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Setting limits on different Majoron modes of 150 Nd. Nasim Fatemi-Ghomi. Signal 2 other backgrounds Eff 5% 5% 5% Act x x 2.7% Stat x 2.6% x.
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Setting limits on different Majoron modesof 150Nd Nasim Fatemi-Ghomi
Signal 2 other backgrounds Eff 5% 5% 5% Act x x 2.7% Stat x 2.6% x Half-life = eff x Number of atoms x ln2 x data taking time/ (Nexp-Nbgr) Systematic considered on the half-life
Limits For different majoron modes • Normalization factor used to normalise the 2 • background: half-life majoron mode Esum<2.0 MeV 9.37+0.27 - 0.25 X1018 1 Esum<1.5 MeV 9.31 +0.37 - 0.32 X1018 2,3 Esum>2.1 MeV 8.84 +0.79 - 0.67 X1018 7
Results Eff N Half-life (year) M1 8.25% <13.99 > 1.55 x 1021 M2 7.95% <36.19 > 5.79 x 1020 M3 5.68% <57.54 > 2.61 x1020 M7 3.84% <266.72 > 3.80 X1019 The efficiency all are found in the energy interval Where the limit has been set
In comparison with Helene method Helene Equation (without considering the uncertainties) M1 [2.0-3.19 MeV] >8.06 X 1020 year M2 [1.5-3.19 MeV] >5.35 X 1020 year M3 [1.5-3.19 MeV] >3.08 X1020 year M7 [0.5-2.1 MeV] >8.70 X 1019 year
Future work • Have to think about a method to set a stronger limit on M7! There is no energy region where that the distribution of 2 background does not depend on the distribution of this mode!