Mass effects in QCD corrections of weak decays

Ho‐Kim, Q.; Pham, Xuan-Yem

doi:10.1016/0370-2693(83)90707-4

Cited by 33 publications

(41 citation statements)

References 11 publications

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“…(13) have been computed at the LO in ref. [16], while the NLO corrections to c (3) have been evaluated in [17]- [22]. The NLO corrections to c (5) are still missing.…”

Section: γ(Hmentioning

confidence: 99%

Next-to-leading order QCD corrections to spectator effects in lifetimes of beauty hadrons

2002

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Theoretical predictions of beauty hadron lifetimes, based on the heavy quark expansion up to and including order 1/m 2 b , do not to reproduce the experimental measurements of the lifetime ratios τ (B + )/τ (B d ) and τ (Λ b )/τ (B d ). Large corrections to these predictions come from phase-space enhanced 1/m 3 b contributions, i.e. hard spectator effects. In this paper we calculate the next-to-leading order QCD corrections to the Wilson coefficients of the local operators appearing at O(1/m 3 b ). We find that these corrections improve the agreement with the experimental data. The lifetime ratio of charged to neutral B-mesons, τ (B + )/τ (B d ), turns out to be in very good agreement with the corresponding measurement, whereas for τ (B s )/τ (B d ) and τ (Λ b )/τ (B d ) there is a residual difference at the 1σ level. We discuss, however, why the theoretical predictions are less accurate in the latter cases.

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“…(13) have been computed at the LO in ref. [16], while the NLO corrections to c (3) have been evaluated in [17]- [22]. The NLO corrections to c (5) are still missing.…”

Section: γ(Hmentioning

confidence: 99%

Next-to-leading order QCD corrections to spectator effects in lifetimes of beauty hadrons

2002

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“…Its general analytic expression is given in [30]. The special case η(x, 0, 0) is given in [31] and it can be approximated numerically by [32]:…”

Section: Frameworkmentioning

confidence: 99%

Phenomenological analysis of heavy hadron lifetimes

Cheng

1997

Phys. Rev. D

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A phenomenological analysis of lifetimes of bottom and charmed hadrons within the framework of the heavy quark expansion is performed. The baryon matrix element is evaluated using the bag model and the nonrelativistic quark model. We find that bottom-baryon lifetimes follow the pat-) nor the absolute decay rates of the Λ b baryon and B mesons can be explained. One way of solving both difficulties is to allow the presence of linear 1/m Q corrections by scaling the inclusive nonleptonic width with the fifth power of the hadron mass m H Q rather than the heavy quark mass m Q . The hierarchy of bottom baryon lifetimes is dramatically modified toThe longest-lived Ω b among bottom baryons in the OPE prescription now becomes shortest-lived. The replacement of m Q by m H Q in nonleptonic widths is natural and justified in the PQCD-based factorization approach formulated in terms of hadron-level kinematics. For inclusive charmed baryon decays, we argue that since the heavy quark expansion does not converge, local duality cannot be tested in this case. We show that while the ansatz of substituting the heavy quark mass by the hadron mass provides a much better description of the charmed-baryon lifetime ratios, it appears unnatural and unpredictive for describing the absolute inclusive decay rates of charmed baryons, contrary to the bottom case.

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“…where η(x, x ℓ , 0) with x ℓ = (m ℓ /m Q ) 2 is the QCD radiative correction to the semileptonic decay rate and its general analytic expression is given in [11]. In Eqs.…”

Section: General Frameworkmentioning

confidence: 99%

Phenomenological analysis ofDmeson lifetimes

Cheng

Yang

1999

Phys. Rev. D

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The QCD-based operator-product-expansion technique is systematically applied to the study of charmed meson lifetimes. We stress that it is crucial to take into account the momentum of the spectator light quark of charmed mesons, otherwise the destructive Pauli-interference effect in D + decays will lead to a negative decay width for the D + . We have applied the QCD sum rule approach to estimate the hadronic matrix elements of color-singlet and color-octet 4-quark operators relevant to nonleptonic inclusive D decays. The lifetime of D + s is found to be longer than that of D 0 because the latter receives a constructive W -exchange contribution, whereas the hadronic annihilation and leptonic contributions to the former are compensated by the Pauli interference. We obtain the lifetime ratio τ (D + s )/τ (D 0 ) ≈ 1.08 ± 0.04, which is larger than some earlier theoretical estimates, but still smaller than the recent measurements by CLEO and E791.

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Mass effects in QCD corrections of weak decays

Cited by 33 publications

References 11 publications

Next-to-leading order QCD corrections to spectator effects in lifetimes of beauty hadrons

Next-to-leading order QCD corrections to spectator effects in lifetimes of beauty hadrons

Phenomenological analysis of heavy hadron lifetimes

Phenomenological analysis ofDmeson lifetimes

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