Quenching of jets tagged with $W$ bosons in high-energy nuclear collisions

Abstract

We carry out the first detailed calculations of jet production associated with W gauge bosons in Pb+Pb collisions at the Large Hadron Collider (LHC). In our calculations, the production of W +jet in p+p collisions as a reference is obtained by Sherpa, which performs next-to-leading-order matrix element calculations matched to the resummation of parton shower simulations, while jet propagation and medium response in the quark-gluon plasma are simulated with the Linear Boltzmann Transport (LBT) model. We provide numerical predictions on seven observables of W +jet production with jet quenching in Pb+Pb collisions: the medium modification factor for the tagged jet cross sections I AA , the distribution in invariant mass between the two leading jets in N jets ≥ 2 events m jj , the missing p T or the vector sum of the lepton and jet transverse momentum | p M iss T |, the summed scalar p T of all the jets in an event S T , transverse momentum imbalance x jW , average number of jets per W boson R jW , and azimuthal angle between the W boson and jets ∆φ jW . The distinct nuclear modifications of these seven observables in Pb+Pb relative to that in p+p collisions are presented with detailed discussions.

Parton splitting scales of reclustered large-radius jets in high-energy nuclear collisions

“…3 shows that the fraction first increases with p jet T in the region p jet T < 80 GeV/c, as also illustrated in Refs. [52,90,91], and reaches its peak value (about 20%) near p jet T ≃ 80 GeV/c, then goes down with p jet T in the region p jet T > 80 GeV/c. The downtrend in the large p jet T region lead to slow increasing nuclear modification factor with p jet T .…”

Imaging nuclear modifications on parton distributions with triple-differential dijet cross sections in proton-nucleus collisions

“…More importantly, the measurements will provide an effective way to help confirm various nuclear effects, e.g., shadowing, anti-shadowing, EMC, and Fermi motion in different regions of x and their variations with probing scale Q 2 . It is also noteworthy that, the studied triple-differential cross sections can be straightforward generalized and applied to the study of other processes, such as vector-boson-tagged jet production [50][51][52] and heavy-quark dijet production [53]. We also hope the more accurate description of the initial-state cold nuclear matter effects provides a baseline to better understand the final-state jet quenching phenomena in relativistic heavyion collisions.…”