Measurement of the two-body photodisintegration of3He in the?(1236) resonance region

Abstract

The 3He(7, p)d reaction has been measured in the photon energy region between 200 MeV and 450 MeV at proton c.m. angles between 20 ~ and 150 ~ Protons and deuterons were detected in coincidence with two time-of-flight spectrometers consisting of scintillation counters; both particles were identified and their energies and angles were measured. The angular distributions show a strong forward peak. The differential cross sections fall off with increasing photon energy without showing a significant influence of the A resonance.

Two-Body Photodisintegration ofHe3between 150 and 350 MeV

“…While the disagreements among the present results and those of Refs. 3 and 4 are outside statistical uncertainties, the relatively large systematic uncertainties of these experiments, 10%-15%, 3 and 10%, 4 mitigate the severity of these disagreements. However, the results of Refs.…”

“…The disagreement among the radiative capture measurements 7 " 9 in the same energy region is not as dramatic, but it is significant. The purpose of the experiment reported here is to provide an improved measurement of the cross section of 3 He(y, d)p. This measurement is part of a complete test of time-reversal invariance including measurements of p(d, y) 3 He and d(p 9 y) 3 Ee by an associated collaboration. 10 In the present experiment absolute differential cross sections were obtained for 3 He(y, d)p at ^(c.m.)…”

“…In view of the well-established absolute normalization in the present measurement, a large disagreement between these data and measurements of the inverse reaction has serious implications. Two new measurements 8 ' 10 of d(p 9 y) 3 He have been completed. Therefore, it is appropriate to defer evaluation of our results in terms of a test of time-reversal invariance until these data 8 ' 10 are published in final form.…”

Production of e+ e− pairs in proton-deuteron capture to He

“…(11), solid and dotted lines include all contributions. The photodisintegration data are taken from [17] and [18]. The TRIUMF points are calculated from the capture data [19]…”

Photodisintegration of and radiative capture to the A = 2, 3, and 4 nuclei

“…Numerous measurements of the differential cross section for photodisintegration (90)(91)(92)(93)(94)(95) and the inverse reaction (96)(97)(98)(99) have been reported in the energy range 100 < E, < 500 MeV. Unfortunately, the data are often in disaccord.…”