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 6.0 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:
-
m
= 4143.4 + 2.9 - 3.0 (stat.) ±
0.6(syst.) MeV/c2
-
&Gamma
= 15.3 + 10.4 - 6.1 (stat.) ±
2.5(syst.) MeV/c2
The statistical significance of the Y(4140) signal is over 5.0 &sigma
We also find evidence for another structure with:
-
m
= 4274.4 + 8.4 - 6.7 (stat.)
-
&Gamma
= 32.3 + 21.9 - 15.3 (stat.)
The statistical significance of the second structure is 3.1 &sigma
 |
| GIF EPS |
 |
| 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
- Dalitz plot GIF, EPS
- Mass difference in B mass window and B sideband GIF, EPS
- Mass difference in B mass window for 2.7 ifb and 6.0ifb GIF, EPS
- Toy MC for Y(4140) GIF, EPS
- Toy MC for Y(4140) with fit to chisq PDF GIF, EPS
- Fit to the second peak GIF, EPS
- Toy MC for the second peak GIF, EPS
