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R. Aaij, C. Abellán Beteta, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. A. Aidala, S. Aiola, Z. Ajaltouni, S. Akar, P. Albicocco, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves, S. Amato, Y. Amhis, L. An, L. Anderlini, G. Andreassi, M. Andreotti, F. Archilli, A. Artamonov, M. Artuso, K. Arzymatov, E. Aslanides, M. Atzeni, B. Audurier, S. Bachmann, J. J. Back, S. Baker, V. Balagura, W. Baldini, A. Baranov, R. J. Barlow, S. Barsuk, W. Barter, M. Bartolini, F. Baryshnikov, J. M. Basels, G. Bassi, V. Batozskaya, B. Batsukh, A. Battig, A. Bay, M. Becker, F. Bedeschi, I. Bediaga, A. Beiter, V. Belavin, S. Belin, V. Bellee, K. Belous, I. Belyaev, G. Bencivenni, E. Ben-Haim, S. Benson, A. Berezhnoy, R. Bernet, D. Berninghoff, H. C. Bernstein, C. Bertella, E. Bertholet, A. Bertolin, C. Betancourt, F. Betti, M. O. Bettler, Ia. Bezshyiko, S. Bhasin, J. Bhom, M. S. Bieker, S. Bifani, P. Billoir, A. Bizzeti, M. Bjørn, M. P. Blago, T. Blake, F. Blanc, S. Blusk, D. Bobulska, V. Bocci, O. Boente Garcia, T. Boettcher, A. Boldyrev, A. Bondar, N. Bondar, S. Borghi, M. Borisyak, M. Borsato, J. T. Borsuk, T. J. V. Bowcock, C. Bozzi, M. J. Bradley, S. Braun, A. Brea Rodriguez, M. Brodski, J. Brodzicka
Abstract
A search for the decays ${B}_{s}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ and ${B}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ is performed using data collected with the LHCb experiment in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and $2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, respectively. No signal is observed. Assuming no contribution from ${B}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ decays, an upper limit on the branching fraction $\mathcal{B}({B}_{s}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}})<9.4(11.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$ is obtained at 90(95)% confidence level. If no ${B}_{s}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ contribution is assumed, a limit of $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}})<2.5(3.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$ is determined at 90(95)% confidence level. These upper limits are more than one order of magnitude lower than the previous values.