Evidence for a newK * $$\bar K$$ state at a mass of 1,530 MeV withIJ PC=01++ observed inK − p interactions at 4.2 GeV/c

Abstract

Evidence is presented for a newK*\(\bar K\)+c.c. resonance with a mass of (1,526±6) MeV, a width of (107±15) MeV and quantum numbersIJPC=01++. We call itD′ meson. Initially it is observed as aK*\(\bar K\)+c.c. enhancement in the reactionsK−p→(K s 0 K±π∓)Λ at 4.2 GeV/c. The isospin assignmentI=0 comes from its further observation in the reactionsK−p→(K s 0 K±π∓)Σ0 andK−p→(K s 0 K±π∓)Σ(1,385)0 but not inK−p→(K+K−π−)Σ+ orK−p→(K s 0 K±π∓)Σ(1,385)+. A maximum likelihood analysis of the (K\(\bar K\)π) decay Dalitz plots in the reactionsK−p→(K s 0 K±π∓) determines theJPC of theD′ meson to be 1++. A satisfactorySU(3) fit is obtained to a 1++ nonet composed of theI-1A1, theI=1/2QA with theD(1,285) and theD′(1,526) as theI=0 members having a mixing angle close to the magic one.