B Decays in the Upsilon Expansion

Theoretical predictions for B decay rates are rewritten in terms of the Upsilon meson mass instead of the b quark mass, using a modified perturbation expansion. The theoretical consistency is shown both at low and high orders. This method improves the behavior of the perturbation series for inclusive and exclusive decay rates, and the largest theoretical error in the predictions coming from the uncertainty in the quark mass is eliminated. Applications to the determination of CKM matrix elements, moments of inclusive decay distributions, and the B -> X_s \gamma photon spectrum are discussed.Comment: 4 pages, Talk given at the International Europhysics Conference on High Energy Physics (EPS-HEP'99), 15-21 July 1999, Tampere, Finlan

Theoretical Developments in Inclusive B Decays

Some recent theoretical work on inclusive B decays relevant for the model independent determination of |V_{ub}| and |V_{cb}| is summarized. The theoretical predictions and their reliability for several differential decay distributions in B -> X_{c,u}e nu and B -> X_s gamma are reviewed. These can be used to determine certain important HQET matrix elements. The upsilon expansion and ways of testing it are discussed.Comment: 11 pages, Invited talk at the DPF'99 Conference, Jan. 5-9, 1999, Los Angeles, C

D0-D0bar Mixing

The main challenge in the Standard Model calculation of the mass and width difference in $D^0 - \bar D^0$ mixing is to estimate the size of SU(3) breaking. We prove that mixing occurs in the Standard Model only at second order in SU(3) violation. We calculate SU(3) breaking due to phase space effects, and find that it can naturally give rise to a width difference $\Delta\Gamma / 2\Gamma \sim 1$, potentially reducing the sensitivity of D mixing to new physics.Comment: 9 pages; Talk given at the XXXVIIth Rencontres de Moriond, Electroweak Interactions and Unified Theories, Les Arcs, March 9-16 2002; and at the 9th International Symposium on Heavy Flavor Physics, Pasadena, California, September 10-13 200

Supermodels: Early new physics at the LHC?

We investigate new physics that could be discovered with very little LHC data, beyond the expected sensitivity of the Tevatron. We construct "supermodels", for which the LHC sensitivity with 10 pb-1 luminosity is already greater than that of the Tevatron with 10 fb-1. The simplest supermodels involve s-channel resonances in the quark-antiquark and especially in the quark-quark channels. In the latter case, the LHC sensitivity with 0.1 pb-1 can already be greater than that of the Tevatron with 10 fb-1. We concentrate on easily visible final states with small standard model backgrounds, and find that there are simple searches, besides those for Z' states, which could discover new physics in early LHC data. Many of these are well-suited to test searches for "conventional" models, often discussed for larger data sets.Comment: 5 pages, 2 figures, talk given at the 35th International Conference on High Energy Physics (ICHEP 2010), Paris, France, July 22-28, 201