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arXiv · 2010.15931

Observation of new excited $B_s^0$ states

LHCb collaboration·R. Aaij·C. Abellán Beteta·T. Ackernley·B. Adeva·M. Adinolfi·H. Afsharnia·C. A. Aidala·S. Aiola·Z. Ajaltouni·S. Akar·J. Albrecht·F. Alessio·M. Alexander·A. Alfonso Albero·Z. Aliouche·G. Alkhazov·P. Alvarez 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. Baladron Rodriguez·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. Bellee·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 Garcia·T. Boettcher·A. Boldyrev·A. Bondar·N. Bondar·S. Borghi·M. Borisyak·M. Borsato·J. T. Borsuk·S. A. Bouchiba·T. J. V. Bowcock·A. Boyer
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Abstract

A structure is observed in the $B^+K^-$ mass spectrum in a sample of proton--proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, collected with the LHCb detector and corresponding to a total integrated luminosity of 9 fb${}^-1$. The structure is interpreted as the result of overlapping excited $B_s^0$ states. With high significance, a two-peak hypothesis provides a better description of the data than a single resonance. Under this hypothesis the masses and widths of the two states, assuming they decay directly to $B^+K^-$, are determined to be $m_1 = 6063.5 \pm 1.2 \text{ (stat)} \pm 0.8\text{ (syst) MeV},$ $\Gamma_1 = 26 \pm 4 \text{ (stat)} \pm 4\text{ (syst) MeV},$ $m_2 = 6114 \pm 3 \text{ (stat)} \pm 5\text{ (syst) MeV},$ $\Gamma_2 = 66 \pm 18 \text{ (stat)} \pm 21\text{ (syst) MeV}.$ Alternative values assuming a decay through $B^{*+}K^-$, with a missing photon from the $B^{*+} \rightarrow B^+\gamma$ decay, which are shifted by approximately 45 MeV are also determined. The possibility of a single state decaying in both channels is also considered. The ratio of the total production cross-section times branching fraction of the new states relative to the previously observed $B_{s2}^{*0}$ state is determined to be $0.87 \pm 0.15 \text{ (stat)} \pm 0.19 \text{ (syst)}$.

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LHCb collaboration, R. Aaij, C. Abellán Beteta, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. A. Aidala, S. Aiola, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, Z. Aliouche, G. Alkhazov, P. Alvarez 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. Baladron Rodriguez, 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. Bellee, 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 Garcia, T. Boettcher, A. Boldyrev, A. Bondar, N. Bondar, S. Borghi, M. Borisyak, M. Borsato, J. T. Borsuk, S. A. Bouchiba, T. J. V. Bowcock, A. Boyer. 2020-10-29. Observation of new excited $B_s^0$ states. https://doi.org/10.1140/epjc%2Fs10052-021-09305-3

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