Measurement of $\hat{I}\yen$ production in $pp$ collisions at $\sqrt{s}=5\mathrm{TeV}$

Abstract

The production cross-sections of $\hat{I}\yen$ mesons, namely $\hat{I}\yen (1S)$, $\hat{I}\yen (2S)$ and $\hat{I}\yen (3S)$, in $pp$ collisions at $\sqrt{s}=5\mathrm{TeV}$ are measured with a data sample corresponding to an integrated luminosity of $9.13\pm 0.18{\mathrm{pb}}^{-1}$ collected by the LHCb detector. The $\hat{I}\yen$ mesons are reconstructed in the decay mode $\hat{I}\yen \to \hat{I}{¼}^{+}\hat{I}{¼}^{-}$. Double differential cross-sections times branching fractions, as functions of the transverse momentum $p_{\mathrm{T}}$ and the rapidity $y$ of the $\hat{I}\yen$ mesons, are measured in the range $p_{\mathrm{T}}<20\mathrm{GeV}/c$ and $2.0<y<4.5$. The results integrated over these $p_{\mathrm{T}}$ and $y$ ranges are $\ddot{I}ƒ(\hat{I}\yen (1S))\times \mathcal{B}(\hat{I}\yen (1S)\to \hat{I}{¼}^{+}\hat{I}{¼}^{-})=2101\pm 33\pm 83\mathrm{pb},$ $\ddot{I}ƒ(\hat{I}\yen (2S))\times \mathcal{B}(\hat{I}\yen (2S)\to \hat{I}{¼}^{+}\hat{I}{¼}^{-})=526\pm 20\pm 21\mathrm{pb},$ $\ddot{I}ƒ(\hat{I}\yen (3S))\times \mathcal{B}(\hat{I}\yen (3S)\to \hat{I}{¼}^{+}\hat{I}{¼}^{-})=242\pm 16\pm 10\mathrm{pb},$ where the first uncertainties are statistical and the second are systematic. The ratios of cross-sections between measurements of two different $\hat{I}\yen$ states and between measurements at different center-of-mass energies are determined. The nuclear modification factor of $\hat{I}\yen (1S)$ at $\sqrt{s}=5\mathrm{TeV}$ is updated as well using the directly measured cross-section results from this analysis.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-036.html (LHCb public pages)