QUARKONIUM CHROMO-POLARIZABILITY FROM THE DECAYS J/ψ(ϒ)→ππℓ+ℓ-

It is pointed out that the diagonal amplitude of the E1–E1 chromo-electric interaction with soft gluon fields (chromo-polarizability) can be measured directly for the J/ψ and ϒ resonances in the decays J/ψ→ππℓ+ℓ- and ϒ→ππℓ+ℓ- with soft pions. For the J/ψ this amplitude is often discussed in connection with the J/ψ interaction with nuclear matter, while for the ϒ the chromo-polarizability enters the estimates of the nonperturbative mass shift of the resonance relevant to precision determination of the b quark mass from the ϒ mass.

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PRECISION DETERMINATION OF αs AND mb FROM QCD SUM RULES FOR $b\bar b$

International Journal of Modern Physics A ◽

10.1142/s0217751x95001364 ◽

1995 ◽

Vol 10 (19) ◽

pp. 2865-2880 ◽

Cited By ~ 86

Author(s):

M.B. VOLOSHIN

Keyword(s):

Cross Section ◽

Quark Mass ◽

Sum Rules ◽

Production Cross ◽

Experimental Uncertainty ◽

Qcd Sum Rules ◽

Precision Determination ◽

B Quark ◽

Existing Data

The QCD sum rules for moments of the production cross section of [Formula: see text] states in e+ e− annihilation are extremely sensitive to the values of mb and αs for moments of large order n. This enables one to extract from the existing data on ϒ resonances the values of these parameters with a high precision by using a nonrelativistic expansion in 1/n. It is found that the sum rules fit the data with [Formula: see text] and mb=4827±7 MeV, where the estimate of the errors includes the theoretical uncertainty due to subleading-in-1/n terms and the experimental uncertainty of the e+ e− annihilation cross section above the [Formula: see text] threshold. The found value of αs, when evolved in two loops up to the Z mass, gives [Formula: see text]. The b quark mass mb corresponds to the “on-shell” value appropriate for one-loop perturbative calculations.

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Bs → Kℓv form factors with 2+1 flavors

EPJ Web of Conferences ◽

10.1051/epjconf/201817513008 ◽

2018 ◽

Vol 175 ◽

pp. 13008 ◽

Cited By ~ 2

Author(s):

Yuzhi Liu ◽

Jon A. Bailey ◽

A. Bazavov ◽

C. Bernard ◽

C. M. Bouchard ◽

...

Keyword(s):

Quark Mass ◽

Strange Quark ◽

Lattice Spacing ◽

Light Quark ◽

Form Factors ◽

Ckm Matrix ◽

Strange Quark Mass ◽

Light Quark Mass ◽

B Quark

Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors f0 and f+ for the semileptonic Bs → Kℓv decay. A total of six ensembles with lattice spacing from ≈ 0.12 to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass m’l is one-tenth the strange quark mass m’s. At the intermediate lattice spacing, the ratio m’l/m’s ranges from 0.05 to 0.2. The valence b quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element |Vub|.

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