Tree-level contribution to \bar{B} -> X_d gamma using fragmentation functions

Abstract

We evaluate the most important tree-level contributions connected with the b-> u \bar{u} d gamma transition to the inclusive radiative decay \bar{B}-> X_d gamma using fragmentation functions. In this framework the singularities arising from collinear photon emission from the light quarks (u, \bar{u} and d) can be absorbed into the (bare) quark-to-photon fragmentation function. We use as input the fragmentation function extracted by the ALEPH group from the two-jet cross section measured at LEP, where one of the jets is required to contain a photon. To get the quark-to-photon fragmentation function at the fragmentation scale μ_F \sim m_b, we use the evolution equation, which we solve numerically. We then calculate the (integrated) photon energy spectrum for b-> u \bar{u} d gamma related to the operators P^u_{1,2}. For comparison, we also give the corresponding results when using nonzero (constituent) masses for the light quarks.

13 pages, 4 figures

References in corpus (9)

• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• Estimate of BR(B -> X_s gamma) at O(alpha_s^2)
• Precision Measurement of the B to X_s γPhoton Energy Spectrum, Branching Fraction, and Direct CP Asymmetry A_{CP}(B to X_{s+d}γ
• Radiative and Electroweak Penguin Decays of B Mesons
• Measurement of B(B-->X_s γ), the B-->X_s γ photon energy spectrum, and the direct CP asymmetry in B-->X_{s+d} γ decays
• Chromomagnetic Dipole-Operator Corrections in Bbar -> X_sgamma at O(beta_0 alpha_s^2)
• Tree-level contributions to B -> Xs gamma
• Phase space analysis for three and four massive particles in final states
• b-> s gamma and b-> d gamma (B factories)

Cited by in corpus (10)

• Updated NNLO QCD predictions for the weak radiative B-meson decays
• Weak Radiative Decays of the B Meson and Bounds on $M_{H^{\pm }}$ in the Two-Higgs-Doublet Model
• Rare $B$ Decays as Tests of the Standard Model
• The (Q_7,Q_{1,2}) contribution to B -> X_s gamma at O(alpha_s^2)
• Update of the flavour-physics constraints in the NMSSM
• NLL QCD contribution of the electromagnetic dipole operator to B -> X_s gamma gamma with a massive strange quark
• The Q_{1,2}-Q_7 interference contributions to b -> s gamma at O(alpha_s^2) for the physical value of m_c
• Improved analysis of the (O_7, O_7) contribution to $\bar{B}\to X_s\gamma \gamma$ at $O({\alpha }_s)$
• (O_8, O_8) contribution to $\bar{B}\to X_s\gamma \gamma$ at O(α_s)
• Multi-parton contributions to $\bar{B}\to X_s\gamma$ at NLO