, nCTEQ15np, and EPPS16 nPDFs. We find that depending on the assumed error on the pseudo-data, it leads to a significant reduction of uncertainties of nPDFs at small x A .…”

Probing the high-x content of the nuclei in the fixed-target mode at the LHC

“…We assume integrated luminosity of 10 fb −1 in the pp case and 100 pb −1 in proton-nucleus case (where we considered the Xe and W nuclei). The projections were done using either the profiling [7,8] or the reweighting method [9,10].…”