1,703 research outputs found
Study of a Long Baseline nu_tau Appearance Neutrino Oscillation Experiment in the Quasi-Elastic Regime
We present a study for a design of a long baseline nu_mu to nu_tau appearance
experiment to probe the high sin^2(2theta) and low Delta m^2 region relevant to
explain the atmospheric neutrino anomaly. The experiment relies on a good
identification of quasi-elastic interactions, which is a clean topology that
has an important contribution in the lowest Delta m^2 part of the region
probed. The detector we studied is a fine grained liquid scintillator detector
of 15 kilotons, optimized to detect electrons from tau -> e bar(nu_e) nu_tau
decays, while rejecting backgrounds from pi^0 in nu_mu interactions and
electrons from the nu_e beam contamination. As a reference, the proposed nu_mu
neutrino beam from CERN to Gran Sasso was used.Comment: 17 page
The Value of Demonstration in Human Maze Learning
In a first experiment, forty subjects were assigned to one of four groups. Each of these groups received one, two or three demonstrations, or no demonstration at all of a task on a bolt-head maze. It was found that number of demonstrations and reduction of errors per trial were positively related up to two demonstrations but no additional increment in performance appeared for three demonstrations. In a second experiment, error making by a demonstrator was contrasted with skilled demonstration. Three demonstrations with errors resulted in significantly fewer errors per trial than two demonstrations with errors. Three skilled errorless demonstration was nonsignificantly superior to three demonstrations with errors
Constraints on Non-Commutative Physics Scale with Neutrino-Electron Scattering
Neutrino-electron scatterings () are purely leptonic processes with
robust Standard Model (SM) predictions. Their measurements can therefore
provide constraints to physics beyond SM. Non-commutative (NC) field theories
modify space-time commutation relations, and allow neutrino electromagnetic
couplings at the tree level. Their contribution to neutrino-electron scattering
cross-section was derived. Constraints were placed on the NC scale parameter
from experiments with reactor and accelerator
neutrinos. The most stringent limit of at 95%
confidence level improves over the direct bounds from collider experiments.Comment: 6 pages, 2 figures, 2 tables, V2: minor revisions to match published
versio
Proposal to Search for Heavy Neutral Leptons at the SPS
A new fixed-target experiment at the CERN SPS accelerator is proposed that
will use decays of charm mesons to search for Heavy Neutral Leptons (HNLs),
which are right-handed partners of the Standard Model neutrinos. The existence
of such particles is strongly motivated by theory, as they can simultaneously
explain the baryon asymmetry of the Universe, account for the pattern of
neutrino masses and oscillations and provide a Dark Matter candidate.
Cosmological constraints on the properties of HNLs now indicate that the
majority of the interesting parameter space for such particles was beyond the
reach of the previous searches at the PS191, BEBC, CHARM, CCFR and NuTeV
experiments. For HNLs with mass below 2 GeV, the proposed experiment will
improve on the sensitivity of previous searches by four orders of magnitude and
will cover a major fraction of the parameter space favoured by theoretical
models.
The experiment requires a 400 GeV proton beam from the SPS with a total of
2x10^20 protons on target, achievable within five years of data taking. The
proposed detector will reconstruct exclusive HNL decays and measure the HNL
mass. The apparatus is based on existing technologies and consists of a target,
a hadron absorber, a muon shield, a decay volume and two magnetic
spectrometers, each of which has a 0.5 Tm magnet, a calorimeter and a muon
detector. The detector has a total length of about 100 m with a 5 m diameter.
The complete experimental set-up could be accommodated in CERN's North Area.
The discovery of a HNL would have a great impact on our understanding of
nature and open a new area for future research
Measurement of Neutrino-Electron Scattering Cross-Section with a CsI(Tl) Scintillating Crystal Array at the Kuo-Sheng Nuclear Power Reactor
The elastic scattering cross-section was measured with
a CsI(Tl) scintillating crystal array having a total mass of 187kg. The
detector was exposed to an average reactor flux of
at the Kuo-Sheng Nuclear Power
Station. The experimental design, conceptual merits, detector hardware, data
analysis and background understanding of the experiment are presented. Using
29882/7369 kg-days of Reactor ON/OFF data, the Standard Model(SM) electroweak
interaction was probed at the squared 4-momentum transfer range of . The ratio of experimental to SM cross-sections
of was measured. Constraints on
the electroweak parameters were placed, corresponding to a weak
mixing angle measurement of \s2tw = 0.251 \pm 0.031({\it stat}) \pm
0.024({\it sys}) . Destructive interference in the SM \nuebar -e process was
verified. Bounds on anomalous neutrino electromagnetic properties were placed:
neutrino magnetic moment at \mu_{\nuebar}< 2.2 \times 10^{-10} \mu_{\rm B}
and the neutrino charge radius at -2.1 \times 10^{-32} ~{\rm cm^{2}} <
\nuchrad < 3.3 \times 10^{-32} ~{\rm cm^{2}}, both at 90% confidence level.Comment: 18 Figures, 7 Tables; published version as V2 with minor revision
from V
Local Orientational Order in Liquids Revealed by Resonant Vibrational Energy Transfer
We demonstrate that local orientational ordering in a liquid can be observed in the decay of the vibrational anisotropy caused by resonant transfer of vibrational excitations between its constituent molecules. We show that the functional form of this decay is determined by the (distribution of) angles between the vibrating bonds of the molecules between which energy transfer occurs, and that the initial drop in the decay reflects the average angle between nearest neighbors. We use this effect to observe the difference in local orientational ordering in the two hydrogen-​bonded liquids ethanol and N-​methylacetamide
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