(He3,t) Reaction at Intermediate Energies

Abstract

Data are presented for the ( 3 He,£) reaction at energies of 600 MeV, 1.2 GeV, and 2 GeV on targets nat C, 54 Fe, and 89 Y. The low-excitation-energy regions of the spectra are dominated by isospin-spin excitations. Cross-section calculations in distorted-wave impulse approximation with parameters from AW data account reasonably well for the data. At 2-GeV bombarding energy a strong excitation of the A resonance is observed for all targets.

Analysis of Δ0(1232) production in collisions of protons with carbon nuclei at 4.2 GeV/c

“…2 . This is due to a large combinatorial background from uncorrelated p π − pairs as was also shown earlier for 16 O+ p collisions [41] at 3 25 A GeV/c, C+C [39], 4 He+C [43], and C+Ta [42] collisions at 4 2 A GeV/c, π − + 12 C interactions at 40 GeV/c [40]. To reduce such contribution as much as possible, the method of analyzing an angle between the proton and pion was used as done successfully in Refs.…”

“…(7) is simply the total excess of the foreground spectrum over the background, i.e. 12 C collisions at 4 2 GeV/c and π − + 12 C interactions [40] at 40 GeV/c, and produced on oxygen nuclei in 16 O+p interactions [41] 16 O+p, 4 He+C, C+C, C+ 181 Ta, and π − + 12 C collisions. On the whole, the average mass shifts of ∆(1232)-resonances, produced on carbon and oxygen nuclei, are in good agreement with theoretical result of W. Weinhold et al [35], mentioned in [11], in which the mass of the ∆ 0 (1232)-resonance was calculated to be shifted by ∆ ∆ ≈ −10 MeV/ 2 when corrections due to the nucleon interaction in the πN loop of the ∆ self energy are taken into account.…”

Excitation of Δ andN*resonances in isobaric charge-exchange reactions of heavy nuclei

“…The position of the Δ peak is shifted towards a low excitation energy by ∼ 65 MeV, becoming insensitive to targets with mass number A ≥ 12. As said in the introduction, this shift was already observed on isobaric chargeexchange reactions with lighter nuclei [1][2][3][4][5], and its origin was the subject of intense debate (see e.g., Refs. [7][8][9][10] and references therein).…”

“…1c, whose expression is formally equal to that of Eq. (8) with the change of the invariant mass √ s T by √ s P = (p 3 + p π ) 2 and the spin-isospin factors C Δ and C N * , respectively, bỹ…”

“…The excitation of the Δ(1232) in (p, n) and ( 3 He,t) reactions was extensively studied in the 1980's [1][2][3][4][5]. A experimental program completely devoted to study the excitation of this resonance in reactions with light and medium mass projectiles was performed at the SATURNE accelerator in Saclay during those years [6].…”