New limits on the nuclear levels excitation of127Iand23Naduring charge nonconservation

New lifetime limits on the charge nonconserving electron capture with excitation of ${}^{127}\mathrm{I}$ and ${}^{23}\mathrm{Na}$ nuclear levels are established. The statistics used is $34866\hspace{0.5em}\mathrm{kg}\mathrm{day}$; it has been collected deep underground at the Gran Sasso National Laboratory of INFN by the highly radiopure $\simeq 100\hspace{0.5em}\mathrm{kg}$ DAMA NaI(Tl) setup. These new limits are in the range $(1.5\mathrm{}–2.4)\times {10}^{23}\hspace{0.5em}\mathrm{y}$, up to two orders of magnitude higher than the ones previously available. Stringent restrictions on the relative strengths of the charge nonconserving processes are derived: ${\varepsilon }_W^2<9.6\mathrm{}\times {10}^{-26}$ and ${\varepsilon }_{\gamma }^2<1.2\mathrm{}\times {10}^{-40}$ (90% C.L.).