Measurement of prompt hadron production ratios in $pp$ collisions at $\sqrt{s}=$ 0.9 and 7 TeV

Abstract

The charged-particle production ratios $\bar{p}/p$, $K^{-}/K^{+}$, $\ddot{I}{€}^{-}/\ddot{I}{€}^{+}$, $(p+\bar{p})/(\ddot{I}{€}^{+}+\ddot{I}{€}^{-})$, $(K^{+}+K^{-})/(\ddot{I}{€}^{+}+\ddot{I}{€}^{-})$ and $(p+\bar{p})/(K^{+}+K^{-})$ are measured with the LHCb detector using $0.3\mathrm{n}{\mathrm{b}}^{-1}$ of $pp$ collisions delivered by the LHC at $\sqrt{s}=0.9$ TeV and $1.8\mathrm{n}{\mathrm{b}}^{-1}$ at $\sqrt{s}=7$ TeV. The measurements are performed as a function of transverse momentum $p_{\mathrm{T}}$ and pseudorapidity $\hat{I}\cdot$. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio $\bar{p}/p$ is also considered as a function of rapidity loss, $\hat{I}”y\equiv y_{\mathrm{beam}}-y$, and is used to constrain models of baryon transport.

Incorrect entries in Table 2 corrected. No consequences for rest of paper