The production of $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ resonances has been measured in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval $-$0.5 $<~$ $y$ $<~$ 0 and the transverse momentum spectra are measured for various multiplicity classes up to $p_{\rm T}$ = 20 GeV/$c$ for $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $p_{\rm T}$ = 16 GeV/$c$ for $\mathrm{\phi(1020)}$. The $p_{\rm T}$ -integrated yields and mean transverse momenta are reported and compared with previous results in pp, p-Pb and Pb-Pb collisions. The $x_{\mathrm{T}}$ scaling for $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ resonance production is newly tested in p-Pb collisions and found to hold in the high-$p_{\rm T}$ region at Large Hadron Collider energies. The nuclear modification factors ($R_{\rm pPb}$) as a function of $p_{\rm T}$ for $\mathrm{K}^{*0}$ and $\mathrm{\phi}$ at $\sqrt{s_{NN}}$ = 8.16 TeV are presented along with the new $R_{\rm pPb}$ measurements of $\mathrm{K}^{*0}$, $\mathrm{\phi}$ , $\Xi$, and $\Omega$ at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. At intermediate $p_{\rm T}$ (2-8 GeV/$c$), $R_{\rm pPb}$ of $\Xi$, $\Omega$ show a Cronin-like enhancement, while $\mathrm{K}^{*0}$ and $\mathrm{\phi}$ show no or little nuclear modification. At high $p_{\rm T}$ ($>$ 8 GeV/$c$), the $R_{\rm pPb}$ values of all hadrons are consistent with unity within uncertainties. The $R_{\rm pPb}$ of $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ at $\sqrt{s_{\rm NN}}$ = 8.16 and 5.02 TeV show no significant energy dependence.
Phys. Rev. C 107 (2023) 055201
HEP Data
e-Print: arXiv:2110.10042 | PDF | inSPIRE
CERN-EP-2021-200
Figure group
Figure 1
Invariant mass distributions for K*$^0$ and $\phi$ in the multiplicity class 0--100$\%$ and transverse momentum range 1.4 $\leq p_{\rm T} <$ 1.6 GeV/$c$ and 0.6 $\leq p_{\rm T} <$ 0.8 GeV/$c$, respectively. In the upper panels, (a) and (b), black markers show the unlike-sign invariant mass distributions and red markers show the normalized mixed event background. After the background subtraction the signals are shown in the lower panels (c) and (d). The K*$^0$ peak is described by a Breit-Wigner function whereas the $\phi$ peak is fitted with a Voigtian function. The residual background is described by the 2$^{nd}$ order polynomial function. |  |
Figure 2
Top panels: Transverse momentum spectrum of K*$^0$ (left) and $\phi$ (right) as a function of $p_{\rm T}$ for the NSD events, measured in the rapidity interval $-$0.5 $< y$ $<$ 0 for p$-$Pb collisions at $\sqrt{s_{\rm NN}} = 8.16$ TeV. The statistical and systematic uncertainties are shown as bars and boxes, respectively. The NSD spectrum is compared with the predictions from EPOS-LHC, DPMJET and HIJING. Bottom panels: The ratios of $p_{\rm T}$ spectra from model to data. The shaded bands around unity describe the statistical and systematic uncertainties of the data point. |   |
Figure 3
Top panels: Energy dependence comparison of the transverse momentum spectra of K*$^0$ (left) and $\phi$ (right) as a function of $p_{\rm T}$ for the NSD events, measured in the rapidity interval $-$0.5 $<$ $y$ $<$ 0 for p$-$Pb collisions at $\sqrt{s_{\rm NN}} =$ 5.02 and 8.16 TeV. Bottom panels: The ratio of $p_{\rm T}$ spectrum at $\sqrt{s_{\rm NN}} =$ 8.16 TeV to the $p_{\rm T}$ spectrum at $\sqrt{s_{\rm NN}} =$ 5.02 TeV. The ratio is compared with the predictions from EPOS-LHC, DPMJET and HIJING. The statistical and systematic uncertainties are shown as bars and boxes, respectively. |   |
Figure 4
Top panels: The transverse momentum spectra of K*$^0$ (left) and $\phi$ (right) for various multiplicity classes, measured in the rapidity interval $-0.5 <$ $y$ $<$ 0 for p$-$Pb collisions at $\sqrt{s_{\rm NN}} =$ 8.16 TeV. Bottom panels: The ratios of $p_{\rm T}$ spectra of given event multiplicity classes to the NSD spectra are shown. The statistical and systematic uncertainties are shown as bars and boxes, respectively. |   |
Figure 5
The multiplicity-scaled integrated yield $((\mathrm{d}N/\mathrm{d}y)/(\langle\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta\rangle_{|\eta|<0.5}))$ (upper panels) and mean transverse momentum $(\langle p_{\mathrm{T}}\rangle)$ (bottom panels) for K*$^0$ (left panels) and $\phi$ (right panels) as a function of $\langle\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta\rangle_{|\eta|<0.5}$ measured in the ALICE central barrel in pp collisions at $\sqrt{s}$ = 7, 13 TeV, in p$-$Pb collisions at $\sqrt{s_{\rm NN}} =$ 5.02 , 8.16 TeV and Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} =$ 2.76 , 5.02 TeV. Measurements are compared with the predictions from EPOS-LHC, DPMJET and HIJING for p$-$Pb collisions at $\sqrt{s_{\rm NN}} =$ 8.16 TeV. Statistical uncertainties are represented as bars, boxes indicate total systematic uncertainties. |  |
Figure 8
Nuclear modification factor of K*$^0$ and $\phi$ as a function of $\pt$ in p$-$Pb collisions at different energies $\snn$ = 5.02 and 8.16 TeV. The statistical and systematic uncertainties are represented by vertical bars and boxes, respectively. The normalization uncertainties are shown in each panel as boxes around $R_{\rm pPb}$ = 1 near $\pt = 0$ GeV/$c$. |  |
Figure 9
The nuclear modification factor $R_{\rm pPb}$ as a function of transverse momentum $\pt$ for different particle species in p$-$Pb collisions at $\snn$ = 5.02 and 8.16 TeV. For comparison the results for $\pi$, K, and p are also shown. The statistical and systematic uncertainties are represented by vertical bars and boxes, respectively. The normalization uncertainties are shown in each panel as boxes around $R_{\rm pPb}$ = 1 near $\pt = 0$ GeV/$c$. |  |