Heavy quark distribution function in QCD and the AC2M2 model

I. Bigi, M. Shifman, N. Uraltsev, A. Vainshtein

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


We show the phenomenological AC2M2 ansatz to be consistent with QCD through order 1/mb in the description of B → lvl + Xu and B → γ + Xs transitions, including their energy spectra and differential distributions. This suggests a concrete realization of the QCD distribution function, which we call the "Roman" function. Yet the AC2M2 description of the end-point domain in B → lvl + Xc is, formally speaking, incompatible with QCD: a different distribution function enters the description of b → c decays as compared to the transitions to massless quarks. The intrinsic limitation of the AC2M2 model could reveal itself in different values of the effective b quark mass from fits of the Λb and B decays.

Original languageEnglish (US)
Pages (from-to)431-440
Number of pages10
JournalPhysics Letters B
Issue number3-4
StatePublished - Jun 2 1994


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