11,073 research outputs found
Construction and commissioning of the SDHCAL technological prototype
International audienceThis proceeding presents the SDHCAL technological prototype. This prototype is a 1 1 1:3m3 high-granularity semi-digital Hadronic calorimeter using GRPC as sensitive medium. It is one of the two HCAL options considered by the ILD collaboration to be proposed for the detector of the future International Linear Collider project. The prototype has been achieved and successfully operated within the CALICE collaboration. The prototype has all the features needed to meet the ILD requirements : power-pulsed embedded electronics, auto-triggering capability, cost-effective technology
Leptoquarks decaying to a top quark and a charged lepton at hadron colliders
We study the sensitivity of the Tevatron and the 7 TeV LHC to a leptoquark S
coupling to a top quark and a charged lepton L (= e, mu, or tau). For the
Tevatron, we focus on the case m_S < m_t, where the leptoquark pair production
cross section is large, and the decay is three-body: S --> W b L^{\pm}. We
argue that existing Tevatron observations could exclude m_S \lsim 160 GeV. For
m_S > m_t, we show that the LHC experiments with low integrated luminosity
could be sensitive to such leptoquarks decaying to tl^{\pm} with l= mu or tau.Comment: 13 pages, 6 figures, minor changes (typos
Magnetization Measurements on Single Crystals of Superconducting Ba0.6K0.4BiO3
Extensive measurements of the magnetization of superconducting single crystal
samples of Ba0.6K0.4BiO3} have been made using SQUID and cantilever force
magnetometry at temperatures ranging between 1.3 and 350 K and in magnetic
fields from near zero to 27 T. Hysteresis curves of magnetization versus field
allow a determination of the thermodynamic critical field, the reversibility
field, and the upper critical field as a function of temperature. The lower
critical field is measured seperately and the Ginzburg-Landau parameter is
found to be temperature dependent. All critical fields have higher T = 0 limits
than have been previously noted and none of the temperature dependence of the
critical fields follow the expected power laws leading to possible alternate
interpretation of the thermodynamic nature of the superconducting transition.Comment: 33 pages, 11 figures, accepted for publication in Philosophical
Magazine B on 7 August 1999. This paper supplies the experimental details for
the argument presented in our PRL 82 (1999) p. 4532-4535 (also at
cond-mat/9904288
Radio to Gamma-Ray Emission from Shell-type Supernova Remnants: Predictions from Non-linear Shock Acceleration Models
Supernova remnants (SNRs) are widely believed to be the principal source of
galactic cosmic rays. Such energetic particles can produce gamma-rays and lower
energy photons via interactions with the ambient plasma. In this paper, we
present results from a Monte Carlo simulation of non-linear shock structure and
acceleration coupled with photon emission in shell-like SNRs. These
non-linearities are a by-product of the dynamical influence of the accelerated
cosmic rays on the shocked plasma and result in distributions of cosmic rays
which deviate from pure power-laws. Such deviations are crucial to acceleration
efficiency and spectral considerations, producing GeV/TeV intensity ratios that
are quite different from test particle predictions. The Sedov scaling solution
for SNR expansions is used to estimate important shock parameters for input
into the Monte Carlo simulation. We calculate ion and electron distributions
that spawn neutral pion decay, bremsstrahlung, inverse Compton, and synchrotron
emission, yielding complete photon spectra from radio frequencies to gamma-ray
energies. The cessation of acceleration caused by the spatial and temporal
limitations of the expanding SNR shell in moderately dense interstellar regions
can yield spectral cutoffs in the TeV energy range; these are consistent with
Whipple's TeV upper limits on unidentified EGRET sources. Supernova remnants in
lower density environments generate higher energy cosmic rays that produce
predominantly inverse Compton emission at super-TeV energies; such sources will
generally be gamma-ray dim at GeV energies.Comment: 62 pages, AASTeX format, including 1 table and 11 figures, accepted
for publication in The Astrophysical Journal (Vol 513, March 1, 1999
Real time decoherence of Landau and Levitov quasi-particles in quantum Hall edge channels
Quantum Hall edge channels at integer filling factor provide a unique
test-bench to understand decoherence and relaxation of single electronic
excitations in a ballistic quantum conductor. In this Letter, we obtain a full
visualization of the decoherence scenario of energy (Landau) and time (Levitov)
resolved single electron excitations at filling factor . We show that
the Landau excitation exhibits a fast relaxation followed by spin-charge
separation whereas the Levitov excitation only experiences spin-charge
separation. We finally suggest to use Hong-Ou-Mandel type experiments to probe
specific signatures of these different scenarios.Comment: 14 pages, 8 figure
Vermont Price Variation Analysis
This analysis documents price variations across the state and suggests a process and methodology that the Vermont Green Mountain Care Board could use to set standard rates. The report determined that inpatient prices among Vermont\u27s 14 hospitals and Dartmouth-Hitchcock Medical Center in New Hampshire vary from 71 to 130 percent of the state average. The analysis identified a number of factors that explain some variation in professional prices among providers and also showed there is no consistency in the share of variation explained by each factor across health services
Long Range Scattering and Modified Wave Operators for some Hartree Type Equations
We study the theory of scattering for a class of Hartree type equations with
long range interactions in space dimension n > 2, including Hartree equations
with potential V(x) = lambda |x|^{- gamma} with gamma < 1. For 1/2 < gamma < 1
we prove the existence of modified wave operators with no size restriction on
the data and we determine the asymptotic behaviour in time of solutions in the
range of the wave operators.Comment: TeX, 89 pages, available http://qcd.th.u-psud.f
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