Measurement of the Double Beta Decay Half Life and Search for the Neutrinoless Double Beta Decay of {48}\rm Ca} with the NEMO 3 Detector
The NEMO 3 experiment at the Modane Underground Laboratory has investigated the double \beta$ decay of {48}\rm Ca} Using $5.25$ yr of data recorded with a $6.99\\rm g} sample of {48}\rm Ca} approximately $150$ double \beta$ decay candidate events have been selected with a signal to background ratio greater than $3$ The half life for the two neutrino double \beta$ decay of {48}\rm Ca} has been measured to be $T^{2\nu}_{1/2}[6.4\ +0.7}_{ 0.6}\rm (stat. +1.2}_{ 0.9}\rm (syst. \times 10^{19}\rm yr} A search for neutrinoless double \beta$ decay of {48}\rm Ca} yields a null result and a corresponding lower limit on the half life is found to be $T^{0\nu}_{1/2} 2.0 \times 10^{22}\rm yr} at $90\ confidence level, translating into an upper limit on the effective Majorana neutrino mass of 6.0 26$ \rm eV} with the range reflecting different nuclear matrix element calculations. Limits are also set on models involving Majoron emission and right handed currents.