Partial wave analysis of ψ(2S)→pp̄η

Abstract

Using a sample of 1.06×108 ψ(2S) events collected with the BESIII detector at BEPCII, the decay ψ(2S)→pp̄η is studied. A partial wave analysis determines that the intermediate state N(1535) with a mass of 1524±5-4+10 MeV/c2 and a width of 130-24-10+27+57 MeV/c2 is dominant in the decay; the product branching fraction is determined to be B(ψ(2S)→N(1535)p̄)×B(N(1535)→pη)+c.c.=(5. 2±0.3-1.2+3.2)×10-5. Furthermore, the branching fraction of ψ(2S)→pp̄η is measured to be (6.4±0.2±0.6) ×10-5. Here, the first error is statistical and the second is systematic.