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Moments in inclusive semileptonic b → u decays

Moments in inclusive semileptonic b → u decays. Paolo Gambino INFN Torino. in collaboration with Giovanni Ossola. Why?. Checking consistency with HQE fits fits of b → c and b → s  moments are remarkably consistent, δ m b almost 50MeV; b → u moments especially sensitive to m b.

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Moments in inclusive semileptonic b → u decays

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  1. Moments in inclusive semileptonic b→u decays Paolo Gambino INFNTorino in collaboration with Giovanni Ossola Paolo Gambino SLAC 11/12/2004

  2. Why? • Checking consistency with HQE fits fits of b→c and b→s moments are remarkably consistent, δmb almost 50MeV; b→u moments especially sensitive to mb Precision measurements must probe limits of HQE & test th. framework • It’s probably time to use b->u data to constrain Shape Function, WA, etc • Moments to validate MC and possibly constrain SF parameters using b->c inputs; use spectra as well? Paolo Gambino SLAC 11/12/2004

  3. b→u hadronic moments • Compared to b→c : • more sensitive to mb • less to higher dimensional paramtrs • Neglecting theory errors, • δ<Mx2> ~ 0.4GeV2 ⇒δmb ~100MeV Our calculation: Mx and q2 moments in the kinetic scheme All known power corrections included at arbitrary El cut, Complete O(s),BLM corrections not yet available Paolo Gambino SLAC 11/12/2004

  4. 11 9 7 Ecut 5 Ecut Ecut Large pQCD corrections especially for high moments 1/mb3 corrections diverge as mc→0 but effect is suppressed by one further power of MB-mb A rough preliminary estimateof the th error is about 5-6%, 15-20%, 20-30% for these three moments, Paolo Gambino SLAC 11/12/2004

  5. Ecut Ecut Fractional moments Fractional moments can be estimated using an expansion in.. Certainly there are additional uncertainties here, but they seem likely to be smaller than other TH systematics... In any case, we can probably live without fractional moments Paolo Gambino SLAC 11/12/2004

  6. Future sensitivity O.Buchmuller Run 1-2 and run 1-4 Babar projected sensitivity Paolo Gambino SLAC 11/12/2004

  7. Perturbative calculation is being improved:there is (limited) room to cut TH uncertainties • Truncated Mx moments with high Mx cut could simplify a lot exp analysis • Moments with explicit El cut • Can we constrain WA from q2 or Mx moments? Probably yes • Can we learn something useful (on SF) from the spectrum itself? • What’s necessary in order to constrain SF parameters from b->u moments? New generator? Paolo Gambino SLAC 11/12/2004

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