38 research outputs found
Neutrino Mass and New Physics
We review the present state of and future outlook for our understanding of
neutrino masses and mixings. We discuss what we think are the most important
perspectives on the plausible and natural scenarios for neutrinos and what may
have the most promise to throw light on the flavor problem of quarks and
leptons. We focus on the seesaw mechanism which fits into the big picture of
particle physics such as supersymmetry and grand unification providing a
unified approach to flavor problem of quarks and leptons. We argue that in
combination with family symmetries, this may be at the heart of a unified
understanding of flavor puzzle. We also discuss other new physics ideas such as
neutrinos in models with extra dimensions and possible theoretical implications
of sterile neutrinos. We outline some tests for the various schemes.Comment: 90 pages and 9 figures; With permission from the Annual Review of
Nuclear and Particle Science. Final version of this material is scheduled to
appear in the Annual Review of Nuclear and Particle Science Vol. 56, to be
published in November 2006 by Annual Reviews (http://www.annualreviews.org);
some references and parts of text update
Solar Neutrinos: Status and Prospects
We describe the current status of solar neutrino measurements and of the
theory -- both neutrino physics and solar astrophysics -- employed in
interpreting measurements. Important recent developments include
Super-Kamiokande's determination of the neutrino-electron elastic scattering
rate for 8B neutrinos to 3%; the latest SNO global analysis in which the
inclusion of low-energy data from SNO I and II significantly narrowed the range
of allowed values for the neutrino mixing angle theta12; Borexino results for
both the 7Be and pep neutrino fluxes, the first direct measurements
constraining the rate of ppI and ppII burning in the Sun; global reanalyses of
solar neutrino data that take into account new reactor results on theta13; a
new decadal evaluation of the nuclear physics of the pp chain and CNO cycle
defining best values and uncertainties in the nuclear microphysics input to
solar models; recognition of an emerging discrepancy between two tests of solar
metallicity, helioseismological mappings of the sound speed in the solar
interior, and analyses of the metal photoabsorption lines based on our best
current description of the Sun's photosphere; a new round of standard solar
model calculations optimized to agree either with helioseismology or with the
new photospheric analysis; and, motivated by the solar abundance problem, the
development of nonstandard, accreting solar models, in order to investigate
possible consequences of the metal segregation that occurred in the proto-solar
disk. We review this progress and describe how new experiments such as SNO+
could help us further exploit neutrinos as a unique probe of stellar interiors.Comment: 82 pages, 11 figure
The Scientific Life Of John Bahcall
This article follows the scientific life of John Norris Bahcall, including
his tenacious pursuit of the solar neutrino problem, his contributions to our
understanding of galaxies, quasars, and their emissions, and his leadership of
and advocacy for astronomy and astrophysics.Comment: Prefactory for Annual Reviews of Nuclear and Particle Science; 23
pages, 6 figure
Quantum systems in weak gravitational fields
Fully covariant wave equations predict the existence of a class of
inertial-gravitational effects that can be tested experimentally. In these
equations inertia and gravity appear as external classical fields, but, by
conforming to general relativity, provide very valuable information on how
Einstein's views carry through in the world of the quantum.Comment: 22 pages. To be published in Proceedings of the 17th Course of the
International School of Cosmology and Gravitation "Advances in the interplay
between quantum and gravity physics" edited by V. De Sabbata and A.
Zheltukhin, Kluwer Academic Publishers, Dordrech
Degenerate and Other Neutrino Mass Scenarios and Dark Matter
I discuss in this talk mainly three topics related with dark matter motivated neutrino mass spectrum and a generic issue of mass pattern, the normal versus the inverted mass hierarchies. In the first part, by describing failure of a nontrivial potential counter example, I argue that the standard 3 mixing scheme with the solar and the atmospheric 's is robust. In the second part, I discuss the almost degenerate neutrino (ADN) scenario as the unique possibility of accommodating dark matter mass neutrinos into the 3 scheme. I review a cosmological bound and then reanalyze the constraints imposed on the ADN scenario with the new data of double beta decay experiment. In the last part, I discuss the 3 flavor transformation in supernova (SN) and point out the possibility that neutrinos from SN may distinguish the normal versus inverted hierarchies of neutrino masses. By analyzing the neutrino data from SN1987A, I argue that the inverted mass hierarchy is disfavored by the data