16580300
Observation of electron-antineutrino disappearance at Daya Bay.
The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GWth reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43,000 ton-GWth-day live-time exposure in 55 days, 10,416 (80,376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940±0.011(stat.)±0.004(syst.). A rate-only analysis finds sin(2)2θ(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework.
119955860
Improved calculation of the energy release in neutron-induced fission
Fission energy is one of the basic parameters needed in the calculation of antineutrino ux from nuclear reactors. Improving the precision of ssion energy calculations is useful for current and future reactor neutrino experiments, which are aimed at more precise determinations of neutrino oscillation parameters. In this article, we give new values for ssion energies of some common thermal reactor fuel isotopes, with improvements on three aspects. One is more recent input data acquired from updated nuclear databases. The second improvement is a consideration of the production yields of ssion fragments from both thermal and fast incident neutrons for each of the four main fuel isotopes. The third improvement is a more careful calculation of the average energy taken away by antineutrinos in thermal ssion involving a comparison of antineutrino spectra from dierent models. The change in calculated antineutrino ux due to the new values of ssion energy is about 0.32%, and the uncertainties of the new values are about 50% smaller.
123724946
Expression of interest to the Superconducting Super Collider Laboratory by the L* Collaboration
117769557
Inclusive $\mu$ and $B$ quark production cross-sections in $p\bar{p}$ collisions at $\sqrt{s} = 1.8$ TeV
We report on a preliminary measurement of the inclusive dimuon cross section in p{bar p} collisions at {radical}s = 1.8 TeV using the D0 detector at the Fermilab Tevatron. From these results, we extract the inclusive b-quark production cross section for the kinematic range {vert_bar}y{sup b}{vert_bar} < 1.0 and 9 GeV/c < p{sub T}{sup b min} < 25 GeV/c. The difference in azimuthal angle in the transverse plane for dimuon pairs from b{bar b} production is also shown.
118534712
Nonlinear realization of spontaneously broken N = 1 supersymmetry revisited
This paper revisits the nonlinear realization of spontaneously broken N = 1 supersymmetry. It is shown that the constrained superfield formalism as proposed in [6] can be reinterpreted in the language of standard realization of nonlinear supersymmetry via a new and simpler route. Explicit formulas of actions are presented for general renormalizable theories with or without gauge interactions. The nonlinearWess-Zumino gauge is discussed and relations are pointed out for different definitions of gauge fields. In addition, a general procedure is provided to deal with theories of arbitrary Kahler potentials.
119251292
Leakage tests of the stainless steel vessels of the antineutrino detectors in the Daya Bay reactor neutrino experiment
The antineutrino detectors for the Daya Bay reactor neutrino experiment are liquid scintillator detectors designed to detect electron anti-neutrino via inverse beta interactions with high efficiency and low backgrounds. Since the antineutrino detector will be installed and immerged in water Cherenkov detector and will run for 3 to 5 years, water tightness is critical to the successful operation of the antineutrino detectors. A special seal technique was used for this purpose. Three leak checking methods have been employed to ensure the seal quality. This paper describes the sealing method and leakage testing results.
119107111
The Goldstino field in linear and nonlinear realizations of supersymmetry
Abstract A Goldstino field in the nonlinear realization of supersymmetry is constructed from an appropriate chiral super-multiplet of the linear theory, in general O'Raifeartaigh-like models. The linear theories can thus be reformulated into their nonlinear versions, via the standard procedure. The Goldstino field disappears totally from the original Lagrangian in the process, but reemerges in the Jacobian of the transformation and covariant derivatives. Vertices with Goldstino fields carry at least one space–time derivative, as one would have expected.
118513311
Cosmological perturbations from a Spectator field during inflation
In this paper we will discuss analytically the perturbations created from a slowly rolling subdominant spectator field which decays much before the end of inflation. The quantum fluctuations of such a spectator field can seed perturbations on very large scales and explain the temperature anisotropy in the cosmic microwave background radiation with moderate non-Gaussianity, provided the relevant modes leave the Hubble patch while the spectator is slowly rolling. Furthermore, the perturbations are purely adiabatic since the inflaton decay dominates and creates all the Standard Model degrees of freedom. We will provide two examples for the spectator field potential, one with a step function profile, and the other with an inflection point. In both the cases we will compute higher order curvature perturbations, i.e. local bispectrum and trispectrum, which can be constrained by the forthcoming Planck data.
118448708
Dark matter constraints on the left-right symmetric model with Z(2) symmetry
In the framework of the left-right symmetric model, we investigate an interesting scenario, in which the so-called vacuum expectation value (VEV)-seesaw problem can be naturally solved with Z(2) symmetry. In such a scenario, we find a pair of stable weakly interacting massive particles (WIMPs), which may be the cold dark matter candidates. However, the WIMP-nucleon cross section is 3-5 orders of magnitude above the present upper bounds from the direct dark matter detection experiments for m similar to 10(2)-10(4) GeV. As a result, the relic number density of two stable particles has to be strongly suppressed to a very small level. Nevertheless, our analysis shows that this scenario cannot provide very large annihilation cross sections so as to give the desired relic abundance except for the resonance case. Only for the case if the rotation curves of disk galaxies are explained by the modified Newtonian dynamics (MOND), the stable WIMPs could be as the candidates of cold dark matter.