STUDY OF SCALAR MESONS AT BES

摘要

Partial wave analyses have been performed on BES data to study scalar mesons. There is evidence for the κ near the Kπ threshold and the pole position is (760 ～ 840)-i(310 ～ 420) MeV. The σ peak is seen in ωπ~+π~- and gives an accurate pole position, (541 ± 39)—i(252 ± 42) MeV. The f_0(980) is seen in both φπ~+π~- and φK~+K~- data. Parameters of the Flatte formula for f_0(980) are: M = 965±8(sta)±6(sys) MeV, g_1 = 165 ± 10(sta)±15(sys) MeV, g_2/g_1 = 4.21±0.25(sta)±0.21(sys). The J/ψ → φπ~+π~- data require f_0(1790) →π~+π~-, distinct from f_0(1710) → K~+K~-. Also f_0(1370) is seen clearly in φπ~+π~- data.