422 research outputs found
Neutrino oscillations in low density medium
For the case of small matter effects: , where is the
matter potential, we develop the perturbation theory using as the expansion parameter. We derive simple and physically
transparent formulas for the oscillation probabilities in the lowest order in
which are valid for arbitrary density profile. The formulas can be
applied for propagation of the solar and supernova neutrinos in matter of the
Earth, substantially simplifying numerical calculations. Using these formulas
we study sensitivity of the oscillation effects to structures of the density
profile situated at different distances from the detector . We show that for
the mass-to-flavor state transitions, {\it e.g.}, , the
sensitivity is suppressed for remote structures: ,
where is the oscillation length and is the energy
resolution of detector.Comment: discussion simplified, clarifications adde
Supernova Neutrino Oscillations
Observing a high-statistics neutrino signal from a galactic supernova (SN)
would allow one to test the standard delayed explosion scenario and may allow
one to distinguish between the normal and inverted neutrino mass ordering due
to the effects of flavor oscillations in the SN envelope. One may even observe
a signature of SN shock-wave propagation in the detailed time-evolution of the
neutrino spectra. A clear identification of flavor oscillation effects in a
water Cherenkov detector probably requires a megatonne-class experiment.Comment: Proc. 129 Nobel Symposium "Neutrino Physics", 19-24 Aug 2004, Swede
Weak Phase From Ratio of Rates
The ratio of partial decay rates for charged and neutral mesons to final states provides information on the weak phase when augmented with information on the CP-violating asymmetry
in the mode. The requirements for a useful determination of
are examined in the light of present information about the decays , , and the corresponding charge-conjugate
modes. The effects of electroweak penguins and rescattering corrections are
noted, and proposals are made for estimating and measuring their importance.Comment: 16 pages, latex, 3 figures, revised version sent to Phys. Rev.
Detecting the Neutrino Mass Hierarchy with a Supernova at IceCube
IceCube, a future km^3 antarctic ice Cherenkov neutrino telescope, is highly
sensitive to a galactic supernova (SN) neutrino burst. The Cherenkov light
corresponding to the total energy deposited by the SN neutrinos in the ice can
be measured relative to background fluctuations with a statistical precision
much better than 1%. If the SN is viewed through the Earth, the matter effect
on neutrino oscillations can change the signal by more than 5%, depending on
the flavor-dependent source spectra and the neutrino mixing parameters.
Therefore, IceCube together with another high-statistics experiment like
Hyper-Kamiokande can detect the Earth effect, an observation that would
identify specific neutrino mixing scenarios that are difficult to pin down with
long-baseline experiments. In particular, the normal mass hierarchy can be
clearly detected if the third mixing angle is not too small, sin^2 theta_13 <
10^-3. The small flavor-dependent differences of the SN neutrino fluxes and
spectra that are found in state-of-the-art simulations suffice for this
purpose. Although the absolute calibration uncertainty at IceCube may exceed
5%, the Earth effect would typically vary by a large amount over the duration
of the SN signal, obviating the need for a precise calibration. Therefore,
IceCube with its unique geographic location and expected longevity can play a
decisive role as a "co-detector" to measure SN neutrino oscillations. It is
also a powerful stand-alone SN detector that can verify the delayed-explosion
scenario.Comment: 19 pages, 6 Figs, final version accepted by JCAP, some references
adde
Final-State Phases in , and Decays
The final-state phases in , and decays
appear to follow a pattern similar to those in , , and decays. Each set of processes is characterized by
three charge states but only two independent amplitudes, so the amplitudes form
triangles in the complex plane. For the first two sets the triangles appear to
have non-zero area, while for the or decays the areas
of the triangles are consistent with zero. Following an earlier discussion of
this behavior for decays, a similar analysis is performed for B decays, and
the relative phases and magnitudes of contributing amplitudes are determined.
The significance of recent results on \ob \to D^{(*)0} \bar{K}^{(*)0} is
noted. Open theoretical and experimental questions are indicated.Comment: 16 pages, LaTeX, 3 figures, to be submitted to Phys. Rev. D.
References added; comments on new experimental results and analysi
Decay
Motivated by the experimental measurement of the decay rate, , and
the longitudinal polarization, , in the Cabibbo favored decay , we have studied theoretical prediction within the context of
factorization approximation invoking several form factors models. We were able
to obtain agreement with experiment for both and by using
experimentally measured values of the form factors ,
and in the semi-leptonic decay . We have also included in our calculation the effect of the
final state interaction () by working with the partial waves amplitudes
, and . Numerical calculation shows that the decay amplitude is
dominated by wave, and that the polarization is sensitive to the
interference between and waves. The range of the phase difference
accommodated by experimental error in
is large.Comment: 7 pages, LaTe
USED PATTERN OF METALS AND MINERALS IN ASHTANG HRIDAYA: THE BIRDS EYE VIEW
Human evolution and progress has count mainly on the discovery of metals. Primitive man used metals first time for making apparatuses and weaponries; as the information advances metals played a significant role in development of agriculture, transport arts, crafts and health care. Ayurveda have faith in the principle of YatPinde Tat Bramhande and therefore all these naturally occurring metals and minerals have major role in restoration of human health and treatment of any kind of illness. Classical treatise Ashtanga Hridaya is a very popular book among the physicians among south India. In this classic, eight types of Dhatu (metals), varieties of Ratna-Uparatna (precious stones and minerals) are mentioned for different purposes. Here an attempt is made to collect all these information of metals and minerals in a collective form to analyse their used pattern in therapeutic, Diagnostic (Nidana Panchaka), Pharmaceutical Benefits, Dincharya/ Pathya- Apathya, Panchakarma and Surgical/Para Surgical Procedure. All these metals and minerals are used in different formulations like Sneha (Oil &Ghee), Sandhana (Fermentation), Churna (powder), Vati (tablet), Lepa (Caoting powder) & Anjana (Collyrium). Human body is composed of almost every natural element found in nature and our civilization is completely reliant on metals and the science of metallurgy is now one of the most widely documented and researched material science
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