Figure 5:-

Caption:- The variation of mixed particle ratios as a function of <Npart> for (a) $K^{+}/\pi^{+} , (b) $p/\pi^{+}, (c) $K^{-}/\pi^{-},and (d) $\bar{p}/\pi^{-} at midrapidity (|y|<0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV. Results are compared with the published results in Au+Au collisions at other STAR energies. 

Figure 6:- 

Caption:-  The energy dependence of the integrated particle yield (dN/dy) normalized by <Npart>/2 for (a) $\pi^{+}(\pi^{-})$, (b)$K^{+}(K^{-})$, (c) p($\bar{p}$) at midrapidity (|y|<0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV for 0-5% centrality. Results are compared with the previous published results in STAR, AGS, SPS, and LHC to the most central collisions. 

 Figure 7:- 

Caption:- The energy dependence of the particle ratios for (a) $\pi^{-}/\pi^{+}$ , (b)  $K^{-}/K^{+}$, and (c) $\bar{p}/p$ at midrapidity (|y|<0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV for 0-5% centrality. Results are compared with the previous published results in STAR, AGS, SPS, and LHC to the most central collisions. 

Figure 8:- 

Caption:- Correlation of K-/K+ and \bar{p}/p ratio for 0-5% centrality at mid rapidity (|y| < 0.1) in Au+Au collisions at $\sqrt{s_{NN}}$  = 54.4 GeV for 0-5% centrality. Results are compared with the previous published results in STAR for the most central collisions. The curve represents the power law behaviour of the form K-/K+ = (\bar{p}/p)^\alpha with \alpha \approx 0.2.

Figure 9:- 

Figure 10:- 

  
Caption:- The energy dependence of  <mT>-m  for (a) $\pi^{+}$( $\pi^{-}$), (b) $K^{+}$( $K^{-}$), (c) p($\bar{p}$) at midrapidity (|y| < 0.1) in Au+Au collisions at $\sqrt{s_{NN}}$  = 54.4 GeV for 0-5% centrality. Results are compared with the previous published results in STAR, AGS, SPS, and LHC to the most central collisions.

Figure 11:-

Caption:- The variation of Tkin with $<\beta>$ is shown for various centralities in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV. The results for all are shown in comparison to the published results obtained for other datasets in Au+Au at various STAR energies.

 Figure 12:- 

Caption:- (a) The energy dependence of the kinetic freeze-out temperature for most central collisions. The curve represents the theoretical predictions of the chemical freeze-out temperature. (b) Energy dependence of the transverse radial flow velocity for central heavy ion collisions in comparison to the STAR and world data. The points for STAR data at 54.4 GeV are for 0-5% centrality. 

Figure 13:- 

Caption:- (a) The estimate of the product of Bjorken energy density and the formation time ( $\epsilon_{BJ} \times \tau$) as a function of centrality at mid rapidity (|y| < 0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV. The results are compared for the values calculated at other STAR and LHC energies. Errors shown are the statistical and systematic uncertainties added in quadrature. (b) as a function of mean integrated yield normalized by transverse area ( $<dN/dy>/S_{\perp}$) at mid rapidity (|y|< 0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV for 0-5% centrality. The results are compared for the values calculated at other STAR energies and the world data for the most central collisions. 

Table: The values of the parameters \alpha and \beta obtained by the fittings shown in Figure 13(a) are shown in table:

Figure 14:- 

Caption:-The centrality dependence of the integrated particle yield (dN/dy) normalized by <Npart>/2 for (a) $\pi^{+}$, (b) $K^{+}$ , (c) p, (d) $\pi^{-}$, (e) $K^{-}$ , (f) $\bar{p}$ at mid-rapidity (|y|<0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV. The error on <Npart> is not included for the clarity of plots. The experimental results are compared with AMPT (Default), AMPT (String Melting) and HIJING models.

Caption:- The centrality dependence of the mean transverse momentum for (a) $\pi^{+}$, (b) $K^{+}$ , (c) p, (d) $\pi^{-}$, (e) $K^{-}$ , (f) $\bar{p}$ at mid-rapidity (|y|<0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV. The experimental results are compared with AMPT (Default), AMPT (String Melting) and HIJING models.

Figure 16:- 

Caption:- The estimate of Bjorken energy density times formation time as a function of <Npart> at mid-rapidity (|y|<0.1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV.  The experimental results are compared with AMPT (Default), AMPT (String Melting) and HIJING models.

 Conclusions:-

• Transverse momentum spectra of \pi^{\pm}, K^{\pm}, p and \bar{p}  in Au+Au collisions at sqrt{s_{NN}} = 54.4 GeV using the STAR data have been studied in mid-rapidity (|y| < 0.1).

•  Normalized pi^{\pm}, K^{\pm} and p yields increase with the increasing number of participating nucleons which may indicate contributions from hard processes. For \bar{p} there is weak clear centrality dependence which can be attributed to an increasing baryon-antibaryon annihilation effects with increasing centrality.
•  \pi^{−}/\pi^{+} and K^{−}/K^{+} ratios show weak centrality dependence. \bar{p}/p ratio shows slight decrease from peripheral to central collisions which can be attributed to the increase in proton yields as a result of baryon stopping in central collisions
•  K^{+}/\pi^{+} and K^{−}/\pi^{−} ratios show slight increase from peripheral to mid-central collisions. p/\pi^{+} ratio slightly increases from peripheral to central collisions and \bar{p}/\pi^{−} ratio decreases slightly from peripheral to central collisions, this can together be attributed to the prominence of baryon stopping in central collisions.
•  ⟨pT⟩ shows clear centrality dependence for all the particles and it increases with the increasing centrality due to the increase in radial flow in central collisions. It also shows an increase with the increasing hadron mass.
•  \pi^{−}/\pi^{+}, K^{−}/K^{+} and \bar{p}/p at 54.4 GeV are in trend with other energies. \pi^{−}/\pi^{+} ratio is close to unity, K^{−}/K^{+} ratio is close to 0.84 and \bar{p}/p ratio is close to 0.4 (for most central collisions).
•  The correlation between K^{−}/K^{+} and \bar{p}/p ratio follows a power-law behaviour with α ≈ 0.2, it gives information on how the kaon production is related to net-baryon density.
•  The K/\pi ratio shows a horn which is suggested as a signature of phase transition from hadron gas to QGP at lower energies. The ratio at 54.4 GeV follows the world data trend.

•  Energy dependence of ⟨mT⟩ − m could possibly reflect the characteristic signatures of first order phase transition. ⟨mT⟩ − m for \pi^{\pm}, K^{\pm}, p and \bar{p} at 54.4 GeV follow the world data trend.
•  Kinetic freeze-out: Tkin increases from central to peripheral collisions (suggesting shorter lived fireball in peripheral collisions) while ⟨β⟩ decreases (indicating more radial flow when the collisions are central). Tkin and ⟨β⟩ are anti-correlated and follow the trend with other energies.
  
• Bjorken energy density: Increases with the increasing centrality and also with the increasing collision energy. For central collisions Bjorken energy densities exceed the phase transition energy density of 1 GeV/fm3 that had been the proposed value above which the quark-gluon plasma can be formed [Ref. Phys. Rev. D 27, 140 (1983)]

• The Bjorken energy density times the formation time shows similar N_{part} dependence (slope) from the lowest energy of 7.7 GeV to the highest LHC energy of 5020 GeV.