3 years ago

QCD Parameters Correlations from Heavy Quarkonia.

Stephan Narison

Correlations between the QCD coupling \alpha_s, the gluon condensate < \alpha_s G^2 >, and the c,b-quark running masses m_c,b in the MS-scheme are explicitly studied (for the first time) from the (axial-)vector and (pseudo)scalar charmonium and bottomium ratios of Laplace sum rules (LSR) evaluated at the \mu-subtraction stability point where PT @N2LO, N3LO and < \alpha_s G^2> @NLO corrections are included. Our results clarify the (apparent) discrepancies between different estimates of < \alpha_s G^2> from J/\psi sum rule but also shows the sensitivity of the sum rules on the choice of the \mu-subtraction scale which does not permit a high-precision estimate of m_c,b. We obtain from the (axial-)vector [resp. (pseudo)scalar] channels <\alpha_s G^2>=(8.5+- 3.0)> [resp. (6.34+-.39)] 10^-2 GeV^4, m_c(m_c)= 1256(30) [resp. 1266(16)] MeV and m_b(m_b)=4192(15) MeV. Combined with our recent determinations from vector channel, one obtains the average: m_c(m_c)= 1263(14) MeV and m_b(m_b) 4184(11) MeV. Adding our value of the gluon condensate with different previous estimates, we obtain the new sum rule average: <\alpha_s G^2>=(6.35+- 0.35) 10^-2 GeV^4. The mass-splittings M_\chi_0c(0b)-M_\eta_c(b) give @N2LO: \alpha_s(M_Z)=0.1182(15)(3) in good agreement with the world average.

Publisher URL: http://arxiv.org/abs/1801.00592

DOI: arXiv:1801.00592v3

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