Signatures of Strong Momentum Localization via Translational-Internal Entanglement

We show that atoms or molecules subject to fields that couple their internal and translational (momentum) states may undergo a crossover from randomization (diffusion) to strong localization (sharpening) of their momentum distribution. The predicted crossover should be manifest by a drastic change of the interference pattern as a function of the coupling fields.Comment: 4 pages, 3 figure

Dilepton asymmetries at BB factories in search of ΔB=−ΔQ\Delta B =- \Delta Q transitions

In order to detect the possible presence of $\Delta B = - \Delta Q$ amplitudes in neutral $B$ meson decays, we consider the measurement of decay time asymmetries involving like-sign dilepton events at the $B$ factories.Comment: 5 pages, latex, no fig

Absence of low-temperature dependence of the decay of 7Be and 198Au in metallic hosts

The electron-capture (EC) decay rate of 7Be in metallic Cu host and the beta-decay rate of 198Au in the host alloy Al-Au have been measured simultaneously at several temperatures, ranging from 0.350 K to 293 K. No difference of the half-life of 198Au between 12.5 K and 293 K is observed to a precision of 0.1%. By utilizing the special characteristics of our double-source assembly, possible geometrical effects that influence the individual rates could be eliminated. The ratio of 7Be to 198Au activity thus obtained also remains constant for this temperatures range to the experimental precision of 0.15(0.16)%. The resulting null temperature dependence is discussed in terms of the inadequacy of the often-used Debye-Huckel model for such measurements.Comment: Four pages, three figures. Accepted for publication in Phys. Rev. C (Rapd Communications

Test of J-matrix inverse scattering potentials on electromagnetic reactions of few-nucleon systems

The J-matrix inverse scattering nucleon-nucleon potentials (JISP), describing both two-nucleon data and bound and resonant states of light nuclei to high accuracy, are tested on the total photoabsorption cross sections of Deuteron, Triton, 3He and 4He. The calculations in the three- and four-body systems are carried out via the Lorentz integral transform method and the hyperspherical harmonics (HH) technique. To this end the HH formalism has been adapted to accommodate non-local potentials. The cross sections calculated with the JISP are compared to those obtained with more traditional realistic interactions, which include two- and three-nucleon forces. While the results of the two kinds of potential models do not differ significantly at lower energies, beyond the resonance peak they show fairly large discrepancies, which increase with the nuclear mass. We argue that these discrepancies may be due to a probably incorrect long range behavior of the JISP, since the one pion exchange is not manifestly implemented there.Comment: 18 pages, 4 figures, 1 tabl

Similarity classes of 3x3 matrices over a local principal ideal ring

In this paper similarity classes of three by three matrices over a local principal ideal commutative ring are analyzed. When the residue field is finite, a generating function for the number of similarity classes for all finite quotients of the ring is computed explicitly.Comment: 14 pages, final version, to appear in Communications in Algebr

Velocity dependent interactions and a new sum rule in bcc He

Recent neutron scattering experiments [PRL,{\bf 88},p.195301 (2002)] on solid $^4$He, discovered a new optic-like mode in the bcc phase. This excitation was predicted by a recently proposed model that describes the correlated atomic zero-point motion in bcc Helium in terms of dynamic electric dipole moments. Modulations of the relative phase of these dipoles between different atoms describes the anomalously soft T$_1$(110) phonon and two new optic-like modes, one of which was recently found in the neutron scattering experiments. In this work we show that the correlated dipolar interactions can be written as a velocity dependent interaction. This then results in a modified f-sum rule for the T$_1$(110) phonon, in good agreement with the recent experimental data.Comment: 5 pages, 3 figure

Total Photoabsorption Cross Sections of A=6 Nuclei with Complete Final State Interaction

The total photoabsorption cross sections of 6He and 6Li are calculated microscopically with full inclusion of the six-nucleon final state interaction using semirealistic nucleon-nucleon potentials. The Lorentz Integral Transform (LIT) method and the effective interaction approach for the hyperspherical formalism are employed. While 6Li has a single broad giant resonance peak, there are two well separated peaks for 6He corresponding to the breakup of the neutron halo and the alpha core, respectively. The comparison with the few available experimental data is discussed.Comment: LaTeX, 8 pages, 3 ps figure

Large effects on \BsBs mixing by vector-like quarks

We calculate the contributions of the vector-like quark model to \BsBs mixing, taking into account the constraints from the decay $B\to X_s\gamma$. In this model the neutral bosons mediate flavor-changing interactions at the tree level. However, \BsBs mixing is dominated by contributions from the box diagrams with the top quark and the extra up-type quark. In sizable ranges of the model parameters, the mixing parameter $x_s$ is much different from the standard model prediction.Comment: 11 pages, 4 figures, To be published in Phys. Rev.