| D meson | |
| Composition: | |
| Statistics: | Bosonic |
| Group: | Mesons |
| Interaction: | Strong, weak, electromagnetic, gravitational |
| Antiparticle: | |
| Discovered: | SLAC (1976) |
| Symbol: | ,,,,, |
| Mass: |
|
| Mean Lifetime: |
|
| Electric Charge: |
|
| Spin: | 0 |
| Strangeness: |
|
| Charm: | +1 |
| Isospin: |
|
| Parity: | -1 |
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 (Ds) were called "F mesons" prior to 1986.[2]
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 and pions .[1]
| class=unsortable | Particle name | Particle symbol | Antiparticle symbol | class=unsortable | Quark content[4] | Rest mass (MeV/c2) | I | JP | S | C | B' | Mean lifetime (s) | class=unsortable | Commonly decays to (>5% of decays) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Charged D meson[5] | 0- | 0 | +1 | 0 | [6] | |||||||||
| Neutral D meson[7] | 0- | 0 | +1 | 0 | [8] | |||||||||
| Strange D meson[9] | 0 | 0- | +1 | +1 | 0 | [10] | ||||||||
| Excited charged D meson[11] | (2010) | (2010) | 1- | 0 | +1 | 0 | ||||||||
| Excited neutral D meson[12] | (2007) | (2007) | 1- | 0 | +1 | 0 | > |
~\left(\Gamma\right)~.
\tau=
| \hbar | |
| \Gamma |
In 2019, an analysis by the LHCb experiment reported the first observation of CP violation in the decays of the neutral 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 meson into pions.[14]
In 2021 it was confirmed with a significance of more than seven standard deviations, that the neutral 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]