Kam-Biu Luk

Particle Experiment

Current Projects

(1) Daya Bay
There are compelling evidences for neutrino oscillation. Oscillations between three kinds of neutrino are completely described by three mixing angles, two mass-squared differences, and one CP-violating phase. CP violation in the lepton sector, if exists, might explain why there is more matter than anti-matter in the Universe. Yet whether the CP-violating effect can be studied with neutrinos or not is dictated by the last unknown mixing angle θ13. The primary goal of the Daya Bay experiment in China is to determine the value of θ13 by measuring the change in flux and the energy spectrum of the antineutrinos generated by the powerful Daya Bay nuclear power complex with three sets of detectors located underground at three different locations that are within 2 km from the reactors.

(2) HyperCP (E871 at Fermilab)
This is a fixed-target experiment designed to search for direct CP Violation in strange-baryon decays with the best precision in the world. CP violation is an important open problem in particle physics that has been pursued rigorously for years. Observation of CP non-conservation in baryon decay would deepen our understanding of this puzzling phenomenon. In HyperCP, we have collected billions of Ξ- → Λπ-, Λ → pπ- and the corresponding anti-Ξ- decays. Test of CP invariance is carried out by comparing the angular distribution of the proton along the
Λ helicity axis to that of the antiproton. Any difference in the distributions is a signal of direct CP violation. In addition, we look for CP violation in charged K decays, time-reversal violating effects and rare decays of strange particles.

Selected Publications

T. Holmstrom, N. Leros et al., (HyperCP Collaboration), Search for CP Violation in Charged-Ξ and Λ Hyperon Decays, Phys. Rev. Lett. 93, 262001 (2004).

X. Gao et al., (Daya Bay Collaboration), A Precision Measurement of the Neutrino Mixing Angle θ13 Using Reactor Antineutrinos At Daya Bay, hep-ex/0701029 (2007).