Searches for parity-violation effects in the gamma transition Li-7*->gamma(M1)-> Li-7 (E-gamma=0.498MeV)

Theoretical calculations and preliminary measurements of the P-odd asymmetr y of photon emission from the deexcitation of the first excited Li-7 level populated in the reaction B-10 (n, alpha)Li-7* --> gamma(M1) --> 7Li induce d by a polarized-neutron beam have been performed. Theoretical results indi cate that weak neutral currents contribute substantially to parity violatio n in this process, Special features of the spectrum of 7Li nuclear states r esult in that the effect under discussion is caused predominantly by the ps eudoscalar-potential-induced mixing of bound states with the states of the alpha + t continuum. The results of preliminary measurements demonstrate a strong potential of the proposed experimental procedure. Upon the upgrade o f some elements of the apparatus used, this procedure will permit achieving a precision on the order of 10(-8) in determining the anistropy of the ang ular distribution of emitted photons, This will make it possible to measure the predicted effect or, at least, to set a rather low upper limit on it, As a result, the process being considered proves very promising in what is concerned with searches for the contribution of neutral currents.