Observation of new excited Bs0 states

LHCb collaboration

doi:10.1140/epjc/s10052-021-09305-3

Observation of new excited Bs0 states

LHCb collaboration

Research output: Contribution to journal › Article › Academic › peer-review

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<mml:mspace width="0.166667em"></mml:mspace>fb-1. The structure is interpreted as the result of overlapping excited Bs0</mml:msubsup> 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 <disp-formula id="Equ2"><mml:mtable><mml:mtr><mml:mtd columnalign="right">m1</mml:mtd><mml:mtd columnalign="left">=6063.5 +/- 1.2<mml:mspace width="0.333333em"></mml:mspace>(stat)+/- 0.8<mml:mspace width="0.333333em"></mml:mspace>(syst)<mml:mspace width="0.166667em"></mml:mspace>Me<mml:mspace width="0.333333em"></mml:mspace>,</mml:mtd></mml:mtr><mml:mtr><mml:mtd columnalign="right">Gamma 1</mml:mtd><mml:mtd columnalign="left">=26 +/- 4<mml:mspace width="0.333333em"></mml:mspace>(stat)+/- 4<mml:mspace width="0.333333em"></mml:mspace>(syst)<mml:mspace width="0.166667em"></mml:mspace>Me<mml:mspace width="0.333333em"></mml:mspace>,</mml:mtd></mml:mtr><mml:mtr><mml:mtd columnalign="right">m2</mml:mtd><mml:mtd columnalign="left">=6114 +/- 3<mml:mspace width="0.333333em"></mml:mspace>(stat)+/- 5<mml:mspace width="0.333333em"></mml:mspace>(syst)<mml:mspace width="0.166667em"></mml:mspace>Me<mml:mspace width="0.333333em"></mml:mspace>,</mml:mtd></mml:mtr><mml:mtr><mml:mtd columnalign="right"><mml:msub>Gamma 2</mml:mtd><mml:mtd columnalign="left">=66 +/- 18<mml:mspace width="0.333333em"></mml:mspace>(stat)+/- 21<mml:mspace width="0.333333em"></mml:mspace>(syst)<mml:mspace width="0.166667em"></mml:mspace>Me<mml:mspace width="0.333333em"></mml:mspace>.</mml:mtd></mml:mtr></mml:mtable><graphic position="anchor" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10052_2021_9305_Article_Equ2.gif"></graphic></disp-formula>Alternative values assuming a decay through B +/- K -/+, with a missing photon from the B +/- -> B +/- gamma decay, which are shifted by approximately 45<mml:mspace width="0.166667em"></mml:mspace>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 Bs20 state is determined to be 0.87 +/- 0.15<mml:mspace width="0.333333em"></mml:mspace>(stat)+/- 0.19<mml:mspace width="0.333333em"></mml:mspace>(syst).

Original language	English
Article number	601
Number of pages	11
Journal	European Physical Journal C
Volume	81
Issue number	7
DOIs	https://doi.org/10.1140/epjc/s10052-021-09305-3
Publication status	Published - 1 Jul 2021

Keywords

MODEL

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Cite this

@article{168407015e0d41b495b6c4f5e74b18c6,

title = "Observation of new excited Bs0 states",

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 9fb-1. The structure is interpreted as the result of overlapping excited Bs0 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 m1=6063.5 +/- 1.2(stat)+/- 0.8(syst)Me,Gamma 1=26 +/- 4(stat)+/- 4(syst)Me,m2=6114 +/- 3(stat)+/- 5(syst)Me,Gamma 2=66 +/- 18(stat)+/- 21(syst)Me.Alternative values assuming a decay through B +/- K -/+, with a missing photon from the B +/- -> B +/- gamma decay, which are shifted by approximately 45MeV, 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 Bs20 state is determined to be 0.87 +/- 0.15(stat)+/- 0.19(syst).",

keywords = "MODEL",

author = "R. Aaij and C.A. Beteta and T. Ackernley and B. Adeva and M. Adinolfi and H. Afsharnia and C.A. Aidala and S. Aiola and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and A.A. Albero and Z. Aliouche and G. Alkhazov and P.A. Cartelle and S. Amato and Y. Amhis and L. An and L. Anderlini and A. Andreianov and M. Andreotti and F. Archilli and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and M. Bachmayer and J.J. Back and S. Baker and P.B. Rodriguez and V. Balagura and W. Baldini and J.B. Leite and R.J. Barlow and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and J.M. Basels and G. Bassi and B. Batsukh and A. Battig and {LHCb collaboration} and {de Vries}, J.A. and M. Merk and C.J. Pawley",

year = "2021",

month = jul,

day = "1",

doi = "10.1140/epjc/s10052-021-09305-3",

language = "English",

volume = "81",

journal = "European Physical Journal C",

issn = "1434-6044",

publisher = "Springer Verlag",

number = "7",

}

TY - JOUR

T1 - Observation of new excited Bs0 states

AU - Aaij, R.

AU - Beteta, C.A.

AU - Ackernley, T.

AU - Adeva, B.

AU - Adinolfi, M.

AU - Afsharnia, H.

AU - Aidala, C.A.

AU - Aiola, S.

AU - Ajaltouni, Z.

AU - Akar, S.

AU - Albrecht, J.

AU - Alessio, F.

AU - Alexander, M.

AU - Albero, A.A.

AU - Aliouche, Z.

AU - Alkhazov, G.

AU - Cartelle, P.A.

AU - Amato, S.

AU - Amhis, Y.

AU - An, L.

AU - Anderlini, L.

AU - Andreianov, A.

AU - Andreotti, M.

AU - Archilli, F.

AU - Artamonov, A.

AU - Artuso, M.

AU - Arzymatov, K.

AU - Aslanides, E.

AU - Atzeni, M.

AU - Audurier, B.

AU - Bachmann, S.

AU - Bachmayer, M.

AU - Back, J.J.

AU - Baker, S.

AU - Rodriguez, P.B.

AU - Balagura, V.

AU - Baldini, W.

AU - Leite, J.B.

AU - Barlow, R.J.

AU - Barsuk, S.

AU - Barter, W.

AU - Bartolini, M.

AU - Baryshnikov, F.

AU - Basels, J.M.

AU - Bassi, G.

AU - Batsukh, B.

AU - Battig, A.

AU - LHCb collaboration

AU - de Vries, J.A.

AU - Merk, M.

AU - Pawley, C.J.

PY - 2021/7/1

Y1 - 2021/7/1

N2 - 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 9fb-1. The structure is interpreted as the result of overlapping excited Bs0 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 m1=6063.5 +/- 1.2(stat)+/- 0.8(syst)Me,Gamma 1=26 +/- 4(stat)+/- 4(syst)Me,m2=6114 +/- 3(stat)+/- 5(syst)Me,Gamma 2=66 +/- 18(stat)+/- 21(syst)Me.Alternative values assuming a decay through B +/- K -/+, with a missing photon from the B +/- -> B +/- gamma decay, which are shifted by approximately 45MeV, 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 Bs20 state is determined to be 0.87 +/- 0.15(stat)+/- 0.19(syst).

AB - 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 9fb-1. The structure is interpreted as the result of overlapping excited Bs0 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 m1=6063.5 +/- 1.2(stat)+/- 0.8(syst)Me,Gamma 1=26 +/- 4(stat)+/- 4(syst)Me,m2=6114 +/- 3(stat)+/- 5(syst)Me,Gamma 2=66 +/- 18(stat)+/- 21(syst)Me.Alternative values assuming a decay through B +/- K -/+, with a missing photon from the B +/- -> B +/- gamma decay, which are shifted by approximately 45MeV, 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 Bs20 state is determined to be 0.87 +/- 0.15(stat)+/- 0.19(syst).

KW - MODEL

U2 - 10.1140/epjc/s10052-021-09305-3

DO - 10.1140/epjc/s10052-021-09305-3

M3 - Article

SN - 1434-6044

VL - 81

JO - European Physical Journal C

JF - European Physical Journal C

IS - 7

M1 - 601

ER -