Elliptic flow of hadrons observed at relativistic heavy ion collision experiments at relativistic heavy ion collider (RHIC) and large hadron collider (LHC) provides us an important signature of possible deconfinement transition from the hadronic phase to partonic phase. However, hadronization processes of deconfined partons back into final hadrons are found to play a vital role in the observed hadronic flow. In the present work, we use a coalescence mechanism also known as recombination (ReCo) to combine quarks into hadrons. To get there, we have used the Boltzmann transport equation in relaxation time approximation to transport the quarks into equilibration and finally to freeze-out the surface, before coalescence takes place. A Boltzmann-Gibbs blast wave (BGBW) function is taken as an equilibrium function to get the final distribution and a power-like function to describe the initial distributions of partons produced in heavy ion collisions. In the present work, we try to estimate the elliptic flow of identified hadrons such as <math id="M2"><mi>π</mi></math>, <math id="M3"><mi>K</mi></math>, and <math id="M4"><mi>p</mi></math>, produced in Pb+Pb collisions at <math id="M5"><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>N</mi><mi>N</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>2.76</mn><mtext> </mtext><mtext>TeV</mtext></math> at the LHC for different centralities. The elliptic flow (<math id="M6"><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>) of identified hadrons seems to be described quite well in the available <math id="M7"><msub><mrow><mi>p</mi></mrow><mrow><mtext>T</mtext></mrow></msub></math> range. After the evolution of quarks until freeze-out time has been calculated using BTE-RTA, the approach used in this paper consists of combining two or more quarks to explain the produced hadrons at intermediate momenta regions. The formalism is found to describe the elliptic flow of hadrons produced in Pb+Pb collisions to a large extent.

India

Raghunath Sahoo

Mohammed Younus

Sushanta Tripathy

Swatantra Kumar Tiwari

Elliptic Flow of Hadrons via Quark Coalescence Mechanism Using the Boltzmann Transport Equation for Pb+Pb Collision at

Xe+Xe collisions at relativistic energies provide us with an opportunity to study a possible system with deconfined quarks and gluons, whose size is in between those produced by <math><mrow><mi>p</mi><mo>+</mo><mi>p</mi></mrow></math> and Pb+Pb collisions. In the present work, we have used a multiphase transport (AMPT) model with nuclear deformation to study the identified particle production, such as (<math><mrow><msup><mi>π</mi><mo>+</mo></msup><mo>+</mo><msup><mi>π</mi><mo>−</mo></msup></mrow></math>), (<math><mrow><msup><mrow><mi>K</mi></mrow><mo>+</mo></msup><mo>+</mo><msup><mrow><mi>K</mi></mrow><mo>−</mo></msup></mrow></math>), <math><msubsup><mi>K</mi><mrow><mi>s</mi></mrow><mn>0</mn></msubsup></math>, (<math><mrow><mi>p</mi><mo>+</mo><mover><mi>p</mi><mo>¯</mo></mover></mrow></math>), <math><mi>ϕ</mi></math>, and (<math><mrow><mi>Λ</mi><mo>+</mo><mover><mi>Λ</mi><mo>¯</mo></mover></mrow></math>) in Xe+Xe collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.44</mn><mspace width="0.28em"></mspace><mi>TeV</mi></mrow></math>. We study the <math><mrow><mi>p</mi><msub><mrow></mrow><mi>T</mi></msub></mrow></math> spectra, integrated yield, and <math><mrow><mi>p</mi><msub><mrow></mrow><mi>T</mi></msub></mrow></math>-differential and <math><mrow><mi>p</mi><msub><mrow></mrow><mi>T</mi></msub></mrow></math>-integrated particle ratios to (<math><mrow><msup><mi>π</mi><mo>+</mo></msup><mo>+</mo><msup><mi>π</mi><mo>−</mo></msup></mrow></math>) and (<math><mrow><msup><mrow><mi>K</mi></mrow><mo>+</mo></msup><mo>+</mo><msup><mrow><mi>K</mi></mrow><mo>−</mo></msup></mrow></math>) as a function of collision centrality. The particle ratios are focused on strange to nonstrange ratios and baryon to meson ratios. The effect of deformations has also been highlighted by comparing our results to the nondeformation case. We have also compared the results from AMPT string melting and the AMPT default version to explore possible effects of the coalescence mechanism. We observe that the differential particle ratios show strong dependence on centrality while the integrated particle ratios show no centrality dependence. We give a thermal model estimation of chemical freeze-out temperature and the Boltzmann-Gibbs Blast Wave analysis of kinetic freeze-out temperature and collective radial flow in Xe+Xe collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.44</mn><mspace width="0.28em"></mspace><mi>TeV</mi></mrow></math>.

Rutuparna Rath

Sudipan De

South Africa

Identified-particle production in Xe <math><mo>+</mo></math> Xe collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.44</mn></mrow></math> TeV using a multiphase transport model

Xe+Xe collision at relativistic energies may provide us with a partonic system whose size is approximately in between those produced by <math><mrow><mi>p</mi><mo>+</mo><mi>p</mi></mrow></math> and Pb+Pb collisions. The experimental results on anisotropic flow in Xe+Xe and Pb+Pb collisions should provide us with an opportunity to study the system size dependence of <math><msub><mi>v</mi><mn>2</mn></msub></math>. In the present work, we have used a multiphase transport model to calculate charged particles' <math><msub><mi>v</mi><mn>2</mn></msub></math> for Xe+Xe collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.44</mn><mspace width="0.16em"></mspace><mi>TeV</mi></mrow></math>. We have also tried to demonstrate the number of constituent quark, <math><msub><mi>N</mi><mi>q</mi></msub></math>, and <math><msub><mi>m</mi><mi>T</mi></msub></math> scaling of the elliptic flow. We find that <math><msub><mi>n</mi><mi>q</mi></msub></math> scaling of <math><msub><mi>v</mi><mn>2</mn></msub></math> is not observed for the identified hadrons. The <math><msub><mi>v</mi><mn>2</mn></msub></math> results from Xe+Xe collisions have also been compared to Pb+Pb collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn><mspace width="0.16em"></mspace><mspace width="4pt"></mspace><mi>TeV</mi></mrow></math>. We find that flow of charged particles in (50–60)% central collisions for xenon nuclei is almost 30% less than particle flow developed in lead ion collisions, implying the important role the system size plays in the development of particle collective motion in relativistic heavy ion collisions.

Predictions for azimuthal anisotropy in Xe+Xe collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.44</mn></mrow></math> TeV using a multiphase transport model