This paper reports the first measurement of the tensor polarization t 2 o ine-d elastic scattering. The polarization of the recoil deuterons was measured for two values of momentum transfer, # = 1.74 and 2.03 fm" 1 , with a high-efficiency polarimeter. The results are in good agreement with reasonable models for the deuteron.PACS numbers: 25.30.Bf, 24.70,+ s, 25.10.+ S A complete experimental determination 1 ' 2 of the electromagnetic current of the deuteron requires the measurement of at least one polarization observable, in addition to the differential cross section. Here we report the first measurement of t 20 in elastic e-d scattering. Measurements of t 20 have previously not been feasible because of the absence of high-efficiency deuteron tensor polarimeters or tensor-polarized targets, and the lack of high-intensity electron beams and large-acceptance magnetic spectrometers. The results are found to be in good agreement with the predictions of t 20 for "reasonable" models of the deuteron, but in disagreement with those of separable-potential models.Electron elastic scattering from the deuteron can be described by three form factors: charge (F c ), quadrupole (FQ), and magnetic (F M ). Thus far, only F M has been isolated 3 in measurements of the cross section. The form factors F c and F Q have not been isolated previously from measurements of the structure function. 4 A determination of these form factors separately would discriminate further among different deuteron wave functions. The sensitivity of t 20 to the deuteron wave function arises from the fact that the leading term in t 2Q is proportional to the ratio of F Q to F c . in this ratio, the poorly known isoscalar electric nucleon form factor drops out. The expression for t 2Q is given 2 by t 20 2 , and/(6>) = i + (l+77)tan 2 (6i/2). Here, q is the four-momentum transfer, M d is the rest mass of the deuteron, and 6 is the angle of the scattered electron. The terms involving powers of X in the numerator are dominant in the momentum transfer region of 1-5 fm" 1 . Thus, t 20 is sensitive to the ratio of F Q to F c . The quantity F Q is sensitive to the tensor part of the N-N interaction, while F c is dominated by the S-wave part of the deuteron wave function at these values of low momentum transfer. Additionally, recent work 1 ' 2 has shown that t 2Q is also sensitive to the isoscalar meson exchange current (MEC) and relativistic corrections, about which there is much controversy. 5 The experiment was performed at the South Experimental Hall of the Massachusetts Institute of Technology-Bates Linear Accelerator Center. A schematic diagram of the experimental arrangement is given in Fig. 1. The electrons from the linac were focused on a windowless D 2 0 target which consisted of a 0.38-or 0.64-mm-thick laminar flow of heavy water. The incident electron energies were 371 ±2 MeVfor ^r=2.03fm" 1 , and 310± 1.8 MeVfor #=1.74 fm" 1 . During the experiment the average current and duty factor of the electron beam varied from 15 to 50 /iA and 0.3% to 0.4%, respec...

Highly polarized tagged photon were used to measure the distribution of Ml transition strength in 206 Pb at excitations between 6.7 and 8.1 MeV. The observed B{ \ Ml) of about \9JJLI can account for most of the isovector Ml strength that is expected in the Pb nucleus. This result in 206 Pb is compared with the current experimental situation in 208 Pb. The discrepancy between predicted and observed Ml strengths in 208 Pb can probably be attributed to local fragmentation of the strength into states that are too weak to have yet all been identified.

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