Search results for "Atomic nucleus"

First identification of rotational band structures inRe9175166

2015

Despite that it is more than 100 years since the atomic nucleus was first dis- covered by Ernest Rutherford and coworkers, many of its features still elude our understanding. The fact that the fundamental interactions between the nuclear constituents; nucleons, and ultimately quarks, are not yet known in detail, and the complexity of the nuclear many-body system compound the great challenges facing theoretical interpretations of experimental data. It is therefore important to focus on distinct phenomena where experimental mea- surements can be compared with theoretical predictions, providing stringent tests of theory. One such area is the nuclear phenomenology of collective excitations rela…

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…

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…

2021

The fundamental nature of the neutrino is presently a subject of great interest. A way to access the absolute mass scale and the fundamental nature of the neutrino is to utilize the atomic nuclei through their rare decays, the neutrinoless double beta (0νββ) decay in particular. The experimentally measurable observable is the half-life of the decay, which can be factorized to consist of phase space factor, axial vector coupling constant, nuclear matrix element, and function containing physics beyond the standard model. Thus reliable description of nuclear matrix element is of crucial importance in order to extract information governed by the function containing physics beyond the standard m…

Rare weak decays and nuclear structure

2014

Abstract. Weak interactions cause the atomic nuclei to decay via beta and double beta decays. Double beta decays are extremely rare since they are weak-interaction processes of the second order. Also (single) beta decays can be extremely rare. This can be caused by either a large di ff erence between the spins of the initial and final state (the so-called “forbidden” beta decays) or an extremely small Q value (decay energy) of the decay. All these cases are discussed in this article, and particular emphasis is given to the neutrino- less double electron capture on the double beta side of decays. peerReviewed

Unified description of hadronic and electromagnetic reactions of the two-nucleon system

2010

Abstract Studies of the two-nucleon system are essential for a profound understanding of nuclear structure and for the exploration of the limits of the effective description of atomic nuclei in terms of nucleons, mesons and isobars. In the present work, a unified description of hadronic and electromagnetic reactions on the two-nucleon system is developed in the framework of a coupled-channel N N / N Δ -approach which is based on one general Hamiltonian and which treats the pion exchange in the hadronic baryon–baryon interaction as well as in the meson exchange currents in the exact retarded manner. Unitarity and gauge invariance are at least approximately fulfilled. Several hadronic and ele…

High-precision mass spectrometer for light ions

2020

The precise knowledge of the atomic masses of light atomic nuclei, e.g. the proton, deuteron, triton and helion, is of great importance for several fundamental tests in physics. However, the latest high-precision measurements of these masses carried out at different mass spectrometers indicate an inconsistency of five standard deviations. To determine the masses of the lightest ions with a relative precision of a few parts per trillion and investigate this mass problem a cryogenic multi-Penning trap setup, LIONTRAP (Light ION TRAP), was constructed. This allows an independent and more precise determination of the relevant atomic masses by measuring the cyclotron frequency of single trapped …

Single-molecule spintronics, or how to measure the magnetic state of a single atomic nucleus

2018

Unified description of structure and reactions: implementing the Nuclear Field Theory program

2015

The modern theory of the atomic nucleus results from the merging of the liquid drop (Niels Bohr and Fritz Kalckar) and of the shell model (Marie Goeppert Meyer and Axel Jensen), which contributed the concepts of collective excitations and of independent-particle motion respectively. The unification of these apparently contradictory views in terms of the particle-vibration (rotation) coupling (Aage Bohr and Ben Mottelson) has allowed for an ever increasingly complete, accurate and detailed description of the nuclear structure, Nuclear Field Theory (NFT, developed by the Copenhagen-Buenos Aires collaboration) providing a powerful quantal embodiment. In keeping with the fact that reactions are…