The deeply bound pionic states (1s,2p)π-⊗ 207Pb were observed for the first time, by investigating the 208Pb(d,3He) reaction at a beam energy of Tdf=604.3 MeV and at ejectile angles around 0°. The measured momentum distribution of the 3He particles was used to determine the Q value spectrum in the region - 145 MeV<Q<-120 MeV with a systematic uncertainty of ±120 keV and a full width at half maximum resolution of 480±60keV. This spectrum shows a prominent peak at Q≃-135.5 MeV, corresponding to the pionic 2p state, coupled mainly to the 3P1/2 and 3p3/2 neutron hole states in 207Pb. A shoulder is seen on the tail of this dominant peak, and is attributed to the population of the pionic 1s state. The cross section for the continuum component at these high excitation energies is d2σ/(dΩdE) = 4.7 μb/srMeV. The net cross section for production of π- states in the bound pion region - 140 MeV<Q<-133 MeV above the continuum amounts to dσ/dΩ = 76 μb/sr.
|ジャーナル||Physical Review C - Nuclear Physics|
|出版ステータス||Published - 2000 8|
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