Gabriel Orebi Gann

Assistant Professor
Experimental Particle Physics
underground.physics.berkeley.edu

Research Interests

I am an experimental particle physicist, with an interest in weakly interacting particles. My research focuses on neutrinos and dark matter - which is about as weakly interacting as you can get!

My primary experimental involvement is in the SNO+ neutrino experiment, located 2km underground in an active nickel mine in northern Ontario, Canada. SNO+ is the successor to the extremely successful SNO experiment, on which I did my thesis work, which resolved the long-standing solar neutrino problem by observing the interactions of neutrinos on a heavy water target. This opened up both the charged-current channel, open to electron neutrinos only, and also the neutral-current interaction, which occurs equally for all flavours of neutrino. SNO was thus able to measure both the pure electron-neutrino flux from the Sun as well as the total flux of all neutrino flavours, thus demonstrating that the theoretically predicted flux of electron neutrinos from the Sun was in fact oscillating to other flavours en route to the Earth.

SNO+ will exchange the heavy water target for a scintillator target, with much higher light yield, allowing us to push much lower in energy. The primary goal of SNO+ is a search for neutrinoless double beta decay, a process which only occurs if the neutrino is in fact a Majorana particle: meaning it is its own antiparticle. This would make the neutrino unique among known particles, and could explain fundamental mysteries of the universe such as the known asymmetry between matter and antimatter. In addition SNO+ will have a board solar neutrino programme, using the Sun to study neutrinos and, at the same time, using neutrinos to study the Sun. We intend to make the first direct measurement of both pep and CNO neutrinos and, potentially, the very low-energy pp neutrinos themselves. This could enable us to resolve many unanswered questions both in the properties and behaviour of neutrinos, and also in the composition of the Sun itself. SNO+ will also be sensitive to reactor neutrino, geoneutrinos, and potential supernova neutrinos.

I am also involved in the DEAP/CLEAN dark matter programme. This is a single-phase liquid noble gas approach to dark matter detection, intending to observe WIMP interactions by looking for the signature of the resultant nuclear recoil. MiniCLEAN, a 100-kg prototype, is currently under construction in the SNOLAB facility in Canada. The ultimate goal of this programme is the 50-ton-scale CLEAN experiment, with interchangeable liquid neon and argon targets, which would allow for both an unprecedented sensitivity to potential WIMP interactions, but also a percent-level precision in observations of the solar pp-neutrino flux.