Distribution amplitudes of Σ and Λ and their electromagnetic form factors

Liu, Yong-Lu; Huang, Ming-Qiu

doi:10.1016/j.nuclphysa.2009.02.003

Cited by 49 publications

(54 citation statements)

References 74 publications

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“…[11,12]. Additional simplification is expected in the kinematic limit of large recoil energy, E Λ → ∞, where the number of independent form factors is known to be reduced further [13], and part of the corrections to this limit should factorize in terms of process-independent hadronic quantities (light-cone distribution amplitudes, LCDAs, [14,15]) and perturbative interaction kernels, in a similar way as it has been discussed for the analogous mesonic transitions [16]. The non-perturbative calculation of the remaining hadronic transition form factors can, for instance, be obtained from QCD sum rules.…”

Section: Motivationmentioning

confidence: 99%

“…We choose 15) which is normalized by the matrix element 16) and thus corresponds to a leading term in the large-energy limit. A sum-rule estimate [15] gives f Λ (6.0 ± 0.3) × 10 −3 GeV 2 for the involved decay constant of the Λ baryon (for comparison, for the nucleon f N 5.6 × 10 −3 GeV 2 has been estimated in [24]). The various light-quark fields can be decomposed into soft and hard-collinear fields to match the above current onto SCET.…”

Section: Soft Form Factormentioning

confidence: 99%

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Form factors forΛb→Λtransitions in the soft-collinear effective theory

2012

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We present a systematic discussion of Λ b → Λ transition form factors in the framework of soft-collinear effective theory (SCET). The universal soft form factor, which enters the symmetry relations in the limit of large recoil energy, is calculated from a sum-rule analysis of a suitable SCET correlation function. The same method is applied to derive the leading corrections from hard-collinear gluon exchange at first order in the strong coupling constant. We present numerical estimates for form factors and form-factor ratios and their impact on decay observables in Λ b → Λµ + µ − decays.

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Section: Motivationmentioning

confidence: 99%

Section: Soft Form Factormentioning

confidence: 99%

Form factors forΛb→Λtransitions in the soft-collinear effective theory

2012

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“…The terms proportional to the gluon field strength are contributed mainly to the four and five particle distribution functions [23][24][25][26][27] and are expected to be very small in our case; hence, when doing calculations, these terms are ignored. The matrix element abc h0ju…”

Section: Theoretical Frameworkmentioning

confidence: 99%

“…(14) and (15) represents the Ã's wave functions, which are calculated in [27], and we list them out for the completeness of this paper in the Appendix. Using the Ã wave functions and the expression of the heavy quark propagator, and after performing the Fourier transformation, the final expressions of the correlation functions for both vertexes are found in terms of the Ã DA's in the QCD or theoretical side.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Analysis of theΛb→Λl+l−decay in QCD

2010

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Taking into account the Ã baryon distribution amplitudes and the most general form of the interpolating current of the Ã b , the semileptonicÀ transition is investigated in the framework of the light cone QCD sum rules. Sum rules for all 12 form factors responsible for the Ã b ! Ã' þ ' À decay are constructed. The obtained results for the form factors are used to compute the branching fraction. A comparison of the obtained results with the existing predictions of the heavy quark effective theory is presented. The results of the branching ratio shows the detectability of this channel at the Large Hadron Collider beauty in the near future is quite high.

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“…In order to reduce the theory uncertainty induced by the Borel mass parameter ω M we will employ the two-point QCD sum rules of the normalization parameter f Λ (ν) [52] at tree level, where the gluon condensate density α s /πGG = 1.2 +0.6 −1.2 × 10 −2 GeV 4 will be used in the numerical analysis.…”

Section: Jhep02(2016)179mentioning

confidence: 99%

Perturbative corrections to Λ b → Λ form factors from QCD light-cone sum rules

Wang

Shen

2016

J. High Energ. Phys.

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We compute radiative corrections to Λ b → Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ b -baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ b -baryon correlation function is justified at leading power in Λ/m b , with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to-B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at O(α s ) shift the Λ b → Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ b → Λ from factors we further investigate several decay observables in the electro-weak penguin Λ b → Λ + − transitions in the factorization limit (i.e., ignoring the "non-factorizable" hadronic effects which cannot be expressed in terms of the Λ b → Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.

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Distribution amplitudes of Σ and Λ and their electromagnetic form factors

Cited by 49 publications

References 74 publications

Form factors forΛb→Λtransitions in the soft-collinear effective theory

Form factors forΛb→Λtransitions in the soft-collinear effective theory

Analysis of theΛb→Λl+l−decay in QCD

Perturbative corrections to Λ b → Λ form factors from QCD light-cone sum rules

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