1,596 research outputs found
Breaking Eight-fold Degeneracies in Neutrino CP Violation, Mixing, and Mass Hierarchy
We identify three independent two-fold parameter degeneracies (\delta,
\theta_{13}), sgn(\delta m^2_{31}) and (\theta_{23}, \pi/2-\theta_{23})
inherent in the usual three-neutrino analysis of long-baseline neutrino
experiments, which can lead to as much as an eight-fold degeneracy in the
determination of the oscillation parameters. We discuss the implications these
degeneracies have for detecting CP violation and present criteria for breaking
them. A superbeam facility with a baseline at least as long as the distance
between Fermilab and Homestake (1290 km) and a narrow band beam with energy
tuned so that the measurements are performed at the first oscillation peak can
resolve all the ambiguities other than the (\theta_{23}, \pi/2-\theta_{23})
ambiguity (which can be resolved at a neutrino factory) and a residual (\delta,
\pi-\delta) ambiguity. However, whether or not CP violation occurs in the
neutrino sector can be ascertained independently of the latter two ambiguities.
The (\delta,\pi-\delta) ambiguity can be eliminated by performing a second
measurement to which only the \cos\delta terms contribute. The hierarchy of
mass eigenstates can be determined at other oscillation peaks only in the most
optimistic conditions, making it necessary to use the first oscillation
maximum. We show that the degeneracies may severely compromise the ability of
the proposed SuperJHF-HyperKamiokande experiment to establish CP violation. In
our calculations we use approximate analytic expressions for oscillation
probabilitites that agree with numerical solutions with a realistic Earth
density profile.Comment: Revtex (singlespaced), 35 pages, 15 postscript figures, uses
psfig.st
Neutrino Factories and the "Magic" Baseline
We show that for a neutrino factory baseline of a
``clean'' measurement of becomes possible, which is
almost unaffected by parameter degeneracies. We call this baseline "magic"
baseline, because its length only depends on the matter density profile. For a
complete analysis, we demonstrate that the combination of the magic baseline
with a baseline of 3000 km is the ideal solution to perform equally well for
the , sign of , and CP violation
sensitivities. Especially, this combination can very successfully resolve
parameter degeneracies even below .Comment: Minor changes, final version to appear in PRD, 4 pages, 3 figures,
RevTe
Design and validation of a socio-emotional questionnaire for youth football players
Con el objetivo de detectar y controlar los factores socio-emocionales que influyen en la progresión del joven futbolista, se diseñó un cuestionario auto-cumplimentado de 40 ítems, agrupados en 3 dimensiones (entorno social, bienestar e inteligencia emocional). Se analizó la validez de contenido mediante la valoración de 14 expertos y la validez de constructo mediante análisis factorial. Se evaluó la fiabilidad del cuestionario, administrándolo a jóvenes futbolistas de élite (n=281) y analizando la consistencia interna por el método del Alfa de Cronbach y la fiabilidad test-retest mediante el coeficiente de correlación intraclase (CCI). El análisis factorial confirmó la existencia de 18 categorías, que en conjunto explican el 65,40% de la varianza total. El Alfa de Cronbach del cuestionario fue de 0,944 (p<0,01) y el CCI de 0,894 (p<0,01). El cuestionario reúne suficientes propiedades psicométricas como para ser considerado una herramienta válida y fiable para medir el entorno socio-emocional de jóvenes futbolistas.The objective of this study was to design a valid questionnaire to detect and manage the socio-emotional factors that influence the performance of young football players. A group of specialists designed a self-completion questionnaire of 40 items grouped into 3 dimensions. Content validity was analysed and evaluated by 14 experts and construct validity was analysed by factorial analysis. To evaluate reliability the questionnaire was administered to young elite football players, and internal consistency was analysed with Cronbach’s alpha. Test-retest reliability was assessed with the intraclass correlation coefficient (ICC). Factor analysis confirmed the existence of 18 factors, which as a whole explained 65.40% of the total variance. The Cronbach’s alpha of the questionnaire was 0.944 (p<0.01) and the ICC of the entire questionnaire was 0.894 (p<0.01). The questionnaire gathers together enough psychometric properties to be considered a valid and reliable tool for gauging the socio-emotional environment of young football players
Diseño y validación de un cuestionario socio-emocional para jóvenes futbolistas de élite. Desing and validation of a socio-emotional questionnaire for yourh footbal players
Validación de un cuestionario socio-emocional en fútbo
Coupling theory for counterion distributions based in Tsallis statistics
It is well known that the Poisson-Boltzmann (PB) equation yields the exact
counterion density around charged objects in the weak coupling limit. In this
paper we generalize the PB approach to account for coupling of arbitrary
strength by making use of Tsallis q-exponential distributions. Both the weak
coupling and the strong coupling limits are reproduced. For arbitrary coupling
we also provide simple analytical expressions which are compared to recent
Monte Carlo simulations by A. G. Moreira and R. R. Netz [Europhys. Lett. 52
(2000) 705]. Excellent agreement with these is obtained.Comment: 17 pages, 2 figures, 1 table. Final version, accepted for publication
in Physica
How two neutrino superbeam experiments do better than one
We examine the use of two superbeam neutrino oscillation experiments with
baselines \lsim 1000 km to resolve parameter degeneracies inherent in the
three-neutrino analysis of such experiments. We find that with appropriate
choices of neutrino energies and baselines two experiments with different
baselines can provide a much better determination of the neutrino mass ordering
than a single experiment alone. Two baselines are especially beneficial when
the mass scale for solar neutrino oscillations is \gsim
5\times10^{-5} eV. We also examine CP violation sensitivity and the
resolution of other parameter degeneracies. We find that the combined data of
superbeam experiments with baselines of 295 and 900 km can provide sensitivity
to both the neutrino mass ordering and CP violation for
down to 0.03 for eV. It
would be highly advantageous to have a 10% determination of before the beam energies and baselines are finalized, although if
is not that well known, the neutrino energies and
baselines can be chosen to give fairly good sensitivity for a range of .Comment: 18 pages, 6 PS figures, added references and revised discussio
Modulating the phase transition temperature of giant magnetocaloric thin films by ion irradiation
Magnetic refrigeration based on the magnetocaloric effect at room temperature
is one of the most attractive alternative to the current gas
compression/expansion method routinely employed. Nevertheless, in giant
magnetocaloric materials, optimal refrigeration is restricted to the narrow
temperature window of the phase transition (Tc). In this work, we present the
possibility of varying this transition temperature into a same giant
magnetocaloric material by ion irradiation. We demonstrate that the transition
temperature of iron rhodium thin films can be tuned by the bombardment of ions
of Ne 5+ with varying fluences up to 10 14 ions cm --2 , leading to optimal
refrigeration over a large 270--380 K temperature window. The Tc modification
is found to be due to the ion-induced disorder and to the density of new
point-like defects. The variation of the phase transition temperature with the
number of incident ions opens new perspectives in the conception of devices
using giant magnetocaloric materials
Matter profile effect in neutrino factory
We point out that the matter profile effect --- the effect of matter density
fluctuation on the baseline --- is very important to estimate the parameters in
a neutrino factory with a very long baseline. To make it clear, we propose the
method of the Fourier series expansion of the matter profile. By using this
method, we can take account of both the matter profile effect and its
ambiguity. For very long baseline experiment, such as L=7332km, in the analysis
of the oscillation phenomena we need to introduce a new parameter ---
the Fourier coefficient of the matter profile --- as a theoretical parameter to
deal with the matter profile effects.Comment: 21 pages, 15 figure
Neutrino oscillation parameters from MINOS, ICARUS and OPERA combined
We perform a detailed analysis of the capabilities of the MINOS, ICARUS and
OPERA experiments to measure neutrino oscillation parameters at the atmospheric
scale with their data taken separately and in combination. MINOS will determine
and to within 10% at the 99% C.L. with
10 kton-years of data. While no one experiment will determine with much precision, if its value lies in the combined
sensitivity region of the three experiments, it will be possible to place a
lower bound of O(0.01) at the 95% C.L. on this parameter by combining the data
from the three experiments. The same bound can be placed with a combination of
MINOS and ICARUS data alone.Comment: Version to appear in PR
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