Kniehl, Bernd A.Penin, Alexander A.Pineda, Antonio (Pineda Ruiz)Smirnov, Vladimir A.Steinhauser, Matthias2019-09-182019-09-182004-06-150031-9007https://hdl.handle.net/2445/140438We sum up the next-to-leading logarithmic corrections to the heavy-quarkonium hyperfine splitting, using the nonrelativistic renormalization group. On the basis of this result, we predict the mass of the η b meson to be M ( η b ) = 9421 ± 11 ( th ) + 9 − 8 ( δ α s )     MeV . The experimental measurement of M ( η b ) with a few MeV error would be sufficient to determine α s ( M Z ) with an accuracy of ± 0.003 . For the hyperfine splitting in charmonium, the use of the nonrelativistic renormalization group brings the perturbative prediction significantly closer to the experimental figure.4 p.application/pdfeng(c) American Physical Society, 2004Física de partículesQuarksParticle physicsQuarksinfo:eu-repo/semantics/article5511622019-09-18info:eu-repo/semantics/openAccess