Contribution from intrinsic charm production to fixed-target interactions with the SMOG Device at LHCb

• Published in: Physical review. C 2023-07, Vol.108 (1), Article 015201
• Main Author: Vogt, R.
• Format: Article
• Language: English
• Subjects: Charmed mesons; Hadron-hadron interactions; NUCLEAR PHYSICS AND RADIATION PHYSICS; QCD in nuclear reactions; Quarkonia
• ISSN: 2469-9985; 2469-9993
• DOI: 10.1103/PhysRevC.108.015201

Intrinsic charm, nonperturbative charm in the hadron wavefunction, has long been speculated but has never been satisfactorily proven. Open charm and J/ψ measurements in a fixed-target configuration at the LHCb searched for this contribution but reported no evidence. $\overline{D}$ meson and J/ψ production is calculated for the SMOG fixed-target configuration in the LHCb experiment using a combination of perturbative QCD and intrinsic charm to see whether intrinsic charm would indeed be observable in the SMOG kinematics. Open charm and J / ψ production is calculated to next-to-leading order in perturbative QCD. Because a gas jet nuclear target is used, cold nuclear matter effects are included in the perturbative calculations. The intrinsic charm is calculated assuming production from a |uudc$\overline{c}$ > Fock state. The differential rapidity and transverse momentum distributions in p + Ne, p + He, and p + Ar fixed-target interactions are calculated in the SMOG acceptance and compared to data. The predicted asymmetries between $\overline{D}$ (leading charm) and D (nonleading charm) are also shown. The contribution from intrinsic charm is small and decreases with center-of-mass energy. The calculations agree well with the current SMOG data, with or without intrinsic charm.