The quantities Ay and P y were remeasured for E p < 4 MeV in the reaction 3 H(p,«) 3 He. Although our A y data confirm previous data, our P y values are appreciably larger than earlier results and in fact agree well with those for A y . Elimination of the previously reported A y -P y difference has important consequences. Charge-symmetry-breaking effects must be small or nonexistent in this reaction; and the previously required/-wave admixture to the lowest J 77 = 2" state of 4 He is no longer necessary.Concern over the inequalities of the analyzing power A y for an incident polarized beam and the polarization P y for an incident unpolarized beam for (p,n) reactions began in 1971 with the reaction 3 H(/>, w) 3 He. Haight et al. 1 compared their A y data to the then existing P y data and observed that the two quantities were essentially the same above 4 MeV, but differed appreciably below this energy, by about 20% of the experimental magnitude. This difference was particularly surprising as chargeindependent R-matrix calculations 1 showed differences of less than 1%. Since then, several pertinent Letters have appeared. First, Arnold et al. 2 showed that the differences in these quantities provided fairly unambiguous evidence for an/-wave admixture to the lowest 2" state in 4 He. Conzett 3 followed by showing that an equality of A y and P y is expected in (p,n) reactions connecting mirror nuclei. More significantly, he recognized that differences in these quantities imply a breaking of exact charge symmetry by the Coulomb interaction and hence measures of these differences provide a mechanism for investigating charge-symmetry-breaking terms in the nuclear interaction. Because of the significance of these differences in the reaction 3 H(£, «) 3 He and because of suspected problems in the earlier experiments, we remeasured both quantities and report our results and conclusions in this Letter.The A y measurements were carried out using The Ohio State University polarized-ion-source facility 4 which yields beams of 50 nA with about 60% polarization. The neutrons were produced in a 0.23 mg/cm 2 titanium-tritium target and were detected by a pair of symmetrically located NE213 scintillators. Recoil spectra, gated for neutrons using conventional n-y discrimination electronics, were accumulated, stored on magnetic disk, and subjected to further off-line data reduction. The A y data were obtained by alternately measuring spectra with the beam polarized and unpolarized for equal total charge. After each A y measurement, the beam polarization was obtained by inserting a 4 He polarimeter in front of the neutron target. Further experimental details will be given by Doyle et al. 5 The results of these A y measurements at 45° in the center-of-mass frame (cm.) for E p = 1.75 to 3.9 MeV are shown in Fig. 1(a) along with the earlier data of Haight et al. 1 and with a curve to guide the eye. The agreement between the two sets of data is quite good over the entire energy range. Besides confirming the earlier data, this agreement ...
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