Production ofJ/ψ and ψ(2S) mesons inπ−Be collisions at 515 GeV/c

We have studied the production of J/ψ and ψ(2S) charmonium mesons in 515 GeV/c ${\mathrm{\pi }}^{\mathrm{-}}$Be collisions in the Feynman-x range 0.1<${\mathit{x}}_{\mathit{F}}$<0.8. J/ψ mesons were detected via their decay into ${\mathrm{\mu }}^{+}$ ${\mathrm{\mu }}^{\mathrm{-}}$, and ψ(2S) mesons were studied in both the ${\mathrm{\mu }}^{+}$ ${\mathrm{\mu }}^{\mathrm{-}}$ and J/ψ${\mathrm{\pi }}^{+}$ ${\mathrm{\pi }}^{\mathrm{-}}$ decay modes. J/ψ differential cross sections have been measured as functions of ${\mathit{x}}_{\mathit{F}}$,${\mathit{p}}_{\mathit{T}}^2$, and the cosine of the Gottfried-Jackson decay angle. We measure an inclusive J/ψ cross section of B(J/ψ→${\mathrm{\mu }}^{+}$ ${\mathrm{\mu }}^{\mathrm{-}}$)σ(${\mathrm{\pi }}^{\mathrm{-}}$Be→J/ψ+X)/A= [9.3±0.1(stat)±1.1(syst)] nb/nucleon for J/ψ ${\mathit{x}}_{\mathit{F}}$≳0.1. Our results are compared with those from other experiments performed at lower beam energies. We also measure the differential ψ(2S) cross section as a function of both ${\mathit{x}}_{\mathit{F}}$ and ${\mathit{p}}_{\mathit{T}}^2$, and a ψ(2S) inclusive cross section of B(ψ(2S)→J/ψ${\mathrm{\pi }}^{+}$ ${\mathrm{\pi }}^{\mathrm{-}}$)σ(${\mathrm{\pi }}^{\mathrm{-}}$Be→ψ(2S)+X)/A=[7. 4±1.5(stat)±1.2(syst)] nb/nucleon for ψ(2S) ${\mathit{x}}_{\mathit{F}}$≳0.1. The fraction of the inclusive J/ψ yield due to ψ(2S) meson decays is 0.083±0.017(stat) ±0.013(syst), and the observed ratio of ψ(2S) decay rates is B(ψ(2S)→J/ψ${\mathrm{\pi }}^{+}$ ${\mathrm{\pi }}^{\mathrm{-}}$)/B(ψ(2S)→${\mathrm{\mu }}^{+}$ ${\mathrm{\mu }}^{\mathrm{-}}$) =30.2±7.2(stat)±6.8(syst). We have searched for production of ‘‘hidden’’ charm resonances decaying into either J/ψ