Search results for "Mass formula"
showing 10 items of 29 documents
The Basics of Nuclear Chemistry and Radiochemistry: An Introduction to Nuclear Transformations and Radioactive Emissions
2019
Radiopharmaceutical chemistry and nuclear medicine make use of radioactive elements and compounds labeled with them. This chapter describes the fundamentals of radioactivity in the context of life sciences. It addresses principal questions such as: What is the composition of an atomic nucleus and what are the forces which hold nucleons bound within the nucleus? Even so, some nuclei are stable, and many others are not—why? The fate of unstable nuclei is transforming into more stable nucleon configurations—but what are the basic pathways to do so? What’s going on inside the nucleus? What are the energetics and velocities of these transformations? And finally, the various changes inside the nu…
Gluon mass generation in the presence of dynamical quarks
2013
We study in detail the impact of dynamical quarks on the gluon mass generation mechanism, in the Landau gauge, for the case of a small number of quark families. As in earlier considerations, we assume that the main bulk of the unquenching corrections to the gluon propagator originates from the fully dressed quark-loop diagram. The nonperturbative evaluation of this diagram provides the key relation that expresses the unquenched gluon propagator as a deviation from its quenched counterpart. This relation is subsequently coupled to the integral equation that controls the momentum evolution of the effective gluon mass, which contains a single adjustable parameter; this constitutes a major impr…
All-order equation of the effective gluon mass
2012
We present the general derivation of the full non-perturbative equation that governs the momentum evolution of the dynamically generated gluon mass, in the Landau gauge. The entire construction hinges crucially on the inclusion of longitudinally coupled vertices containing massless poles of non-perturbative origin, which preserve the form of the fundamental Slavnov-Taylor identities of the theory. The mass equation is obtained from a previously unexplored version of the Schwinger-Dyson equation for the gluon propagator, particular to the PT-BFM formalism, which involves a reduced number of "two-loop dressed" diagrams, thus simplifying the calculational task considerably. The two-loop contri…
Renormalization group analysis of the gluon mass equation
2014
In the present work we carry out a systematic study of the renormalization properties of the integral equation that determines the momentum evolution of the effective gluon mass. A detailed, all-order analysis of the complete kernel appearing in this particular equation reveals that the renormalization procedure may be accomplished through the sole use of ingredients known from the standard perturbative treatment of the theory, with no additional assumptions. However, the subtle interplay of terms operating at the level of the exact equation gets distorted by the approximations usually employed when evaluating the aforementioned kernel. This fact is reflected in the form of the obtained sol…
High-accuracy mass measurements on neutron deficient neon isotopes
2005
International audience; The atomic masses of the short-lived nuclides 17Ne and 19Ne have been measured with the triple-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The obtained mass excess for both nuclides deviates significantly from the literature value, in the case of 17Ne about 40 keV. The mass value of 17Ne can be applied for a test of the isobaric multiplet mass equation with respect to an isospin T = 3/2 quartet. In addition, both masses can contribute to the data analysis of collinear laser-spectroscopy experiments where mean-square nuclear-charge radii are determined.
Breakdown of the Isobaric Multiplet Mass Equation atA=33,T=3/2
2001
Mass measurements on ${}^{33,34,42,43}\mathrm{Ar}$ were performed using the Penning trap mass spectrometer ISOLTRAP and a newly constructed linear Paul trap. This arrangement allowed us, for the first time, to extend Penning trap mass measurements to nuclides with half-lives below one second ( ${}^{33}\mathrm{Ar}$: ${T}_{1/2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}174\mathrm{ms}$). A mass accuracy of about ${10}^{\ensuremath{-}7}$ $(\ensuremath{\delta}m\ensuremath{\approx}4\mathrm{keV})$ was achieved for all investigated nuclides. The isobaric multiplet mass equation was checked for the $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}33$, $T\phantom{\rule{0ex}{0ex}}=\phantom…
Improved Skyrme forces for Hartree-Fock seniority calculations
1992
Abstract The relationship between Skyrme parameters and physical quantities in nuclear matter is discussed in detail and bounds for some parameters are derived. Improved density-dependent two-body Skyrme forces are obtained by a least-squares fit of all the parameters simultaneously to a large set of data, including nuclear matter, mass formula and Landau parameters, and data of finite nuclei. Special attention is paid to the pairing properties of the interaction. These forces are used to perform self-consistent calculations in spherical closed-shell nuclei and Ca open-shell isotopes, within the Hartree-Fock seniority method. Good agreement with experimental data is obtained.
Fission barriers of doubly charged silver clusters
1999
The monomer evaporation energies and fission barriers of doubly charged silver cluster ions in the size range 9≤n≤25 are measured by collision induced dissociation. They are compared to the dissociation energies of singly charged silver clusters. A macroscopic liquid drop model combined with empirical microscopic corrections successfully describes the measured fission barriers.
Stability limits of elemental 2D metals in graphene pores
2019
Two-dimensional (2D) materials can be used as stabilizing templates for exotic nanostructures, including pore-stabilized, free-standing patches of elemental metal monolayers. Although these patches represent metal clusters under extreme conditions and are thus bound for investigations, they are poorly understood as their energetic stability trends and the most promising elements remain unknown. Here, using density-functional theory simulations and liquid drop model to explore the properties of 45 elemental metal candidates, we identify metals that enable the largest and most stable patches. Simulations show that pores can stabilize patches up to $\sim 8$ nm$^2$ areas and that the most promi…
Decays of T Z = − 3/2 nuclei 23Al, 31Cl, and 41Ti
2012
This article gives an overview on the decay spectroscopy of T Z = − 3/2 nuclei 23Al, 31Cl, and 41Ti performed at the Ion Guide Isotope Separator On-Line (IGISOL) facility. The results of the IGISOL experiments are compared to the experimental results that have been published since. The isobaric multiplet mass equation (IMME) has been studied for the T = 3/2 quartets at A = 23 and A = 31. For 41Ti, a detailed comparison to the Gamow–Teller strengths obtained for the analog transitions via charge-exchange reactions has been done. Further improvements in the experimental instrumentation and methods and possible implementations for studying T Z = − 3/2 nuclei at the new IGISOL facility are di…