The results of the model analysis of hadron femtoscopic correlations and factorial moments of particle multiplicity in heavy ion collisions for the energy range of the Beam Energy Scan (BES) program ...at RHIC and future NICA collider are presented. For this purpose, the simulation of Au+Au collisions at center-of-mass energies 7.7 and 11.5 GeV per nucleon pair using the UrQMD, vHLLE+UrQMD (with the crossover and first-order equation of states), and HYDJET++ event generators was performed. The sensitivity of pion and kaon correlation radii and the dependence of the factorial moments on heavy ion beam energy to quark–hadron phase transition details was studied. In addition, the possible influence of some relevant detector effects on the corresponding experimental observables is discussed.
The Monte Carlo event generator HYDJET++ (HYDrodynamics with JETs) contains the description of both soft and hard processes in relativistic heavy-ion collisions by combining the parametrized ...hydrodynamics with the treatment of jets. The interplay of hard and soft processes describes the violation of the mass hierarchy of meson and baryon elliptic (v2) and triangular (v3) flows at intermediate transverse momenta, the fall-off of the flow harmonics after the certain pT threshold, and the worsening of the number-of-constituent-quark (NCQ) scaling of v2 and v3 at LHC energies compared to that at RHIC ones. The role of this interplay in di-hadron correlations and in production of open and hidden charm in heavy-ion collisions at RHIC and LHC energies is also discussed.
We study the influence of spatial and dynamical anisotropies in relativistic heavy-ion collisions on the differential elliptic and triangular flows of charged hadrons and, simultaneously, on the ...second- and third-order oscillations of the femtoscopic radii. Calculations of Pb + Pb collisions at s = 2.76 TeV were done within the HYDrodynamics with JETs (HYDJET++) event generator, which allows one to investigate the role of each of the anisotropy kinds separately. It is found that the bare geometric anisotropy provides either the wrong sign of elliptic and triangular flows or out-of-phase oscillations of R2out and R2side, respectively. Dynamical anisotropy is able to describe qualitatively both characteristics correctly. For the correct quantitative description of the data, one has to employ both spatial and dynamical anisotropies.
HYDJET++ model combines the description of soft processes with the treatment of hard partons propagating medium. The model is employed for the analysis of PbPb collisions at LHC energies, ...particularly, the azimuthal anisotropy phenomena, flow, femtoscopy, hard probes. The influence of geometric and dynamical anisotropies on the development of flow harmonics and, simultaneously, on the second- and third-order oscillations of femtoscopy radii were studied. The interplay of soft hydro-like processes and jets is able to describe the violation of the mass hierarchy of meson and baryon elliptic and triangular flows at transverse momentum pT>2 GeV/c, the fall-off of the anisotropic flow harmonics at intermediate transverse momenta, and the worsening of the number-of-constituent-quark (NCQ) scaling of elliptic/triangular flow at LHC compared to RHIC energies. The cross-talk of elliptic and triangular flows leads to emergence of higher order harmonics in the model and to appearance of ridge structure in dihadron angular correlations in a broad pseudorapidity range. Recently, the model was further extended to describe quantitatively the event-by-event fluctuations of the anisotropic flow. The model calculations agree well with the experimental data.
Nuclear geometry of jet quenching Lokhtin, I.P.; Snigirev, A.M.
The European physical journal. C, Particles and fields,
09/2000, Letnik:
16, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The most suitable way to study jet quenching as a function of the distance traversed is varying the impact parameter b of the ultrarelativistic nucleus–nucleus collision (the initial energy density ...in the nuclear overlapping zone is almost independent of b up to \(b \sim R_A\)). It is shown that the b-dependences of the medium-induced radiative and collisional energy losses of a hard parton jet propagating through dense QCD matter are very different. The experimental verification of this phenomenon could be performed for a jet with non-zero cone size based on the essential difference between the angular distributions of the collisional and radiative energy losses.
The status of CMS jet simulations and physics analysis in heavy ion collisions is presented. Jet reconstruction and high-pT particle tracking in the high multiplicity environment of heavy ion ...collisions at the LHC using the CMS calorimetry and tracking system are described. The Monte Carlo tools used to simulate jet quenching are discussed.
We discuss the modification of a jet fragmentation function due to medium-induced partonic energy loss in context of leading particle observables in ultrarelativistic nucleus–nucleus interactions. We ...also analyze the relation between in-medium softening jet fragmentation function and suppression of the jet rates due to energy loss outside the jet cone. The predicted anticorrelation between two effects allows to probe a fraction of partonic energy loss carried out of the jet cone and truly lost to the jet.
The potential of coming experiments on the Large Hadron Collider (LHC) to observe the rescattering and energy loss of heavy quarks in the dense matter created in heavy ion collisions is discussed. We ...analyze the sensitivity of high-mass \(\mu^+\mu^-\) pairs from \(B \overline{B}\) semileptonic decays and secondary \(J/\psi\)'s from single B decays to the medium-induced bottom quark energy loss.
Angular structure of radiative and collisional energy losses of a hard parton jet propagating through dense QCD-matter is investigated. For small angular jet cone sizes,
θ
0≲5°, the radiative energy ...loss is shown to dominate over the collisional energy loss due to final state elastic rescattering of the hard projectile on thermal particles in the medium. Due to coherent effects, the radiative energy loss decreases with increasing the angular size the jet. It becomes comparable with the collisional energy loss for
θ
0≳5°−10°.
The azimuthal anisotropy of jet spectra due to energy loss of jet partons in azimuthally non-symmetric volume of dense quark–gluon matter is considered for semi-central nuclear interactions at ...collider energies. We develop the techniques for event-by-event analysing the jet azimuthal anisotropy using particle and energy elliptic flow, and suggest a method for calculation of coefficient of jet azimuthal anisotropy without reconstruction of nuclear reaction plane.
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