Heavy ion collisions provide a unique probe of the quark-gluon plasma properties. The role of partonic degrees of freedom in p-Pb collisions at $sqrt{s_{NN}}$ = 5 TeV by studying the production cross section is studied. Experimental observable like the number of K$_S$ mesons is sensitive to the kinematic properties of the reaction. Our results demonstrate the importance of angular distribution for the partonic degrees of freedom in hadronization process.
We investigate probing the hot and dense nuclear matter with strange vector mesons ($K^*, bar{K}^*$). Our analysis is based on PHSD which incorporates partonic and hadronic dof and describes the full dynamics of HICs. This allows to study the $K^*$ a
nd $bar{K}^*$ meson formation from the QGP and the in-medium effects related to the modification of their properties during the propagation in dense and hot matter. We employ relativistic Breit-Wigner spectral functions for the $K^*,bar{K}^*$ mesons with self-energies obtained from a G-matrix approach to study the role of in-medium effects on the $K^*$ and $bar{K}^*$ meson dynamics in HIC from FAIR/NICA to LHC energies. According to our analysis most of the final $K^*/bar{K}^*$s, that can be observed experimentally, are produced during the late hadronic phase and stem dominantly from the $K (bar{K}) + pi to K^*(bar{K}^*)$ formation channel. The amount of $K^*/bar{K}^*$s originating from the QGP channel is comparatively small even at LHC energies and such $K^*/bar{K}^*$s can hardly be reconstructed experimentally due to the rescattering of final pions and (anti-)kaons. This mirrors the results from our previous study on the strange vector-meson production in HICs at RHIC energies. The influence of the in-medium effects on the dynamics of the $K^*/bar{K}^*$ is rather small since they are mostly produced at low baryon densities. Additional cuts on the shape of the observed signal and the range of the invariant mass region of the $K^*/bar{K}^*$ also affect the final spectra. We demonstrate that the $K^*/bar{K}^*$ in-medium effects are more visible at lower beam energy, e.g. FAIR/NICA and BES RHIC energies, where the production of $K^*/bar{K}^*$s occurs at larger baryon densities. Finally, we present the experimental procedures to extract information on the in-medium masses and widths by fitting final mass spectra at LHC energies.
The observed strong suppression of heavy flavored hadrons produced with high $p_T$, is caused by final state interactions with the created dense medium. Vacuum radiation of high-pT heavy quarks ceases at a short time scale, as is confirmed by pQCD ca
lculations and by LEP measurements of the fragmentation functions of heavy quarks. Production of a heavy flavored hadrons in a dense medium is considerably delayed due to prompt breakup of the hadrons by the medium. This causes a strong suppression of the heavy quark yield because of the specific shape of the fragmentation function. The parameter-free description is in a good accord with available data.
It is shown that hadron abundances in high energy e+e-, pp and p{bar p} collisions, calculated by assuming that particles originate in hadron gas fireballs at thermal and partial chemical equilibrium, are in very good agreement with the data. The fre
eze-out temperature of the hadron gas fireballs turns out to be nearly constant over a large center of mass energy range and not dependent on the initial colliding system. The only deviation from chemical equilibrium resides in the incomplete strangeness phase space saturation. Preliminary results of an analysis of hadron abundances in S+S and S+Ag heavy ion collisions are presented.
In this paper we estimate the double parton scattering (DPS) contribution for the heavy quark production in $pA$ collisions at the LHC. The cross sections for the charm and bottom production are estimated using the dipole approach and taking into acc
ount the saturation effects, which are important for high energies and for the scattering with a large nucleus. We compare the DPS contribution with the single parton scattering one and demonstrate that in the case of charm production both are similar in the kinematical range probed by the LHC. Predictions for the rapidity range analysed by the LHCb Collaboration are also presented. Our results indicate that the study of the DPS contribution for the heavy quark production in $pPb$ collisions at the LHC is feasible and can be useful to probe the main assumptions of the approach.
It is demonstrated that the fragmentation functions at large momentum fraction play a key role in hard hadron production from relativistic proton-proton collisions. We find that this region of the fragmentation functions is not strongly constrained b
y the electron-positron data. This freedom can be used (together with the transverse momentum distribution of partons) to reproduce hard pion-to-proton ratio data in relativistic proton-proton collisions.
O. Kot
,T. Obikhod
,O. Okhrimenko
.
(2020)
.
"Probing approach of the Parton-Hadron-String Dynamics in production for K$_S$ mesons"
.
Ievgenii Petrenko
هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا