First measurement of the ratio of $\psi (2S)$-to-$J/\psi$ inclusive production in $p\mathrm{Ar}$ and $pp$ collisions at $\sqrt{s_{\mathrm{NN}}}=113\mathrm{GeV}$ with SMOG2

LHCb collaboration, R. Aaij, M. Abdelfatah +1162

A measurement of the $\psi (2S)$-to-$J/\psi$ production cross-section ratio is performed in proton-argon ($p\mathrm{Ar}$) and proton-proton ($pp$) collisions in fixed-target mode at $\sqr…