Search results for "probability"
showing 10 items of 3417 documents
Primordial Nucleosynthesis, Majorons and Heavy Tau Neutrinos
1996
We determine the restrictions imposed by primordial nucleosynthesis upon a heavy tau neutrino, in the presence of nu-tau annihilations into Majorons, as expected in a wide class of particle physics models of neutrino mass. We determine the equivalent number of light neutrino species $N_{eq}$ as a function of nu-tau mass and the nu-tau-Majoron coupling $g$. We show that for theoretically plausible $g$ values $\gsim 10^{-4}$ present nucleosynthesis observations can not rule out nu-tau masses in the MeV range. Moreover, these models give $N_{eq} \leq 3$ in the nu-tau mass region 1-10 MeV, for very reasonable values of $g \geq 3 \times 10^{-4}$. The evasion of the cosmological limits brings new…
Monte Carlo simulation of virtual Compton scattering below pion threshold
2006
This paper describes the Monte Carlo simulation developed specifically for the VCS experiments below pion threshold that have been performed at MAMI and JLab. This simulation generates events according to the (Bethe-Heitler + Born) cross section behaviour and takes into account all relevant resolution-deteriorating effects. It determines the `effective' solid angle for the various experimental settings which are used for the precise determination of photon electroproduction absolute cross section.
Experimental Linear Energy Transfer of Heavy Ions in Silicon for RADEF Cocktail Species
2009
Experimental linear energy transfer values of heavy ions in silicon are presented with comparison to estimations from different semi empirical codes widely used among the community. This paper completes the experimental LET data for the RADEF cocktail ions in silicon.
Wavelet analysis of experimental results for coupled structural–hydraulic behavior of the EURISOL target mock-up
2009
During test runs of the The European Isotope Separation On-Line (EURISOL) target mock-up performed in December 2008, data were recorded for strain gages and for acceleration sensors. In this paper, the applicability of wavelet analysis for detecting the onset and the status of flow-induced cavitation is investigated for the first time. Even under noisy conditions, the detection of incipient cavitation was possible when combining measurements with data from structural and fluid dynamic simulations. The distribution of coefficients of suitably selected wavelets yields a quantitative measure for the extent of cavitation in the EURISOL target mock-up under representative flow conditions. Withou…
Lifetime measurement in 195Po
2009
The lifetime of the 17/2+ yrast state in 195Po has been measured using the recoil distance Doppler-shift technique to be $ \tau$ = 43(11) ps. The lifetime was extracted from the singles $ \gamma$ -ray spectra obtained by using the recoil-decay tagging method. The present work provides more information of the coupling schemes, shapes and configuration mixing in neutron-deficient odd-mass Po nuclei.
Instabilities of infinite matter with effective Skyrme-type interactions
2002
The stability of the equation of state predicted by Skyrme-type interactions is examined. We consider simultaneously symmetric nuclear matter and pure neutron matter. The stability is defined by the inequalities that the Landau parameters must satisfy simultaneously. A systematic study is carried out to define interaction parameter domains where the inequalities are fulfilled. It is found that there is always a critical density $\rho_{cr}$ beyond which the system becomes unstable. The results indicate in which parameter regions one can find effective forces to describe correctly finite nuclei and give at the same time a stable equation of state up to densities of 3-4 times the saturation de…
Nuclear physics far from stability and explosive nucleosynthesis processes
1998
In this paper, we discuss the astrophysically relevant nuclear-physics input for a selected set of explosive nucleosynthesis scenarios leading to rapid protonand neutron-capture processes. Observables (like,e.g., luminosity curves or abundance distributions) witness the interplay between nuclear-structure aspects far from β-stability and the appropriate astrophysical environments, and can give guidance to and constraints on stellar conditions and/or key features of reaction and decay data for radioactive isotopes.
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.
STUDIES OF SUPERHEAVY ELEMENTS AT SHIP
2007
An overview of present experimental investigation of superheavy elements is given. The data are compared with theoretical descriptions. Results are reported from an experiment to confirm production of element 112 isotopes in irradiation of 238 UF 4 with 48 Ca . One spontaneous fission event was measured, which agrees with three events of previously measured data which had been assigned to the decay of 283112. However, more experimental work is needed in order to obtain an independent and unambiguous confirmation of previous results.
β− Strength function phenomena of exotic nuclei: A critical examination of the significance of nuclear model predictions
1984
Abstract Reliable predictions of β-decay properties of nuclei far from stability require knowledge of the β-strength distribution, S β ( E ). By comparison of experimental strength functions of neutron-rich Rb isotopes in the transitional region around A = 100 with S β ( E ) from different nuclear models, the sensitivity and physical significance of S β ( E ) on various integral and spectral β-decay properties are examined. The reliability of extrapolations and the applicability to different fields in nuclear physics, astrophysics and reactor technology are discussed. It is shown that, although there has been considerable progress in the physical understanding of the decay properties of nuc…