422 research outputs found

    Neutrino oscillations in low density medium

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    For the case of small matter effects: VΔm2/2EV \ll \Delta m^2/2E, where VV is the matter potential, we develop the perturbation theory using ϵ2VE/Δm2\epsilon \equiv 2VE/\Delta m^2 as the expansion parameter. We derive simple and physically transparent formulas for the oscillation probabilities in the lowest order in ϵ\epsilon 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 dd. We show that for the mass-to-flavor state transitions, {\it e.g.}, ν2νe\nu_2 \to \nu_e, the sensitivity is suppressed for remote structures: d>lνE/ΔEd > l_{\nu} E/\Delta E, where lνl_{\nu} is the oscillation length and ΔE/E\Delta E/E is the energy resolution of detector.Comment: discussion simplified, clarifications adde

    Supernova Neutrino Oscillations

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    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 γ\gamma From Ratio of BKπB \to K \pi Rates

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    The ratio of partial decay rates for charged and neutral BB mesons to KπK \pi final states provides information on the weak phase γArg(Vub)\gamma \equiv {\rm Arg} (V_{ub}^*) when augmented with information on the CP-violating asymmetry in the K±πK^\pm \pi^\mp mode. The requirements for a useful determination of γ\gamma are examined in the light of present information about the decays B0K+πB^0 \to K^+ \pi^-, B+K0π+B^+ \to K^0 \pi^+, 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

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    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 BDπ,DπB \to D \pi, D^* \pi, and DρD \rho Decays

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    The final-state phases in BˉDπ,Dπ\bar{B} \to D \pi, D^* \pi, and DρD \rho decays appear to follow a pattern similar to those in DKˉπD \to \bar{K} \pi, Kˉπ\bar{K}^* \pi, and Kˉρ\bar{K} \rho 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 DρD \rho or Kˉρ\bar{K} \rho decays the areas of the triangles are consistent with zero. Following an earlier discussion of this behavior for DD 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

    Ds+ϕρ+D_s^+ \to \phi \rho^+ Decay

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    Motivated by the experimental measurement of the decay rate, Γ\Gamma, and the longitudinal polarization, PLP_L, in the Cabibbo favored decay Ds+ϕρ+D_s^+\to \phi {\rho}^{+}, 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 Γ\Gamma and PLP_L by using experimentally measured values of the form factors A1Dsϕ(0)A_1^{D_s\phi}(0), A2Dsϕ(0)A_2^{D_s\phi}(0) and VDsϕ(0)V^{D_s\phi}(0) in the semi-leptonic decay Ds+ϕl+νlD_s^+\to \phi l^{+}\nu_{l}. We have also included in our calculation the effect of the final state interaction (fsifsi) by working with the partial waves amplitudes SS, PP and DD. Numerical calculation shows that the decay amplitude is dominated by SS wave, and that the polarization is sensitive to the interference between SS and DD waves. The range of the phase difference δSD=δSδD\delta_{SD} = \delta_S - \delta_D accommodated by experimental error in PLP_L is large.Comment: 7 pages, LaTe

    USED PATTERN OF METALS AND MINERALS IN ASHTANG HRIDAYA: THE BIRDS EYE VIEW

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    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&nbsp;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 &amp;Ghee), Sandhana (Fermentation), Churna (powder), Vati (tablet), Lepa (Caoting powder) &amp; 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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