140089864
Critical current, electro-mechanical properties and specific heat of bronze Nb-3_Sn conductors
45704861
Evidence for neutrino oscillations from muon decay at rest.
A search for {bar {nu}}{sub {mu}}{r_arrow}{bar {nu}}{sub {ital e}} oscillations has been conducted at the Los Alamos Meson Physics Facility using {bar {nu}}{sub {mu}} from {mu}{sup +} decay at rest. The {bar {nu}}{sub {ital e}} are detected via the reaction {bar {nu}}{sub {ital ep}}{r_arrow}{ital e}{sup +}{ital n}, correlated with the 2.2 MeV {gamma} from {ital np}{r_arrow}{ital d}{gamma}. The use of tight cuts to identify {ital e}{sup +} events with correlated {gamma} rays yields 22 events with {ital e}{sup +} energy between 36 and 60MeV and only 4.6{plus_minus}0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1{times}10{sup {minus}8}. A {chi}{sup 2} fit to the entire {ital e}{sup +} sample results in a total excess of 51.0{sub {minus}19.5}{sup +20.2}{plus_minus}8.0 events with {ital e}{sup +} energy between 20 and 60MeV. If attributed to {bar {nu}}{sub {mu}}{r_arrow}{bar {nu}}{sub {ital e}} oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of (0.31{plus_minus}0.12{plus_minus}0.05){percent}. {copyright} {ital 1996 The American Physical Society.}
10036888
Measurement of the kaon content of three-prong tau decays.
We present branching fraction measurements of three-prong decays of the [tau][sup [minus]] lepton based on data from the TPC/Two-Gamma detector at SLAC PEP. The decays are classified according to the identities of the charged tracks to give simultaneous measurements of [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][pi][sup +][pi][sup [minus]]]=0.58[sub [minus]0.13][sup +0.15]% and [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][ital K][sup +][pi][sup [minus]]]=0.15[sub [minus]0.07][sup +0.09]%, and upper limits of [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]][pi][sup [minus]][ital K][sup +][pi][sup [minus]]][lt]0.25%, [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][pi][sup +][ital K][sup [minus]]][lt]0.09%, and [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][ital K][sup +][ital K][sup [minus]]][lt]0.21%, where additional neutrals may be present in each case. The branching fractions are normalized to the world average three-prong topological branching fraction and there is an estimated 20% systematic error in addition to the listed statistical errors. We find the mass distributions in the [ital K][sup [minus]][pi][sup +][pi][sup [minus]] decay are consistent with [ital K][sub 1] dominance, and obtain branching fractions of [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sub 1][sup [minus]](1270)]=0.41[sub [minus]0.35][sup +0.41]% and [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sub 1][sup [minus]](1400)]=0.76[sub [minus]0.33][sup +0.40]%.
18317704
Measurement of Tau branching ratios
Using the data accumulated at LEP in 1989 and 1990 with the ALEPH detector, the inclusive and exclusive branching ratios of the τ lepton have been measured assuming lepton universality inZ0 decays. The inclusive branching fractions for the τ decay into one, three, and five charged particles have been determined to be (85.45±0.97)%, (14.35±0.48)%, and (0.10±0.05)%, respectively, in agreement with the world averages. New undetected decay modes are determined to have a branching fraction of less than 2.1% at 95% CL. The measured branching ratios for quasi-exclusive channels are slightly larger than, but consistent with the world averages, except for the modes τ→3 hadrons+vτ andτ→hadron+2π0vτ, which are significantly larger. These latter branching ratios have been found to be (9.5±0.7)% and (10.2±1.1)%, respectively. The sum of all the measured quasi-exclusive branching ratios is (100.4±1.8)%. A fully exclusive analysis of modes with neutral pions shows no evidence for new photonic decay modes with a branching fraction limit of 3.4% at 95% CL.
16829835
Prospect of a very long baseline neutrino oscillation experiment HIPA to Beijing
We discuss the prospects of a very long baseline neutrino oscillation experiment from HIPA to Beijing. The current understanding of neutrino oscillations, both theoretically and experimentally, are summarized. The figure of merits for interested physics measurements are defined and compared at different distances: 300 km, 700 km, 2100 km and 3000 km. We conclude that a baseline more than 2100 km is optimal. A large water cerenkov calorimeter was proposed and its performance is satisfactory from a Monte Carlo simulation study. Such a large detector can do many other measurements on cosmic-rays physics and astrophysics.
240158
Constraints on Extra Dimensions From Cosmological and Terrestrial Measurements
If quantum fields exist in extra compact dimensions, they will give rise to a quantum vacuum or Casimir energy. That vacuum energy will manifest itself as a cosmological constant. The fact that supernova and cosmic microwave background data indicate that the cosmological constant is of the same order as the critical mass density to close the universe supplies a lower bound on the size of the extra dimensions. Recent laboratory constraints on deviations from Newton's law place an upper limit. The allowed region is so small as to suggest that either extra compact dimensions do not exist, or their properties are about to be tightly constrained by experimental data.
73704898
A New Design for ILC 3.2 km Damping Ring Based on FODO Cell
In this paper, we made a new design for ILC 3.2 km damping ring with 2 arcs based on FODO cell and 2 straight sections which are nearly the same as the new version of the 6.4 km ring DCO4 [1]. This new lattice uses less magnets than DCO4 and less quadrupoles than the present SuperB like lattice [1], and has a freely tunable momentum compaction factor. The work of lattice design and dynamic aperture study will be presented in detail. INTRODUCTION After ILC enter the Technical Design Phase 1 by the end of 2008, the Minimum Machine study [2] based on RDR baseline was launched as the essential strategy of cost-reduction. The term “minimum machine” which try to redesign the machine does not refer to any definable true minimum, but instead is a euphemism for higher level alternative design concepts which promise significant cost-reduction while maintaining the machine performance. With the new machine parameter, a reduction in the number of bunches by a factor of two allows a reduction by the same factor in the circumference of the damping ring, while keeping the current (bunch spacing) in the rings constant. To first order, this could result in a reduction of the damping rings’ cost by almost a factor of two. However, the actual cost savings will depend on the exact lattice design. The design study of ILC 6 km damping ring has started very early and gone through intense competition. The 6.4 km DCO4 based on FODO arc cell is the final version adopted by RDR baseline in 2008. But for the 3.2 km ring, the study which was started by the end of 2008 seems to be immature. The only existent design for the smaller ring is DSB3 based on SuperB lattice. Considering the advantage of FODO lattice such as smaller number of quadrupoles and sextupoles per cell, freely tuable momentum compaction, and better dynamic aperture, we try to make a new design for the smaller ring using FODO arc cell which can also provide a reference for DSB3 design. We named our new design as DMC1 for convenience. GLOBAL CONSIDERATION AND PARAMETER CALCULATION In our design, we adopted the racetrack structure as the 6.4 km baseline design (DCO4). The layout of our 3.2 km damping ring is shown in Figure 1 with the electron and positron beams counter-rotating in the two rings. The advantage of this kind of structure is that the ————————————— injection and extraction beam lines for e+ and erings can be in the same tunnel. Also, the rf section and wigglers are located near each other in order to minimize cryogenic transfer lines, while the rf section must be upstream to avoid the radiation damage. Figure 1: Layout of the 3.2 km ILC damping ring. The first parameter should be considered before lattice design is the damping time. ILC damping ring has a very fast damping time (about 25 ms) which is decided by the 5 Hz machine repetition rate. The damping time for a damping ring is given by [3]
1289258
Energetic electrons associated with magnetic reconnection in the magnetic cloud boundary layer.
Here is reported in situ observation of energetic electrons (∼100-500 keV) associated with magnetic reconnection in the solar wind by the ACE and Wind spacecraft. The properties of this magnetic cloud driving reconnection and the associated energetic electron acceleration problem are discussed. Further analyses indicate that the electric field acceleration and Fermi-type mechanism are two fundamental elements in the electron acceleration processes and the trapping effect of the specific magnetic field configuration maintains the acceleration status that increases the totally gained energy.
16037890
Supersymmetric black rings and non-linear sigma models
In this paper we investigate the non-linear sigma model arising in the reduction of D=5 supergravity to D=3, and present the application of this sigma model to supersymmetric black ring solutions in five-dimensional minimal supergravity. With the ansatz of stationary solutions with R×U(1)×U(1) isometry, we obtain a two-dimensional Lagrangian corresponding to geodesic motion of a string-like object on the coset G2(+2)/SO(4), and study the algebra of conserved charges and supersymmetry constraints of supersymmetric black ring.