부산대학교 도서관

Diffractive dissociation reactions at COMPASS provide clean access to mesons with masses below ≈ 2.5 GeV/c2. This paper presents a partial wave analysis of about 420 000 π-Pb → π-π-π+Pb events at 190 GeV/c beam momentum and with four-momentum transfer t' ∈ [0.1,1] GeV2/c2. The well-known a1(1260), a2(1320) and π2(1670) mesons are resolved with high quality. Also the less established states π(1800) and a4(2040) are seen. In addition, a resonance in the spin-exotic JPC = 1-+ wave is observed. A mass-dependent fit results in a mass and width of $1.660_{-0.074}^{+ 0.010}$ and $0.269_{-0.085}^{+0.063}\ {\rm GeV/}c^2$, respectively, which is consistent with the disputed hybrid candidate π1(1600). [ABSTRACT FROM AUTHOR]