Direct Measurements of Neutrino Mass

Abstract

Los Alamos Nahonal Laboratory ib operated by the University of Caldornia for the United States Department of Energy under contract W-7405-ENG-36.

Assessment of molecular effects on neutrino mass measurements from tritiumβdecay

“…The 209 transition is allowed, and the spectrum is not significantly modified by a shape factor depen-210 dent on the kinetic energy of the electron. Hence the shape of the beta decay spectrum is 211 determined by the neutrino mass m ν ; electron mass m e ; total electron energy E e ; maximum 212 energy of the electron, E max = Q − E kin rec + m e ; and the energies V k and probabilities P k asso- Cabibbo angle, F (Z, E e ) is the Fermi function correcting for the interaction between the 220 electron and the nucleus, and Θ(E max − E e − V k − m νi ) is a Heaviside step function ensuring 221 energy conservation [10]. Units are chosen where c = 1.…”

The Q-value of tritium β-decay and the neutrino mass

“…The wave numbers of oscillations are proportional to the differences of the squared masses m 2 ij = |m 2 (ν i ) − m 2 (ν j )|, of which two have been determined to be m 2 12 = 7.92(1 ± 0.09) × 10 −5 eV 2 /c 4 and m 2 23 = 2.4(1 +0. 21 −0.26 ) × 10 −3 eV 2 /c 4 , respectively [1]. Hence, the absolute mass scale could range from a hierarchical ordering with m 2 1 or m 2 3 being much smaller than either of the measured m 2 ij values to a quasi-degenerate situation where these differences are sitting on a much higher pedestal m 2 m 2 ij .…”

Bayesian perspectives on the discovery of the Higgs particle

“…One of those suggestions, realized in Robertson andKnapp 1988 anddiscussed e.g. in Cousins 1994, adopted a Bayesian perspective in order to limit the statistical analysis to the physically allowed parameter region.…”

“…In some special cases, however, HEP-statisticians have suggested Bayesian elements of reasoning in order to extract satisfactory quantitative results from the data. Examples are Robertson and Knapp 1988, Cousins 1994, Read 2002and Lyons 2013. Clearly, Bayesian ideas were deployed in those cases with the principle of a general Bayesian embedding of data analysis in mind.…”