Mass formula

About: Mass formula is a research topic. Over the lifetime, 1248 publications have been published within this topic receiving 22043 citations.

Mass formula for Einstein-Yang-Mills solitons

Abstract: The isolated horizon formalism, together with a simple phenomenological model for colored black holes was recently used to predict a formula for the ADM mass of the solitons of the EYM system in terms of horizon properties of black holes for all values of the horizon area. In this Brief Report, this formula is tested numerically\char22{}up to a large value of the area\char22{}for spherically symmetric solutions and shown to yield the known masses of the solitons.

A semiempirical mass formula for spherical Coulomb crystals

Abstract: In analogy to the Bethe–Weizs¨ acker formula for nuclei we establish a semiempirical mass formula for the energies of Coulomb crystals including Madelung, surface, compression and curvature energy terms. The surface tension and the incompressibility are extracted as well. The coefficients are fitte da td ata obtained from molecular dynamics calculations for spherically confined systems of charged particles with particle numbers up to about 100 000 under their mutual Coulomb repulsion and under constant radial focusing. The systems are cooled down until the excess energy stays constant up to 10 −8 . Fo rp article numbers below about 10 000, they settle in icosahedral structures whose faces are rounded off. At about 10 000 particles there is a transition to body centred cubic (bcc) crystals where particles are arranged in parallel layers. The icosahedra have lower surface energy but slightly higher Madelung energy of −0.8949, in contrast to the bcc crystals which have the lower Madelung energy of −0.8959 but essentially larger surface energy. The icosahedra are more compressible than the bcc crystals. (Some figures in this article are in colour only in the electronic version)

SU 3-invariant spinor theory without quarks

Abstract: A phenomenological spinor theory is developed which incorporatesSU3 symmetry in the form of octet spinor fields rather than triplet quark fields. This allows the use of more conventional procedures in attacking the dynamical problem. A development of such aSU3 theory based on Weyl spinors proves too restrictive, since, in particular, it is unable to produce a nontrivialF/D ratio for the 0−-boson-octet-baryon interaction in the lowest approximation. Hence the main emphasis is based on theories involving Dirac spinor fields. It is demonstrated that in the octet formulation the Weyl-typeV−A interaction is the only four-spinor interaction which has exactlySU3×SU3 as maximal internal symmetry group (besides the two gauge groups). TheSU3×SU3 invariant interactions involving Dirac-scalar terms have higher symmetry. For theories involving among others a scalar interaction an appropriate regularization procedure allows one to formulate the continuity equations for the currents in the conventional form. Mass values and coupling constants for the simplest baryon and boson multiplets can be calculated in terms of one free regularization constant. There exists a uniquely determinedSU3-breaking four-spinor interaction which is proportional to an octet operator and does not mixSU3 multiplets. The formalism is exemplified in some preliminary models.

Isospin mass splittings of hadrons with heavy quarks

Abstract: Following the previous proposal that isospin mass splittings of hadrons can be extracted in a model-independent way by the quark-mass interpolation scheme, we derived a compact expression for the mass splittings of baryons and mesons. We have shown that the mass splitting approaches the asymptotic limit within 0.3 MeV for a quark mass greater than 5 GeV. Therefore we can predict the isospin mass splittings of hadrons containing any unknown heavy quarks. In particular M/sup asterisk+/(ut-bar )-M/sup asterisk0/(dt-bar ) roughly-equalM/sup +/(ut-bar ) = -3.7 MeV.

Alpha-decay Half-lives and Fission Barriers for Superheavy Nuclei Predicted by a Nuclear Mass Formula

Abstract: We estimate α-decay half-lives from Qα values with phenomenological formulas. The parameter values of the formulas are adjusted by using experimental half-lives and Q values of the Evaluated Nuclear Structure Data File (ENSDF) for a wide nuclidic region. The half-lives Tα for unknown nuclei are estimated by this phenomenological formula with the use of Qα values taken from KUTY mass formula. In addition to the half-lives, we estimate spontaneous fission barriers calculated by the method to obtain the shell energies of KUTY formula. In the superheavy region, the barrier heights of the nuclei near the nucleus 304 122 are about 8 MeV and their widths are fairly wide. Therefore these spontaneous-fission half-lives are expected to be very long. On the other hand, there are some neutron-deficient nuclei whose spontaneous-fission half-lives expected to be rather short because their fission barrier heights are small and the widths of them are narrow.