Prospects for Charm CP Violation Studies in BTeV.pdf

a r X i v : h e p - e x / 0 1 1 1 0 4 4 v 1 1 2 N o v 2 0 0 1 IIT-HEP-01/8 Prospects for Charm CP Violation Studies in BTeV? Daniel M. Kaplan? Illinois Institute of Technology, Chicago, IL 60616 for the BTeV Collaboration Abstract The BTeV experiment at Fermilab could reconstruct 109 charm decays, three orders of magnitude beyond the largest extant sample. The experiment is likely to run during Tevatron Run II. It will have significant new-physics reach in the areas of charm CP violation, flavor-changing neutral-current and lepton-number-violating decays, and D0D0 mixing, and could observe direct CP violation in Cabibbo-suppressed D decays if it occurs at the level predicted by the Standard Model. ? Presented at the Snowmass Summer Study on the Future of Particle Physics, Snowmass, Colorado, June 30–July 21, 2001. ?kaplan@ 1 I. INTRODUCTION Particle physics at the turn of the millennium faces two key mysteries: the origin of mass and the existence of multiple fermion generations. While the former mystery may be resolved by the LHC, the latter appears to originate at higher mass scales, which can be studied only indirectly. Such effects as CP violation, mixing, and flavor-changing neutral or lepton-number- violating currents may hold the key to physics at these new scales [1, 2, 3]. Because in the charm sector the Standard Model (SM) contributions to these effects are small, these are areas in which charm studies can provide unique information. In contrast, in the s- and b-quark sectors, in which such studies are typically pursued, there are large SM contributions to mixing and CP violation [4, 5], which for new-physics searches constitute backgrounds. II. CHARM CP VIOLATION Both direct and indirect CP violation are possible in charm decay. The Standard Model (SM) predicts direct CP violation in singly Cabibbo-suppressed (SCS) charm decays at the O(10?3) level [6], arising from the interference of tree-level processes with penguins (Fig. 1). The observation of C