D mesons in a magnetic field

TL;DR

This paper studies how external magnetic fields affect the mass spectra of open heavy flavor D mesons using QCD sum rules, revealing significant mass shifts due to mixing and Landau level effects.

Contribution

It introduces spectral ans"atze to account for mixing and Landau levels in QCD sum rules for D mesons in magnetic fields, extending previous models.

Findings

Neutral D mesons experience a significant positive mass shift.

Charged D mesons' mass shifts are dominated by Landau level effects.

Mass shifts for charged D mesons are nearly saturated by combined effects.

Abstract

We investigate the mass spectra of open heavy flavor mesons in an external constant magnetic field within QCD sum rules. Spectral ans\"atze on the phenomenological side are proposed in order to properly take into account mixing effects between the pseudoscalar and vector channels, and the Landau levels of charged mesons. The operator product expansion is implemented up to dimension-5 operators. As a result, we find for neutral D mesons a significant positive mass shift that goes beyond simple mixing effects. In contrast, charged D mesons are further subject to Landau level effects, which together with the mixing effects almost completely saturate the mass shifts obtained in our sum rule analysis.