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Baker, M. J., Bordes, J., Dominguez, C. A., Peñarrocha, J., & Schilcher, K. (2014). B meson decay constants f(Bc), f(Bs) and f(B) from QCD sum rules. J. High Energy Phys., 07(7), 032–16pp.
Abstract: Finite energy QCD sum rules with Legendre polynomial integration kernels are used to determine the heavy meson decay constant f(Bc), and revisit f(B) and f(Bs). Results exhibit excellent stability in a wide range of values of the integration radius in the complex squared energy plane, and of the order of the Legendre polynomial. Results are f(Bc) = 528 +/- 19 MeV, f(B) = 186 +/- 14 MeV, and f(Bs) = 222 +/- 12 MeV.
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Bordes, J., Dominguez, C. A., Moodley, P., Peñarrocha, J., & Schilcher, K. (2012). Corrections to the SU(3) x SU(3) Gell-Mann-Oakes-Renner relation and chiral couplings L-8(r) and H-r(2). J. High Energy Phys., 10(10), 102–11pp.
Abstract: Next to leading order corrections to the SU(3) x SU(3) Gell-Mann-OakesRenner relation (GMOR) are obtained using weighted QCD Finite Energy Sum Rules (FESR) involving the pseudoscalar current correlator. Two types of integration kernels in the FESR are used to suppress the contribution of the kaon radial excitations to the hadronic spectral function, one with local and the other with global constraints. The result for the pseudoscalar current correlator at zero momentum is psi(5)(0) = (2.8 +/- 0.3) x 10(-3) GeV4, leading to the chiral corrections to GMOR: delta(K) = (55 +/- 5)%. The resulting uncertainties are mostly due to variations in the upper limit of integration in the FESR, within the stability regions, and to a much lesser extent due to the uncertainties in the strong coupling and the strange quark mass. Higher order quark mass corrections, vacuum condensates, and the hadronic resonance sector play a negligible role in this determination. These results confirm an independent determination from chiral perturbation theory giving also very large corrections, i.e. roughly an order of magnitude larger than the corresponding corrections in chiral SU(2) x SU(2). Combining these results with our previous determination of the corrections to GMOR in chiral SU(2) x SU(2), delta(pi), we are able to determine two low energy constants of chiral perturbation theory, i.e. L-8(r) = (1.0 +/- 0.3) x 10(-3), and H-2(r) = -(4.7 +/- 0.6) x 10(-3), both at the scale of the rho-meson mass.
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Dehnadi, B., Hoang, A. H., Mateu, V., & Zebarjad, S. M. (2013). Charm mass determination from QCD charmonium sum rules at order alpha(3)(s). J. High Energy Phys., 09(9), 103–56pp.
Abstract: We determine the (MS) over bar charm quark mass from a charmonium QCD sum rules analysis. On the theoretical side we use input from perturbation theory at O (alpha(3)(s)). Improvements with respect to previous O (alpha(3)(s)) analyses include (1) an account of all available e(+)e(-) hadronic cross section data and (2) a thorough analysis of perturbative uncertainties. Using a data clustering method to combine hadronic cross section data sets from di ff erent measurements we demonstrate that using all available experimental data up to c. m. energies of 10 : 538 GeV allows for determinations of experimental moments and their correlations with small errors and that there is no need to rely on theoretical input above the charmonium resonances. We also show that good convergence properties of the perturbative series for the theoretical sum rule moments need to be considered with some care when extracting the charm mass and demonstrate how to set up a suitable set of scale variations to obtain a proper estimate of the perturbative uncertainty. As the fi nal outcome of our analysis we obtain (m(c)) over bar((m(c)) over bar) = 1 : 282 +/- (0.009)(stat) +/- (0.009)(syst) +/- (0.019)(pert) +/- (0.010)(alpha s) +/- (0.002)(< GG >) GeV. The perturbative error is an order of magnitude larger than the one obtained in previous O (alpha(3)(s)) sum rule analyses.
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Hoang, A. H., Ruiz-Femenia, P., & Stahlhofen, M. (2012). Renormalization group improved bottom mass from (gamma) sum rules at NNLL order. J. High Energy Phys., 10(10), 188–30pp.
Abstract: We determine the bottom quark mass from non-relativistic large-n gamma sum rules with renormalization group improvement at next-to-next-to-leading logarithmic order. We compute the theoretical moments within the vNRQCD formalism and account for the summation of powers of the Coulomb singularities as well as of logarithmic terms proportional to powers of alpha(s) ln(n). The renormalization group improvement leads to a substantial stabilization of the theoretical moments compared to previous fixed-order analyses, which did not account for the systematic treatment of the logarithmic alpha(s) ln(n) terms, and allows for reliable single moment fits. For the current world average of the strong coupling (alpha(s) (M-Z) = 0.1183 +/- 0.0010) we obtain M-b(1S) = 4.755 +/- 0.057(pert) +/- 0.009 alpha(s) +/- 0.003(exp) GeV for the bottom 1S mass and (m) over bar (b) ((m) over bar (b)) = 4.235 +/- 0.055(pert) +/- 0.003(exp) GeV for the bottom (MS) over bar mass, where we have quoted the perturbative error and the uncertainties from the strong coupling and the experimental data.
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Zamiralov, V. S., Ozpineci, A., & Erkol, G. (2013). QCD sum rules for the coupling constants of vector mesons to octet baryons. Mosc. Univ. Phys. Bull., 68(3), 205–209.
Abstract: The QCD sum rules on the light cone proposed by Wang for the coupling constants of the rho meson are generalized to the vector mesons omega and phi and all octet baryons, the I >-hyperon included. A comparison with other results is given.
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