16,785 research outputs found
An evaluation of the analytic continuation by duality technique
In Nucl. Phys. B391 (1993) 127, the value of the oblique correction parameter
S for walking technicolor theories was estimated using a technique called
Analytic Continuation by Duality (ACD). We apply the ACD technique to the
perturbative vacuum polarization function and find that it fails to reproduce
the well known result S=1/6\pi. This brings into question the reliability of
the ACD technique and the ACD estimate of S.Comment: 8 pages, LaTeX, 1 postscript figure. Uses cite.sty, sprocl.sty, and
epsfig.sty. Talk presented at the 1996 International Workshop on Perspectives
of Strong Coupling Gauge Theories (SCGT'96), 13-16 Nov. 1996, Nagoy
CP, T and CPT Violations in the K^0 - bar{K^0} System -- Present Status --
Possible violation of CP, T and CPT symmetries in the K^0 - bar{K^0} system
is studied in a way as phenomenological and comprehensive as possible. For this
purpose, we first introduce parameters which represent violation of these
symmetries in mixing parameters and decay amplitudes in a convenient and
well-defined way and, treating these parameters as small, derive formulas which
relate them to the experimentally measured quantities. We then perform
numerical analyses to derive constraints to these symmetry-violating
parameters, with the latest data reported by KTeV Collaboration, NA48
Collaboration and CPLEAR Collaboration, along with those compiled by Particle
Data Group, used as inputs. The result obtained by CPLEAR Collaboration from an
unconstrained fit to a time-dependent leptonic asymmetry, aided by the
Bell-Steinberger relation, enables us to determine or constrain most of the
parameters separately. It is shown among the other things that (1) CP and T
symmetries are violated definitively at least at the level of 10^{-4} in 2 pi
decays, (2) CP and T symmetries are violated at least at the level of 10^{-3}
in the K^0 - bar{K^0} mixing, and (3) CPT symmetry is at present tested to the
level of 10^{-5} at the utmost.Comment: 20 page
Magnetic and Electronic Properties of LiCoO Single Crystals
Measurements of electrical resistivity (), DC magnetization () and
specific heat () have been performed on layered oxide LiCoO
(0.250.99) using single crystal specimens. The versus
temperature () curve for =0.90 and 0.99 is found to be insulating but a
metallic behavior is observed for 0.250.71. At 155 K, a sharp anomaly is observed in the , and
curves for =0.66 with thermal hysteresis, indicating the
first-order charactor of the transition. The transition at 155
K is observed for the wide range of =0.460.71. It is found that the
curve measured after rapid cool becomes different from that after
slow cool below , which is 130 K for =0.460.71. is found to agree with the temperature at which the motional narrowing in
the Li NMR line width is observed, indicating that the Li ions stop
diffusing and order at the regular site below . The ordering of Li
ions below 130 K is likely to be triggered and stabilized by
the charge ordering in CoO layers below .Comment: 8 pages, 7 figure
Neutrinoless Double Beta Decay, the Inverted Hierarchy and Precision Determination of theta(12)
Ruling out the inverted neutrino hierarchy with neutrinoless double beta
decay experiments is possible if a limit on the effective mass below the
minimal theoretically possible value is reached. We stress that this lower
limit depends strongly on the value of the solar neutrino mixing angle: it
introduces an uncertainty of a factor of 2 within its current 3 sigma range. If
an experiment is not background-free, a factor of two in effective mass
corresponds to a combined factor of 16 improvement for the experimental
parameters running time, detector mass, background level and energy resolution.
Therefore, a more precise determination of theta(12) is crucial for the
interpretation of experimental results and the evaluation of the potential and
requirements for future experiments. We give the required half-lifes to exclude
(and touch) the inverted hierarchy regime for all double beta decay isotopes
with a Q-value above 2 MeV. The nuclear matrix elements from 6 different groups
and, if available, their errors are used and compared. We carefully put the
calculations on equal footing in what regards various convention issues. We
also use our compilation of matrix elements to give the reachable values of the
effective mass for a given half-life value.Comment: 26 pages, 6 figures. v2: error corrected (misprint in paper we took a
value from), slightly modifying the result
Nonlocal Position Changes of a Photon Revealed by Quantum Routers
Since its publication, Aharonov and Vaidman's three-box paradox has undergone
three major advances: i). A non-counterfactual scheme by the same authors in
2003 with strong rather than weak measurements for verifying the particle's
subtle presence in two boxes. ii) A realization of the latter by Okamoto and
Takeuchi in 2016. iii) A dynamic version by Aharonov et al. in 2017, with
disappearance and reappearance of the particle. We now combine these advances
together. Using photonic quantum routers the particle acts like a quantum
"shutter." It is initially split between Boxes A, B and C, the latter located
far away from the former two. The shutter particle's whereabouts can then be
followed by a probe photon, split in both space and time and reflected by the
shutter in its varying locations. Measuring the former is expected to reveal
the following time-evolution: The shutter particle was, with certainty, in
boxes A+C at t1, then only in C at t2, and finally in B+C at t3. Another branch
of the split probe photon can show that boxes A+B were empty at t2. A Bell-like
theorem applied to this experiment challenges any alternative interpretation
that avoids disappearance-reappearance in favor of local hidden variables.Comment: Revised versio
Far-Ultraviolet and Far-Infrared Bivariate Luminosity Function of Galaxies: Complex Relation between Stellar and Dust Emission
Far-ultraviolet (FUV) and far-infrared (FIR) luminosity functions (LFs) of
galaxies show a strong evolution from to , but the FIR LF
evolves much stronger than the FUV one. The FUV is dominantly radiated from
newly formed short-lived OB stars, while the FIR is emitted by dust grains
heated by the FUV radiation field. It is known that dust is always associated
with star formation activity. Thus, both FUV and FIR are tightly related to the
star formation in galaxies, but in a very complicated manner. In order to
disentangle the relation between FUV and FIR emissions, we estimate the UV-IR
bivariate LF (BLF) of galaxies with {\sl GALEX} and {\sl AKARI} All-Sky Survey
datasets. Recently we invented a new mathematical method to construct the BLF
with given marginals and prescribed correlation coefficient. This method makes
use of a tool from mathematical statistics, so called "copula". The copula
enables us to construct a bivariate distribution function from given marginal
distributions with prescribed correlation and/or dependence structure. With
this new formulation and FUV and FIR univariate LFs, we analyze various FUV and
FIR data with {\sl GALEX}, {\sl Spitzer}, and {\sl AKARI} to estimate the UV-IR
BLF. The obtained BLFs naturally explain the nonlinear complicated relation
between FUV and FIR emission from star-forming galaxies. Though the faint-end
of the BLF was not well constrained for high- samples, the estimated linear
correlation coefficient was found to be very high, and is remarkably
stable with redshifts (from 0.95 at to 0.85 at ). This implies
the evolution of the UV-IR BLF is mainly due to the different evolution of the
univariate LFs, and may not be controlled by the dependence structure.Comment: 10 pages, 7 figures, Earth, Planets and Space, in pres
An Analytic Approach to the Wave Packet Formalism in Oscillation Phenomena
We introduce an approximation scheme to perform an analytic study of the
oscillation phenomena in a pedagogical and comprehensive way. By using Gaussian
wave packets, we show that the oscillation is bounded by a time-dependent
vanishing function which characterizes the slippage between the mass-eigenstate
wave packets. We also demonstrate that the wave packet spreading represents a
secondary effect which plays a significant role only in the non-relativistic
limit. In our analysis, we note the presence of a new time-dependent phase and
calculate how this additional term modifies the oscillating character of the
flavor conversion formula. Finally, by considering Box and Sine wave packets we
study how the choice of different functions to describe the particle
localization changes the oscillation probability.Comment: 16 pages, 7 figures, AMS-Te
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