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Improved Upper Limits on the Flavor-Changing Neutral Current Decays B → K ℓ + ℓ − </…

2001; American Physical Society; Volume: 87; Issue: 18 Linguagem: Inglês

10.1103/physrevlett.87.181803

1092-0145

S. Anderson, V. V. Frolov, Y. Kubota, S. J. Lee, R. Poling, A. Smith, C. J. Stepaniak, J. Urheim, S. Ahmed, M. S. Alam, S. B. Athar, L. Jian, L. Ling, M. Saleem, S. Timm, F. Wappler, A. Anastassov, E. Eckhart, K. K. Gan, C. Gwon, T. Hart, K. Honscheid, D. Hufnagel, H. Kagan, R. Kass, T. K. Pedlar, J. B. Thayer, E. von Toerne, M. M. Zoeller, S. J. Richichi, H. Severini, P. Skubic, A. Undrus, V. Savinov, S. Chen, J. W. Hinson, J. Lee, D. H. Miller, E. I. Shibata, I. P. J. Shipsey, V. Pavlunin, D. Cronin-Hennessy, Y.-J. Kwon, A. L. Lyon, W. Park, E. H. Thorndike, T. E. Coan, Y. S. Gao, Y. Maravin, I. Narsky, R. Stroynowski, J. Ye, T. Wlodek, M. Artuso, K. Benslama, C. Boulahouache, K. Bukin, E. Dambasuren, G. Majumder, R. Mountain, T. Skwarnicki, S. Stone, J. C. Wang, A. Wolf, S. Köpp, M. Kostin, A. H. Mahmood, S. E. Csorna, I. Dankó, K. W. McLean, Z. Xu, R. Godang, G. Bonvicini, D. Cinabro, M. Dubrovin, S. McGee, A. Bornheim, G. Eigen, E. Lipeles, S. P. Pappas, A. Shapiro, W. Sun, A. J. Weinstein, D. E. Jaffe, R. Mahapatra, G. Masek, H. P. Paar, A. Eppich, R. J. Morrison, R. A. Briere, G. P. Chen, T. Ferguson, H. Vogel, J. Alexander, C. Bebek, B. E. Berger, K. Berkelman, F. Blanc, V. Boisvert, D. G. Cassel, P. S. Drell, J. E. Duboscq, K. M. Ecklund, R. Ehrlich, P. Gaidarev, L. Gibbons, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, L. Hsu, C. D. Jones, J. Kandaswamy, D. L. Kreinick, M. Lohner, A. Magerkurth, H. Mahlke-Krüger, T. O. Meyer, N. B. Mistry, E. Nordberg, M. Palmer, J. R. Patterson, D. Peterson, D. Riley, A. Romano, H. Schwarthoff, J. G. Thayer, D. Urner, B. Valant-Spaight, G. H. A. Viehhauser, A. Warburton, P. Avery, C. Prescott, A. I. Rubiera, H. Stoeck, J. Yelton, G. Brandenburg, A. Ershov, D. Y.-J. Kim, R. Wilson, B. I. Eisenstein, J. Ernst, G. E. Gladding, G. D. Gollin, R. M. Hans, E. Johnson, I. Karliner, M. A. Marsh, C. Plager, C. Sedlack, M. Selen, J. J. Thaler, J. S. Williams, K. W. Edwards, A. J. Sadoff, R. Ammar, A. Bean, D. Besson, X. Zhao,

High-Energy Particle Collisions Research

We have searched a sample of $9.6\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events for the flavor-changing neutral current decays $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ and $B\ensuremath{\rightarrow}{K}^{*}(892){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$. We subject the latter decay to the requirement that the dilepton mass ${m}_{\ensuremath{\ell}\ensuremath{\ell}}$ exceed 0.5 GeV. There is no indication of a signal. We obtain the $90%$ confidence level upper limits $B(B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}})<1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $B(B\ensuremath{\rightarrow}{K}^{*}(892){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}{)}_{{m}_{\ensuremath{\ell}\ensuremath{\ell}}>0.5\mathrm{GeV}}<3.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. We also obtain an upper limit on the weighted average $0.65B(B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}})+0.35B(B\ensuremath{\rightarrow}{K}^{*}(892){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}{)}_{{m}_{\ensuremath{\ell}\ensuremath{\ell}}>0.5\mathrm{GeV}}<1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. The weighted-average limit is only $50%$ above the standard model prediction.