J. C. D'Olivo

Active sterile neutrino oscillations and pulsar kicks

Departamento de Fi ´sica de Altas Energias, Instituto de Ciencias Nucleares, Universidad Nacional Auto´nomadeMexico, Apartado Postal70-543, 04510 Me ´xico, Distrito Federal, Mexico~Received 24 February 2004; published 18 August 2004!We develop a thorough description of neutrino oscillations in a magnetized protoneutron star, based on aresonance layer for neutrinos with different momentum directions. We apply our approach to the calculation ofthe asymmetry in the neutrino emission during the birth of a neutron star and the pulsar acceleration in the caseof an active-sterile neutrino resonant conversion. The observed velocities can be obtained with the magneticfields expected in the interior of a protoneutron star, for sterile neutrino masses of the order of KeV and smallmixing angles.DOI: 10.1103/PhysRevD.70.043005 PACS number~s!: 97.60.Gb, 14.60.Pq, 98.70.RzI. INTRODUCTION

Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB

We present results of a dark matter search performed with a 0.6 kg d exposure of the DAMIC experiment at the SNOLAB underground laboratory. We measure the energy spectrum of ionization events in the bulk silicon of charge-coupled devices down to a signal of 60 eV electron equivalent. The data are consistent with radiogenic backgrounds, and constraints on the spin-independent WIMP-nucleon elastic-scattering cross section are accordingly placed. A region of parameter space relevant to the potential signal from the CDMS-II Si experiment is excluded using the same target for the first time. This result obtained with a limited exposure demonstrates the potential to explore the low-mass WIMP region (<10  GeV c-2) with the upcoming DAMIC100, a 100 g detector currently being installed in SNOLAB.

Chirality-preserving neutrino oscillations in an external magnetic field

Abstract Neutrinos propagating in matter acquire an effective electromagnetic vertex induced by their weak interactions with the charged particles in the background. In the presence of an external magnetic field the induced vertex affects the flavor transformations of mixed neutrinos in a way that, in contrast to the oscillations driven by an intrinsic magnetic moment interaction, preserve chirality. We derive the evolution equation for this case and discuss some of the physical consequences in environments such as a supernova. For small values of the square mass difference the resonance for neutrinos and antineutrinos occur within regions which are close. In that case, the resonance condition becomes independent of the vacuum parameters and is approximately the same for both.

Cherenkov radiation by massless neutrinos

Abstract Due to their weak interactions, neutrinos can polarize a medium and acquire an induced charge. We consider the Cherenkov radiation emitted by neutrinos due to their effective electromagnetic interactions as they pass through a polarizable medium. The effect exists even for massless, chiral neutrinos, where no physics beyond the standard model needs to be assumed.

Measurement of radioactive contamination in the high-resistivity silicon CCDs of the DAMIC experiment

We present measurements of radioactive contamination in the high-resistivity silicon charge-coupled devices (CCDs) used by the DAMIC experiment to search for dark matter particles. Novel analysis methods, which exploit the unique spatial resolution of CCDs, were developed to identify

Results of the engineering run of the Coherent Neutrino Nucleus Interaction Experiment (CONNIE)

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Right-handed neutrino production in dense and hot plasmas

and

Pulsar motions from neutrino oscillations induced by a violation of the equivalence principle

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The CONNIE experiment

particles. Uranium and thorium contamination in the CCD bulk was measured through

Perturbative exponential expansion and matter neutrino oscillations

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