Search results for "Velocity"
showing 10 items of 881 documents
High-resolution (3He,t) reaction on the double-βdecaying nucleus136Xe
2011
A (${}^{3}\text{He},t$) charge-exchange reaction experiment on the double-beta decaying nucleus ${}^{136}$Xe has been performed at an incident energy of 420 MeV with the objective to measure the Gamow-Teller (GT) strength distribution in ${}^{136}$Cs. The measurements have been carried out at the dispersion-matched WS beam line and the Grand Raiden spectrometer of the Research Center for Nuclear Physics in Osaka, where an energy resolution of 42 keV was achieved. A new gas cell with thin windows made of polyethylene naphthalate has been employed as a target. The extracted GT strength distribution is confronted with the rather long $2\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ deca…
On the existence of higher waves in a layer of superfluid helium
1973
The two implicit equations that contain the dispersion laws of waves propagating in a He II layer of variable thickness are formally investigated for solutions that go beyond those associated with the layer modifications of first and second sound: A series of symmetric and antisymmetric layer modes are found to exist by calculating the distribution of roots of the dispersion equations in the complex wave number plane as a function of layer thickness and angular frequency. All these modes turn out to be strongly attenuated and can be regarded as layer modifications of the viscous wave. Phase velocities, attenuation coefficients, and velocity profiles of some of them are calculated numericall…
$\beta$ - decay of the M$_{T}$=-1 nucleus $^{58}$Zn studied by selective laser ionization
1998
$\beta$ - decay of $^{58}$Zn has been studied for the first time. A new laser ion-source concept has been used to produce mass-separated sources for $\beta$ and $\gamma$ - spectroscopy. The half-life of $^{58}$Zn was determined to be 86(18) ms. Comparisons are made with previous data from charge-exchange reactions. Our Gamow-Teller strength to the 1$^{+}$ state at 1051 keV excitation in $^{58}$Cu agrees well with the value extracted from a recent ($^{3}$He, t) study. Extensive shell-model calculations are presented.
MR-tomographische Messung der diastolischen Relaxation hypertrophierter linker Ventrikel mit Single-slice-multi-phase-Technik
1993
In order to assess diastolic ventricular function in hypertensive patients, a single-slice multiphase sequence was used in order to measure contraction and early diastolic relaxation. There was no difference in the contraction velocity between hypertensives and normals (Vsys. n.r. = 56.1 +/- 13.8% LVDV/s vs. 51.7 +/- 8.6% LVEDV/s, stat, n. sign.). Early diastolic relaxation velocity in hypertensives was reduced as compared with the control group (Vdiast. 1n.r. = 37.9 +/- 13.1% LVEDV/s vs. 47.1 +/- 9.6% LVEDV/s, p < 0.05). There was no linear relation between abnormal relaxation and the extent of myocardial hypertrophy. Hypertensives with myocardial hypertrophy frequently had reduced early d…
Constraints on r-process conditions from beta-decay properties far off stability and r-abundances.
1988
The measured beta -decay properties of the 'waiting-point' nuclei 130Cd and 80Zn, together with improved shell model predictions of T1/2 and Pn-values for their experimentally unknown N approximately=82 and 50 neighbours, can be directly related to the observed r-abundances in the A approximately=130 and 80 abundance peaks. Based on this result, new constraints are given on the stellar conditions under which the r-process has operated.
Microscopic study of muon-capture transitions in nuclei involved in double-beta-decay processes
2003
Abstract Total and partial ordinary muon-capture (OMC) rates to 1 + and 2 − states are calculated in the framework of the proton–neutron quasiparticle random-phase approximation (pnQRPA) for several nuclei involved in double-beta-decay processes. The aim is to obtain information on intermediate states involved in double-beta-decay transitions having these nuclei as either daughter or parent nuclei. It is found that the OMC observables, just like the 2 νββ -decay amplitudes, strongly depend on the particle–particle part of the proton–neutron interaction. First experiments measuring the partial OMC rates for nuclei involved in double beta decays have recently been performed.
Determination of γ and−2βsfrom charmless two-body decays of beauty mesons
2015
Using the latest LHCb measurements of time-dependent CP violation in the B-s(0) -> K+K- decay, a U-spin relation between the decay amplitudes of B-s(0) -> K+K- and B-0 -> p(+)p(-) decay processes allows constraints to be placed on the angle gamma of the unitarity triangle and on the B-s(0) mixing phase -2 beta(s). Results from an extended approach, which uses additional inputs on B-0 -> pi(0)pi(0) and B+ -> pi(+)pi(0) decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value gamma =( 63.5(-6.7)(+7.2))degrees modulo 180 degrees is determined. In an a…
Nuclear matrix elements and the neutrinoless double beta decay
2005
Systematics of the nuclear matrix elements related to the neutrinoless double beta ( 0 ν β β ) decay are discussed. The calculation of the related nuclear matrix elements in the framework of the proton-neutron quasiparticle random-phase approximation (pnQRPA) is analyzed. In particular, the extraction of a proper value of the proton-neutron particle-particle interaction parameter in this theory is addressed. The relevance of different multipoles in the multipole decomposition of the 0 ν β β matrix element is also discussed.
STUDIES OF 12C USING β-DECAYS
2008
The nuclear structure of states in 12 C have been a subject of interest for both theory and experiment since the early days of nuclear physics. Many open questions remain, especially concerning the existence and properties of 0+ and 2+ states in the triple alpha continuum. A series of experiments have been performed using β-decay of 12 N and 12 B to probe these states. The latest experiment was performed at KVI using an implantation method, measuring the sum energy of the three α-particles directly. Preliminary results from this experiment will be presented.
Collectivity and Configuration Mixing inPb186,188andPo194
2006
Lifetimes of prolate intruder states in {sup 186}Pb and oblate intruder states in {sup 194}Po have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift lifetime measurements. In addition, lifetime measurements of prolate states in {sup 188}Pb up to the 8{sup +} state were carried out using the recoil-gating method. The B(E2) values have been deduced from which deformation parameters vertical bar {beta}{sub 2} vertical bar =0.29(5) and vertical bar {beta}{sub 2} vertical bar =0.17(3) for the prolate and the oblate bands, respectively, have been extracted. The results also shed new light on the mixing between different shapes.