45 research outputs found

    Neutrino Physics: an Update

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    We update our recent didactic survey of neutrino physics, including new results from the Sudbury Neutrino Observatory and KamLAND experiments, and recent constraints from WMAP and other cosmological probes.Comment: latex; 19 pages; five figure

    Neutrino Physics

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    The basic concepts of neutrino physics are presented at a level appropriate for integration into elementary courses on quantum mechanics and/or modern physics.Comment: Prepared for the American Journal of Physics; 50 pages; 11 figures (10 included); late

    SHEDDING NEW LIGHT ON EXPLODING STARS: TERASCALE SIMULATIONS OF NEUTRINO-DRIVEN SUPERNOVAE AND THEIR NUCLEOSYNTHESIS

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    This project was focused on simulations of core-collapse supernovae on parallel platforms. The intent was to address a number of linked issues: the treatment of hydrodynamics and neutrino diffusion in two and three dimensions; the treatment of the underlying nuclear microphysics that governs neutrino transport and neutrino energy deposition; the understanding of the associated nucleosynthesis, including the r-process and neutrino process; the investigation of the consequences of new neutrino phenomena, such as oscillations; and the characterization of the neutrino signal that might be recorded in terrestrial detectors. This was a collaborative effort with Oak Ridge National Laboratory, State University of New York at Stony Brook, University of Illinois at Urbana-Champaign, University of California at San Diego, University of Tennessee at Knoxville, Florida Atlantic University, North Carolina State University, and Clemson. The collaborations tie together experts in hydrodynamics, nuclear physics, computer science, and neutrino physics. The University of Washington contributions to this effort include the further development of techniques to solve the Bloch-Horowitz equation for effective interactions and operators; collaborative efforts on developing a parallel Lanczos code; investigating the nuclear and neutrino physics governing the r-process and neutrino physics; and exploring the effects of new neutrino physics on the explosion mechanism, nucleosynthesis, and terrestrial supernova neutrino detection

    The second-phase development of the China JinPing underground Laboratory

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    During 2013-2015 an expansion of the China JinPing underground Laboratory (CJPL) will be undertaken along a main branch of a bypass tunnel in the JinPing tunnel complex. This second phase of CJPL will increase laboratory space to approximately 96,000 m^3, which can be compared to the existing CJPL-I volume of 4,000 m^3. One design configuration has eight additional hall spaces, each over 60 m long and approximately 12 m in width, with overburdens of about 2.4 km of rock, oriented parallel to and away from the main water transport and auto traffic tunnels. Concurrent with the excavation activities, planning is underway for dark matter and other rare-event detectors, as well as for geophysics/engineering and other coupled multi-disciplinary sensors. In the town meeting on 8 September, 2013 at Asilomar, CA, associated with the 13th International Conference on Topics in Astroparticle and Underground Physics (TAUP), presentations and panel discussions addressed plans for one-ton expansions of the current CJPL germanium detector array of the China Darkmatter EXperiment (CDEX) collaboration and of the duel-phase xenon detector of the Panda-X collaboration, as well as possible new detector initiatives for dark matter studies, low-energy solar neutrino detection, neutrinoless double beta searches, and geoneutrinos. JinPing was also discussed as a site for a low-energy nuclear astrophysics accelerator. Geophysics/engineering opportunities include acoustic and micro-seismic monitoring of rock bursts during and after excavation, coupled-process in situ measurements, local, regional, and global monitoring of seismically induced radon emission, and electromagnetic signals.Comment: 9 pages, 3 figures. 13th International Conference on Topics in Astroparticle and Underground Physics, TAUP 201

    Neutrino physics: An update

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    The Gallium Anomaly

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    In order to test the end-to-end operations of gallium solar neutrino experiments, intense electron-capture sources were fabricated to measure the responses of the radiochemical SAGE and GALLEX/GNO detectors to known fluxes of low-energy neutrinos. Such tests were viewed at the time as a cross-check, given the many tests of 71^{71}Ge recovery and counting that had been routinely performed, with excellent results. However, the four 51^{51}Cr and 37^{37}Ar source experiments yielded rates below expectations, a result commonly known as the Ga anomaly. As the intensity of the electron-capture sources can be measured to high precision, the neutrino lines they produce are fixed by known atomic and nuclear rates, and the neutrino absorption cross section on 71^{71}Ga is tightly constrained by the lifetime of 71^{71}Ge, no simple explanation for the anomaly has been found. To check these calibration experiments, a dedicated experiment BEST was performed, utilizing a neutrino source of unprecedented intensity and a detector optimized to increase statistics while providing some information on counting rate as a function of distance from the source. The results BEST obtained are consistent with the earlier solar neutrino calibration experiments, and when combined with those measurements, yield a Ga anomaly with a significance of approximately 4σ4\sigma, under conservative assumptions. But BEST found no evidence of distance dependence and thus no explicit indication of new physics. In this review we describe the extensive campaigns carried out by SAGE, GALLEX/GNO, and BEST to demonstrate the reliability and precision of their experimental procedures, including 71^{71}Ge recovery, counting, and analysis. We also describe efforts to define uncertainties in the neutrino capture cross section. With the results from BEST, an anomaly remains.Comment: Invited submission to Progress in Particle and Nuclear Physic

    A Mathematica script for harmonic oscillator nuclear matrix elements arising in semileptonic electroweak interactions

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    Semi-leptonic electroweak interactions in nuclei - such as \beta decay, \mu capture, charged- and neutral-current neutrino reactions, and electron scattering - are described by a set of multipole operators carrying definite parity and angular momentum, obtained by projection from the underlying nuclear charge and three-current operators. If these nuclear operators are approximated by their one-body forms and expanded in the nucleon velocity through order |\vec{p}|/M, where \vec{p} and M are the nucleon momentum and mass, a set of seven multipole operators is obtained. Nuclear structure calculations are often performed in a basis of Slater determinants formed from harmonic oscillator orbitals, a choice that allows translational invariance to be preserved. Harmonic-oscillator single-particle matrix elements of the multipole operators can be evaluated analytically and expressed in terms of finite polynomials in q^2, where q is the magnitude of the three-momentum transfer. While results for such matrix elements are available in tabular form, with certain restriction on quantum numbers, the task of determining the analytic form of a response function can still be quite tedious, requiring the folding of the tabulated matrix elements with the nuclear density matrix, and subsequent algebra to evaluate products of operators. Here we provide a Mathematica script for generating these matrix elements, which will allow users to carry out all such calculations by symbolic manipulation. This will eliminate the errors that may accompany hand calculations and speed the calculation of electroweak nuclear cross sections and rates. We illustrate the use of the new script by calculating the cross sections for charged- and neutral-current neutrino scattering in ^{12}C.Comment: 15 pages, 2 tables, Mathematica notebook included in the form of figures. Mathematica package and documentation available at http://www.int.washington.edu/users/lunardi/7o.htm. Replaced version has improved graphics; text unchange

    From Hadrons to Nuclei: Crossing the Border

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    The study of nuclei predates by many years the theory of quantum chromodynamics. More recently, effective field theories have been used in nuclear physics to ``cross the border'' from QCD to a nuclear theory. We are now entering the second decade of efforts to develop a perturbative theory of nuclear interactions using effective field theory. This work describes the current status of these efforts.Comment: 141 pages, 58 figs, latex. To appear in the Boris Ioffe Festschrift, ed. by M. Shifman, World Scientifi
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