Charm Mixing - Theory

We discuss Standard Model (SM) and New Physics (NP) descriptions of D0 mixing. The SM part of the discussion addresses both quark level and hadron level contributions. The NP part describes our recent works on the rate difference Delta Gamma_D and the mass difference Delta M_D. In particular, we describe how the recent experimental determination of Delta M_D is found to place tightened restrictions on parameter spaces for 17 of 21 NP models considered in a recent paper by Hewett, Pakvasa, Petrov and myself.Comment: 6 pages, to be published in the proceedings of CHARM07, Ithaca, NY, August 2007, eConf C07080

Charm Mixing and CP-violations - Theory

I begin by commenting on the most recent experimental compilation of D^0 mixing data, emphasizing the so-called 'strong phase' issue. This is followed by a review of the theory underlying charm mixing, both Standard Model and New Physics. The mechanism of R_p-violation is used to illustrate the methodology for New Physics contributions and the relation of this to rare D^0 decays is pointed out. Finally, I address the subject of CP-violating asymmetries by describing some suggestions for future experimental studies and a recent theoretical analysis of New Physics contributions.Comment: Flavor Physics & CP Violation Conference, Taipei, 2008; 8 pages, 4 figure

Two-loop analysis of axial vector current propagators in chiral perturbation theory

We perform a calculation of the isospin and hypercharge axial vector current propagators [ΔA3μν(q) and ΔA8μν(q)] to two loops in SU(3)×SU(3) chiral perturbation theory. A large number of O(p6) divergent counterterms are fixed, and complete two-loop renormalized expressions for the pion and eta masses and decay constants are obtained. The calculated isospin and hypercharge axial vector polarization functions are used as input in new chiral sum rules, valid to second order in the light quark masses. Some phenomenological implications of these sum rules are considered

Chiral sum rules to second order in quark mass

A new calculation of the isospin and hypercharge axialvector current propagators ($\Delta_{A33}^{\mu\nu}(q^2)$ and $\Delta_{A88}^{\mu\nu}(q^2)$) to two loops in SU(3) x SU(3) chiral perturbation theory is used to derive chiral spectral function sum rules valid to second order in the light quark masses. Explicit forms are given for the three-pion isospin axialvector spectral functions at low energy and application of the sum rules to the determination of counterterms of the chiral lagrangian is discussed.Comment: Figures extended down to threshold; Eq. (19) expressed in simplified for

QCD condensates for the light quark V-A correlator

We use the procedure of pinched-weight finite energy sum rules to determine the operator product expansion (OPE) coefficients a6,…,a16 of the flavor ud V-A correlator in terms of existing hadronic τ decay data. We show by appropriate weight choices that the error on the dominant d=6 contribution, which is known to be related to the K⃗ππ matrix elements of the electroweak penguin operator in the chiral limit, may be reduced to below the ∼15% level. The values we obtain for OPE coefficients with d\u3e8 are shown to naturally account for the discrepancies between our results for the d=6 and d=8 terms and those of previous analyses, which were obtained neglecting d\u3e8 contributions

Two-point function of strangeness-carrying vector-currents in two-loop Chiral Perturbation Theory

We calculate the correlator between two external vector-currents having the quantum-numbers of a charged kaon. We give the renormalized expression to two loops in standard chiral perturbation theory in the isospin limit, which, as a physical result, is finite and scale-independent. Applications include a low energy theorem, valid at two loop order, of a flavor breaking combination of vector current correlators as well as a determination of the phenomenologically relevant finite $O(p^6)$-counterterm combination $Q_V$ by means of inverse moment finite energy sum rules. This determination is less sensitive to isospin-breaking effects than previous attempts.Comment: 24 pages, revtex, 4 figures, 2 tables, revised version, one ref. adde

Heavy Quark Lifetimes, Mixing and CP Violation

This paper emphasizes four topics that represent some of the year's highlights in heavy quark physics. First of all, a review is given of charm lifetime measurements and how they lead to better understanding of the mechanisms of charm decay. Secondly, the CLEO collaboration's new search for charm mixing is reported, which significantly extends the search for new physics in that sector. Thirdly, important updates in Bs mixing are summarized, which result in a new limit on the mass difference, and which further constrain the unitarity triangle. Finally, the first efforts to measure CP violation in the B system are discussed. Results are shown for the CDF and ALEPH measurements of sin(2beta), as well as the CLEO branching fraction measurements of B-->Kpi,pipi, which have implications for future measurements of alpha.Comment: 25 pages, 15 figures. Talk given at the XIX International Symposium on Lepton and Photon Interactions, Stanford University, August 9-14, 199