Di-electron and two-photon widths in charmonium

• Published in: Physics of atomic nuclei Vol. 72; no. 7; pp. 1206 - 1213
• Main Authors: Badalian, A. M., Danilkin, I. V.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01-07-2009
• Subjects: BOSONS; BRANCHING RATIO; CHARMONIUM; COLOR MODEL; COMPOSITE MODELS; CORRECTIONS; DECAY; DIMENSIONLESS NUMBERS; ELECTRONS; ELEMENTARY PARTICLES; Elementary Particles and Fields; ENERGY RANGE; FERMIONS; FIELD THEORIES; HADRONS; J PSI-3097 MESONS; KEV RANGE; LEPTONS; MASSLESS PARTICLES; MATHEMATICAL MODELS; MESONS; Particle and Nuclear Physics; PARTICLE MODELS; PARTICLE PROPERTIES; PARTICLE WIDTHS; PHOTONS; Physics; Physics and Astronomy; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PSEUDOSCALAR MESONS; PSI-3770 MESONS; QUANTUM CHROMODYNAMICS; QUANTUM FIELD THEORY; QUARK MODEL; QUARKONIUM; RADIATIVE CORRECTIONS; VECTOR MESONS; 14.40.Gx; 12.40.Yx; 13.66.Bc
• ISSN: 1063-7788; 1562-692X
• DOI: 10.1134/S106377880907014X

The vector and pseudoscalar decay constants are calculated in the framework of the Field Correlator Method. Di-electron widths: Γ
ee
(
J/ψ
) = 5.41 keV, Γ
ee
(
ψ
′(3686)) = 2.47 keV, Γ
ee
(
ψ
″(3770)) = 0.248 keV, in good agreement with experiment, are obtained with the same coupling,
α
s
= 0.165, in the QCD radiative corrections. We show that the larger
α
s
= 0.191 ± 0.004 is needed to reach agreement with experiment for Γ
γγ
(
χ
c
) = 7.22 keV, Γ
γγ
(
χ
c
(
3
P
0)) = 3.3 keV, Γ
γγ
χ
c
(
3
P
2
)) = 0.54 keV, and also for Γ(
J/ψ
→ 3
g
) = 59.5 keV, Γ(
J/ψ
→
γ
2
g
) = 5.7 keV. Meanwhile, even larger
α
s
= 0.238 gives rise to good description of Γ(
ψ
′ → 3
g
) = 52.7 keV, Γ(
ψ
′ →
γ
2
g
) = 3.5 keV, and provides correct ratio of the branching fractions:
.