Tests of physics beyond the Standard Model with future low energy neutrino experiments

Neutrino-electron scattering can be used to probe neutrino electromagnetic properties at low-threshold underground detectors with good recoil electron energy resolution. We study the sensitivity of Helium detector experiments, such as HELLAZ, for artificial anti-neutrino sources. We show that, for a $^{90}Sr-Y$ source, one expects a sensitivity to the neutrino magnetic moment at the level of $\mu_{\nu}= 2 \times 10^{-11}\mu_{B}$. We also report the sensitivity that these experiments could have in searching for an additional gauge boson in $E_6$ models.