Charming penguins in B decays
Abstract
Full expressions of the B_{d}^{0} → π^{+}π^{} and B_{d}^{0} → π^{0}π^{0} amplitudes, given in terms of matrix elements of operators of the effective weak Hamiltonian, are used to study the dependence of the relevant branching ratios on the different contributions. The uncertainty in the extraction of the weak phase α from the measurement of the timedependent asymmetry in B_{d}^{0} → π^{+}π^{} decays is also analyzed. We find that, among several effects which may enhance the B_{d}^{0} → π^{0}π^{0} branching ratio, the most important is due to "charming penguin" diagrams. These diagrams easily increase BR( B_{d}^{0} → π^{0}π^{0}) up to a value of 13 × 10 ^{6}. The same effect produces, however, a large error in the extraction of a from the measurement of the B_{d}^{0} → π^{+}π^{} timedependent asymmetry. We show that it is possible to determine charmingpenguin amplitudes from the experimental measurement of many decay rates. Their effect is impressive in B^{+} → π^{+}K^{0} and B_{d}^{0} → K^{+}π^{} decays, where charmingpenguin contributions easily give values of BR( B^{+} → π^{+}K^{0}) and BR( B_{d}^{0} → K^{+}π^{}) of about 1 × 10 ^{5}. Among other possibilities, we also suggest to use B _{d}^{0} → K ^{0}overlineK^{0}, the BR of which can be as large as 23 x 10 ^{6}, to determine the size of charmingpenguin amplitudes.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1997
 DOI:
 10.1016/S05503213(97)00388X
 arXiv:
 arXiv:hepph/9703353
 Bibcode:
 1997NuPhB.501..271C
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 LaTeX, 28 pages, 8 figures