Search results for "nucleus"
showing 10 items of 1803 documents
Structure of the neutron-rich nucleus 37 94 rb57
1989
A level scheme has been established for 37 94 Rb57 based on studies at the fission-product separator JOSEF ofγγ coincidences following theβ- decay of94Kr. For the 190.7 keV level a half-life of 2.5(8) ns has been determined through the centroid-shift method. The majorβ-decay branch of94Kr proceeds with log ft=3.7 into the 988.4 keV state in94Rb. This transition must be of the 0+→1+ GT type involving the transitionνg7/2→πg9/2. IBFFM calculations have been performed for94Rb, starting from the parametrization used in the previous IBM investigations for the isotope93Rb and the isotone96Y. A theoretical interpretation of the low-lying levels including propositions for the spins is given in a com…
Two-particle correlations in 400 GeV proton-nucleus interactions
1980
Two-particle inclusive correlations are studied by means of the two-particle rapidity correlation function. The data for the analysis come from an exposure of emulsion plates to a 400 GeV proton beam at FNAL. Predominant short-range correlations among shower particles are found, but this does not allow to exclude some long-range correlation behaviour, in agreement with the results obtained in lower-energy experiments.
Studies of Hyperons and Antihyperons in Nuclei
2010
Stored antiproton beams at the international FAIR facility will provide unique opportunities to study hyperons as well as antihyperons in nuclear systems. Precise γ-spectroscopy of multistrange hypernuclei will serve as a laboratory for the hyperon-hyperon interaction. Exclusive hadron-antihadron pair production close to threshold can measure the potential of a antihadron relative to that of the coincident hadrons. In the present work we explore the production of excited states in double hypernuclei following the micro-canonical break-up of an initially excited double hypernucleus which is created by the absorption and conversion of a stopped Ξ− hyperon. Generally the formation of excited h…
A theoretical view on bound antikaon-nuclear states
2008
We present an overview of the latest theoretical studies on the antikaon properties in the nuclear medium, in connection with the recent experimental claims of very deeply bound antikaon-nuclear states. We argue that proper many-body formulations using modern realistic antikaon-nucleon interactions are not able to generate such systems. Instead, a simple two-nucleon antikaon absorption mechanism where the remaining nucleus acts as spectator explains the peak in the semi-inclusive proton momentum spectrum, observed on a 4He target at KEK (but later not confirmed in an inclusive experiment) and on a 6Li target at FINUDA. This signal is clearly seen in another FINUDA experiment measuring the i…
Scattering of Strongly Interacting Particles on Nuclei
1996
This chapter deals with the interaction of strongly interacting particles (hadrons) with nuclei, at low and intermediate energies. The hadronic projectiles are used as probes of nuclear properties and of the hadron-nucleon interaction in the nuclear medium, and they are selected accordingly. We discuss mainly the case of pions, to some extent also kaons, because of the specific properties of the pion-(kaon)-nucleon system. Some of the methods and results can also be applied to nucleons if these are chosen to be projectiles, but we do not go into the full complexity of the spin analysis of the nucleon-nucleon system. In this sense this field is distinct from the conventional topic of nuclear…
Nuclear Ground-State Properties from Laser and Mass Spectroscopy
1990
Atomic physics played an important role in establishing our present-day knowledge on the atomic nucleus. Especially mass spectrometry and optical spectroscopy were the main sources of information on nuclear properties in the early days of nuclear physics. Still now, precise information on nuclear masses (or binding energies) are obtained by mass spectrometry whereas mass differences between two isotopes are usually determined by nuclear-spectroscopy techniques via a determination of the Q-value of nuclear reactions or decay. Almost all our information on the nuclear spins I, the nuclear magnetic dipole moment μ I, the spectroscopic quadrupole moment Q, and the changes in the mean-square cha…
The limits of the nuclear landscape
2012
In 2011, 100 new nuclides were discovered. They joined the approximately 3,000 stable and radioactive nuclides that either occur naturally on Earth or are synthesized in the laboratory. Every atomic nucleus, characterized by a specific number of protons and neutrons, occupies a spot on the chart of nuclides, which is bounded by 'drip lines' indicating the values of neutron and proton number at which nuclear binding ends. The placement of the neutron drip line for the heavier elements is based on theoretical predictions using extreme extrapolations, and so is uncertain. However, it is not known how uncertain it is or how many protons and neutrons can be bound in a nucleus. Here we estimate t…
Medium-spin levels and the character of the 20.4 ns isomer in 145Gd
1982
Abstract Levels of the N = 81 nucleus 145Gd have been investigated by in-beam γ-ray and conversion electron spectroscopy with the 144Sm(3He, 2n) reaction. Fourteen new low- and medium-spin states between 1.0 and 2.4 MeV excitation, the known yrast levels up to spin 21 2 + , five other high-spin non-yrast states and a new 20.4 ns 13 2 isomer at 2200.2 keV in 145Gd have been observed. The isomer decays via a fast 927.3 keV E3 transition with B(E3) = 48 ± 7 W.u. Another weaker decay branch is a mixed, strongly hindered E1 + M2 + E3 transition to the v h −1 11 2 state. We propose an octupole v f 7 2 j −2 × 3 − main configuration for the isomer, analogous to the 997 keV 13 2 + isomer in 147Gd. T…
γ-ray spectroscopy approaching the limits of existence of atomic nuclei: A study of the excited states ofPt168andPt169
2009
Excited states in the $N=90$ and $N=91$ Pt nuclei have been investigated using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. These nuclei were populated via the reactions $^{92}\mathrm{Mo}(^{78}\mathrm{Kr},2n)$ and $^{94}\mathrm{Mo}(^{78}\mathrm{Kr},3n)$ at 335 and 348 MeV, respectively. The recoil-decay tagging technique has been used to correlate prompt $\ensuremath{\gamma}$ radiation with the characteristic $\ensuremath{\alpha}$ decays of $^{168}\mathrm{Pt}$ and $^{169}\mathrm{Pt}$. A $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ analysis has allowed a level scheme for $^{168}\mathrm{Pt}$ to be reported for the first time and the l…
Maximally aligned states in the proton drip line nucleus 106Sb
2005
High-spin states in Sb-106 have been investigated in the Fe-54(Ni-58, 1α 1p1n) reaction by in-beam γ-spectroscopic methods using the EUROBALL detector array equipped with charged particle and neutr ...