2021/03/31 by LHCb collaboration, R. Aaij, C. Abellán Beteta +953 · 2 citations
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1103/physrevlett.127.082001
published as Phys. Rev. Lett. 127, 082001 (2021) · All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-044.html (LHCb public pages)
arxiv created 2021/09/15 · arxiv updated 2021/09/16
The first observation of exotic states with a new quark content c c u s decaying to the J/ψK+ final state is reported with high significance from an amplitude analysis of the B+ → J/ψϕK+ decay. The analysis is carried out using proton-proton collision data corresponding to a total integrated luminosity of 9 fb-1 collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV. The most significant state, Zcs(4000)+, has a mass of 4003±6 ^+ \phantom04- 14 MeV, a width of 131±15±26 MeV, and spin-parity JP=1+, where the quoted uncertainties are statistical and systematic, respectively. A new 1+ X(4685) state decaying to the J/ψϕ final state is also observed with high significance. In addition, the four previously reported J/ψϕ states are confirmed and two more exotic states, Zcs(4220)+ and X(4630), are observed with significance exceeding five standard deviations.