TY - JOUR
T1 - ηc puzzle in quantum chromodynamics
AU - Shifman, M. A.
AU - Vainshtein, A. I.
AU - Voloshin, M. B.
AU - Zakharov, V. I.
PY - 1978/7/17
Y1 - 1978/7/17
N2 - The mass of the ηc meson is calculated by means of QCD sum rules. If the spectrum of the 0- states of charmonium contains a single prominent resonance, like the J ψ in the case of vector states, then the ηc mass is 3.0 GeV, not 2.83. There is a possibility however that there are two mixed 0- states with close masses. Then the X(2.83) could be one of them. The other one however has a much larger coupling to the pseudoscalar current of c quarks and is a "true" ηc. The ηc mass in the case of two mixed states is 3.0-3.2 GeV.
AB - The mass of the ηc meson is calculated by means of QCD sum rules. If the spectrum of the 0- states of charmonium contains a single prominent resonance, like the J ψ in the case of vector states, then the ηc mass is 3.0 GeV, not 2.83. There is a possibility however that there are two mixed 0- states with close masses. Then the X(2.83) could be one of them. The other one however has a much larger coupling to the pseudoscalar current of c quarks and is a "true" ηc. The ηc mass in the case of two mixed states is 3.0-3.2 GeV.
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U2 - 10.1016/0370-2693(78)90206-X
DO - 10.1016/0370-2693(78)90206-X
M3 - Article
AN - SCOPUS:0002932175
VL - 77
SP - 80
EP - 83
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
IS - 1
ER -