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Measuring Neutrino Masses Using Radio-Frequency Techniques
Get PDFWe describe a new technique by which the energy spectrum of low energy electrons can be extracted. The technique relies on the detection and measurement of coherent radiation created from the cyclotron motion of charged particles, such as electrons, in strong magnetic fields. The technique proposed relies on the principle that the frequency of cyclotron radiation emitted by the particle depends inversely on its Lorentz boost. Detection and measurement of the coherent radiation emitted is tantamount to measuring the kinetic energy of the electron. As the technique inherently involves the measurement of a frequency in a non-destructive manner, it can, in principle, achieve a high degree of precision and accuracy; estimated to be better than 1 part in 106 for electrons with kinetic energies between 5 and 50 keV. One immediate application of this technique is in the measurement of the endpoint spectrum from tritium beta decay, which is directly sensitive to the absolute mass scale of neutrinos
Neutrino Experiments Come Closer to Seeing
Get PDFThe T2K experiment has measured the largest number of events associated with muon neutrinos oscillating into electron neutrinos, an important step toward seeing CP violation in neutrino interactions. Subject Areas: Particles and Field
Measurement of Atmospheric Neutrinos at the Sudbury Neutrino Observatory
Get PDFThe Sudbury Neutrino Observatory consists of a 1 kiloton heavy water Cherenkov detector able to detect and reconstruct high-energy muons created from cosmic ray showers and atmospheric neutrino interactions. By measuring the flux of through-going muons as a function of zenith angle, the SNO experiment can distinguish between the oscillated and un-oscillated portion of the neutrino flux. This report describes SNO's measurements of the flux of cosmic ray muons and neutrino-induced muon flux at a depth of 5890 meters water equivalent
Project 8: Using Radio-Frequency Techniques to Measure Neutrino Mass
No full textThe 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. 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. As the technique inherently involves the measurement of a frequency in a non-destructive manner, it can, in principle, achieve a high degree of resolution and accuracy
Direct neutrino mass measurements after PLANCK
Get PDFThe absolute mass scale of neutrinos remains an open question subject to experimental investigation from both particle physics and cosmology. Over the next decade, a number of experiments from both disciplines will attempt to probe the mass scale further to the very limits of the predictions from oscillation results. This paper provides a broad overview of the experimental program in neutrino mass scale measurements, with a particular focus on direct experimental probes due to come online over the next decade.United States. Dept. of Energy (Contract DE-FG02-06ER-41420
From eV to EeV: Neutrino cross sections across energy scales
No full textSince its original postulation by Wolfgang Pauli in 1930, the neutrino has played a prominent role in our understanding of nuclear and particle physics. In the intervening 80 years, scientists have detected and measured neutrinos from a variety of sources, both man made and natural. Underlying all of these observations, and any inferences we may have made from them, is an understanding of how neutrinos interact with matter. Knowledge of neutrino interaction cross sections is an important and necessary ingredient in any neutrino measurement. With the advent of new precision experiments, the demands on our understanding of neutrino interactions is becoming even greater. The purpose of this article is to survey our current knowledge of neutrino cross sections across all known energy scales: from the very lowest energies to the highest that we hope to observe. The article covers a wide range of neutrino interactions including coherent scattering, neutrino capture, inverse beta decay, low-energy nuclear interactions, quasielastic scattering, resonant pion production, kaon production, deep inelastic scattering, and ultrahigh energy interactions. Strong emphasis is placed on experimental data whenever such measurements are available.United States. Dept. of Energy (Grant DE-FG02-06ER-41420
Resolving the reactor neutrino anomaly with the KATRIN neutrino experiment
No full textAbstractThe KArlsruhe TRItium Neutrino experiment (KATRIN) combines an ultra-luminous molecular tritium source with an integrating high-resolution spectrometer to gain sensitivity to the absolute mass scale of neutrinos. The projected sensitivity of the experiment on the electron neutrino mass is 200 meV at 90% C.L. With such unprecedented resolution, the experiment is also sensitive to physics beyond the Standard Model, particularly to the existence of additional sterile neutrinos at the eV mass scale. A recent analysis of available reactor data appears to favor the existence of such a sterile neutrino with a mass splitting of |Δmsterile|2⩾1.5 eV2 and mixing strength of sin22θsterile=0.17±0.08 at 95% C.L. Upcoming tritium beta decay experiments should be able to rule out or confirm the presence of the new phenomenon for a substantial fraction of the allowed parameter space
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Annual modulation of cosmic relic neutrinos
Get PDFThe cosmic neutrino background (CνB), produced about one second after the big bang, permeates the Universe today. New technological advancements make neutrino capture on beta-decaying nuclei (NCB) a clear path forward towards the detection of the CνB. We show that gravitational focusing by the Sun causes the expected neutrino capture rate to modulate annually. The amplitude and phase of the modulation depend on the phase-space distribution of the local neutrino background, which is perturbed by structure formation. These results also apply to searches for sterile neutrinos at NCB experiments. Gravitational focusing is the only source of modulation for neutrino capture experiments, in contrast to dark-matter direct-detection searches where the Earth’s time-dependent velocity relative to the Sun also plays a role.MIT Department of Physics Pappalardo ProgramNational Science Foundation (U.S.) (Grant PHY-1205175)National Science Foundation (U.S.) (Grant PHY-1205100
Relativistic cyclotron radiation detection of tritium decay electrons as a new technique for measuring the neutrino mass
No full textThe 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 mνβ<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.Department of Energy Office of Nuclear Physic
Sterile neutrinos, coherent scattering, and oscillometry measurements with low-temperature bolometers
No full textCoherent neutrino-nucleon scattering offers a unique approach in the search for physics beyond the standard model. When used in conjunction with monoenergetic neutrino sources, the technique can be sensitive to the existence of light sterile neutrinos. The ability to utilize such reactions has been limited in the past due to the extremely low-energy threshold (10–50 eV) needed for detection. In this paper, we discuss an optimization of cryogenic solid-state bolometers that enables reaching extremely low kinetic energy thresholds. We investigate the sensitivity of an array of such detectors to neutrino oscillations to sterile states. A recent analysis of available reactor data appears to favor the existence of such a sterile neutrino with a mass splitting of |Δm[subscript sterile]|[superscript 2]≥1.5 eV[superscript 2] and mixing strength of sin[superscript 2]2θ[subscript sterile]=0.17±0.08 at 95% confidence level. An array of such low-threshold detectors would be able to make a definitive statement as to the validity of the interpretation.United States. Dept. of Energy (Grant No. DE-FG02-06ER-41420National Science Foundation (U.S.) (Grant No. PHY-0847342
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