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., May 16, 2013, at 3:00 PM (refreshments at 2:40 PM)

Neutrino Oscillations: Early Hints of the Mass Hierarchy

Bernadette Kafwimbi Cogswell, Vanderbilt University
ORNL, Bldg. 6008 Large Conference Room

The only experimentally observed phenomenon that lies outside the standard model is neutrino oscillations: the coherent mixing of propagating neutrino mass eigenstates that leads to neutrino flavor conversion in the lab. A current goal in the field is to determine the values of the mixing angles and mass splittings that characterize this mixing. However, a related open question is the hierarchy question, which mass state is lightest and which heaviest? We point out a broken symmetry in the oscillation probability relevant to this question. For the recently measured, surprisingly large, value of the mixing angle theta-13, we find that this broken symmetry lifts a four-fold degeneracy. This symmetry breaking effect proves very meaningful for the hierarchy question: in the global data, it leads to a preference for the inverse hierarchy at the 97.2% level.

Contact: Alfredo Galindo-Uribarri, 574-6124