Search for the xi(2220) and Study of the X(3872) at BABAR
Abstract
The BABAR Collaboration performed a search for xi(2220) production in the initial-state radiation process e+e- --> gamma J/psi, J/psi --> gamma K+K- or J/psi --> gamma K0SK0S. No evidence for the xi(2220) resonance has been found. The 90% confidence level upper limits on the product of branching fractions are sensitive to the spin and helicity hypotheses. These upper limits are of the order 10-5, below the values reported in previous experiments. Also at BABAR, the decays B --> J/psi pi+ pi- pi0 K are studied to search for the decay X(3872) --> J/psi omega. This search yields a four standard deviation evidence for X(3872) --> J/psi omega, with product branching fractions of B(B+ --> X(3872)K+) x B(X(3872) --> J/psi omega)=[0.6 +- 0.2(stat) +- 0.1(syst) ] x 10-5, and B(B0 --> X(3872)K0) x B(X(3872) --> J/psi omega =[0.6 +- 0.3(stat) +- 0.1(syst) ] x 10-5. A detailed study of the pi+ pi- pi0 mass distribution from X(3872) decay favors a negative-parity assignment but does not rule out the positive-parity hypothesis.