We report the results of a search for a charmoniumlike state produced in the process in the mass region. We observe a significant enhancement, which is well described by a resonant shape with mass and total width . This enhancement may be related to one or more of the three charmoniumlike states so far reported in the mass region.
DOI:https://doi.org/10.1103/PhysRevLett.104.092001
©2010 American Physical Society
(a) The distribution just after the dilepton selection. (b) The distribution after the tight selection. Events between the arrows are rejected as consistent with production.
Reuse & Permissions(a) Scatter plot of vs for the experimental data, with all the other cuts applied. The rectangle shows the signal region. (b) The and (c) distributions with all the other cuts applied, and requiring . Entries due to multiple candidates in a given event are included. Points with error bars show the data; the dashed histograms show signal MC events, normalized to the data yield in the selection area, with the scaled sideband yield subtracted. The arrows show the selection regions.
Reuse & PermissionsThe distribution of the final candidate events (dots with error bars). The shaded histogram is the distribution of non- backgrounds estimated from the sideband distributions. The bold solid, thinner solid and dashed curves are the total, resonance, and background contributions, respectively, from the standard fit (see the text). The dot-dashed curve is the fit without a resonance.
Reuse & Permissions(a) Scatter plot of balance vs for the final candidate events in which only requirement (xii) is omitted. (b) The projection onto the balance axis for events with . The dashed histogram is the expectation from signal MC events, normalized to the number of signal candidates in the selected region. The balance requirement is indicated by the arrow.
Reuse & Permissions
