Production ofZ⁰and ${W}^{+}{/W}^{-}$ in relativistic heavy-ion collisions at the LHC

Abstract

The productions of massive gauge bosons, Z 0 and W + /W − , in heavy-ion reactions at the LHC, provide an excellent tool to study the cold nuclear matter effects in high-energy nuclear collisions. In this paper we investigate Z 0 and W + /W − productions in p+Pb and Pb+Pb at the LHC, at NLO and NNLO with DYNNLO incorporating the nuclear PDFs (nPDFs) parametrization sets EPS09 and DSSZ, within the framework of perturbative QCD. The numerical simulations of the transverse momentum spectra, rapidity dependence, and related nuclear modification factors for Z 0 and W particles, as well as the charge asymmetry for W boson, are provided and tested against the latest experimental data. It is found that the theoretical results with EPS09 and DSSZ nPDFs can give good descriptions of the recent data on Z 0 and W ± particles in p+Pb and Pb+Pb within the experimental error bars, though some differences between results with EPS09 and DSSZ can be observed, especially in the rapidity dependence of the Z 0 yield. Theoretical predictions for future measurements on Z 0 and W in p+Pb and Pb+Pb collisions at the LHC are also provided.

Global analysis of nuclear parton distribution functions and their uncertainties at next-to-next-to-leading order

“…Some experimental studies on different aspects of heavy-ion collisions are presented in Refs [101][102][103][104][105][106][107][108][109][110][111][112][113][114]. W and Z boson production in proton-nucleus (p-A) and nucleus-nucleus (A-A) collisions at the CERN-LHC offer a unique opportunity to probe nuclear PDFs.…”

Probing shadowed nuclear sea with massive gauge bosons in the future heavy-ion collisions

“…The CMS measurement is made in the finalstate phase volume defined by the invariant mass, transverse momentum, and pseudorapidity of the dilepton as: 60 GeV < m ll < 120 GeV, p l T > 20 GeV, and |η l | < 2.1. The DYNNLO program has also been shown to give good agreement with the CMS data on the Z 0 rapidity distribution, and with the transverse momentum spectra of Z 0 and W measured by ATLAS [11].…”

“…[11]. In hadronic collisions, the differential cross section of vector boson production A + B → V + X → ll + X through the Drell-Yan mechanism [31,32] could be calculated within the QCDimproved parton model [33,34].…”

“…The production of massive vector bosons Z 0 /W ± in highenergy nuclear collisions has long been regarded as an excellent tool to probe the initial-state cold nuclear matter (CNM) a e-mail: pengru@mail.dlut.edu.cn b e-mail: bwzhang@mail.ccnu.edu.cn effects in the ultra-relativistic heavy-ion collisions (HIC) at the LHC because Z 0 /W ± do not participate in strong interactions and the mean-free-path of massive vector bosons (or more precisely, the leptons decayed from Z 0 /W ± ) is rather long [1][2][3][4][5][6][7][8][9][10][11]. In proposed heavy-ion programs at the Future Circular Collider (FCC) at CERN [12], and the Circular Electron Positron Collider with a subsequent Super proton-proton Collider (CEPC-SPPC) in China [13], the vector gauge boson productions may still play a very important role in investigating the high-density QCD in the initial state and making precise constraints on CNM effects and nuclear parton distribution functions (nPDFs) at very small x.…”

“…Recent studies have shown that the heavy gauge boson production in nuclear reactions at the LHC energies could shed light on several CNM effects, especially the shadowing and anti-shadowing effects (for Z /W ) and isospin effect (for W ± ) [11,[19][20][21][22][23]. In the conceptual designs of FCC [15] and CEPC-SPPC [24] the center-of-mass energy for protonproton collisions could reach up to 100 TeV, which may give an energy of about √ s N N = 63 TeV for proton-lead collisions and about √ s N N = 39 TeV for lead-lead collisions.…”