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arXiv · 1701.08705

Observation of the suppressed decay $\Lambda^{0}_{b}\rightarrow p\pi^{-}\mu^{+}\mu^{-}$

LHCb collaboration·R. Aaij·B. Adeva·M. Adinolfi·Z. Ajaltouni·S. Akar·J. Albrecht·F. Alessio·M. Alexander·S. Ali·G. Alkhazov·P. Alvarez Cartelle·A. A. Alves Jr·S. Amato·S. Amerio·Y. Amhis·L. An·L. Anderlini·G. Andreassi·M. Andreotti·J. E. Andrews·R. B. Appleby·F. Archilli·P. d'Argent·J. Arnau Romeu·A. Artamonov·M. Artuso·E. Aslanides·G. Auriemma·M. Baalouch·I. Babuschkin·S. Bachmann·J. J. Back·A. Badalov·C. Baesso·S. Baker·W. Baldini·R. J. Barlow·C. Barschel·S. Barsuk·W. Barter·M. Baszczyk·V. Batozskaya·B. Batsukh·V. Battista·A. Bay·L. Beaucourt·J. Beddow·F. Bedeschi·I. Bediaga·L. J. Bel·V. Bellee·N. Belloli·K. Belous·I. Belyaev·E. Ben-Haim·G. Bencivenni·S. Benson·J. Benton·A. Berezhnoy·R. Bernet·A. Bertolin·C. Betancourt·F. Betti·M. -O. Bettler·M. van Beuzekom·Ia. Bezshyiko·S. Bifani·P. Billoir·T. Bird·A. Birnkraut·A. Bitadze·A. Bizzeti·T. Blake·F. Blanc·J. Blouw·S. Blusk·V. Bocci·T. Boettcher·A. Bondar·N. Bondar·W. Bonivento·I. Bordyuzhin·A. Borgheresi·S. Borghi·M. Borisyak·M. Borsato·F. Bossu·M. Boubdir·T. J. V. Bowcock·E. Bowen·C. Bozzi·S. Braun·M. Britsch·T. Britton·J. Brodzicka·E. Buchanan·C. Burr·A. Bursche·J. Buytaert
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Abstract

The suppressed decay $\Lambda^{0}_{b}\rightarrow p\pi^{-}\mu^{+}\mu^{-}$, excluding the $J/\psi$ and $\psi(2S)\rightarrow \mu^{+}\mu^{-}$ resonances, is observed for the first time with a significance of 5.5 standard deviations. The analysis is performed with proton-proton collision data corresponding to an integrated luminosity of $3\mathrm{fb}^{-1}$ collected with the LHCb experiment. The $\Lambda^{0}_{b}\rightarrow p\pi^{-}\mu^{+}\mu^{-}$ branching fraction is measured relative to the $\Lambda^{0}_{b}\rightarrow J/\psi(\rightarrow \mu^{+}\mu^{-})p\pi^{-}$ branching fraction giving \begin{align} \nonumber \frac{\mathcal{B}(\Lambda^{0}_{b}\rightarrow p\pi^{-}\mu^{+}\mu^{-})}{\mathcal{B}({\Lambda^{0}_{b}\rightarrow J/\psi(\rightarrow \mu^{+}\mu^{-})p\pi^{-}})} &= 0.044\pm0.012\pm0.007, \end{align} where the first uncertainty is statistical and the second is systematic. This is the first observation of a $b\rightarrow d$ transition in a baryonic decay.

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LHCb collaboration, R. Aaij, B. Adeva, M. Adinolfi, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves Jr, S. Amato, S. Amerio, Y. Amhis, L. An, L. Anderlini, G. Andreassi, M. Andreotti, J. E. Andrews, R. B. Appleby, F. Archilli, P. d'Argent, J. Arnau Romeu, A. Artamonov, M. Artuso, E. Aslanides, G. Auriemma, M. Baalouch, I. Babuschkin, S. Bachmann, J. J. Back, A. Badalov, C. Baesso, S. Baker, W. Baldini, R. J. Barlow, C. Barschel, S. Barsuk, W. Barter, M. Baszczyk, V. Batozskaya, B. Batsukh, V. Battista, A. Bay, L. Beaucourt, J. Beddow, F. Bedeschi, I. Bediaga, L. J. Bel, V. Bellee, N. Belloli, K. Belous, I. Belyaev, E. Ben-Haim, G. Bencivenni, S. Benson, J. Benton, A. Berezhnoy, R. Bernet, A. Bertolin, C. Betancourt, F. Betti, M. -O. Bettler, M. van Beuzekom, Ia. Bezshyiko, S. Bifani, P. Billoir, T. Bird, A. Birnkraut, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J. Blouw, S. Blusk, V. Bocci, T. Boettcher, A. Bondar, N. Bondar, W. Bonivento, I. Bordyuzhin, A. Borgheresi, S. Borghi, M. Borisyak, M. Borsato, F. Bossu, M. Boubdir, T. J. V. Bowcock, E. Bowen, C. Bozzi, S. Braun, M. Britsch, T. Britton, J. Brodzicka, E. Buchanan, C. Burr, A. Bursche, J. Buytaert. 2017-01-30. Observation of the suppressed decay $\Lambda^{0}_{b}\rightarrow p\pi^{-}\mu^{+}\mu^{-}$. https://doi.org/10.1007/jhep04(2017)029

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