Charm Physics with BES-III at BEPC-II.pdf

a r X i v : h e p - e x / 0 6 0 5 0 0 4 v 2 8 M a y 2 0 0 6 Charm Physics with BES-III at BEPC-II Haibo Lia ? aInstitute of High Energy Physics, P.O.Box 918, Beijing 100049, China We report on the charm physics potential at BES-III at BEPC-II which will make significant contribution to quark flavor physics this decade. The charm physics program will include studies of leptonic, semileptonic and hadronic charm decays, and tests for physics beyond the Standard Model. Event samples of the order of 30 million DD pairs, 2 million D+ S D? S pairs at threshold and 10 × 109 J/ψ decays will be produced with one year design luminosity. High precision charm data will enable us to validate forthcoming Lattice QCD calculations at the few percent level. These can then be used to make precise measurements of CKM elements, Vcd, Vcs, Vub, Vcb and Vts, which are useful to improve the accuracy of test of the CKM unitarity. 1. Introduction BES-III at BEPC-II under construction in Bei- jing will focus on charm and QCD physics in the range √ s = 2.0 ? 4.2 GeV. The physics program at BES-III includes a variety of mea- surements that will improve the understanding of the Standard Model (SM) processes as well as provide the opportunity to probe for physics that lies beyond the SM. However, the possibil- ity of new physics may be diluted by the large hadronic uncertainty in D decays. The study of weak interactions in the charm sector, and the extraction of quark mixing matrix parameters re- main limited by our capacity to cope with non- perturbative QCD. Thus, it will be of great bene- fit if we can understand the effects of strong cou- pling in QCD. High precision predictions of QCD will then remove road blocks for many weak and flavor physics measurements. Lattice QCD (LQCD) [1] had matured over the last decade. Recent advances in LQCD have produced a wide variety of calculations of non- perturbative quantities with accuracies in the 10- 20% level for D decay constant and form factors