arXiv subjects
Publications and source records attributed to Boris Kayser.
The physics of neutrino oscillation is summarized, and then the results of oscillation experiments, including the most recent results, are discussed. The possibility that neutrinos are their own antiparticles is examined. What we have learned so far about the neutrinos is reviewed, and the questions to be answered through future experiments are discussed.
We explain the physics of neutrino oscillation in vacuum and in matter. We attempt to clarify several features of oscillation that can be puzzling when neutrinos are their own antiparticles.
We briefly report on a study intended to help shape the future of neutrino physics -- an area to which Professor Gustavo Branco has made distinguished contributions.
Thanks to compelling evidence that neutrinos can change flavor, we now know that they have nonzero masses, and that leptons mix. In these lectures, we explain the physics of neutrino flavor change, both in vacuum and in matter. Then, we describe what the flavor-change data have taught us about neutrinos. Finally, we consider some of the questions raised by the discovery of neutrino mass, explaining why these questions are so interesting, and how they might be answered experimentally,
It is shown that the scattering of electromagnetic waves by Langmuir ones taking into the account the electric drift motion of particles, is the most intense nonlinear process and should be responsible for the formation of radiation spectrum of radio pulsars. Performed analysis indicates that in the case of existence of inertial interval formation of stationary spectra is possible. Analysis of linear mechanisms of wave generation and silk allows to conclude that only possible stationary solution has spectral index $α=-1.5$. Obtained spectrum is in good agreement with observational data.
Is the relatively isolated member of the neutrino mass spectrum heavier or lighter than the two closely-spaced members? This question - the character of the neutrino mass hierarchy - is of great theoretical interest. All previously identified experiments for addressing it via neutrino oscillations require that the currently unknown size of the U_e3 element of the leptonic mixing matrix (parameterized by the unknown theta_13 mixing angle) be sufficiently large, and will utterly fail in the limit theta_13=0. For this reason, we explore alternative oscillation approaches that would still succeed even if theta_13 vanishes. We identify several alternatives that require neither a nonzero |U_e3| nor the presence of significant matter effects. All include multiple percent-level neutrino oscillation measurements, usually involving muon-neutrino (or antineutrino) disappearance and very long baselines. We comment on the degree of promise that these alternative approaches show.
To answer the very interesting questions raised by the discovery of neutrino mass, an effective, coherent strategy is needed. To foster the development of such a strategy, the American Physical Society's Divisions of Nuclear Physics and of Particles and Fields, together with the Divisions of Astrophysics and the Physics of Beams, have sponsored this yearlong Study on the Physics of Neutrinos. The study has endeavored to identify the most important open questions, to evaluate the physics reach of various proposed ways of answering them, and to determine an effective, fruitful U.S. role within a global experimental program. An important -- if challenging -- goal of the study has been to achieve consensus regarding the future of neutrino physics.
We recount some of the highlights of the 2003 Moriond Workshop on Electroweak Interactions and Unified Theories.
The discoveries and open questions in neutrino physics, as reported at Neutrino 2002 and more recently, are reviewed from a theoretical perspective.
We summarize what has been learned about the neutrino mass spectrum and neutrino mixing, identify interesting open questions that can be answered by accelerator neutrino facilities of the future, and discuss the importance and physics of answering them.
We hunt for and discuss manifestly CP-violating effects which are mediated by Majorana phases. These phases are present if the Standard Model neutrinos are Majorana particles. We argue that while Majorana phases do affect the strength of neutrinoless double beta decay (a well known fact), they do so in a way that involves no manifest violation of CP. The conditions for manifestly CP-violating phenomena -- differences between the rates for CP-mirror-image processes -- are presented, and three examples are discussed: (i) neutrino-antineutrino oscillation; (ii) rare decays of K and B mesons and their antiparticles and (iii) the lepton asymmetry generated by the decay of hypothetical very heavy right-handed "see-saw" neutrinos. We also find that, for the case of degenerate light neutrinos, manifestly CP-violating effects in neutrino-antineutrino oscillation vanish, although flavor-changing transitions do not. Finally, we comment on leptogenesis with degenerate right-handed neutrinos, and contrast it to the neutrino-antineutrino oscillation case.
The theoretical basics of neutrino mass and mixing are reviewed. Dirac and Majorana masses are explained, and added together to produce the see-saw picture of the lightness of neutrinos. This picture predicts that neutrinos are Majorana particles. The character, and an apparent paradox, of Majorana neutrinos are examined. The physics of neutrino flavor change (oscillation), in vacuo and in matter, is reviewed.
Do neutrinos have nonzero masses? If they do, then these masses are very tiny, and can be sought only in very sensitive experiments. The most sensitive of these search for neutrino oscillation, a quantum interference effect which requires neutrino mass and leptonic mixing. In these lectures, we explain what leptonic mixing is, and then develop the physics of neutrino oscillation, including the general formalism and its application to special cases of practical interest. We also see how neutrino oscillation is affected by the passage of the oscillating neutrinos through matter.
We argue that the evidence for neutrino mass is quite compelling. This mass raises a number of questions, which we enumerate, about neutrinos. Then we focus on one of these questions---the issue of the possible neutrino mass spectra. In particular, we explain that one can have a four-neutrino spectrum which does not require significant sterile-neutrino involvement in either the atmospheric or solar neutrino oscillations.
The experimental discovery that neutrinos almost certainly have masses and mix raises a number of fundamental questions about the neutrinos. We discuss what is presently known about the answers to these questions, and how we can learn more.
The question of neutrino mass is one of the major riddles in particle physics. Recently, strong evidence that neutrinos have nonzero masses has been found. While tiny, these masses could be large enough to contribute significantly to the mass density of the universe. The evidence for nonvanishing neutrino masses is based on the apparent observation of neutrino oscillation -- the transformation of a neutrino of one type or "flavor" into one of another. We explain the physics of neutrino oscillation, and review and weigh the evidence that it actually occurs in nature. We also discuss the constraints on neutrino mass from cosmology and from experiments with negative results. After presenting illustrative neutrino mass spectra suggested by the present data, we consider how near- and far-future experiments can further illuminate the nature of neutrinos and their masses.
We discuss the three major hints of neutrino mass: the strong evidence of mass from the behavior of atmospheric neutrinos, the very promising further hint from the behavior of solar neutrinos, and the so-far unconfirmed hint from the LSND experiment. Then, we describe two illustrative neutrino-mass scenarios suggested by the observed hints. We identify the needed future tests of both the present hints and the neutrino-mass scenarios.
We review what has been learned about CP violation in the K system. It is natural to hypothesize that the observed CP-violating effects are caused by the Standard Model weak interaction. We describe the stringent future test of this hypothesis via experiments on the B system. Then, we see how new physics beyond the Standard Model could be revealed by this test.