191 research outputs found

    Correlation between the quenching of total GT+ strength and the increase of E2 strength

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    Relations between the total beta+ Gamow-Teller (GT+) strength and the E2 strength are further examined. It is found that in shell-model calculations for N=Z nuclei, in which changes in deformation are induced by varying the single-particle energies, the total GT+ or GT- strength decreases monotonically with increasing values of the B(E2) from the ground state to the first excited J=2+ state. Similar trends are also seen for the double GT transition amplitude (with some exceptions) and for the spin part of the total M1 strength as a function of B(E2).Comment: 11 pages and 3 figures (Figures will be sent on request

    Are Electrons Oscillating Photons, Oscillating “Vacuum," or Something Else? The 2015 Panel Discussion: An Unprecedented Engineering Opportunity: A Dynamical Linear Theory of Energy as Light and Matter

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    Platform: What physical attributes separate EM waves, of the enormous band of radio to visible to x-ray, from the high energy narrow band of gamma-ray? From radio to visible to x-ray, telescopes are designed based upon the optical imaging theory; which is an extension of the Huygens-Fresnel diffraction integral. Do we understand the physical properties of gamma rays that defy us to manipulate them similarly? One demonstrated unique property of gamma rays is that they can be converted to elementary particles (electron and positron pair); or a particle-antiparticle pair can be converted into gamma rays. Thus, EM waves and elementary particles, being inter-convertible; we cannot expect to understand the deeper nature of light without succeeding to find structural inter-relationship between photons and particles. This topic is directly relevant to develop a deeper understanding of the nature of light; which will, in turn, help our engineers to invent better optical instruments

    Effect of the unpolarized spin state in spin-correlation measurement of two protons produced in the 12C(d,2He) reaction

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    In this note we discuss the effect of the unpolarized state in the spin-correlation measurement of the 1S0^1S_0 two-proton state produced in 12C(d,2He) reaction at the KVI, Groningen. We show that in the presence of the unpolarized state the maximal violation of the CHSH-Bell inequality is lower than the classical limit if the purity of the state is less than ∌70% \sim \verb+70%+. In particular, for the KVI experiment the violation of the CHSH-Bell inequality should be corrected by a factor ∌10%\sim\verb+10%+ from the pure 1S0^1S_0 state.Comment: 6 pages, to appear in J. Phys.

    Universality of Symmetry and Mixed-symmetry Collective Nuclear States

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    The global correlation in the observed variation with mass number of the E2E2 and summed M1M1 transition strengths is examined for rare earth nuclei. It is shown that a theory of correlated SS and DD fermion pairs with a simple pairing plus quadrupole interaction leads naturally to this universality. Thus a unified and quantitative description emerges for low-lying quadrupole and dipole strengths.Comment: In press, Phys. Rev. Lett. 199

    Polarization Correlations of 1S0 Proton Pairs as Tests of Bell and Wigner Inequalities

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    In an experiment designed to overcome the loophole of observer dependent reality and satisfying the counterfactuality condition, we measured polarization correlations of 1S0 proton pairs produced in 12C(d,2He) and 1H(d,He) reactions in one setting. The results of these measurements are used to test the Bell and Wigner inequalties against the predictions of quantum mechanics.Comment: 8 pages, 4 figure

    Orbital and Spin Magnetic Dipole Strength in a shell model calculation with ΔN\Delta N=22 excitations: ^8\mbox{Be}

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    The magnetic dipole strength and energy-weighted strength distribution is calculated in ^8\mbox{Be}, as well as the separate orbit and spin parts. All ΔN\Delta N=22 excitations over and above (and including) the configuration 0s40s^40p40p^4 are included. The interaction has a central, two-body spin-orbit and a tensor part. The energy- independent and energy-weighted {\underline orbital} strength distribution is remarkably insensitive to the presence or absence of the spin-orbit or tensor interaction -not so the spin strength. The energy-weighted strength distribution can be divided into a low enegy and a high energy part. The high energy orbital part is somewhat less but close to the low energy part, in fair agreement with a prediction that they be equal by de Guerra and Zamick and by Nojarov. There is a wide plateau separating the low energy part from the high energy part.Comment: 12 pages (4 figs/on request) \#RU944

    Measurement of K^+ \to \pi^0 \mu^+ \nu \gamma decay using stopped kaons

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    The K^+ \to \pi^0 \mu^+ \nu \gamma (KÎŒ3ÎłK_{\mu 3 \gamma}) decay has been measured with stopped positive kaons at the KEK 12 GeV proton synchrotron. A KÎŒ3ÎłK_{\mu 3 \gamma} sample containing 125 events was obtained. The partial branching ratio Br(KÎŒ3Îł,EÎł>30MeV,ΞΌ+Îł>20∘)Br(K_{\mu 3 \gamma}, E_{\gamma}>30 {\rm MeV}, \theta_{\mu^+ \gamma}>20^{\circ}) was found to be [2.4±0.5(stat)±0.6(syst)]×10−5[2.4 \pm 0.5(stat) \pm 0.6(syst)]\times 10^{-5}, which is in good agreement with theoretical predictions.Comment: 12 pages, 3 figures, to be published in Physics Letters

    First measurement of the T-violating muon polarization in the decay K^+ --> mu^+ nu gamma

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    We present the result of the first measurement of the T-violating muon polarization P_T in the decay K^+ --> mu^+ nu gamma. This polarization is sensitive to new sources of CP-violation in the Higgs sector. Using data accumulated in the period 1996-98 we have obtained P_T = (-0.64 +- 1.85(stat) +- 0.10(syst))x10^{-2} which is consistent with no T-violation in this decay.Comment: 11 pages, 8 figure

    Effects of the Spin-Orbit and Tensor Interactions on the M1M1 and E2E2 Excitations in Light Nuclei

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    The effects of varying the spin-orbit and tensor components of a realistic interaction on M1M1 excitation rates and B(E2)â€ČsB(E2)'s are studied on nuclei in the 0p0p and 1s−0d1s-0d shells. Not only the total M1M1 but also the spin and orbital parts separately are studied. The single-particle energies are first calculated with the same interaction that is used between the valence nucleons. Later this stringent condition is relaxed somewhat and the 1s1s level is raised relative to 0d0d. For nuclei up to 28Si^{28}Si, much better results i.e stronger B(M1)B(M1) rates are obtained by increasing the strength of the spin-orbit interaction relative to the free value. This is probably also true for 32S^{32}S, but 36Ar^{36}Ar presents some difficulties. The effects of weakening the tensor interaction are also studied. On a more subtle level, the optimum spin-orbit interaction in the lower half of the s−ds-d shell, as far as M1M1 excitations are concerned, is substantially larger than the difference E(J=3/2+)1−E(J=5/2+)1=5.2 MeVE(J=3/2^+)_1-E(J=5/2^+)_1=5.2~MeV in 17O^{17}O. A larger spin-orbit splitting is also needed to destroy the triaxiality in 22Ne^{22}Ne. Also studied are how much M1M1 orbital and spin strength lies in an observable region and how much is buried in the grass at higher energies. It is noted that for many nuclei the sum B(M1)orbital+B(M1)spinB(M1)_{orbital}+B(M1)_{spin} is very close to B(M1)totalB(M1)_{total}, indicating that the summed cross terms are very small.Comment: 39 pages, revtex 3.
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