Hypersharp resonant capture of neutrinos as a laboratory probe of the Planck length.
The 18.6 keV antineutrino (nue) line from the two-body decay of 3H in crystals can be emitted with a natural width because of motional averaging by lattice vibrations despite the very long lifetime of 3H and contrary to commonly held views of linewidths in such a case. It can be resonantly captured in 3He with geometrical cross section sigma approximately 10(-17) cm2. Using its hypersharp sensitivity DeltaE/E approximately 10(-29) and the method of "time-filtered" resonance, the basic energy width approximately 10(-24) eV expected of the 3H state can be measured to test if ultimate nuclear widths are limited by the Planck length rather than time-energy uncertainty.
Raghavan
R S
RS
Institute of Particle, Nuclear and Astronomical Sciences and Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.