1,408 research outputs found
On the Sensitivity of a Hollow Sphere as a Multi-modal Resonant Gravitational Wave Detector
We present a numerical analysis to simulate the response of a spherical
resonant gravitational wave detector and to compute its sensitivity. Under the
assump- tion of optimal filtering, we work out the sensitivity curve for a
sphere first taking into account only a single transducer, and then using a
coherent analysis of the whole set of transducers.Comment: 24 pages, 11 figures, published versio
Neutron optical beam splitter from holographically structured nanoparticle-polymer composites
We report a breakthrough in the search for versatile diffractive elements for
cold neutrons. Nanoparticles are spatially arranged by holographical means in a
photopolymer. These grating structures show remarkably efficient diffraction of
cold neutrons up to about 50% for effective thicknesses of only 200 micron.
They open up a profound perspective for next generation neutron-optical devices
with the capability to tune or modulate the neutron diffraction efficiency.Comment: 4 pages, 2 figure
Measurement of Exclusive rho^0 rho^0 Production in Two-Photon Collisions at High Q^2 at LEP
Exclusive rho rho production in two-photon collisions involving a single
highly virtual photon is studied with data collected at LEP at centre-of-mass
energies 89GeV < \sqrt{s} < 209GeV with a total integrated luminosity of
854.7pb^-1 The cross section of the process gamma gamma^* -> rho rho is
determined as a function of the photon virtuality, Q^2 and the two-photon
centre-of-mass energy, Wgg, in the kinematic region: 1.2GeV^2 < Q^2 < 30GeV^2
and 1.1GeV < Wgg < 3GeV
Search for antihelium in cosmic rays
The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle
Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320
and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity
range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper
limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.Comment: 18 pages, Latex, 9 .eps figure
Search for a Higgs Boson Decaying to Weak Boson Pairs at LEP
A Higgs particle produced in association with a Z boson and decaying into
weak boson pairs is searched for in 336.4 1/pb of data collected by the L3
experiment at LEP at centre-of-mass energies from 200 to 209 GeV. Limits on the
branching fraction of the Higgs boson decay into two weak bosons as a function
of the Higgs mass are derived. These results are combined with the L3 search
for a Higgs boson decaying to photon pairs. A Higgs produced with a Standard
Model e+e- --> Zh cross section and decaying only into electroweak boson pairs
is excluded at 95% CL for a mass below 107 GeV
A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01
The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics
experiment that will study cosmic rays in the to range and will be installed on the International Space Station
(ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the
space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected
cosmic ray triggers. Part of the \emph{Mir} space station was within the
AMS-01 field of view during the four day \emph{Mir} docking phase of this
flight. We have reconstructed an image of this part of the \emph{Mir} space
station using secondary and emissions from primary cosmic rays
interacting with \emph{Mir}. This is the first time this reconstruction was
performed in AMS-01, and it is important for understanding potential
backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor
stylistic and grammer change
Search for an invisibly decaying Higgs boson in e^+e^- collisions at \sqrt{s} = 183 - 189 GeV
A search for a Higgs boson decaying into invisible particles is performed
using the data collected at LEP by the L3 experiment at centre-of-mass energies
of 183 GeV and 189 GeV. The integrated luminosities are respectively 55.3 pb^-1
and 176.4 pb^-1. The observed candidates are consistent with the expectations
from Standard Model processes. In the hypothesis that the production cross
section of this Higgs boson equals the Standard Model one and the branching
ratio into invisible particles is 100%, a lower mass limit of 89.2 GeV is set
at 95% confidence level
Measurement of the Tau Branching Fractions into Leptons
Using data collected with the L3 detector near the Z resonance, corresponding
to an integrated luminosity of 150pb-1, the branching fractions of the tau
lepton into electron and muon are measured to be
B(tau->e nu nu) = (17.806 +- 0.104 (stat.) +- 0.076 (syst.)) %,
B(tau->mu nu nu) = (17.342 +- 0.110 (stat.) +- 0.067 (syst.)) %.
From these results the ratio of the charged current coupling constants of the
muon and the electron is determined to be g_mu/g_e = 1.0007 +- 0.0051. Assuming
electron-muon universality, the Fermi constant is measured in tau lepton decays
as G_F = (1.1616 +- 0.0058) 10^{-5} GeV^{-2}. Furthermore, the coupling
constant of the strong interaction at the tau mass scale is obtained as
alpha_s(m_tau^2) = 0.322 +- 0.009 (exp.) +- 0.015 (theory)
Higgs Candidates in e+e- Interactions at root(s) = 206.6 GeV
In a search for the Standard Model Higgs boson, carried out on 212.5 pb-1 of
data collected by the L3 detector at the highest LEP centre-of-mass energies,
including 116.5 pb-1 above root(s) = 206GeV, an excess of candidates for the
process e+e- -> Z* -> HZ is found for Higgs masses near 114.5GeV. We present an
analysis of our data and the characteristics of our strongest candidates.Comment: Footnote added, matches the version to be published in Physics
Letters
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