8,563 research outputs found
Time Reversal Violation from the entangled B0-antiB0 system
We discuss the concepts and methodology to implement an experiment probing
directly Time Reversal (T) non-invariance, without any experimental connection
to CP violation, by the exchange of "in" and "out" states. The idea relies on
the B0-antiB0 entanglement and decay time information available at B factories.
The flavor or CP tag of the state of the still living neutral meson by the
first decay of its orthogonal partner overcomes the problem of irreversibility
for unstable systems, which prevents direct tests of T with incoherent particle
states. T violation in the time evolution between the two decays means
experimentally a difference between the intensities for the time-ordered (l^+
X, J/psi K_S) and (J/psi K_L, l^- X) decays, and three other independent
asymmetries. The proposed strategy has been applied to simulated data samples
of similar size and features to those currently available, from which we
estimate the significance of the expected discovery to reach many standard
deviations.Comment: 17 pages, 2 figures, 6 table
Graded Hecke algebras for disconnected reductive groups
We introduce graded Hecke algebras H based on a (possibly disconnected)
complex reductive group G and a cuspidal local system L on a unipotent orbit of
a Levi subgroup M of G. These generalize the graded Hecke algebras defined and
investigated by Lusztig for connected G.
We develop the representation theory of the algebras H. obtaining complete
and canonical parametrizations of the irreducible, the irreducible tempered and
the discrete series representations. All the modules are constructed in terms
of perverse sheaves and equivariant homology, relying on work of Lusztig. The
parameters come directly from the data (G,M,L) and they are closely related to
Langlands parameters.
Our main motivation for considering these graded Hecke algebras is that the
space of irreducible H-representations is canonically in bijection with a
certain set of "logarithms" of enhanced L-parameters. Therefore we expect these
algebras to play a role in the local Langlands program. We will make their
relation with the local Langlands correspondence, which goes via affine Hecke
algebras, precise in a sequel to this paper.Comment: Theorem 3.4 and Proposition 3.22 in version 1 were not entirely
correct as stated. This is repaired in a new appendi
High resolution simulations of the reionization of an isolated Milky Way - M31 galaxy pair
We present the results of a set of numerical simulations aimed at studying
reionization at galactic scale. We use a high resolution simulation of the
formation of the Milky Way-M31 system to simulate the reionization of the local
group. The reionization calculation was performed with the post-processing
radiative transfer code ATON and the underlying cosmological simulation was
performed as part of the CLUES project. We vary the source models to bracket
the range of source properties used in the literature. We investigate the
structure and propagation of the galatic ionization fronts by a visual
examination of our reionization maps. Within the progenitors we find that
reionization is patchy, and proceeds locally inside out. The process becomes
patchier with decreasing source photon output. It is generally dominated by one
major HII region and 1-4 additional isolated smaller bubbles, which eventually
overlap. Higher emissivity results in faster and earlier local reionization. In
all models, the reionization of the Milky Way and M31 are similar in duration,
i.e. between 203 Myr and 22 Myr depending on the source model, placing their
zreion between 8.4 and 13.7. In all models except the most extreme, the MW and
M31 progenitors reionize internally, ignoring each other, despite being
relatively close to each other even during the epoch of reionization. Only in
the case of strong supernova feedback suppressing star formation in haloes less
massive than 10^9 M_sun, and using our highest emissivity, we find that the MW
is reionized by M31.Comment: Accepted for publication in ApJ. 14 pages, 4 figures, 1 tabl
Nonleptonic charmless two-body decays
In this work we have studied hadronic charmless two-body B decays involving
p-wave mesons in final state. We have calculated branching ratios of
decays (where and denotes a axial-vector and a tensor meson,
respectively), using form factors obtained in the covariant
light-front (CLF) approach, and the full effective Hamiltonian. We have
obtained that ,
,
(with ) for ,
with
, for
where . It seems that these decays can be measured
in experiments at factories. Additionally, we have found that
and
ratios could be useful to determine numerical values of mixing angles
and , respectively.Comment: 12 page
Eddy current effects in plain and hollow cylinders spinning inside homogeneous magnetic fields: Application to magnetic resonance
International audienceWe present a thorough analysis of eddy currents that develop in a rectangular cross section toroid rotating in a uniform magnetic field. The slow rotation regime is assumed. Compact expressions for the current density, the total dissipated power, and the braking torque are given. Examination of the topology of current lines reveals that depending upon the relative dimensions of the side and length of the toroid two different regimes exist. The conditions of existence of the two regimes are analytically established. In view of nuclear magnetic resonance (NMR) applications, we derive the angular variation of the magnetic field created by eddy currents and lay down the formalism necessary for calculating the effect of this field on the NMR spectra of the conductor itself or of a sample co-rotating with the conductor, a situation encountered when dealing with rotating detectors. Examples of calculations for cases of practical interest are presented. The theory is confronted with available data, and we give guidelines for the design of optimized rotating micro-coils
Emotions while awaiting lung transplantation : a comprehensive qualitative analysis
Patients awaiting lung transplantation are at risk of negative emotional and physical experiences. How do they talk about emotions? Semi-structured interviews were performed (15 patients). Categorical analysis focusing on emotion-related descriptions was organized into positive–negative–neutral descriptions: for primary and secondary emotions, evaluation processes, coping strategies, personal characteristics, emotion descriptions associated with physical states, (and) contexts were listed. Patients develop different strategies to maintain positive identity and attitude, while preserving significant others from extra emotional load. Results are discussed within various theoretical and research backgrounds, in emphasizing their importance in the definition of emotional support starting from the patient’s perspective
Radiative and Semileptonic B Decays Involving Higher K-Resonances in the Final States
We study the radiative and semileptonic B decays involving a spin-
resonant with parity for and for
in the final state. Using the large energy effective theory (LEET)
techniques, we formulate transition form factors in the large
recoil region in terms of two independent LEET functions
and , the values of
which at zero momentum transfer are estimated in the BSW model. According to
the QCD counting rules, exhibit a dipole
dependence in . We predict the decay rates for ,
and . The
branching fractions for these decays with higher -resonances in the final
state are suppressed due to the smaller phase spaces and the smaller values of
. Furthermore, if the spin of
becomes larger, the branching fractions will be further suppressed due to the
smaller Clebsch-Gordan coefficients defined by the polarization tensors of the
. We also calculate the forward backward asymmetry of the decay, for which the zero is highly insensitive to the
-resonances in the LEET parametrization.Comment: 27 pages, 4 figures, 7 tables;contents and figures corrected, title
and references revise
Facteurs de localisation de l'emploi résidentiel en France
Cette communication a pour objectif d'analyser la distribution spatiale des activités de services destinés à la population ainsi que les facteurs d'hétérogénéité spatiale de la densité des emplois relevant de ces secteurs, examinée à l'échelle des bassins de vie. Deux grandes catégories de facteurs explicatifs sont examinées en mobilisant des méthodes statistiques : l'effet du potentiel de marché et la propension à consommer localement. L'estimation des emplois relevant du tourisme permet de prendre en compte la dynamique des services attachée à l'attractivité et à l'équipement des différents espaces. La communication débouche, d'une part, sur l'identification des facteurs structurels relevant de la demande locale et, d'autre part, sur la mise en évidence des configurations territoriales les plus propices au développement de l'emploi résidentiel.ECONOMIE;ANALYSE STATISTIQUE;EMPLOI;ECONOMIE RESIDENTIELLE;FACTEUR DE LOCALISATION
The UTfit Collaboration Average of D meson mixing data: Spring 2012
We derive constraints on the parameters , and
that describe meson mixing using all available data, allowing
for CP violation. We also provide posterior distributions and predictions for
observable parameters appearing in physics.Comment: 5 pages, 3 figure
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