arXiv subjects

P. Sett

Publications and source records attributed to P. Sett.

4 recordsLinked to original sources

arXiv2014

Pion $p_T$ spectra in $p+p$ collisions as a function of $\sqrt{s}$ and event multiplicity

We study the charged pion transverse momentum ($p_T$) spectra in $p$+$p$ collisions as a function of collision energy $\sqrt{s}$ and event multiplicity using Tsallis distribution. This study gives an insight of the pion production process in $p+p$ collisions. The study covers pion spectra measured in $p+p$ collisions at SPS energies (6.27-17.27 GeV), RHIC energies (62.4 GeV and 200 GeV) and LHC energies (900 GeV, 2.76 TeV and 7 TeV). The Tsallis parameters have been obtained and parameterized as a function of $\sqrt{s}$. The study suggests that as we move to higher energy more and more hard processes contribute to the spectra. We also study the charged pion spectra for different event multiplicities in $p$+$p$ collisions for LHC energies using Tsallis distribution. The variation of the Tsallis parameters as a function of event multiplicity has been obtained and their behavior is found to be independent of collision energy.

hep-ph↗

arXiv2013

System size dependence of hadron $p_T$ spectra in p+p and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

We make a systematic study of transverse momentum ($p_T$) spectra of hadrons produced in $p+p$ and in different centralities of Au+Au collisions at $\sqrt{s}=200$\,GeV using phenomenological fit functions. The Tsallis distribution gives a very good description of hadron spectra in $p+p$ collisions with just two parameters but does not produce the same in Au+Au collisions at intermediate $p_{T}$. To explain the hadron spectra in heavy ion collisions in a wider $p_{T}$ range we propose a modified Tsallis function by introducing an additional parameter which accounts for collective flow. The new analytical function gives a very good description of both mesons and baryons spectra at all centralities of Au+Au collisions in terms of parameters having a potential physics interpretation. With this modified Tsallis function we study the spectra of pions, kaons, protons, $Λ(1115)$ and $Ξ^{-}$ as a function of system size at $\sqrt{s_{NN}}$ = 200 GeV. The parameter representing transverse flow increases with system size and is found to be more far baryons than that for mesons in central Au+Au collisions. The freeze-out temperature for baryons increases with centrality in Au+Au collisions more rapidly than for mesons.

nucl-th↗

arXiv2013

Hadron spectra in p+p collisions at RHIC and LHC energies

We present the systematic analysis of transverse momentum ($p_T$) spectra of identified hadrons in p+p collisions at RHIC ($\sqrt{s}$ = 62.4 and 200 GeV) and at LHC energies ($\sqrt{s}$ = 0.9, 2.76 and 7.0 TeV) using phenomenological fit functions. We review various forms of Hagedorn and Tsallis distributions and show their equivalence. We use Tsallis distribution which successfully describes the spectra in p+p collisions using two parameters, Tsallis temperature $T$ which governs the soft bulk spectra and power $n$ which determines the initial production in partonic collisions. We obtain these parameters for pions, kaons and protons as a function of center of mass energy ($\sqrt{s}$). It is found that the parameter $T$ has a weak but decreasing trend with increasing $\sqrt{s}$. The parameter $n$ decreases with increasing $\sqrt{s}$ which shows that production of hadrons at higher energies are increasingly dominated by point like qq scatterings. Another important observation is with increasing $\sqrt{s}$, the separation between the powers for protons and pions narrows down hinting that the baryons and mesons are governed by same production process as one moves to the highest LHC energy.

hep-ph↗

arXiv2012

Transverse mass spectra and scaling of hadrons at RHIC and LHC energies

We present a systematic study of transverse mass spectra ($m_T$) of mesons and baryons at RHIC and LHC energies. In an earlier study, it was shown that all the mesons produced in p+p and d+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV follow $m_T$ scaling while in Au+Au collisions at same energy the mesons with strange and charm quark contents do not follow $m_T$ scaling which can be attributed to medium modifications. We extend this study for baryons produced in all above colliding systems at $\sqrt{s_{NN}}$ = 200 GeV. Although all available baryon spectra behave differently from mesons but are found to scale with protons for both p+p and d+Au collisions. In case of Au+Au collisions, the strange baryons behave differently from protons. This study has also been performed on the meson spectra in p+p collisions at 62.4 GeV which lies in between the highest RHIC energy and SPS energy where the $m_T$ scaling was first observed and we arrive at same conclusions as those at 200 GeV. We test the $m_T$ scaling at LHC with the first meson spectra measured in p+p collisions at 900 GeV and find that the $m_T$ spectra of kaons and $ϕ$ do not scale with pions. Thus $m_T$ scaling which was working well up to p+p collisions at 200 GeV seems to be broken. Here we use all data measured in the mid rapidity region. Baryon to meson ratio is studied as a function of $m_T$, at different energies and for different systems and is found that this ratio for p+p at 900 GeV is quite different from that in p+p collisions at RHIC energies.

hep-ph↗