Recent Results on Charm Photoproduction

TL;DR

This paper reports on measurements of charm meson photoproduction at HERA, comparing experimental results with QCD predictions, and observes orbitally excited charm mesons, providing insights into charm production mechanisms.

Contribution

It presents new measurements of charm meson production, compares them with QCD calculations, and reports the observation of orbitally excited charm mesons in photoproduction.

Findings

Measured $D_s^{ m iny ext{±}}$ meson photoproduction cross sections.

Observed orbitally excited P-wave charm mesons in $D^{* m iny ext{±}} o D^{* m iny ext{±}} ext{π}$ final states.

No evidence found for radially excited mesons decaying to $D^{* m iny ext{±}} ext{π}^+ ext{π}^-$.

Abstract

Photoproduction of $D_s^{\pm}$ mesons has been measured in the ZEUS detector at HERA and compared with predictions of NLO pQCD calculations. The ratio of $D_s^{*\pm}$ to $D^{*\pm}$ cross sections has been compared to results from $e^{+}e^{-}$ experiments. Orbitally excited P-wave charm mesons have been observed in the $D^{*\pm}\pi^{\mp}$ final state. The fraction of $D^{*\pm}$ 's originating from these mesons has been calculated and compared with that from $e^{+}e^{-}$ interactions. No evidence for radially excited mesons decaying to $D^{*\pm}\pi^{+}\pi^{-}$ was found. The inelastic production of J/$\psi$ mesons has been measured and compared to LO and NLO pQCD predictions.