arXiv subjects

Joseph A. Formaggio

Publications and source records attributed to Joseph A. Formaggio.

21 records · Page 2Linked to original sources

arXiv2009

Relativistic Cyclotron Radiation Detection of Tritium Decay Electrons as a New Technique for Measuring the Neutrino Mass

The shape of the beta decay energy distribution is sensitive to the mass of the electron neutrino. Attempts to measure the endpoint shape of tritium decay have so far seen no distortion from the zero-mass form, thus placing an upper limit of m_nu_beta < 2.3 eV. Here we show that a new type of electron energy spectroscopy could improve future measurements of this spectrum and therefore of the neutrino mass. We propose to detect the coherent cyclotron radiation emitted by an energetic electron in a magnetic field. For mildly relativistic electrons, like those in tritium decay, the relativistic shift of the cyclotron frequency allows us to extract the electron energy from the emitted radiation. We present calculations for the energy resolution, noise limits, high-rate measurement capability, and systematic errors expected in such an experiment.

nucl-ex↗

arXiv2007

Spallation nuclei in substellar objects: a new dark-matter signature?

Although dark matter makes up 80% of the gravitational mass of our Galaxy, its composition is not known. One hypothesis is that dark matter consists of massive particles called WIMPs. WIMPs are expected to accumulate and coannihilate in the cores of stars, but the only signature of this accumulation has been thought to be hard- to-observe high-energy neutrinos. Here we propose an entirely new observable signature. WIMP coannihilations in the core of a very low-mass star, brown dwarf, or planetary-mass object should alter the star's chemical composition via spallation reactions. Very close to the Galactic center, these stars may acquire extremely high lithium, beryllium, and boron abundances, even for models with otherwise- undetectable WIMP-nucleon cross sections. These abundances should be measurable in certain stellar systems and phenomena.

astro-ph↗

arXiv2002

Potential for Supernova Neutrino Detection in MiniBooNE

The MiniBooNE detector at Fermilab is designed to search for $ν_μ\to ν_e$ oscillation appearance at $E_ν\sim 1 {\rm GeV}$ and to make a decisive test of the LSND signal. The main detector (inside a veto shield) is a spherical volume containing 0.680 ktons of mineral oil. This inner volume, viewed by 1280 phototubes, is primarily a Čerenkov medium, as the scintillation yield is low. The entire detector is under a 3 m earth overburden. Though the detector is not optimized for low-energy (tens of MeV) events, and the cosmic-ray muon rate is high (10 kHz), we show that MiniBooNE can function as a useful supernova neutrino detector. Simple trigger-level cuts can greatly reduce the backgrounds due to cosmic-ray muons. For a canonical Galactic supernova at 10 kpc, about 190 supernova $\barν_e + p \to e^+ + n$ events would be detected. By adding MiniBooNE to the international network of supernova detectors, the possibility of a supernova being missed would be reduced. Additionally, the paths of the supernova neutrinos through Earth will be different for MiniBooNE and other detectors, thus allowing tests of matter-affected mixing effects on the neutrino signal.

hep-ph↗