Search results for "Proton"
showing 10 items of 5886 documents
β-decay half-life of70Kr: A bridge nuclide for therpprocess beyondA=70
2000
The -decay half-life of 70 Kr has been measured for the first time at the ISOLDE PSB Facility at CERN. Mass separated 70 Kr ions were produced by 1 GeV proton induced spallation reactions in a Nb foil. The measured half-life is 57(21) ms. This value is consistent with the half-life calculated assuming a pure Fermi decay, but is clearly lower than the value used in a recent rp-process reaction flow calculation. The result shows that the reaction flow via two-proton-capture of 68 Se is 2.5 times faster than previously calculated assuming an astrophysical temperature of 1.5 GK and a density of 10 6 g/cm 3 .
β-decay of 35Ca
1999
Abstract The β-decay of the T z =− 5 2 nucleus 35 Ca was studied at the LISE3 spectrometer at GANIL. The 35 Ca decay scheme was deduced from its β-delayed proton emission into the ground and excited states of 34 Ar and from its β-delayed two-proton emission. The 35 Ca half-life was determined to be 25.7±0.2 ms. The measured transition strength function B(GT) is compared to results obtained from large-scale sd-shell model calculations.
Search for a right-handed gauge boson decaying into a high-momentum heavy neutrino and a charged lepton in pp collisions with the ATLAS detector at s…
2019
A search for a right-handed gauge boson WR, decaying into a boosted right-handed heavy neutrino NR, in the framework of Left-Right Symmetric Models is presented. It is based on data from proton–proton collisions with a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider during the years 2015, 2016 and 2017, corresponding to an integrated luminosity of 80 fb$^{−1}$. The search is performed separately for electrons and muons in the final state. A distinguishing feature of the search is the use of large-radius jets containing electrons. Selections based on the signal topology result in smaller background compared to the expected signal. No significant d…
Nuclear matrix elements of ββ decay from β-decay data
2005
Abstract The evaluation of the nuclear matrix elements (NME) of the two-neutrino double beta ( 2 ν β β ) decay and neutrinoless double beta ( 0 ν β β ) decay using the proton–neutron quasiparticle random-phase approximation (pnQRPA) is addressed. In particular, the extraction of a proper value of the proton–neutron particle–particle interaction parameter, g pp , of this theory is analyzed in detail. Evidence is shown, that it can be misleading to use the experimental half-life of the 2 ν β β decay to extract a value for g pp . Rather, arguments are given in favour of using the available data on single beta decay for this purpose.
Search for the terminating27−state inNd140
2015
In the search for the fully aligned 27(-) state in Nd-140 predicted by cranked Nilsson-Strutinsky calculations, new close-to-spherical high-spin states have been discovered. Both the close-to-spherical and the triaxial calculated states are in good agreement with the experimental results, supporting the existence of shape coexistence up to very high spins. Shell-model calculations using a newly developed effective interaction for the 50 <= N, Z <= 82 mass region are in good agreement with the observed spherical states. The comparison between the experimental and calculated level energies allowed the relative energy to be established between several proton and neutron orbitals at high energy…
High-power production targets for the Super-FRS using a fast extraction scheme
2003
Abstract The high-power production target of the Super-FRS [H. Geissel et al., these Proceedings] will be irradiated by very intense heavy-ion beams which will be delivered from the future SIS100/200 [An International Accelerator Facility for Beams of Ions and Antiprotons, GSI-Report, 2001] synchrotron facility at the Gesellschaft fur Schwerionenforschung (GSI) Darmstadt. This paper presents calculations of the thermodynamic and the hydrodynamic response of such a target, considering that a uranium ion beam with an energy of 1 GeV/u and an intensity of 10 12 particles will impinge within 50 ns on a solid carbon target with a thickness of 4 g/cm 2 . Due to the high beam intensity the target …
Decay studies ofAu170,171,Hg171–173, andTl176
2004
The $^{170,171}\mathrm{Au}$ isotopes were produced in the fusion-evaporation reaction of a $^{78}\mathrm{Kr}$ ion beam with a $^{96}\mathrm{Ru}$ target. For $^{170}\mathrm{Au}$ the proton and $\ensuremath{\alpha}$ emission from the ground state were observed for the first time and the decay of the isomeric state was measured with improved accuracy. In addition, the decay of $^{171}\mathrm{Au}$ was measured with high statistics. A new $\ensuremath{\alpha}$-emitting nucleus $^{171}\mathrm{Hg}$ and the previously known $^{172}\mathrm{Hg}$ and $^{167,168,169,170}\mathrm{Pt}$ isotopes were also studied. The ground-state proton emission was identified for a new proton emitter $^{176}\mathrm{Tl}$ …
New isomers in $^{125}$Pd$_{79}$ and $^{127}$Pd$_{81}$: Competing proton and neutron excitations in neutron-rich palladium nuclides towards the $N = …
2019
The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the N=82 neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in Pd and Pd studied using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity U beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of (23/2 ) and (19/2 ) in Pd and Pd, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitation…
Isomeric states in proton-unbound 187, 189Bi isotopes
2002
Prompt and delayed gamma-ray spectroscopy of very neutron-deficient bismuth isotopes 187, 189Bi has been performed using the Recoil Decay Tagging (RTD) method. The isomeric i 13/2 states have been identified and their lifetimes have been measured. The systematics of these long-lived M2 isomers has been extended to the proton-unbound isotopes. The general behaviour of single-proton states is discussed within the systematics and interpreted within the shell-model framework.
Multiple coulomb excitation of202Hg and204Hg
1985
Multiple Coulomb excitation measurements on202, 204Hg have been performed with 5 MeV/u208Pb projectiles. The ground bands are excited up to the newly discovered 6+ states and B(E2) values are derived for the 4+→2+ and 6+→4+ transitions. Whereas the 2+ and 4+ levels in the Hg isotopes with 196≦A≦204 have an almost constant energy, the 6+ levels increase in202Hg and204Hg, compared to the lighter isotopes, by approximately 100 and 300 keV, respectively. The relative B(E2) values in both nuclei show that the collectivity in the neutron rich Hg nuclei is of more complex origin than expected from the few proton and neutron holes with respect to the 82 and 126 major shells.