Short distance analysis of (B)over-bar -> D(*)0e+e- and (B)over-bar -> J/psi e+e-

Over a large fraction of phase space a combination of an operator product a nd heavy quark expansions effectively turn the decay (B) over bar --> D-(*( )0)e(+)e(-) into a "short distance" process, i.e., one in which the weak an d electromagnetic interactions occur through single local operators. These processes have an underlying W-exchange quark diagram topology and are ther efore Cabibbo allowed but suppressed by combinatoric factors and short dist ance QCD corrections. Our technique allows a clearer exploration of these e ffects. For the decay (B) over bar(d,s) --> J/psi(eta(c))e(+)e(-) one must use a non-relativistic (NRQCD) expansion, in addition to an operator produc t expansion and a heavy quark effective theory expansion. We estimate the d ecay rates for (B) over bar d,s --> J/psi e(+)e(-), (B) over bar(d,s) --> e ta(c)e+e-, (B) over bar(d,s -->) D*(0)e(+)e(-) and (B) over bar(d,s) --> D( 0)e(+)e(-). (C) 2000 Elsevier Science B.V. All rights reserved.