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D meson - Wikipedia

From Wikipedia, the free encyclopedia

D meson
Composition	D⁺ : c d D⁻ : d c D⁰ : c u D⁰ : u c D⁺ _s: c s D⁻ _s: s c
Statistics	Bosonic
Family	Mesons
Interactions	Strong, weak, electromagnetic, gravitational
Symbol	D⁺ , D⁻ , D⁰ , D⁰ , D⁺ _s, D⁻ _s
Antiparticle	D⁺ : D⁻ D⁰ : D⁰ D⁺ _s: D⁻ _s
Discovered	SLAC (1976)
Mass	D^± : 1869.62±0.20 MeV/c² D⁰ , D⁰ : 1864.84±0.17 MeV/c² D^± _s: 1968.47±0.33 MeV/c²
Mean lifetime	D^± : (1.040±0.007)×10⁻¹² D⁰ , D⁰ : (4.101±0.015)×10⁻¹³ D^± _s: (5.00±0.07)×10⁻¹³
Electric charge	D^± , D^± _s: ±1 e D⁰ , D⁰ : 0 e
Spin	0
Strangeness	D^± , D⁰ , D⁰ : 0 D^± _s: ±1
Charm	+1
Isospin	D⁺ , D⁰ : +⁠1/2⁠ D⁻ , D⁰ : −⁠1/2⁠ D^± _s: 0
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 (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

D mesons
Particle name	Particle symbol	Antiparticle symbol	Quark content^[4]	Rest mass (MeV/c²)	I	J^P	S	C	Mean lifetime (s)	Commonly decays to (>5% of decays)
Charged D meson^[5]	D⁺	D⁻	c d	1869.62±0.20	⁠1/2⁠	0⁻	0	+1	(1.040±0.007)×10⁻¹²	^[6]
Neutral D meson^[7]	D⁰	D⁰	c u	1864.84±0.17	⁠1/2⁠	0⁻	0	+1	(4.101±0.015)×10⁻¹³	^[8]
Strange D meson^[9]	D⁺ _s	D⁻ _s	c s	1968.47±0.33	0	0⁻	+1	+1	(5.00±0.07)×10⁻¹³	^[10]
Excited charged D meson^[11]	D^∗+ (2010)	D^∗− (2010)	c d	2010.27±0.17	⁠1/2⁠	1⁻	0	+1	(6.9±1.9)×10⁻²¹^{^‡}	D⁰ + π⁺ or D⁺ + π⁰
Excited neutral D meson^[12]	D^∗0 (2007)	D^∗0 (2007)	c u	2006.97±0.19	⁠1/2⁠	1⁻	0	+1	>3.1×10⁻²²^{^‡}	D⁰ + π⁰ or D⁰ + γ

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

References

^ ^a ^b Nave, G., ed. (2016). "D meson". Department of Physics & Astronomy. HyperPhysics. Atlanta, GA: Georgia State University.
^ Wohl, C.G. (1984). "Review of Particle Physics" (PDF). Reviews of Modern Physics. 56 (2, Part II). Particle Data Group. doi:10.1103/RevModPhys.56.S1.
^ Kudryavtsev, Vitaly A. "Charmed mesons" (course files). Physics 466. University of Sheffield.^{[permanent dead link‍]}
^ Amsler, C.; et al. (Particle Data Group) (2008). "Quark Model" (PDF). Lawrence Berkeley Laboratory.
^ Amsler, C.; et al. (Particle Data Group) (2008). "
D^±
" (PDF). Particle listings. Lawrence Berkeley Laboratory.
^ Amsler, C.; et al. (Particle Data Group) (2008). "
D^±
" (PDF). Decay modes. Lawrence Berkeley Laboratory.
^ Amsler, C.; et al. (Particle Data Group) (2008). "
D⁰
" (PDF). Particle listings. Lawrence Berkeley Laboratory.
^ Amsler, C.; et al. (Particle Data Group) (2008). "
D⁰
" (PDF). Decay modes. Lawrence Berkeley Laboratory.
^ Nakamura, N.; et al. (Particle Data Group) (2010). "
D^±
_s" (PDF). Particle listings. Lawrence Berkeley Laboratory.
^ Nakamura, N.; et al. (Particle Data Group) (2010). "
D⁺
_s" (PDF). Decay modes. Lawrence Berkeley Laboratory.
^ Amsler, C.; et al. (Particle Data Group) (2008). "
D^∗±
" (PDF). Decay modes. Lawrence Berkeley Laboratory.
^ Amsler, C.; et al. (Particle Data Group) (2008). "
D^∗0
(2007)" (PDF). Decay modes. Lawrence Berkeley Laboratory.
^ Aaij, R.; et al. (LHCb collaboration) (29 May 2019) [21 March 2019]. "Observation of CP Violation in Charm Decays". Physical Review Letters. 122 (21): 211803. arXiv:1903.08726. Bibcode:2019PhRvL.122u1803A. doi:10.1103/PhysRevLett.122.211803. PMID 31283320. 1903.08726.
^ Aaij, R.; et al. (LHCb collaboration) (29 August 2023) [9 September 2022]. "Measurement of the Time-Integrated CP Asymmetry in D0 -> KK Decays". Physical Review Letters. 131 (9): 091802. arXiv:2209.03179. doi:10.1103/PhysRevLett.131.091802. PMID 37721849. 1903.08726.
^ Aaij, R.; et al. (LHCb collaboration) (14 September 2021) [7 June 2021]. "Observation of the mass difference between neutral charm-meson eigenstates". Physical Review Letters. 127 (11): 111801. arXiv:2106.03744. Bibcode:2021PhRvL.127k1801A. doi:10.1103/PhysRevLett.127.111801. PMID 34558945. S2CID 235358523. 2106.03744. Published 2021 in Physical Review Letters 127, 111801. Report numbers: LHCb-PAPER-2021-009, CERN-EP-2021-099.

Particles in physics

Elementary

Fermions

Quarks	Up (quark antiquark) Down (quark antiquark) Charm (quark antiquark) Strange (quark antiquark) Top (quark antiquark) Bottom (quark antiquark)
Leptons	Electron Positron Muon Antimuon Tau Antitau Neutrino Electron neutrino Electron antineutrino Muon neutrino Muon antineutrino Tau neutrino Tau antineutrino

Bosons

Gauge	Photon Gluon W and Z bosons
Scalar	Higgs boson

Ghost fields

Faddeev–Popov ghosts

Hypothetical

Superpartners

Gauginos	Gluino Gravitino Photino
Others	Axino Chargino Higgsino Neutralino Sfermion (Stop squark)

Others

Composite

Hadrons

Baryons	Nucleon Proton Antiproton Neutron Antineutron Delta baryon Lambda baryon Sigma baryon Xi baryon Omega baryon
Mesons	Pion Rho meson Eta and eta prime mesons Bottom eta meson Phi meson J/psi meson Omega meson Upsilon meson Kaon B meson D meson Quarkonium
Exotic hadrons	Tetraquark (Double-charm tetraquark) Pentaquark