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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Test of Lorentz and CPT violation with Short Baseline Neutrino Oscillation Excesses

The sidereal time dependence of MiniBooNE $ν_e$ and $\bar{ν}_e$ appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov–Smirnov (K–S) test shows both the $ν_e$ and $\bar{ν}_e$ appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the $ν_e$ appearance data prefer a sidereal time-independent solution, and the $\bar{ν}_e$ appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10-20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for $ν_μ$→$ν_e$ and $\bar{ν}_μ$→$\bar{ν}_e$ oscillations. The fit values and limits of combinations of SME coefficients are provided.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Long, Cold, Early r Process? Neutrino-Induced Nucleosynthesis in He Shells Revisited

We revisit a {nu}-driven r-process mechanism in the He shell of a core-collapse supernova, finding that it could succeed in early stars of metallicity Z < or approx. 10{sup -3}Z{sub {center_dot}}, at relatively low temperatures and neutron densities, producing A{approx}130 and 195 abundance peaks over {approx}10-20 s. The mechanism is sensitive to the {nu} emission model and to {nu} oscillations. We discuss the implications of an r process that could alter interpretations of abundance data from metal-poor stars, and point out the need for further calculations that include effects of the supernova shock.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗