Photoproduction of D* and Jets at H1

TL;DR

This paper reports on the measurement of photoproduction events involving a D* meson and two jets at HERA II, comparing experimental data with various Monte Carlo simulations to understand charm quark production.

Contribution

It provides the first detailed measurement of D* meson and jet production in photoproduction at HERA II, including differential cross sections and comparisons with multiple MC models.

Findings

Measured differential cross sections for D* and jets

Compared data with PYTHIA, CASCADE, and MC@NLO models

Found discrepancies and agreements with theoretical predictions

Abstract

Photoproduction events containing a charmed meson $D^{*\pm}$ and two jets were investigated with the H1 detector using the HERA II data sample. The $D^*$ meson was reconstructed in the decay channel, $D^{*\pm}\rightarrow D^0\pi^\pm\rightarrow K^\mp\pi^\pm\pi^\pm$. Jets were reconstructed using the inclusive $k_t$ algorithm and were selected if they have transverse momenta $p_t(\textrm{jet})>3.5\gev$. One of the jets was associated with the $D^*$ meson itself, such that the jet originating from the parent charmed quark as the meson can be tagged. The phase space of the measurement is limited within central rapidity for the $D^*$ meson and the $D^*_\textrm{jet}$, $|\eta|<1.5$ while the second jet was measured within, $-1.5<\eta<2.9$. Single differential cross sections and double differential distributions were measured and compared to Leading Order Monte Carlo (MC) event generators, \PYTHIA and \CASCADE and with the Next--to--Leading order MC generator \MCATNLO