Search for the Rare Decays B →

We present preliminary results from a search for the flavor-changing neutral current decays B → K`+`− and B → K∗(892)`+`− using a sample of 22.7×106 Υ (4S) → BB̄ decays collected with the BABAR detector at the PEP-II B Factory. We have reconstructed the following final states: B+ → K+`+`−, B0 → K0`+`− (K0 s → π+π−), B+ → K∗+`+`− (K∗+ → K0 sπ), and B0 → K∗0`+`− (K∗0 → K+π−), where `+`− is either an e+e− or μ+μ− pair. We obtain the 90% C.L. upper limits B(B → K`+`−) < 0.6 × 10−6 and B(B → K∗`+`−) < 2.5 × 10−6, close to the Standard Model predictions for these branching fractions. Submitted to the International Europhysics Conference on High Energy Physics, 7/12—7/18/2001, Budapest, Hungary Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94309 Work supported in part by Department of Energy contract DE-AC03-76SF00515. The BABAR Collaboration, B. Aubert, D. Boutigny, J.-M. Gaillard, A. Hicheur, Y. Karyotakis, J. P. Lees, P. Robbe, V. Tisserand Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux, France A. Palano Università di Bari, Dipartimento di Fisica and INFN, I-70126 Bari, Italy G. P. Chen, J. C. Chen, N. D. Qi, G. Rong, P. Wang, Y. S. Zhu Institute of High Energy Physics, Beijing 100039, China G. Eigen, P. L. Reinertsen, B. Stugu University of Bergen, Inst. of Physics, N-5007 Bergen, Norway B. Abbott, G. S. Abrams, A. W. Borgland, A. B. Breon, D. N. Brown, J. Button-Shafer, R. N. Cahn, A. R. Clark, M. S. Gill, A. V. Gritsan, Y. Groysman, R. G. Jacobsen, R. W. Kadel, J. Kadyk, L. T. Kerth, S. Kluth, Yu. G. Kolomensky, J. F. Kral, C. LeClerc, M. E. Levi, T. Liu, G. Lynch, A. B. Meyer, M. Momayezi, P. J. Oddone, A. Perazzo, M. Pripstein, N. A. Roe, A. Romosan, M. T. Ronan, V. G. Shelkov, A. V. Telnov, W. A. Wenzel Lawrence Berkeley National Laboratory and University of California, Berkeley, CA 94720, USA P. G. Bright-Thomas, T. J. Harrison, C. M. Hawkes, D. J. Knowles, S. W. O’Neale, R. C. Penny, A. T. Watson, N. K. Watson University of Birmingham, Birmingham, B15 2TT, United Kingdom T. Deppermann, K. Goetzen, H. Koch, J. Krug, M. Kunze, B. Lewandowski, K. Peters, H. Schmuecker, M. Steinke Ruhr Universität Bochum, Institut für Experimentalphysik 1, D-44780 Bochum, Germany J. C. Andress, N. R. Barlow, W. Bhimji, N. Chevalier, P. J. Clark, W. N. Cottingham, N. De Groot, N. Dyce, B. Foster, J. D. McFall, D. Wallom, F. F. Wilson University of Bristol, Bristol BS8 1TL, United Kingdom K. Abe, C. Hearty, T. S. Mattison, J. A. McKenna, D. Thiessen University of British Columbia, Vancouver, BC, Canada V6T 1Z1 S. Jolly, A. K. McKemey, J. Tinslay Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom V. E. Blinov, A. D. Bukin, D. A. Bukin, A. R. Buzykaev, V. B. Golubev, V. N. Ivanchenko, A. A. Korol, E. A. Kravchenko, A. P. Onuchin, A. A. Salnikov, S. I. Serednyakov, Yu. I. Skovpen, V. I. Telnov, A. N. Yushkov Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia D. Best, A. J. Lankford, M. Mandelkern, S. McMahon, D. P. Stoker University of California at Irvine, Irvine, CA 92697, USA A. Ahsan, K. Arisaka, C. Buchanan, S. Chun University of California at Los Angeles, Los Angeles, CA 90024, USA