Physics:D meson

From HandWiki
D meson
Composition
  • D+: cd
  • D−: dc
  • D0: cu
  • D0: uc
  • D+s: cs
  • D−s: sc
StatisticsBosonic
InteractionsStrong, weak, electromagnetic, gravitational
SymbolD+, D−, D0, D0, D+s, D−s
antiparticle
  • D+: D−
  • D0: D0
  • D+s: D−s
DiscoveredSLAC (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
Spin0
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 (Ds) 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 (Kaon) and pions (Pion).[1]

List of D mesons

D mesons
Particle
name 		Particle
symbol 		Antiparticle
symbol 		Quark
content[4] 		Rest mass (MeV/c2) I JP S C B' Mean lifetime (s) Commonly decays to
(>5% of decays)
Charged D meson[5] D+ D− Charm quarkDown antiquark 1869.62±0.20 1/2 0− 0 +1 0 (1.040±0.007)×10−12 [6]
Neutral D meson[7] D0 D0 Charm quarkup antiquark 1864.84±0.17 1/2 0− 0 +1 0 (4.101±0.015)×10−13 [8]
Strange D meson[9] D+s D−s Charm quarkstrange antiquark 1968.47±0.33 0 0− +1 +1 0 -13.1 (5.00±0.07)×10−13


[10]
Excited charged D meson[11] D∗+(2010) D∗−(2010) Charm quarkDown antiquark 2010.27±0.17 1/2 1− 0 +1 0 (6.9±1.9)×10−21‡ D0 + Pion+ or
D+ + Pion0
Excited neutral D meson[12] D∗0(2007) D∗0(2007) Charm quarkup antiquark 2006.97±0.19 1/2 1− 0 +1 0 >3.1×10−22‡ D0 + Pion0 or
D0 + Photon

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

See also


References

  1. ↑ 1.0 1.1 Nave, G., ed (2016). "D meson". Georgia State University. http://hyperphysics.phy-astr.gsu.edu/hbase/particles/dmeson.html. 
  2. ↑ Wohl, C.G. (1984). "Review of Particle Physics". Reviews of Modern Physics (Particle Data Group) 56 (2, Part II). doi:10.1103/RevModPhys.56.S1. https://cds.cern.ch/record/153729/files/RevModPhys.56.S1.pdf. 
  3. ↑ Kudryavtsev, Vitaly A.. "Charmed mesons". University of Sheffield. http://www.kudryavtsev.staff.shef.ac.uk/phy466/charmed-mesons_files/charmed-mesons.ppt. [yes|permanent dead link|dead link}}]
  4. ↑ Amsler, C. (2008). "Quark Model". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2008/reviews/quarkmodrpp.pdf. 
  5. ↑ Amsler, C. (2008). "D±". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2008/listings/s031.pdf. 
  6. ↑ Amsler, C. (2008). "D±". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2008/listings/s031.pdf. 
  7. ↑ Amsler, C. (2008). "D0". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2008/listings/s032.pdf. 
  8. ↑ Amsler, C. (2008). "D0". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2008/listings/s032.pdf. 
  9. ↑ Nakamura, N. (2010). "D±s". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2010/listings/rpp2010-list-Ds-plus-minus.pdf. 
  10. ↑ Nakamura, N. (2010). "D+s". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2010/listings/rpp2010-list-Ds-plus-minus.pdf. 
  11. ↑ Amsler, C. (2008). "D∗±". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2008/listings/m062.pdf. 
  12. ↑ Amsler, C. (2008). "D∗0 (2007)". Lawrence Berkeley Laboratory. http://pdg.lbl.gov/2008/listings/m061.pdf. 
  13. ↑ Aaij, R. (29 May 2019). "Observation of CP Violation in Charm Decays". Physical Review Letters 122 (21): 211803. doi:10.1103/PhysRevLett.122.211803. 1903.08726. 
  14. ↑ Aaij, R. (29 August 2023). "Measurement of the Time-Integrated CP Asymmetry in D0 -> KK Decays". Physical Review Letters 131 (9): 091802. doi:10.1103/PhysRevLett.131.091802. 1903.08726. 
  15. ↑ Aaij, R. (14 September 2021). "Observation of the mass difference between neutral charm-meson eigenstates". Physical Review Letters 127 (11): 111801. doi:10.1103/PhysRevLett.127.111801. 2106.03744. PMID 34558945. Bibcode: 2021PhRvL.127k1801A. "Published 2021 in Physical Review Letters 127, 111801. Report numbers: LHCb-PAPER-2021-009, CERN-EP-2021-099.". 




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