CORRECTIONS FROM LOW MOMENTUM PHYSICS TO HEAVY-QUARK SYMMETRY-RELATIONS FOR B-]DE(V)OVER-BAR(E) AND B-]D-ASTERISK-E(V)OVER-BAR(E) DECAY

Heavy quark symmetry relations for B-->De<(nu)over bar>(e) and B-->De <(nu)over bar>(e) form factors receive corrections suppressed by power s of the charm quark mass. For small up and down quark masses the lead ing corrections of order (1/m(c))(n+2), n=0,1,2,..., have a nonanalyti c dependence on the light quark masses of the form lnm(pi)(2), for n=0 and (1/m(pi))(n) for n=1,2,.... These corrections arise from very low momentum physics (i.e., well below the chiral-symmetry-breaking scale ) and are computed using chiral perturbation theory. They are typicall y of the order of a few percent.