Evidence for a Narrow Near-Threshold Structure in the J/&psi &phi Mass Spectrum in B+ → J/ψ φ K+

arXiv:0903.2229

This web page summarizes the results of the search for exotics in the J/&psi &phi Mass Spectrum in B+ → J/ψ φ K+ decays. The search is based on data comprising 2.7 fb-1 of integrated luminosity. Using the fully reconstructed decay

B+ → Y(4140)K+;     Y(4140) →J/ψ φ ;     J/Ψ → μ+μ-;     φ → K+ K-    
 
we measure:

The statistical significance of the Y(4140) signal is over 3.8 &sigma



GIF EPS



GIF EPS

Major points of the analysis

  • Use Lxy to separate B vertex from primary vertex
  • Use kaon particle identification to reduce combinatorial background

Plots

  • B sideband subtracted invariant mass of KK GIF, EPS
  • Dalitz plot GIF, EPS
  • B mass before applying Lxy and kaon PID GIF, EPS
  • B mass before applying kaon PID but after Lxy GIF, EPS
  • Control signal B+ → J/ψ K+ GIF, EPS
  • Control signal Bs → J/ψ φ GIF, EPS
  • Dalitz plot from phase space Monte Carlo GIF, EPS
  • Mass difference from phase space Monte Carlo GIF, EPS
  • Dalitz plot from Bs contamination channel (Monte Carlo) GIF, EPS
  • Mass difference for Lxy >100 um GIF, EPS
  • Mass difference for vertex probability>0.00001 and # of SVT hits>=3 GIF, EPS


Documentation