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Sonia Kabana

Publications and source records attributed to Sonia Kabana.

14 recordsLinked to original sources

Beam energy dependence of identified particle production in heavy-ion collisions using a parton-hadron string dynamics model

We report predictions for the transverse momentum ($p_T$) spectra of $π^{\pm}$, $K^{\pm}$, $p$, and $\bar{p}$ in various collision centrality from Au + Au collisions at beam energies ($E_{lab}$) of 6.7, 8, 11, and 25 A~GeV using a parton-hadron string dynamics (PHSD) transport model. We studied the dependence of particle yields ($dN/dy$), mean transverse momenta ($\langle p_T \rangle$), and particle ratios on collision energy and centrality to understand the underlying mechanisms of particle production. A comparison of the PHSD model results with available experimental measurements provides a qualitative description of these observables. Our results highlight the importance of baryon stopping, strangeness production, pair production, and baryon-antibaryon annihilation in the high baryon density region. These findings also provide theoretical insights relevant to the ongoing beam energy scan program at RHIC and the future heavy-ion programs at FAIR and NICA.

nucl-th

Elliptic flow of charged hadrons in d+Au collisions at $\sqrt{s_{NN}} =$ 200 GeV using a multi-phase transport model

This study presents a comprehensive analysis of the elliptic flow coefficient, $v_2$, for charged hadrons at mid-rapidity in d+Au collisions at $\sqrt{s_{\mathrm{NN}}} = 200\mathrm{~GeV}$. Utilizing the AMPT model in both default and string melting modes, we examine the dependence of $v_2$ on transverse momentum, collision centrality, and particle type. Furthermore, we present $v_2$ scaled by participant eccentricity, which indicates a similar level of collectivity across different centrality intervals in d+Au collisions at $\sqrt{s_{\mathrm{NN}}} = 200\mathrm{~GeV}$ within the AMPT-SM model. Our results indicate that the early-stage partonic phase significantly influences $v_2$, as observed by variations in parton scattering cross-section, while the later stage hadronic rescattering shows minimal impact. Comparisons with STAR and PHENIX experimental data show that the AMPT model effectively captures the transverse momentum dependence of $v_2$, underlining the importance of parton scattering mechanisms and the need for careful interpretation of experimental results in asymmetric systems.

nucl-th

Anisotropic flow coefficients for charged hadrons in $O+O$ collisions at $\sqrt{s_{\mathrm{NN}}}=7$ TeV using AMPT

In this article, we report on the predictions of $v_2$, $v_3$ and $v_4$ for charged hadrons in O+O collisions at $\sqrt{s_{\mathrm{NN}}}~=~7$~TeV using both AMPT-default and AMPT-String Melting. These predictions are compared with the existing published data of $p+p$, $p+Pb$, and $Pb+Pb$ collisions at LHC energies. The transverse momentum ($p_T$) dependence of $v_2$ is also investigated for different centrality classes. $O+O$ collisions provide a unique opportunity to bridge the gap between small and large collision systems, offering critical insight into the onset of collective behavior in QCD matter.

hep-ph

Coalescence production of sexaquark with three diquarks in high-energy nuclear collisions

The coalescence production of sexaquark, a hypothetical stable state with quark content $(uuddss)$, is investigated by the parton and hadron cascade model PACIAE in $pp$ collisions at $\sqrt s = 7$ TeV. In this work, the compact sexaquark bound state of three diquarks is formed in the final partonic state by a two-step approach, which involves ``diquark" formation via partonic coalescence and sexaquark construction with dynamically constrained phase-space coalescence model successively. The yields, yield ratios, and dependences of spatial parameters (the size of diquark $D_{0}$ and the radius of sexaquark $R_{0}$) of (anti-)sexaquark are predicted. The yields of a hadronic molecule H-dibaryon $\mathrm{H}(ΛΛ)$ generated in the final hadronic state are also compared. These estimates provide references for future sexaquark searches and other exotic state studies, such as dibaryons.

hep-ph

Elliptic flow of inclusive charged hadrons in Au+Au collisions at $E_{lab} = 35\mathrm{~A~GeV}$ using the PHSD model

Elliptic flow ($v_2$) measurements of inclusive charged hadrons at mid-rapidity ($|η| <$ 1.0) in Au+Au collisions at $E_{lab} = 35\mathrm{~A~GeV}$ using the Parton Hadron String Dynamics (PHSD) model are presented as a function of centrality, transverse momentum ($p_\mathrm{T}$) and pseudo-rapidity ($η$). The $v_2$ results are obtained using the $η$-sub event plane method with respect to event plane angle ($ψ_{2}$) and participant plane angle ($ψ_{2}^{PP}$). $p_\mathrm{T}$-integrated charged hadron $v_2$ shows a strong centrality dependence in Au+Au collisions at $E_{lab} = 35\mathrm{~A~GeV}$. The eccentricity scaled elliptic flow ($v_2/\varepsilon_2$) also shows centrality dependence. The higher values of $v_2/\varepsilon_2$ in central collisions suggest development of stronger collectivity. The measurements are compared with the results from Au+Au collisions at $\sqrt{s_{\mathrm{NN}}} = 7.7\mathrm{~GeV}$ published by the STAR experiment at RHIC. We also compare results of HSD and PHSD modes of the model to investigate contribution of hadronic and partonic phases of the medium on the measured $v_2$. The current results serve as a prediction of the collective behavior of the matter produced in baryon rich and moderate temperature conditions for the upcoming Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR). These predictions are also useful for the interpretation of data measured at RHIC Beam Energy Scan (BES) program.

nucl-ex

Thermal production of sexaquarks in heavy-ion collisions

We present new results on the thermal production yield of a hypothetical state made of six quarks $uuddss$ assuming its production in heavy-ion collisions at the CERN LHC. A state with this quark content and mass low enough to be stable against decay in timescales of the order of the age of the Universe, has been hypothesized by one of us (G.F.) and has been discussed as a possible dark matter candidate. In this work we address for the first time the thermal production rate that can be expected for this state in heavy-ion collisions at colliders. For this estimate we use a thermal model which has been shown to describe accurately the production of hadrons and nuclei in heavy-ion collisions at LHC energy. This estimate is of great relevance for sexaquark searches at colliders as well as for its consideration as a dark matter candidate and for the composition of neutron stars.

hep-ph

New physics searches with heavy-ion collisions at the LHC

This document summarises proposed searches for new physics accessible in the heavy-ion mode at the CERN Large Hadron Collider (LHC), both through hadronic and ultraperipheral $γγ$ interactions, and that have a competitive or, even, unique discovery potential compared to standard proton-proton collision studies. Illustrative examples include searches for new particles -- such as axion-like pseudoscalars, radions, magnetic monopoles, new long-lived particles, dark photons, and sexaquarks as dark matter candidates -- as well as new interactions, such as non-linear or non-commutative QED extensions. We argue that such interesting possibilities constitute a well-justified scientific motivation, complementing standard quark-gluon-plasma physics studies, to continue running with ions at the LHC after the Run-4, i.e. beyond 2030, including light and intermediate-mass ion species, accumulating nucleon-nucleon integrated luminosities in the accessible fb$^{-1}$ range per month.

hep-ph

Highlights from the STAR experiment at RHIC

Experiments using heavy ion collisions at ultrarelativistic energies aim to explore the QCD phase transition and map out the QCD phase diagram. A wealth of remarkable results in this field have been reported recently, for example the Upsilon suppression discovered recently. We discuss recent results from the STAR experiment focusing on strangeness, charm and beauty production.

nucl-ex

$ϕ$ Meson As a Probe of QCD Equation of State

In this work, we extract the QCD Equation of State (EoS) using experimental results of the $ϕ$ meson produced in nuclear collisions at AGS, SPS and RHIC energies. The data are confronted to simple thermodynamic expectations and lattice results. The experimental data indicate a first order phase transition, with a mixed phase stretching energy density between $\sim$ 1 and 3.2 GeV/$fm^3$.

hep-ph

The QCD Equation of State with Thermal Properties of $ϕ$ mesons

In this work a first attempt is made to extract the Equation of State (EoS) using experimental results of the $ϕ$ meson produced in nuclear collisions at AGS, SPS and RHIC energies. The data are confronted to simple thermodynamic expectations and lattice results. The experimental data indicate a first order phase transition, with a mixed phase stretching energy density between $\sim$ 1 and 3.2 GeV/$fm^3$.

nucl-ex

Review of the experimental evidence on pentaquarks and critical discussion

We review and discuss the experimental evidence on predicted baryonic states made by 4 quarks and one antiquark, called pentaquarks. Theoretical and experimental advances in the last few years led to the observation of pentaquark candidates by some experiments, however with relatively low individual significance. Other experiments did not observed those candidates. Furthermore, the masses of the $θ^+$(1540) candidates exhibit a large variation in different measurements. We discuss to which extend these contradicting informations may lead to a consistent picture.

hep-ex

Pentaquarks: review of the experimental evidence

Pentaquarks, namely baryons made by 4 quarks and one antiquark have been predicted and searched for since several decades without success. Theoretical and experimental advances in the last 2 years led to the observation of a number of pentaquark candidates. We review the experimental evidence for pentaquarks as well as their non-observations by some experiments, and discuss to which extend these sometimes contradicting informations may lead to a consistent picture.

hep-ex

Strangeness observables and pentaquarks

We review the experimental evidence on firstly, strangeness production as a signature for the QCD phase transition and secondly, pentaquarks, the latest and most exotic manifestations of strangeness in hadrons.

hep-ph

Exotic particle searches with STAR at RHIC

We present preliminary results of the STAR experiment at RHIC on exotic particle searches in minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. We observe a narrow peak at 1734 $\pm$ 0.5 $\pm$ 5 MeV in the $ΛK^0_s$ invariant mass with width consistent with the experimental resolution of about 6 MeV within the errors. The statistical significance can be quantified between 3 and 6 $σ$ depending on cuts and methods. If this peak corresponds to a real particle state it would be a candidate for the $N^0$ or the $Ξ^0$ I=1/2 pentaquark states.

hep-ex