120548922
EXPERIMENTAL LIMITS ON THE PRODUCTION OF EXCITED LEPTONS AND STABLE HEAVY-LEPTONS
The results are reported of a search for excited muons (..mu..*) and electrons (e*) and for a stable charged heavy lepton by measurements of the e/sup +/e/sup -/..--> mu../sup +/..mu../sup -/, ..mu../sup +/..mu../sup -/..gamma.., ..mu../sup +/..mu../sup -/..gamma gamma.., and ..gamma gamma.. final states. Excluded are large regions of the lambda (coupling constant), M (mass) planes for spin-(1/2) ..mu..* and e*, and a new stable charged heavy lepton with mass<14 GeV.
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.
140089864
Critical current, electro-mechanical properties and specific heat of bronze Nb-3_Sn conductors
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]%.
125293645
EXPERIMENTAL STUDY OF HEAVY CHARGED LEPTONS AT PETRA
18463747
THE LIQUID SCINTILLATOR NEUTRINO DETECTOR AND LAMPF NEUTRINO SOURCE
Abstract A search for neutrino oscillations of the type ν μ → ν c has been conducted at the Los Alamos Meson Physics Facility using ν μ from muon decay at rest. Evidence for this transition has been reported previously. This paper discusses in detail the experimental setup, detector operation and neutrino source, including aspects relevant to oscillation searches in the muon decay-at-rest and pion decay in flight channels.
15809159
Evidence for weak lensing of supernovae
Due to the deflection of light by density fluctuations along the line of sight, weak lensing is an unavoidable systematic uncertainty in the use of type Ia supernovae (SNe Ia) as cosmological distance indicators. We derive the expected weak lensing signatures of SNe Ia by convolving the intrinsic distribution in SN Ia peak luminosity with magnification distributions of point sources. We find that current SN Ia data at high z show both the presence of a non-Gaussian tail at the bright end (possibly due to high magnifications), and a faint-ward shift of the peak of the distribution (possibly due to demagnifications). Weak lensing effect may have begun to set in as a non-negligible systematic uncertainty in the use of SNe Ia as a cosmological probe, and should be minimized by flux-averaging. Subject headings: cosmology: observations—cosmology: theory—gravitational lensing
118863203
One-side forward-backward asymmetry in top quark pair production at the CERN Large Hadron Collider
Both D0 and CDF at Tevatron reported the measurements of forward-backward asymmetry in top pair production, which showed possible deviation from the standard model QCD prediction. In this paper, we explore how to examine the same higher-order QCD effects at the more powerful Large Hadron Collider.
118431292
One-side forward-backward asymmetry at the LHC
Forward-backward asymmetry AFB is an essential observable to study the nature of coupling in the standard model and physics beyond the standard model, as shown at LEP and Tevatron. As a proton-proton collider, the LHC does not have the preferred direction contrary to her counterpart, namely, LEP and Tevatron. Therefore AFB is not applicable at the LHC. However for the proton the momentum of valence quark is usually larger than that of the sea quark. Utilizing this feature we have defined a so-called one-side forward-backward asymmetry AOFB for the top quark pair production at LHC in the previous work. In this paper we extend our studies to the charged leptons and bottom quarks as the final states. Our numerical results show that at the LHC AOFB can be utilized to study the nature of the couplings once enough events are collected.
116061767
20 MeV Electron Linear Accelerator in Nanjing University
32300667
Non-relativistic Josephson junction from holography
A bstractWe construct a Josephson junction in non-relativistic case with a Lifshitz geometry as the dual gravity. We investigate the effect of the Lifshitz scaling in comparison with its relativistic counterpart. The standard sinusoidal relation between the current and the phase difference is found for various Lifshitz scalings characterised by the dynamical critical exponent. We also find the exponential decreasing relation between the condensate of the scalar operator within the barrier at zero current and the width of the weak link, as well as the relation between the critical current and the width. Nevertheless, the coherence lengths obtained from two exponential decreasing relations generically have discrepancies for non-relativistic dual.