High statistics calorimetric measurements of the beta spectrum of Re-187 are being performed with arrays of silver perrhenate crystals operated at low temperature. After a substantial modification of the experimental setup, a new measurement with ten silver perrhenate microbolometers has been running since July 2002. The crystals have masses around 300 mug and their average FWHM energy resolution is of 28.3 eV at the beta end point. The Kurie plot collected during 4485 hxmg effective running time has an end-point energy of 2466.10.8(stat)1.5(syst) eV, while the half lifetime of the decay is found to be 43.20.2(stat)0.1(syst) Gy. These values are the most precise obtained so far for Re-187. The best fit value for m((ν) over bare)(2) is 147237(stat)90(syst) eV(2), which corresponds to an upper limit for the electron antineutrino mass m((ν) over bare)less than or equal to21.7 eV at 90% C.L.
Arnaboldi, C., Brofferio, C., Cremonesi, O., Fiorini, E., Lo Bianco, C., Martensson, L., et al. (2003). Bolometric bounds on the antineutrino mass. PHYSICAL REVIEW LETTERS, 91(16), 1618021-1618024 [10.1103/PhysRevLett.91.161802].
Bolometric bounds on the antineutrino mass
ARNABOLDI, CLAUDIO;BROFFERIO, CHIARA;CREMONESI, OLIVIERO;FIORINI, ETTORE;NUCCIOTTI, ANGELO ENRICO LODOVICO;PAVAN, MAURA;PESSINA, GIANLUIGI EZIO;PREVITALI, EZIO;SISTI, MONICA;GIULIANI, ANDREA;
2003
Abstract
High statistics calorimetric measurements of the beta spectrum of Re-187 are being performed with arrays of silver perrhenate crystals operated at low temperature. After a substantial modification of the experimental setup, a new measurement with ten silver perrhenate microbolometers has been running since July 2002. The crystals have masses around 300 mug and their average FWHM energy resolution is of 28.3 eV at the beta end point. The Kurie plot collected during 4485 hxmg effective running time has an end-point energy of 2466.10.8(stat)1.5(syst) eV, while the half lifetime of the decay is found to be 43.20.2(stat)0.1(syst) Gy. These values are the most precise obtained so far for Re-187. The best fit value for m((ν) over bare)(2) is 147237(stat)90(syst) eV(2), which corresponds to an upper limit for the electron antineutrino mass m((ν) over bare)less than or equal to21.7 eV at 90% C.L.
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