D meson mass increase by restoration of chiral symmetry in nuclear matter

TL;DR

This paper investigates how the masses of D mesons increase in nuclear matter due to chiral symmetry restoration, using QCD sum rules and maximum entropy methods to analyze spectral functions without phenomenological assumptions.

Contribution

It introduces a novel analysis of D meson spectral functions in nuclear matter via QCD sum rules and maximum entropy, revealing in-medium mass modifications and charge conjugation effects.

Findings

D meson masses increase with nuclear density

Mass splitting between D+ and D- is about -15 MeV at saturation density

Chiral condensate reduction causes mass growth in D mesons

Abstract

Spectral functions of the pseudoscalar $D$ meson in the nuclear medium are analyzed using QCD sum rules and the maximum entropy method. This approach enables us to extract the spectral functions without any phenomenological assumption, and thus to visualize in-medium modification of the spectral functions directly. It is found that the reduction of the chiral condensates of dimension 3 and 5 causes the masses of both $D^+$ and $D^-$ mesons to grow gradually at finite density. Additionally, we construct charge-conjugate-projected sum rules and find a $D^+$-$D^-$ mass splitting of about -15 MeV at nuclear saturation density.