相关论文: Subleading Shape Functions and the Determination o…
We calculate the subleading twist contributions to the endpoint of the inclusive lepton energy spectrum in B -> X_u l \nu. We show that the same two subleading twist functions that appear in the decay B -> X_s \gamma govern the subleading…
We derive a class of formulae relating moments of B -> Xu l nu to B -> Xs gamma in the shape function region, where m_X^2 ~ m_b Lambda_QCD. We also derive an analogous class of formulae involving the decay B -> Xs l+ l-. These results…
We study the O(Lambda/mb) corrections to the singly and doubly differential hadronic invariant mass spectra d\Gamma/dsH and d\Gamma/dsH dq^2 in b -> u decays, and discuss the implications for the extraction of the CKM matrix element |Vub|.…
It has recently been pointed out that a new class of subleading shape functions involving B-meson matrix elements of non-local four-quark operators contributes at order Lambda_{QCD}/m_b to B->X_u+l+nu decay distributions in the endpoint…
The charged lepton spectrum in semileptonic $B\to X_u \ell\bar\nu$ decay near maximal lepton energy receives important corrections from subleading structure functions that are formally suppressed by powers of $\Lambda_{QCD}/m_b$ but are…
We present ``state-of-the-art'' theoretical expressions for the triple differential B->X_u l^- nu decay rate and for the B->X_s gamma photon spectrum, which incorporate all known contributions and smoothly interpolate between the…
A leading-power factorization formula for weight functions relating the B to Xs gamma photon spectrum to arbitrary partial decay rates in B to Xu l nu is derived. These weight functions are independent of the hadronic shape function and…
Owing to the fact that m_c^2 ~ m_b \Lambda_QCD, the endpoint region of the charged lepton energy spectrum in the inclusive decay B -> X_c l \nu_l is affected by the Fermi motion of the initial-state b quark bound in the B meson. This effect…
In this paper we investigate the subleading twist corrections to the photon energy spectrum in the decay Lambda_b -> X_s \gamma and to the lepton energy spectrum in Lambda_b -> X_u l \bar{\nu}. As a first step we rederive the matching…
Measuring the photon energy spectrum in radiative B decays provides essential help for gaining theoretical control over semileptonic B transitions. The hadronic recoil mass distribution in B -> X_u \ell\nu promises the best environment for…
The contributions of subleading shape functions to inclusive decay distributions of B mesons are derived from a systematic two-step matching of QCD current correlators onto soft-collinear and heavy-quark effective theory. At tree-level, the…
We present a QCD-based approach to the endpoint region of the lepton spectrum in $\bar B\to X_u\,\ell\,\bar\nu$ decays. We introduce a genuinely nonperturbative form factor, the shape function, which describes the fall-off of the spectrum…
We perform factorization of the most general distribution in semileptonic B -> X_u decays and we resum the threshold logarithms to next-to-leading order. From this (triple-differential) distribution, any other distribution is obtained by…
We discuss the implications of charged lepton energy cut to the hadronic invariant mass spectrum in charmless semileptonic B decays. Charged-lepton energy cut is inevitable in order to remove secondary leptonic events such as b -> c, tau ->…
The invariant mass spectrum of the lepton pair in inclusive semileptonic $\bar B\to X_u \ell\bar\nu$ decay yields a model independent determination of $|V_{ub}|$. Unlike the lepton energy and hadronic invariant mass spectra, nonperturbative…
It is shown that measuring the lepton invariant mass spectrum in inclusive semileptonic B -> X_u l nu decay yields a model independent determination of |V_{ub}|. Unlike the lepton energy and hadronic invariant mass spectra, nonperturbative…
Using a combination of the operator product and heavy quark expansions, we resum the leading nonperturbative contributions to the inclusive photon spectrum in $B\to X_s\,\gamma$ decays. The shape of the spectrum is determined by a universal…
The invariant mass spectrum of the lepton pair in inclusive semileptonic $\bar B\to X_u \ell\bar\nu$ decay yields a model independent determination of $|V_{ub}|$. Unlike the lepton energy and hadronic invariant mass spectra, nonperturbative…
Using methods of effective field theory, factorized expressions for arbitrary B -> X_u l nu decay distributions in the shape-function region of large hadronic energy and moderate hadronic invariant mass are derived. Large logarithms are…
A shape-function independent relation is derived between the partial B->X_u+l+nu decay rate with a cut on P_+=E_X-P_X<Delta and a weighted integral over the normalized B->X_s+gamma photon-energy spectrum. The leading-power contribution to…