M. Deniz

Search of neutrino magnetic moments with a high-purity germanium detector at the Kuo-Sheng nuclear power station

A search of neutrino magnetic moments was carried out at the Kuo-Sheng nuclear power station at a distance of 28 m from the 2.9 GW reactor core. With a high purity germanium detector of mass 1.06 kg surrounded by scintillating NaI(Tl) and CsI(Tl) crystals as anti-Compton detectors, a detection threshold of 5 keV and a background level of 1 kg{sup -1} keV{sup -1} day{sup -1} near threshold were achieved. Details of the reactor neutrino source, experimental hardware, background understanding, and analysis methods are presented. Based on 570.7 and 127.8 days of Reactor ON and OFF data, respectively, at an average Reactor ON electron antineutrino flux of 6.4x10{sup 12} cm{sup -2} s{sup -1}, the limit on the neutrino magnetic moments of {mu}{sub {nu}{sub e}}<7.4x10{sup -11}{mu}{sub B} at 90% confidence level was derived. Indirect bounds on the {nu}{sub e} radiative decay lifetimes were inferred.

New limits on spin-independent and spin-dependent couplings of low-mass WIMP dark matter with a germanium detector at a threshold of 220 eV

An energy threshold of (220{+-}10) eV was achieved at an efficiency of 50% with a four-channel ultralow-energy germanium detector, each with an active mass of 5 g. This provides a unique probe to weakly interacting massive particles (WIMP) dark matter with mass below 10 GeV. With a data acquisition live time of 0.338 kg-day at the Kuo-Sheng Laboratory, constraints on WIMPs in the galactic halo were derived. The limits improve over previous results on both spin-independent WIMP-nucleon and spin-dependent WIMP-neutron cross-sections for WIMP mass between 3 and 6 GeV. Sensitivities for full-scale experiments are projected. This detector technique makes the unexplored sub-keV energy window accessible for new neutrino and dark matter experiments.

Constraints on nonstandard neutrino interactions and unparticle physics with {nu}{sub e}-e{sup -} scattering at the Kuo-Sheng nuclear power reactor

(TEXONO Collaboration) 1 Institute of Physics, Academia Sinica, Taipei 11529, Taiwan. 2 Department of Physics, Middle East Technical University, Ankara 06531, Turkey. 3 Institute of High Energy Physics, Chinese Academy of Science, Beijing 100039, China. 4 Department of Engineering Physics, Tsinghua University, Beijing 100084, China. 5 Department of Nuclear Physics, Institute of Atomic Energy, Beijing 102413, China. 6 Department of Physics, Banaras Hindu University, Varanasi 221005, India. (Dated: August 10, 2010)

Search of axions at the Kuo-Sheng nuclear power station with a high-purity germanium detector

A search of axions produced in nuclear transitions was performed at the Kuo-Sheng 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 were monoenergetic lines produced by their Primakoff or Compton conversions at the detector. Based on 459.0/96.3 days of reactor ON/OFF data, no evidence of axion emissions were observed and constraints on the couplings g{sub a{gamma}}{sub {gamma}} and g{sub aee} versus axion mass m{sub a} within the framework of invisible axion models were placed. The KSVZ and DFSZ models can be excluded for 10{sup 4} eV < or approx. m{sub a} < or approx. 10{sup 6} eV. Model-independent constraints on g{sub a{gamma}}{sub {gamma}}{center_dot}g{sub aNN}{sup 1}<7.7x10{sup -9} GeV{sup -2} for m{sub a} < or approx. 10{sup 5} eV and g{sub aee}{center_dot}g{sub aNN}{sup 1}<1.3x10{sup -10} for m{sub a} < or approx.10{sup 6} eV at 90% confidence level were derived. This experimental approach provides a unique probe for axion mass at the keV-MeV range not accessible to the other techniques.

Coherency in Neutrino-Nucleus Elastic Scattering

Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter (

Constraints on scalar-pseudoscalar and tensorial nonstandard interactions and tensorial unparticle couplings from neutrino-electron scattering

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Final results of ν̄e — e scattering cross-section measurements and constraints on new physics

) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold and target nucleus are studied. The ranges of

Measurement of neutrino-electron scattering cross section and the EW parameters at the Kuo-Sheng reactor neutrino laboratory

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Prospects of cold dark matter searches with an ultra-low-energy germanium detector

which can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in

Production and decay of the 73Ge*(1/2−) metastable state in a low-background germanium detector

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