Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTesting of coalescence mechanism in high energy heavy ion collisions using two-particle correlations with identified particle trigger
106
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In central Au-Au collisions at top RHIC energy, two particle correlation measurements with identified hadron trigger have shown attenuation of near side proton triggered jet-like yield at intermediate transverse momentum ($p{_T}$), 2$< p{_T} <$ 6 GeV/$it{c}$. The attenuation has been attributed to the anomalous baryon enhancement observed in the single inclusive measurements at the same $p{_T}$ range. The enhancement has been found to be in agreement with the models invoking coalescence of quarks as a mechanism of hadronization. Baryon enhancement has also been observed at LHC in the single inclusive spectra. We study the consequence of such an enhancement on two particle correlations at LHC energy within the framework of A Multi Phase Transport (AMPT) model that implements quark coalescence as a mode of hadronization. In this paper we have calculated the proton over pion ratio and the near side per trigger yield associated to pion and proton triggers at intermediate $p{_T}$ from String Melting (SM) version of AMPT. Results obtained are contrasted with the AMPT Default (Def.) which does not include coalescence. Baryon enhancement has been observed in AMPT SM at intermediate $p{_T}$. Near side jet-like correlated yield associated to baryon (proton) trigger in the momentum region where baryon generation is enhanced is found to be suppressed as compared to the corresponding yields for the meson (pion) trigger in most central Pb-Pb events. No such effect has been found in the Default version of AMPT.
rate research
Read More
In this paper, we give an account of the peripheral-tube model, which has been developed to give an intuitive and dynamical description of the so-called ridge effect in two-particle correlations in high-energy nuclear collisions. Starting from a realistic event-by-event fluctuating hydrodynamical model calculation, we first show the emergence of ridge + shoulders in the so-called two-particle long-range correlations, reproducing the data. In contrast to the commonly used geometric picture of the origin of the anisotropic flow, we can explain such a structure dynamically in terms of the presence of high energy-density peripheral tubes in the initial conditions. These tubes violently explode and deflect the near radial flow coming from the interior of the hot matter, which in turn produces a two-ridge structure in single-particle distribution, with approximately two units opening in azimuth. When computing the two-particle correlation, this will result in characteristic three-ridge structure, with a high near-side ridge and two symmetric lower away-side ridges or shoulders. Several anisotropic flows, necessary to producing ridge + shoulder structure, appear naturally in this dynamical description. Using this simple idea, we can understand several related phenomena, such as centrality dependence and trigger-angle dependence.
Two-particle rapidity (or pseudorapidity) correlation function $C(y_1, y_2)$ was used in analysing fluctuation of particle density distribution in rapidity in high-energy heavy-ion collisions. In our research, we argue that for a centrality window, some additional correlation may be caused by a centrality span, when the mean two- and single-particle densities over a centrality window are used directly in the calculation , just like $left<N(y_1, y_2) right> / left[left<N(y_1)right>left<N(y_2)right>right]$. We concentrate on removing the influence of collision-centrality span on correlation function, and two calculation methods are raised. In one method, correlation coefficients are considered to be the ratios of probabilities (not the particle density). In the other method, a relative multiplicity is introduced to unity the events of different centralities. For testing the methods, {sc ampt} model is used and a toy granular model is built to simulate the fluctuation of particle density in rapidity.
We review studies of vortical motion and the resulting global polarization of $Lambda$ and $bar{Lambda}$ hyperons in heavy-ion collisions, in particular, within 3FD model. 3FD predictions for the global midrapidity polarization in the FAIR-NICA energy range are presented. The 3FD simulations indicate that energy dependence of the observed global polarization of hyperons in the midrapidity region is a consequence of the decrease of the vorticity in the central region with the collision energy rise because of pushing out the vorticity field into the fragmentation regions. At high collision energies this pushing-out results in a peculiar vortical structure consisting of two vortex rings: one ring in the target fragmentation region and another one in the projectile fragmentation region with matter rotation being opposite in these two rings.
We study the production of (hyper-)nuclei and di-baryons in most central heavy Ion collisions at energies of $E_{lab}=1-160 A$ GeV. In particular we are interested in clusters produced from the hot and dense fireball. The formation rate of strange and non-strange clusters is estimated by assuming thermal production from the intermediate phase of the UrQMD-hydro hybrid model and alternatively by the coalescence mechanism from a hadronic cascade model. Both model types are compared in detail. For most energies we find that both approaches agree in their predictions for the yields of the clusters. Only for very low beam energies, and for di-baryons including $Xi$s, we observe considerable differences. We also study the production of anti-matter clusters up to top RHIC energies and show that the observation of anti-$^4He$ and even anti-$^4_{Lambda}He$ is feasible. We have found a considerable qualitative difference in the energy dependence of the strangeness population factor $R_H$ when comparing the thermal production with the coalescence results.
Particle production in relativistic collisions of heavy nuclei is analyzed in a wide range of incident energies 2.7 GeV $le sqrt{s_{NN}}le$ 62.4 GeV. The analysis is performed within the three-fluid model employing three different equations of state (EoS): a purely hadronic EoS, an EoS with the first-order phase transition and that with a smooth crossover transition. It is found that the hadronic scenario fails to reproduce experimental yields of antibaryons (strange and nonstrange), starting already from lower SPS energies, i.e. $sqrt{s_{NN}}>$ 5 GeV. Moreover, at energies above the top SPS one, i.e. $sqrt{s_{NN}}>$ 17.4 GeV, the mid-rapidity densities predicted by the hadronic scenario considerably exceed the available RHIC data on all species. At the same time the deconfinement-transition scenarios reasonably agree (to a various extent) with all the data. The present analysis demonstrates certain advantage of the deconfinement-transition EoSs. However, all scenarios fail to reproduce the strangeness enhancement in the incident energy range near 30A GeV (i.e. a horn anomaly in the $K^+/pi^+$ ratio) and yields of $phi$-mesons at 20A--40A GeV.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
