Craig N. Burrell

Subleading shape function contributions to the hadronic invariant mass spectrum in anti-B ---> X(u) l anti-nu(l) decay

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|. Using simple models for the subleading shape functions, the effects of subleading operators are estimated to be at thefew percent level for experimentally relevant cuts. The subleading corrections proportional to the leading shape function are larger, but largely cancel in the relation between the hadronic invariant mass spectrum and the photon spectrum in B -> X_s \gamma. We also discuss the applicability of the usual prescription of convoluting the partonic level rate with the leading light-cone wavefunction of the b quark to subleading order.

Nonperturbative corrections to B→Xsℓ+ℓ− with phase space restrictions

Abstract We study nonperturbative corrections up to O (1/m b 3 ) in the inclusive rare B decay B → X s l + l − by performing an operator product expansion. The values of the matrix elements entering at this order are unknown and introduce uncertainties into physical quantities. Imposing a phase space cut to eliminate the c c resonances we find that the O (1/m b 3 ) corrections introduce an O (10%) uncertainty in the measured rate. We also find that the contributions arising at O (1/m b 3 ) are comparable to the ones arising at O (1/m b 2 ) over the entire region of phase space.

Renormalon analysis of heavy-light exclusive B decays

We study two-body exclusive decays of the form

Phenomenology of B ---> pi pi, pi K decays at O(alpha**2(s)Beta0) in QCD factorization

\overline{B}\ensuremath{\rightarrow}{D}^{(*)}L (L=\ensuremath{\pi},\ensuremath{\rho},\dots{})

Phenomenology of B{yields}{pi}{pi}, {pi}K decays at O({alpha}{sub s}{sup 2}{beta}{sub 0}) in QCD factorization

in the heavy-quark limit. We perform a renormalon analysis of such processes to determine the order at which nonperturbative factorization-breaking power corrections enter the amplitude. We find that a class of leading power corrections to the color octet matrix element, of

Phenomenology ofB→ππ,πKdecays atO(αs2β0)in QCD factorization

\mathcal{O}({\ensuremath{\Lambda}}_{\mathrm{QCD}}{/m}_{b}),

Power corrections to the rare decay B→Xsl+l−

vanishes in the limit of a symmetric light meson parton distribution function. We discuss the phenomenological significance of this result.

Phenomenology of B?pp, pK decays at O(as20) in QCD factorization

We study O(alpha^2 beta_0) perturbative corrections to matrix elements entering two-body exclusive decays of the form B -> pi pi, pi K in the QCD factorization formalism, including chirally enhanced power corrections, and discuss the effect of these corrections on direct CP asymmetries, which receive their first contribution at O(alpha). We find that the O(alpha^2 beta_0) corrections are often as large as the O(alpha) corrections. We find large uncertainties due to renormalization scale dependence as well as poor knowledge of the non-perturbative parameters. We assess the effect of the perturbative corrections on the direct CP violation parameters of B -> pi^+ pi^-.

Phenomenology of B-->pipi, piK decays at O(alphas2beta0) in QCD factorization

We study O(alpha^2 beta_0) perturbative corrections to matrix elements entering two-body exclusive decays of the form B -> pi pi, pi K in the QCD factorization formalism, including chirally enhanced power corrections, and discuss the effect of these corrections on direct CP asymmetries, which receive their first contribution at O(alpha). We find that the O(alpha^2 beta_0) corrections are often as large as the O(alpha) corrections. We find large uncertainties due to renormalization scale dependence as well as poor knowledge of the non-perturbative parameters. We assess the effect of the perturbative corrections on the direct CP violation parameters of B -> pi^+ pi^-.

Phenomenology of B, K decays at O(α{sub s}²β) in QCD factorization

We study O(alpha^2 beta_0) perturbative corrections to matrix elements entering two-body exclusive decays of the form B -> pi pi, pi K in the QCD factorization formalism, including chirally enhanced power corrections, and discuss the effect of these corrections on direct CP asymmetries, which receive their first contribution at O(alpha). We find that the O(alpha^2 beta_0) corrections are often as large as the O(alpha) corrections. We find large uncertainties due to renormalization scale dependence as well as poor knowledge of the non-perturbative parameters. We assess the effect of the perturbative corrections on the direct CP violation parameters of B -> pi^+ pi^-.