Measurement of charm production at central rapidity in proton-proton collisions at $\sqrt{s} = 2.76$ TeV

TL;DR

This paper measures charm meson production cross sections in proton-proton collisions at 2.76 TeV, providing data to test QCD predictions and improve understanding of charm quark production mechanisms.

Contribution

It presents the first detailed measurement of prompt charm meson cross sections at 2.76 TeV and compares results with theoretical models and previous measurements.

Findings

Measured charm production cross section at 2.76 TeV

Compared results with perturbative-QCD calculations

Determined the vector state fraction of D mesons

Abstract

The $p_{\rm T}$-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D$^0$, D$^+$, and D$^{*+}$ in the rapidity range $|y|<0.5$, and for transverse momentum $1< p_{\rm T} <12$ GeV/$c$, were measured in proton-proton collisions at $\sqrt{s} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D$^0 \rightarrow $K$\pi$, D$^+ \rightarrow $K$\pi\pi$, D$^{*+} \rightarrow $D$^0\pi$, and their charge conjugates, and was performed on a $L_{\rm int} = 1.1$ nb$^{-1}$ event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at $\sqrt{s} = 2.76$ TeV and at 7 TeV was evaluated by extrapolating to the full phase space the $p_{\rm T}$-differential production cross sections at $\sqrt{s} = 2.76$ TeV and our previous measurements at $\sqrt{s} = 7$ TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.