Observation of a New Excited <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>D</mml:mi><mml:mi>s</mml:mi><mml:mo>+</mml:mo></mml:msubsup></mml:math> Meson in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>B</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>D</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:msup><mml:mi>D</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>K</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> Decays
R. Aaij, Carlos Abellán Beteta, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. A. Aidala, Simone Aiola, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, Z. Aliouche, G. Alkhazov, P. Álvarez Cartelle, S. Amato, Y. Amhis, L. An, L. Anderlini, A. Andreianov, M. Andreotti, F. Archilli, A. Artamonov, M. Artuso, K. Arzymatov, E. Aslanides, M. Atzeni, B. Audurier, S. Bachmann, M. Bachmayer, J. J. Back, S. Baker, P. Baladrón Rodríguez, V. Balagura, W. Baldini, J. Baptista Leite, R. J. Barlow, S. Barsuk, W. Barter, M. Bartolini, F. Baryshnikov, J. M. Basels, G. Bassi, B. Batsukh, A. Battig, A. Bay, M. Becker, F. Bedeschi, I. Bediaga, A. Beiter, V. Belavin, S. Belin, V. Bellée, K. Belous, I. Belov, I. Belyaev, G. Bencivenni, E. Ben-Haim, 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, L. Bian, M. S. Bieker, S. Bifani, P. Billoir, M. Birch, F. C. R. Bishop, A. Bizzeti, M. Bjørn, M. P. Blago, T. Blake, F. Blanc, S. Blusk, D. Bobulska, J. A. Boelhauve, O. Boente García, T. Boettcher, A. Boldyrev, A. Bondar, N. Bondar, S. Borghi, M. Borisyak, M. Borsato, J. T. Borsuk, Sonia Amina Bouchiba, T. J. V. Bowcock, A. Boyer, C. Bozzi
Abstract
Using $pp$ collision data corresponding to an integrated luminosity of $5.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the LHCb detector at a center-of-mass energy of 13 TeV, the ${B}^{0}\ensuremath{\rightarrow}{D}^{\ensuremath{-}}{D}^{+}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay is studied. A new excited ${D}_{s}^{+}$ meson is observed decaying into the ${D}^{+}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ final state with large statistical significance. The pole mass and width, and the spin parity of the new state are measured with an amplitude analysis to be ${m}_{R}=2591\ifmmode\pm\else\textpm\fi{}6\ifmmode\pm\else\textpm\fi{}7\text{ }\text{ }\mathrm{MeV}$, ${\mathrm{\ensuremath{\Gamma}}}_{R}=89\ifmmode\pm\else\textpm\fi{}16\ifmmode\pm\else\textpm\fi{}12\text{ }\text{ }\mathrm{MeV}$, and ${J}^{P}={0}^{\ensuremath{-}}$, where the first uncertainty is statistical and the second systematic. Fit fractions for all components in the amplitude analysis are also reported. The new resonance, denoted as ${D}_{s0}(2590{)}^{+}$, is a strong candidate to be the ${D}_{s}(2{^{1}S}_{0}{)}^{+}$ state, the radial excitation of the pseudoscalar ground-state ${D}_{s}^{+}$ meson.