Measurement of D*+- meson production in ep scattering at low Q^2

TL;DR

This paper reports on the measurement of D* meson production in low Q^2 ep scattering at HERA, providing data that agree with NLO QCD predictions and comparing with previous photoproduction and DIS results.

Contribution

First measurement of D* meson production cross sections in low Q^2 ep scattering, extending understanding of charm production in this regime.

Findings

Measured differential cross sections as functions of Q^2, y, p_T, and eta.

Results agree with two different NLO QCD calculations.

Compared with previous ZEUS measurements in different regimes.

Abstract

The production of D*+-(2010) mesons in ep scattering in the range of exchanged photon virtuality 0.05 < Q^2 < 0.7 GeV^2 has been measured with the ZEUS detector at HERA using an integrated luminosity of 82 pb-1. The decay channels D*+ -> D0 pi+ with D0 -> K- pi+ and corresponding antiparticle decay were used to identify D* mesons and the ZEUS beampipe calorimeter was used to identify the scattered electron. Differential D* cross sections as functions of Q^2, inelasticity, y, transverse momentum of the D* meson, p_T(D*), and pseudorapidity of the D* meson, eta(D*), have been measured in the kinematic region 0.02 < y < 0.85, 1.5 < p_T(D*) < 9.0 GeV and |eta(D*)| < 1.5. The measured differential cross sections are in agreement with two different NLO QCD calculations. The cross sections are also compared to previous ZEUS measurements in the photoproduction and DIS regimes.