New results on P -odd asymmetry of [FORMULA] -quanta emission in 10B(n,[FORMULA])7Li*[FORMULA][FORMULA] + 7Li(g.s.) nuclear reaction

A series of ultra-sensitive experiments has been carried out in 2001-2009 at the ILL measuring P -odd asymmetry in [FORMULA] -quanta emission in the nuclear reaction 10 B (n,[FORMULA]) 7 Li * [FORMULA][FORMULA] + $ 7 Li$(g.s.) with polarized cold neutrons. The resulting value of the asymmetry coefficient is [FORMULA] . These experiments profited from high-intensity PF1B neutron facility and a new version of the integral measuring method: for decreasing experimental uncertainties, the frequency of neutron spin-flip was higher than a typical reactor power noise frequency. Using the new value, we constrain the weak neutral current constant in the cluster model framework to [FORMULA] (at 90% c.l.). This constraint agrees with that following from the nuclear reaction 6 Li (n,[FORMULA]) 3 H : [FORMULA] (at 90% c.l.). However, they both contradict the “best” value in the quark model by Desplanques, Donoughe, and Holstein [FORMULA] . We invite experts in the field to contribute to the theoretical analysis of the problem.