Search

Low energy neutrinos play important role in nuclear and astrophysical processes. Such neutrinos with energy below $\sim$100 MeV are able to scatter off the nucleus via elastic scattering. Neutrino-nucleus elastic scattering ($\nu A_{el}$) provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions. We present the detailed study and formulation of coherency effects, relate this to nuclear form factors and experimental cross-section ratios. The parameters chosen to quantify the coherency are universally applicable to different neutrino sources and target nuclei. We characterize how the energy dependence of the coherence factor leads to complementary among measurements at various neutrino sources with different targets. We also provide the constraints on coherency for the first generation discovery measurements of $\nu A_{el}$ with CsI target and theoretical expectations from Argon and Germanium target.

An energy threshold of (220±10) eV was achieved at an efficiency of 50% with a four-channel ultra-low-energy germanium detector each with an active mass of 5 g[1]. This provides a unique probe to WIMP dark matter with mass below 10 GeV. With low background data taken at the Kuo-Sheng Laboratory, constraints on WIMPs in the galactic halo were derived. Both spin-independent WIMP-nucleon and spin-dependent WIMP-neutron bounds improve over previous results for WIMP mass between 3 6 GeV. These results, together with those on spin-dependent couplings, will be presented. Sensitivities for full-scale experiments were projected. This detector technique makes the unexplored sub-keV energy window accessible for new neutrino and dark matter experiments. 1. MOTIVATIONS Weakly Interacting Massive Particles (WIMP, denoted by �) are the leading candidates for Cold Dark Matter (CDM)[2]. There are intense experimental efforts to look for WIMPs through direct detection of nuclear recoils

This article reports the first study of possible emissions of axions from power reactors using Primakoff and Compton conversions as the detection mechanisms. The experiment was performed at the Kuo-Sheng (KS) Nuclear Power Station with a high-purity germanium detector of mass 1.06 kg at a distance of 28 m from the 2.9 GW reactor core. The expected experimental signatures are mono-energetic lines produced by Primakoff or Compton conversions of axions at the detector. Based on 459.0/96.3 days of reactor ON/OFF data, no evidence of axion emission was observed and constraints on axion couplings gaγγ and gaee versus axion mass ma within the framework of invisible axion models were placed. The KSVZ and DFSZ models can be excluded for 104 eV