$\varphi$-meson production at forward/backward rapidity in high-energy nuclear collisions from a multiphase transport model

Within the framework of a multiphase transport model (AMPT), the $\varphi$-meson production is studied in $d+\text{Au}$ collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=200$ GeV in the forward ($d$-going, $1.2<y<2.2$) and backward (Au-going, $-2.2<y<-1.2$) directions. The AMPT model with string melting version (parton cascade turning on) describes the experimental data well, while the pure hadronic transport scenario of the AMPT model underestimates the $\varphi$-meson production rate in comparison with the data. Detailed investigations including the rapidity, transverse momentum, and collision system size dependencies of $\varphi$-meson nuclear modification factor indicate that a combination of the initial-state effect and a follow-up parton cascade is required in the AMPT model to describe the data. Similar calculations are also present in $p+\text{Pb}$ collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=5.02$ TeV and $p+p$ collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=2.76$ TeV. The findings from a comparison of AMPT model study with the data are consistent with that at RHIC energy.

Figure 1

(a) Invariant yields of $\varphi$ mesons as a function of $p_T$ in the $d$-going direction in $d+\text{Au}$ collisions and the results from $p+p$ collisions at $\sqrt{s_{NN}}$ = 200 GeV. (b) Invariant yields of $\varphi$ mesons as a function of $p_T$ in the Au-going direction. Experimental data from PHENIX Collaboration are also plotted for comparison. (c) Ratio of the results from the AMPT model with string melting version divided by the results from the AMPT model with the default version.

Figure 2

The nuclear modification factor of $\varphi$ meson as a function of rapidity. The line presents the results from the AMPT model with string melting scenario, while the solid circle data points show the experimental data from the PHENIX Collaboration [10].

Figure 3

The $R_{AA}$ as a function of $p_T$ from $d+\text{Au}$, Cu+Au, and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. Lines represent results from the AMPT model with string melting version and data points are experimental results from the PHENIX Collaboration.

Figure 4

The $R_{dAu}$ of $\varphi$ (top), $\pi$ (middle), and K (bottom) mesons as a function of $p_T$ in the forward rapidity region (left) and backward rapidity region (right) from the AMPT model with string melting scenario (solid lines). Results from the AMPT model without final-state interactions are also plotted to address the FSI contributions (dashed lines).

Figure 5

(a) Invariant yields of $\varphi$ mesons as a function of $p_T$ in the $p$-going direction in $p+\text{Pb}$ collisions at $\sqrt{s_{NN}}$ = 5.02 TeV and the results from $p+p$ collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. (b) Invariant yields of $\varphi$ mesons as a function of $p_T$ in the Pb-going direction. Curves represent the results from the AMPT model, while data points are experimental results from the ALICE Collaboration [11].