Search

This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.

The glueball-to-vacuum matrix elements of local gluonic operators in scalar, tensor, and pseudoscalar channels are investigated numerically on several anisotropic lattices with the spatial lattice spacing ranging from 0.1–0.2 fm. These matrix elements are needed to predict the glueball branching ratios in J/ψ radiative decays which will help identify the glueball states in experiments. Two types of improved local gluonic operators are constructed for a self-consistent check and the finite-volume effects are studied. We find that lattice spacing dependence of our results is very weak and the continuum limits are reliably extrapolated, as a result of improvement of the lattice gauge action and local operators. We also give updated glueball masses with various quantum numbers.

The Daya Bay Reactor Neutrino Experiment has measured a non-zero value for the neutrino mixing angle $\theta_{13}$ with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GW$_{\rm th}$ 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-GW_{\rm th}-day livetime exposure in 55 days, 10416 (80376) 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 $R=0.940\pm 0.011({\rm stat}) \pm 0.004({\rm syst})$. A rate-only analysis finds $\sin^22\theta_{13}=0.092\pm 0.016({\rm stat})\pm0.005({\rm syst})$ in a three-neutrino framework., Comment: 5 figures. Version to appear in Phys. Rev. Lett

We examine the possibility of embedding a 17-keV neutrino in a left-right model with three generations of left- and right-handed neutrinos. In particular, we study scenarios where the 17-keV neutrino is a pseudo Dirac neutrino and its mass is generated radiatively. Two heavy right-handed neutrinos have their mass scale set by the SU(2)[sub [ital R]]-breaking scale, and the two light-neutrino masses are then determined by a seesaw mechanism. This scenario requires new Higgs bosons beyond those necessary in a minimal left-right model. The left-right symmetry leads to relations between the charged- and neutral-lepton mass matrices. We examine the constraints on the model from charged-lepton masses, leptonic flavor-changing neutral currents, neutrino data, cosmology, and astrophysics.

The production of the neutral technicolor pseudo Goldstone bosons ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ at large transverse momentum in pp\ifmmode\bar\else\textasciimacron\fi{} collisions, pp\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}g(q)${\mathrm{P}}^{0\ensuremath{'}}$(${\mathrm{P}}_{8}^{0\ensuremath{'}}$)X, has been investigated at the Superconducting Super Collider (SSC) energy. The major two-body and three-body decay modes in tree diagrams are also investigated in detail. The tt\ifmmode\bar\else\textasciimacron\fi{} decay channel would dominate the decays of both ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ if it is allowed. Otherwise, gg and 3g will be the dominant decay modes unless the mass of the ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ are below 40 GeV, where bb\ifmmode\bar\else\textasciimacron\fi{} becomes dominant. The tt\ifmmode\bar\else\textasciimacron\fi{} channel will be the ideal signal for detecting these bosons since the signal is much larger than the QCD background. However, in the absence of the tt\ifmmode\bar\else\textasciimacron\fi{} channel, the \ensuremath{\tau}\ensuremath{\tau}\ifmmode\bar\else\textasciimacron\fi{} mode can be used to identify ${\mathrm{P}}^{0\ensuremath{'}}$ up to ${\mathrm{m}}_{\mathrm{P}}$=300 GeV in the transverse-momentum range ${\mathrm{P}}_{\mathrm{\ensuremath{\perp}}}$\ensuremath{\lesssim}100 GeV. Similarly, the bb\ifmmode\bar\else\textasciimacron\fi{} decay mode can serve as a useful signal for the identification of ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ up to ${\mathrm{m}}_{\mathrm{P}}$=300 GeV for ${\mathrm{P}}_{\mathrm{\ensuremath{\perp}}}$ between 500 and 700 GeV. Our results show that these high-transverse-momentum production processes are useful in searching for the ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ at the SSC.

Carolina Rinse Solution (CRS) was applied topically and intraluminally to ischaemic (Group 1; n = 5) and distended equine jejunum (Group 2; n = 5). Mesenteric blood flow, ORC (osmotic reflection coefficient), wet weight to dry weight ratios (WW/DW), serosal thickness, and neutrophil accumulation in the serosa were measured. After 60 min ischaemia followed by reperfusion (Group 1), mesenteric blood flow remained greater than baseline values. The mean ORC was similar to that previously reported in normal bowel or ischaemic intestine treated with CRS by arterial perfusion. The ORC after distention and decompression (Group 2) increased and was similar to that previously reported in a comparable untreated experimental model. The WW/DW after both ischaemia and distention increased compared to specimens collected from noninstrumented jejunum proximal to the experimental segments in the same horses. There was no difference in neutrophil numbers in the serosa of either ischaemic or distended intestine compared to the noninstrumented proximal jejunum. CRS-treated ischaemic intestine maintained microvascular permeability similar to that reported for normal intestine whereas treated distended intestine did not. Combined topical and intraluminal application of CRS to ischaemic intestine may reduce complications due to acute inflammation during reperfusion.

The authors studies the cognitive, affective, and functional status of 172 mentally healthy patients, age 55 and older, who were undergoing elective surgery under general anesthesia. Patients were interviewed before and after surgery; this report focuses on changes 1 month postoperatively. Authors compared the mental status and function of 190 nonsurgical patients of comparable age. Surgical patients showed a temporary functional decline. Linear regression predictors of affective, cognitive, and functional change at follow-up included demographics, baseline measures of mental status and function, surgery type, and intraoperative measures. Longer duration of anesthesia--but not type of surgery--predicted short-term decline in activities of daily living but not cognition or affect. Authors discuss results in the context of previous findings in which surgery had no impact on mental status or function at 10-month follow-up.

This supporting document contains a database of waste transactions and waste status reports for all the waste tanks in the northeast quadrant of the 200 Area of the Hanford Site.

This supporting document contains a database of waste transactions and waste status reports for all the waste tanks in the northwest quadrant of the 200 West Area of the Hanford Site.

Direct production of positron-electron pairs is reported for 360-GeV/c pions incident on the Fermilab 30-in. hydrogen bubble chamber. These high-energy data are the first with liquid hydrogen, and are shown to be in agreement with quantum-electrodynamic calculations. For the region of four-momentum transfer considered, quantum electrodynamics predicts essentially equal contributions from production in the Coulomb field of the nucleus and the atomic electron. (AIP)

The existence of vector mesons with masses above 3 GeV suggests study of their contributions to the Compton sum rule. The Compton sum rule is used to place upper limits on photoproduction cross sections for such recently discovered and yet to be found J/sup p/ = 1$sup -$ particles. We are led to the result that the total proton photoabsorption cross section and forward Compton-scattering cross section will rise in the range of energies available for photon experiments at the Fermilab accelerator. Discussion is given on the implications of such a rising photon--proton cross section for vector-meson dominance (VMD), the quark model, generalized VMD, and the new duality, and for scaling breaking. (AIP)