Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268


Thu., September 18, 2014, at 3:00 PM - 4:00 PM (refreshments served at 2:40 PM)

The EXO Program and the Quest for Majorana Neutrino Masses

Giorgio Gratta, Physics Dept., Stanford University, Stanford, CA
ORNL, Physics Division, Bldg. 6008 Large Conference Room

With the definitive evidence for neutrino oscillations collected in the last decade, we now believe that neutrino masses are non-zero. Oscillation measurements, however, only measure mass differences and give us little information about the absolute values of neutrino masses.

The hypothetical phenomenon of neutrino-less double-beta decay can probe the neutrino mass scale with exquisite sensitivity. This process, if observed, would also imply that neutrinos, unlike all other spin-1/2 particles, are of the Majorana type, that is they have wave functions with only two components. The observation of the neutrino-less double-beta decay would also imply the non-conservation of the lepton number.

Following the well-known principle that there is no free lunch in life, interesting half-lives for neutrino-less double-beta decay exceed 1025 years (or ~1015 times the age of the Universe) making experiments rather challenging. I will describe the EXO program, including the recent measurements by EXO-200 that establish the present state of the art and the plans for a 5-ton enriched Xe detector, nEXO, that will have a sensitivity to Majorana masses below 10 meV.

Contact: Alfredo Galindo-Uribarri, (865) 574-6124