138 research outputs found
Effect of the unpolarized spin state in spin-correlation measurement of two protons produced in the 12C(d,2He) reaction
In this note we discuss the effect of the unpolarized state in the
spin-correlation measurement of the 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 . In particular, for the KVI experiment the violation of the
CHSH-Bell inequality should be corrected by a factor from the
pure state.Comment: 6 pages, to appear in J. Phys.
Universality of Symmetry and Mixed-symmetry Collective Nuclear States
The global correlation in the observed variation with mass number of the
and summed transition strengths is examined for rare earth nuclei. It is
shown that a theory of correlated and 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
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
Measurement of K^+ \to \pi^0 \mu^+ \nu \gamma decay using stopped kaons
The K^+ \to \pi^0 \mu^+ \nu \gamma () decay has been
measured with stopped positive kaons at the KEK 12 GeV proton synchrotron. A
sample containing 125 events was obtained. The partial
branching ratio was found to be , 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
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
Measurement of direct photon emission in decay using stopped positive kaons
The radiative decay () has
been measured with stopped positive kaons. A sample
containing 4k events was analyzed, and the branching ratio
of the direct photon emission process was determined to be . No interference pattern with internal
bremsstrahlung was observed.Comment: 12 pages, 6 figures, 2 tables, to be published in Phys. Lett.
Solution of the Nuclear Shell Model by Symmetry-Dictated Truncation
The dynamical symmetries of the Fermion Dynamical Symmetry Model are used as
a principle of truncation for the spherical shell model. Utilizing the usual
principle of energy-dictated truncation to select a valence space, and
symmetry-dictated truncation to select a collective subspace of that valence
space, we are able to reduce the full shell model space to one of manageable
dimensions with modern supercomputers, even for the heaviest nuclei. The
resulting shell model then consists of diagonalizing an effective Hamiltonian
within the restricted subspace. This theory is not confined to any symmetry
limits, and represents a full solution of the original shell model if the
appropriate effective interaction of the truncated space can be determined. As
a first step in constructing that interaction, we present an empirical
determination of its matrix elements for the collective subspace with no broken
pairs in a representative set of nuclei with . We demonstrate
that this effective interaction can be parameterized in terms of a few
quantities varying slowly with particle number, and is capable of describing a
broad range of low-energy observables for these nuclei. Finally we give a brief
discussion of extending these methods to include a single broken collective
pair.Comment: invited paper for J. Phys. G, 57 pages, Latex, 18 figures a macro are
available under request at [email protected]
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