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

Research paper by ** LHCb collaboration, R. Aaij, C. Abellan Beteta, A. Adametz, B. Adeva, M. Adinolfi, C. Adrover, A. Affolder, Z. Ajaltouni, J. Albrecht, F. Alessio, M. Alexander, S. Ali, G. Alkhazov, P. Alvarez Cartelle, et al.**

Indexed on: **30 Sep '13**Published on: **30 Sep '13**Published in: **High Energy Physics - Experiment**

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#### Abstract

The charged-particle production ratios $\bar{p}/p$, $K^-/K^+$, $\pi^-/\pi^+$,
$(p + \bar{p})/(\pi^+ + \pi^-)$, $(K^+ + K^-)/(\pi^+ + \pi^-)$ and $(p +
\bar{p})/(K^+ + K^-)$ are measured with the LHCb detector using $0.3 {\rm
nb^{-1}}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 0.9$ TeV and
$1.8 {\rm nb^{-1}}$ at $\sqrt{s} = 7$ TeV. The measurements are performed as a
function of transverse momentum $p_{\rm T}$ and pseudorapidity $\eta$. 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, $\Delta y \equiv y_{\rm beam} - y$, and is used to constrain models of
baryon transport.