Inclusive Semileptonic Decays from Lattice QCD

Gambino, Paolo; Hashimoto, S.

doi:10.1103/physrevlett.125.032001

Cited by 70 publications

(96 citation statements)

References 41 publications

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“…in which the authors also use a spectral representation involving a smooth theta function, but in a different context. The details of their intriguing proposal differ from those presented here, most importantly because, in refs [65,66],. the range of sampled energies is given a physical interpretation as a phase-space integral defining a scattering cross section.…”

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confidence: 63%

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Variations on the Maiani-Testa approach and the inverse problem

Bruno

Hansen

2021

J. High Energ. Phys.

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We discuss a method to construct hadronic scattering and decay amplitudes from Euclidean correlators, by combining the approach of a regulated inverse Laplace transform with the work of Maiani and Testa [1]. Revisiting the original result of ref. [1], we observe that the key observation, i.e. that only threshold scattering information can be extracted at large separations, can be understood by interpreting the correlator as a spectral function, ρ(ω), convoluted with the Euclidean kernel, e−ωt, which is sharply peaked at threshold. We therefore consider a modification in which a smooth step function, equal to one above a target energy, is inserted in the spectral decomposition. This can be achieved either through Backus-Gilbert-like methods or more directly using the variational approach. The result is a shifted resolution function, such that the large t limit projects onto scattering or decay amplitudes above threshold. The utility of this method is highlighted through large t expansions of both three- and four-point functions that include leading terms proportional to the real and imaginary parts (separately) of the target observable. This work also presents new results relevant for the un-modified correlator at threshold, including expressions for extracting the Nπ scattering length from four-point functions and a new strategy to organize the large t expansion that exhibits better convergence than the expansion in powers of 1/t.

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contrasting

confidence: 63%

“…We also point the reader to refs [65,66],. in which the authors also use a spectral representation involving a smooth theta function, but in a different context.…”

mentioning

confidence: 94%

Variations on the Maiani-Testa approach and the inverse problem

Bruno

Hansen

2021

J. High Energ. Phys.

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“…Gambino & Hashimoto have a proposal to address inclusive decays on the lattice [83]. Given the longstanding discrepancy between inclusive and exclusive determinations of |V ub |, any new line of attack is welcome.…”

Section: Semileptonic B → U Decaysmentioning

confidence: 99%

Quark flavor physics and lattice QCD

Wingate

2021

Eur. Phys. J. A

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For a long time, investigation into the weak interactions of quarks has guided us toward understanding the Standard Model we know today. Now in the era of high precision, these studies are still one of the most promising avenues for peering beyond the Standard Model. This is a large-scale endeavour with many tales and many protagonists. In these pages I follow a few threads of a complex story, those passing through the realm of lattice gauge theory.

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“…A lot of experimental improvement regarding semileptonic decays is expected in the future [67][68][69]. For progress, form factor results from lattice QCD [30,[70][71][72][73][74][75][76][77][78][79][80][81][82][83][84] and also LCSRs [85][86][87][88] are very important. A lot of progress has been made in the research of the ability of new physics (NP) models, including from the beginning scalar models, to explain the data [12,17,18,36,48,50,[89][90][91].…”

Section: Jhep10(2020)163mentioning

confidence: 99%

Relations between b → cτν decay modes in scalar models

Schacht

Soni

2020

J. High Energ. Phys.

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As a consequence of the Ward identity for hadronic matrix elements, we find relations between the differential decay rates of semileptonic decay modes with the underlying quark-level transition b → cτν, which are valid in scalar models. The decay-mode dependent scalar form factor is the only necessary theoretical ingredient for the relations. Otherwise, they combine measurable decay rates as a function of the invariant mass-squared of the lepton pair q2 in such a way that a universal decay-mode independent function is found for decays to vector and pseudoscalar mesons, respectively. This can be applied to the decays $$ B\to {D}^{\ast}\tau v,{B}_s\to {D}_s^{\ast}\tau v,{B}_c\to J/\psi \tau v $$ B → D ∗ τv , B s → D s ∗ τv , B c → J / ψτv and B → Dτv, Bs → Dsτv, Bc → ηcτv, with implications for R(D(*)), $$ R\left({D}_s^{\left(\ast \right)}\right) $$ R D s ∗ , R(J/ψ), R(ηc), and ℬ(Bc → τv). The slope and curvature of the characteristic q2-dependence is proportional to scalar new physics parameters, facilitating their straight forward extraction, complementary to global fits.

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Inclusive Semileptonic Decays from Lattice QCD

Cited by 70 publications

References 41 publications

Variations on the Maiani-Testa approach and the inverse problem

Variations on the Maiani-Testa approach and the inverse problem

Quark flavor physics and lattice QCD

Relations between b → cτν decay modes in scalar models

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