5.4. W. H. Auden: “In Memory of W. B. Yeats” (1939)

Effects of the magnetic moment interaction between nucleons on observables in the3Ncontinuum

“…This factor approximately corresponds to the ratio of the squares of the neutron and proton magnetic moments, µ 2 p /µ 2 n = 2.13. This behavior of the FSI cross sections is of interest in view of recently reported values for the 1 S 0 nn and np scattering lengths extracted from nd breakup measurements [24,25].…”

“…7 for the corresponding configurations of ref. [25], together with the effects induced by the MMI's on the FSI peaks.…”

“…[24], [25], and [26] for the scattering lengths must be corrected for such effects. Based on the sensitivity of the theoretical point-geometry FSI cross sections to specific values of a np and a nn for the geometries of the experiments described in [24], [25], and [26], the MMI associated corrections for the a np and a nn scattering lengths are shown in column 3 of Tables I and II, respectively. While the correction to the nn scattering length is rather small, the correction to the np scattering length moves the a np values obtained from the nd breakup reaction away from the free np scattering result by ≈ 1 fm. The corrections given in Tables I and II are for point geometry, i.e., they do not include the finite geometry of the experimental setup and the associated energy smearing.…”

“…The cross section for this geometry is characterized by a pronounced peak when the relative energy of the final-state interacting pair reaches zero (exact FSI condition). Due to the large sensitivity of this enhancement to the 1 S 0 NN scattering lengths, the FSI geometry has recently been studied in nd breakup with the aim of determining the nn 1 S 0 scattering length [24,25]. The np FSI cross-section measurements performed simultaneously in [24] and in two consecutive experiments in [25,26] seem to indicate that indeed, this configuration is a reliable tool for determining the NN 1 S 0 scattering length: the values obtained for a np agreed with the result known from free np scattering [27].…”

“…Due to the large sensitivity of this enhancement to the 1 S 0 NN scattering lengths, the FSI geometry has recently been studied in nd breakup with the aim of determining the nn 1 S 0 scattering length [24,25]. The np FSI cross-section measurements performed simultaneously in [24] and in two consecutive experiments in [25,26] seem to indicate that indeed, this configuration is a reliable tool for determining the NN 1 S 0 scattering length: the values obtained for a np agreed with the result known from free np scattering [27]. However, the values obtained for a nn in [24,25] are in striking disagreement with each other, with the result of [24] in excellent agreement with the accepted value for a nn .…”