Performance of a spherical high pressure gas TPC for neutrino magnetic moment measurement

The measurement of neutrino magnetic moment larger than ${10}^{-19}{\mu }_B$ would be a clear signature of physics beyond the standard model other than the existence of massive Dirac neutrinos. The use of a spherical proportional counter detector filled with gas at 40 bar located near a nuclear reactor would be a simple way to perform such a measurement exploiting the developments made on such a technology for the search of dark matter and neutrinoless double beta decay. Different targets can be used just by replacing the gas: xenon, CF${}_4$ and argon were compared and the sensitivity in one year of data taking could reach the level of $4.3\times {10}^{-12}{\mu }_B$, $6.5\times {10}^{-12}{\mu }_B$, and $8.5\times {10}^{-12}{\mu }_B$, respectively.