Signals of quark combination at hadronization in pp collisions at s=200 GeV

Abstract

We find signals of quark combination at hadronization from the experimental data of ${p}_{T}$ spectra of hadrons at midrapidity in $pp$ collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$. The first is the constituent quark number scaling property for ${p}_{T}$ spectra of ${\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}}$ and $\ensuremath{\phi}$ and that for ${p}_{T}$ spectra of $p$ and ${\ensuremath{\rho}}^{0}$. The second is that ${p}_{T}$ spectra of $\mathrm{\ensuremath{\Lambda}}$, ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}$, and ${K}^{*0}$ can be self-consistently described using the spectrum of strange quarks from $\ensuremath{\phi}$ data and that of up/down quarks from $p$ data in the equal-velocity combination mechanism. The third is that experimental data for ${p}_{T}$ spectrum of ${D}^{*+}$ are also well described by the spectrum of up/down quarks from $p$ data and a spectrum of charm quarks which is consistent with theoretical calculations of the fixed-order next-to-leading-logarithmic approach. These results indicate a similarity between hadron production in $pp$ collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$ and that at LHC energies. We predict ${p}_{T}$ spectra of single-charm hadrons and their spectrum ratios. We suggest systematic measurements in $pp$ collisions at $\sqrt{s}=200\text{ }\text{ }\mathrm{GeV}$ in the future so as to better understand the property of the small parton system created in $pp$ collisions at different collision energies.