Search for rare hadronic B decays

• Published in: Physics letters. B 1994-10, Vol.337 (3), p.393-404
• Main Authors: Akers, R., Barlow, R.J., Batley, J.R., Beaudoin, G., Beeston, C., Bella, G., Bethke, S., Bloodworth, I.J., Braibant, S., Bright-Thomas, P., Brown, R.M., Burgard, C., Capiluppi, P., Carnegie, R.K., Chu, S.L., Clayton, J.C., Clowes, S.G., Coupland, M., Dallapiccola, C., Dittmar, M., Dunwoody, U.C., Etzion, E., Evans, H.G., Fabbri, F., Fanti, M., Fischer, P., Fong, D.G., Fürtjes, A., Gagnon, P., Gary, J.W., Geddes, N.I., Gentit, F.X., Giacomelli, P., Gibson, V., Gibson, W.R., Gillies, J.D., Goldberg, J., Gorn, W., Grannis, P., Hagemann, J., Heuer, R.D., Hilse, T., Hobson, P.R., Humbert, R., Ihssen, H., Imrie, D.C., Jawahery, A., Karlen, D., Kawagoe, K., Layter, J.G., Le Du, P., Lefebvre, E., Lehto, M.H., Leroy, C., Liu, F., Lorazo, B., Ludwig, J., Markus, C., Mättig, P., Maur, U., McKenna, J., McNab, A.I., Merritt, F.S., Middleton, R.P., Mildenberger, J., Mir, R., Mori, T., O'Neale, S.W., Oakham, F.G., Oreglia, M.J., Pilcher, J.E., Plane, D.E., Poffenberger, P., Rigby, D., Rison, M., Robins, S.A., Robinson, D., Rozen, Y., Runge, K., Schaile, A.D., Schulz, M., Schwiening, J., Shears, T.G., Skillman, A., Stegmann, C., Stephens, K., Steuerer, J., Stockhausen, B., Ströhmer, R., Tarem, S., Teixeira-Dias, P., Van den plas, D., Van Kooten, R., Wagner, A., Ward, C.P., Watkins, P.M., Wermes, N., Wilson, J.A., Wolf, G., Zorn, G.T.
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(94)90993-8

A search for rare decays of B hadrons has been performed using approximately two million hadronic Z 0 decays collected by the OPAL experiment between 1990 and 1993. The exclusive decay channels B d 0 → π + π −, B d 0 → K +π −, B s 0 → π +K − and B s 0 → K +K − have been studied. Such decays include contributions from flavour changing neutral current processes such as hadronic penguin decays. No significant excess of events has been observed in the π +π −, π +K − and K +K − invariant mass distributions. Consequently, upper limits on the B d 0 branching ratios, Br(B d 0→ π + π −) < 4.7 × 10 −5 and Br(B d 0→K + π −) < 8.1 × 10 −5, and on the B s 0 branching ratios, Br(B s 0→ π +K −) < 2.6 × 10 −4 and Br(B s 0→K +K −) < 1.4 × 10 −4, have been set at the 90% confidence level. These limits assume that the ratio of the partial decay widths of the Z 0, λ (Z 0 → bb̄)/λ(Z 0 → hadrons), is 0.217 and that the fractions of B d 0 and B s 0 mesons produced during fragmentation are 39.5% and 12% respectively. The B s 0 branching ratio limits are the first such limits obtained.