${\mathrm{D}}_{\mathrm{s}}^{+}$ meson production at central rapidity in proton–proton collisions at $\sqrt{s}=7\text{TeV}$

Abstract

The $p_{\mathrm{T}}$-differential inclusive production cross section of the prompt charm-strange meson ${\mathrm{D}}_{\mathrm{s}}^{+}$ in the rapidity range $|y|<0.5$ was measured in proton–proton collisions at $\sqrt{s}=7\text{TeV}$ at the LHC using the ALICE detector. The analysis was performed on a data sample of $2.98\times {10}^8$ events collected with a minimum-bias trigger. The corresponding integrated luminosity is $L_{\mathrm{int}}=4.8{\text{nb}}^{-1}$. Reconstructing the decay ${\mathrm{D}}_{\mathrm{s}}^{+}\to \varphi {\pi }^{+}$, with $\varphi \to {\mathrm{K}}^{-}{\mathrm{K}}^{+}$, and its charge conjugate, about 480 ${\mathrm{D}}_{\mathrm{s}}^{\pm }$ mesons were counted, after selection cuts, in the transverse momentum range $2<p_{\mathrm{T}}<12\text{GeV}/c$. The results are compared with predictions from models based on perturbative QCD. The ratios of the cross sections of four D meson species (namely ${\mathrm{D}}^0$, ${\mathrm{D}}^{+}$, ${\mathrm{D}}^{⁎+}$ and ${\mathrm{D}}_{\mathrm{s}}^{+}$) were determined both as a function of $p_{\mathrm{T}}$ and integrated over $p_{\mathrm{T}}$ after extrapolating to full $p_{\mathrm{T}}$ range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$, ep and pp interactions at various centre-of-mass energies.