The production of eta pi - system at low mass by the pi- beam in the Coulomb field of Be nuclei was studied. The cross section of the reaction pi- Be --> eta pi- Be was compared to the experimental data on the decay eta --> pi+ pi- gamma and to the theoretical predictions.
The results of the patial wave analysis(PWA) of the pi+pi-pi- and omegapi-pi0 systems are presented. The a3 and a4(2040) signals are observed in the rho(770)pi and f2(1270)pi channels. Indications of the a1' meson existence was found in the 1+0+ rhopi S-wave. The decay branching ratio of the a2(1320)- to omegapi-pi0 was measured. The 2+1+ wave shows a broad bump at M~1.7GeV. The decays of the pi2(1670), a4(2040) and pi(1740) into omegarho- were found. The resonance in the b1(1235)pi wave with exotic quantum numbers jpc=1-+ at M~1.6 is observed and the simultaneous analysis of the 1-+ wave in the b1(1235)pi, etha'pi and rhopi final states is presented.
Results of the ethapi+pi- and omegaomega final state partial wave analysis(PWA) are presented. The mass-independent and the mass-dependent PWA were performed. The ethapi+pi- system PWA results in the observation of the resonances in the JPC=1–,3–,2++ and 4++ waves. The results of the omegaomega system PWA confirms the existence of the f2(1565) and f4(2050). The f2(1950) is observed. There is evidence for a f4(2300) meson.
The results of patial wave analysis of the omega pi- pi0 system, produced in the reaction pi- Be --> pi+ 2pi- 2pi0 Be at beam momentum of 37 GeV are presented. An indication of the resonant type structure with mass near 1.74 GeV and JpMetha=0-0+ in the omega rho- system was found. The decay branching ratio of a2(1320)- to omega pi- pi0 was measured. A wave with JpMetha=2+1+ shows a broad bump at M near 1.7 GeV. The decays pi2(1670)- --> omega rho- and a4(2040)- --> omega rho- were observed for the first time. The bump in the b1(1235)pi wave with exotic quantum numbers Jpc=1-+ at M near 1.7 GeV was observed.
The reaction π−p→η′η′n has been studied atpπ=37 GeV/c. Total of 14 events of this reaction have been selected. It has been shown that in the effective mass spectrum of the η′η′ system the events are concentrated mainly near the reaction threshold, which might be caused by the decayX(1910)→η′η′. The reaction cross-section has been evaluated: σ(π−p→η′η′n)=110±40 nb.
The reactionπ−C→π−η′C has been studied at 36 GeV/c. A clear signal for the decaya 2 − (1320)→π−·′ is observed in theπ−η′ mass spectrum. The measured ratio of branchings is BR (a 2 − →π−η′)/BR(a 2 − →π−η);(3.4±0.8±0.5)·10−2.
The ωω system produced in the reactionπ−p→ωωn atp π − = 36 GeV/c has been studied at the IHEP VES setup. PWA has been performed and characteristics of objects in the wavesJ PC =2++ and 4++ have been determined.