Some Possibilities for Charm Studies at B-factories.pdf

a r X i v : h e p - p h / 9 7 0 6 5 4 8 v 1 3 0 J u n 1 9 9 7 SOME POSSIBILITIES FOR CHARM STUDIES AT B-FACTORIES E. GOLOWICH Physics Department, University of Massachusetts, Amherst, MA 01003, USA To provide focus to my review of charm theory at the B-Physics and CP-Violation conference, I consider theoretical issues related to possible charm studies at B- factories. A few topics of interest to the author are stressed – rare decays, CP- violating asymmetries and D?0 ?D0 mixing. 1 Introduction To me, the CKM matrix is first and foremost an object of phenomenological study. When I look at it, it is natural to associate with each matrix element at least one experiment, as in? ? Vud Vus VubVcd Vcs Vcb Vtd Vts Vtb ? ? ? ? ? β decay K → π?ν? Bd → Xu?ν?νN → μμ?X D → K??ν? B → D??ν? Bd ? B?d b → sγ t → bW ? ? . The gradual and painstaking determination of the CKM matrix over a long period of time is a remarkable accomplishment of our field, and hopefully it will attain a level of completion from the B-factory studies to come. The emphasis of B-factories will be on the physics of b quarks and de- servedly so. Already, there is discovery of a ?B = 2 process (Bd?Bd mixing) and an EW-penguin decay (B → K? γ). The future observation of CP viola- tions (CPV) in B decays would top the list. However, B factories will provide opportunities for doing c quark studies as well. I would hope that the following items be given some consideration in the planning now underway: ? Search for flavor-changing neutral current (FCNC) charm decays, espe- cially D → Mγ (M denotes a J 0 non-charm meson), D → M ′?+?? (M ′ denotes a non-charm meson), ? Tighten the limit on CPV asymmetries in D± decay, ? Tighten the limit on D0 ? D?0 mixing. Although many more possible studies of charm systems come to mind, this talk will concentrate on just these few. 1 Table 1: Measured Phases. Mode δI ? δI′ KK? (28+9 ?17) o Kπ (97+12 ?13) o K?π (90± 16)o Kρ (10± 47)o K?ρ (33± 57)o ππ (81± 10)o 2 Current Status