3
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      A new model-independent way of extracting |V_ub/V_cb|

      Preprint
      , ,

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The ratio between the photon spectrum in B -> X_s gamma and the differential semileptonic rate wrt the hadronic variable M_X/E_X is a short-distance quantity calculable in perturbation theory and independent of the Fermi motion of the b quark in the B meson. We present a NLO analysis of this ratio and show how it can be used to determine |V_ub/V_cb| independently of any model for the shape function. We also discuss how this relation can be used to test the validity of the shape-function theory on the data.

          Related collections

          Most cited references3

          • Record: found
          • Abstract: found
          • Article: found
          Is Open Access

          Bremsstrahlung corrections to the decay \(b \to s \gamma\)

          We calculate the O(\(\alpha_s\)) gluon Bremsstrahlung corrections to the inclusive decay \(b \rightarrow s \gamma\), involving the full operator basis \(\hat O_1\) -- \(\hat O_8\). Confirming and extending earlier calculations of Ali and Greub, we give formulas for the total decay width as well as the perturbative photon spectrum, regarding the former as a necessary part of the forthcoming complete NLO analysis. We explore in detail the renormalization scale dependence of our results and find it considerably increased.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: found
            Is Open Access

            Precision determination of |V_{ub}| from inclusive decays

            We propose determining |V_{ub}| from inclusive semileptonic B decay using combined cuts on the leptonic and hadronic invariant masses to eliminate the b->c background. Compared to a pure dilepton invariant mass cut, the uncertainty from unknown order (\Lambda_{QCD}/m_b)^3 terms in the OPE is significantly reduced and the fraction of b->u events is roughly doubled. Compared to a pure hadronic invariant mass cut, the uncertainty from the unknown light-cone distribution function of the b quark is significantly reduced. We find that |V_{ub}| can be determined with theoretical uncertainty at the 5-10% level.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Short-Distance Expansion of Heavy-Light Currents at Order 1/m

              The short-distance expansion of the heavy-light currents \(\bar q\,\gamma^\mu Q\) and \(\bar q\,\gamma^\mu\gamma_5\,Q\) is constructed to order \(1/m_Q\), and to next-to-leading order in renormalization-group improved perturbation theory. It is shown that the \(10\times 10\) anomalous dimension matrix, which describes the scale dependence of the dimension-four effective current operators in the heavy quark effective theory, is to a large extent determined by the equations of motion, heavy quark symmetry, and reparameterization invariance. The next-to-leading order expressions for the Wilson coefficients at order \(1/m_Q\) depend on only five unknown two-loop anomalous dimensions, among them that of the chromo-magnetic operator.
                Bookmark

                Author and article information

                Journal
                12 April 2002
                Article
                10.1016/S0550-3213(02)00464-9
                hep-ph/0204140
                bbda9976-714a-412d-b7f0-6f60a155109f
                History
                Custom metadata
                CERN-TH/2002-069, RM3-TH/02-4
                Nucl.Phys.B637:427-444,2002
                20 pages, 3 figs
                hep-ph

                Comments

                Comment on this article