10,627 research outputs found

    Precision Measurement of sin^2 theta_W at a Reactor

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    This paper presents a strategy for measuring sin^2 theta_W to ~1% at a reactor-based experiment, using antineutrinos electron elastic scattering. This error is comparable to the NuTeV, SLAC E158, and APV results on sin^2 theta_W, but with substantially different contributions to the systematics. An improved method for identifying antineutrino proton events, which serve both as a background and as a normalization sample, is described. The measurement can be performed using the near detector of the presently proposed reactor-based oscillation experiments. We conclude that an absolute error of delta(sin^2 theta_W)=0.0019 may be achieved.Comment: To be Submitted to Phys. Rev.

    Using Reactors to Measure θ13\theta_{13}

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    A next-generation neutrino oscillation experiment using reactor neutrinos could give important information on the size of mixing angle θ13\theta_{13}. The motivation and goals for a new reactor measurement are discussed in the context of other measurements using off-axis accelerator neutrino beams. The reactor measurements give a clean measure of the mixing angle without ambiguities associated with the size of the other mixing angles, matter effects, and effects due to CP violation. The key question is whether a next-generation experiment can reach the needed sensitivity goals to make a measurement for sin22θ13\sin^{2}2\theta_{13} at the 0.01 level. The limiting factors associated with a reactor disappearance measurement are described with some ideas of how sensitivities can be improved. Examples of possible experimental setups are presented and compared with respect to cost and sensitivity

    A strong ν¨ν˙\ddot{\nu} - \dot{\nu} correlation in radio pulsars with implications for torque variations

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    We present an analysis of the spin-down parameters for 131 radio pulsars for which ν¨\ddot\nu has been well determined. These pulsars have characteristic ages ranging from 10310810^{3} - 10^{8} yr and spin periods in the range 0.4--30 s; nearly equal numbers of pulsars have ν¨>0\ddot\nu>0 as ν¨<0\ddot\nu<0. We find a strong correlation of ν¨\ddot\nu with ν˙\dot{\nu}, {\em independent of the sign of} ν¨\ddot\nu. We suggest that this trend can be accounted for by small, stochastic deviations in the spin-down torque that are directly proportional (in magnitude) to the spin-down torque.Comment: MNRAS, 4 pages, 2 figures. Minor editorial changes and typos correcte

    Differential thresholds for motions in the periphery

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    Differential thresholds for rotary and linear motion in the peripher

    Pentaquark searches at FOCUS

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    We find no evidence for high-energy photoproduction of pentaquarks at 1540 MeV/c2c^2, 1862 MeV/c2c^2, or 3099 MeV/c2c^2 using decay modes pKS0pK_S^0, Ξπ\Xi^-\pi^-, and D()pD^{(*)-}p, respectively.Comment: Proceedings from talk at 2004 DPF Meeting at University of California, Riversid