# Charm production nearby threshold in pA-interactions at 70 GeV

## TL;DR

This paper reports on measurements of charm meson and baryon production near threshold in proton-nucleus collisions at 70 GeV, providing cross sections, lifetimes, and mass data that challenge existing QCD predictions.

## Contribution

It presents the first experimental measurements of open charm production cross sections near threshold in pA interactions at 70 GeV, with results exceeding theoretical expectations.

## Key findings

- Measured open charm production cross section at 11.8 GeV is 7.1 μb/nucleon.
- Lifetimes and masses of charm particles agree with PDG data.
- Charm production yields vary with energy and target material.

## Abstract

The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70 GeV proton beam with C, Si and Pb targets were studied to detect decays of charmed $D^0$, $\overline D^0$, $D^+$, $D^-$ mesons and $\Lambda _c^+$ baryon near their production threshold. Measurements of lifetimes and masses are shown a good agreement with PDG data. The inclusive cross sections of charm production and their A-dependencies were obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measured cross section of the total open charm production ($\sigma _{\mathrm {tot}}(c\overline c)$ = 7.1 $\pm $ 2.3(stat) $\pm $1.4(syst) $\mu $b/nucleon) at the collision c.m. energy $\sqrt {s}$ = 11.8 GeV is well above the QCD model predictions. The contributions of different species of charmed particles to the total cross section of the open charm production in proton-nucleus interactions vary with energy.