The weak decays Ξ(b) → Λ(b) π and Ξ(c) → Λ(c) π, in which the heavy quark is not destroyed, are discussed. The branching fractions for these decays, corresponding to an absolute rate of order 0.01 ps-1, should be at a one percent level for the b hyperons and at a (few) per mill level for Ξ(c), possibly making feasible their experimental study in future. It is shown, through an application of the heavy quark limit, the flavor SU(3) symmetry, and PCAC, that the ΔI = 1/2 rule should hold very well in these decays, and also that the Ξ(b) decays are purely S wave in the symmetry limit, while the difference between the S wave amplitudes of the Ξ(c) decays and those for the Ξ(b) is related, in terms of the heavy quark expansion, to the difference of the total decay rates within the (Ξ(c), Λ(c) triplet of charmed hyperons. We also comment on the amplitudes of the semileptonic transitions Ξ(Q) → Λ(Q) l ν and on the weak radiative decays Ξ(Q) → Λ(Q) γ. (C) 2000 Published by Elsevier Science B.V.
|Original language||English (US)|
|Number of pages||6|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Mar 16 2000|
Bibliographical noteFunding Information:
This work is supported in part by DOE under the grant number DE-FG02-94ER40823.