Abstract
We have searched for exclusive production of exotic charmonia in the reaction μ+N→μ+(J/ψπ+π−)π±N′ using COMPASS data collected with incoming muons of 160 GeV/c and 200 GeV/c momentum. In the J/ψπ+π− mass distribution we observe a signal with a statistical significance of 4.1 σ. Its mass and width are consistent with those of the X(3872). The shape of the π+π− mass distribution from the observed decay into J/ψπ+π− shows disagreement with previous observations for X(3872). The observed signal may be interpreted as a possible evidence of a new charmonium state. It could be associated with a neutral partner of X(3872) with C=−1 predicted by a tetraquark model. The product of cross section and branching fraction of the decay of the observed state into J/ψπ+π− is determined to be 71±28(stat)±39(syst) pb.
Highlights
We have searched for exclusive production of exotic charmonia in the reaction μ+ N → μ+( J/ψπ +π −)π ± N
The observed signal may be interpreted as a possible evidence of a new charmonium state
It could be associated with a neutral partner of X(3872) with C = −1 predicted by a tetraquark model
Summary
Search for muoproduction of X(3872) at COMPASS and indication of a new state X(3872). Since the dimuon mass resolution of the setup for the J /ψ peak is about 50 MeV/c2 [35], candidates for J /ψ decaying into a pair of oppositely charged muons are accepted if their reconstructed mass lies in the range from 3.02 GeV/c2 to 3.18 GeV/c2. Since at COMPASS the experimental resolution for E = E − Ebeam is about 2 GeV, we require | E| < 4 GeV in order to select exclusive production of the J /ψ3π final state.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
