The D mesons are the lightest particle containing charm quarks. They are often studied to gain knowledge on the weak interaction.^[1] The strange D mesons (D_s) were called "F mesons" prior to 1986.^[2]

Overview

The D mesons were discovered in 1976 by the Mark I detector at the Stanford Linear Accelerator Center.^[3]

Since the D mesons are the lightest mesons containing a single charm quark (or antiquark), they must change the charm (anti)quark into an (anti)quark of another type to decay. Such transitions involve a change of the internal charm quantum number, and can take place only via the weak interaction. In D mesons, the charm quark preferentially changes into a strange quark via an exchange of a W particle, therefore the D meson preferentially decays into kaons (
K
) and pions (
π
).^[1]

List of D mesons

‡ ^ PDG reports the resonance width ${\displaystyle ~\left(\Gamma \right)~.}$ Here the conversion ${\displaystyle \;\tau ={\frac {\hbar }{\Gamma ))\;}$ is given instead.

CP violation

In 2019, an analysis by the LHCb experiment reported the first observation of CP violation in the decays of the neutral
D⁰
meson, with a significance of over five standard deviations.^[13] The results of a subsequent data analysis by the same collaboration was presented in 2022, which announced that they found evidence of direct CP violation in the decay of the
D⁰
meson into pions.^[14]

D
–
D
oscillations

In 2021 it was confirmed with a significance of more than seven standard deviations, that the neutral
D⁰
meson spontaneously transforms into its own antiparticle and back. This phenomenon is called flavor oscillation and was prior known to exist in the neutral K meson and B meson.^[15]