Nuclear parton distribution functions (nPDFs) of quarks and antiquarks affect the production of electroweak bosons in proton-lead (pPb) collisions. In this presentation, a new measurement of the Drell-Yan (DY) process is presented in pPb collision at the center of mass energy of 8.16 TeV with the CMS detector. The rapidity dependence of this process is particularly sensitive to nPDFs, but...
Dileptons are a prime probe of the deconfined state of strongly interacting matter, the Quark–Gluon Plasma (QGP), produced in high energy heavy ion collisions, as they are not affected by secondary strong interactions. A measurement of the thermal radiation from the QGP in the dielectron intermediate mass region allows to estimate the medium temperature. In this region the main component of...
At RHIC energies high pT direct photons are mainly produced by the
quark-gluon Compton scattering process. Being not disturbed by fragmentation
processes, they provide access to initial condition of partonic collisions.
Direct photon production in pp collisions serves an ideal probe for gluon
parton distribution functions (PDF), whereas quark PDFs are well constrained
by deeply inelastic...
ATLAS measurements of dimuons produced via $\gamma\gamma$ scattering processes in inelastic, non-ultra-peripheral Pb+Pb collisions at 5.02 TeV are presented using an integrated luminosity of 1.9 nb$^{-1}$. The $\gamma\gamma\rightarrow\mu^+\mu^-$ pairs are identified via selections on pair momentum asymmetry and acoplanarity, and the contribution from the heavy flavor decay background is...
High transverse momentum direct photons are penetrating probes in
relativistic heavy ion collisions. Once produced, they leave the collision
region virtually unaffected, even if a hot, dense partonic medium was
formed. This is also the reason why direct photons are immune to the
suppression observed for high pT hadrons and jets in heavy ion collisions,
but can probe the initial state...
The suppression of heavy quarkonia states in heavy-ion collisions is a phenomenon understood as a consequence of QGP formation in the hot, dense system produced in high
energy heavy ion collisions. A full assessment of the physics scenario requires a detailed study of effects present in Pb+Pb, in comparison to $pp$ collisions. In this poster, we present the results from the studies of prompt...
Recently, two scenarios have been proposed to resolve the discrepancy between photon yield and the flow coefficients measured in nuclear collisions at RHIC and the LHC. In the first, additional photons are produced from the early pre-equilibrium stage computed from the "bottom-up" thermalization scenario [1-3]. In the second, the thermal rates are enhanced close to the pseudo-critical...
