Speaker
Richard Alexander Barbieri
(Massachusetts Inst. of Technology (US))
Description
Studies of dijet and photon-jet properties in pPb collisions are of great importance to
establish a QCD baseline for hadronic interactions with cold nuclear matter. Dijet and
photon-jet production have been measured in pPb collisions at a nucleon-nucleon center-of-mass
energy of 5.02 TeV. The transverse momentum balance and azimuthal angle correlations are studied
in both dijet and photon-jet channels, leading to the observation that there is no significant
modification, which allows these systems to be used as tools to probe the nuclear modifications
of the parton distribution functions (PDFs). In the dijet system, pseudorapidity distributions
are studied as a function of the transverse energy in the forward calorimeters
(${\rm E_T}^{HF}$). The mean value of the dijet pseudorapidity is found to change
monotonically with increasing $\mathrm{E}_\mathrm{T}^{HF}$, indicating a correlation between the
energy emitted at large pseudorapidity and the longitudinal motion of the dijet frame. The
pseudorapidity distribution of the dijet system is compared with next-to-leading-order
perturbative QCD predictions obtained from both nucleon and nuclear PDFs, and the data more
closely match the latter.
In addition to the studies of initial state, the photon-jet measurements related to quenching in
PbPb are updated to have a more precise pp reference based on the 2013 LHC run at 2.76 TeV.
| On behalf of collaboration: | CMS |
|---|
Primary author
Richard Alexander Barbieri
(Massachusetts Inst. of Technology (US))
