Measurements of the Y (10860) and Y (11020) resonances via σ(e+e-→Y(nS)π+π-)

We report new measurements of the total cross sections for eþe- → ΥðnSÞπþπ- (n ¼ 1, 2, 3) and eþe- → b¯b from a high-luminosity fine scan of the region ffiffiffi ps ¼ 10.63–11.05 GeV with the Belle detector. We observe that the ΥðnSÞπþπ- spectra have little or no nonresonant component and extract from them the masses and widths of Υð10860Þ and Υð11020Þ and their relative phase. We find M10860 ¼ ð10891.1 * 3.2þ0.6 -1.7 Þ MeV=c2 and Γ10860 ¼ ð53.7þ7.1 þ1.3 -5.6 -5.4 Þ MeV and report first measurements M11020 ¼ ð10987.5þ6.4 þ9.0 -2.5 -2.1 Þ MeV=c2, Γ11020 ¼ ð61þ9 þ2 -19 -20Þ MeV, and Φ11020 - Φ10860 ¼ ð-1.0 * 0.4þ1.4 -0.1 Þ rad.