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 baryon resonances

Abstract: Light-baryon resonances with u, d, and s quarks only can be classified using the nonrelativistic quark model. When we assign intrinsic orbital angular momenta L and spin S to baryon resonances with total angular momenta J, we make the following observations: plotting the squared masses of the light-baryon resonances against these intrinsic orbital angular momenta L, ${\ensuremath{\Delta}}^{*}'\mathrm{s}$ with even and odd parity can be described by the same Regge trajectory. For a given L, nucleon resonances with spin $S=3/2$ are approximately degenerate in mass with $\ensuremath{\Delta}$ resonances of same total orbital momentum L. To which total angular momentum L and S couple has no significant impact on the baryon mass. Nucleons with spin 1/2 are shifted in mass; the shift is---in units of squared masses---proportional to the component in the wave function which is antisymmetric in spin and flavor. Sequential resonances in the same partial wave are separated in mass square by the same spacing as observed in orbital angular momentum excitations. Based on these observations, a new baryon mass formula is proposed which reproduces nearly all known baryon masses.

Nuclear Sizes and the Weiszäcker Mass Formula

Abstract: A Bethe-Weiszacker type mass surface provides the best account of nuclear masses at a Coulomb radius parameter in agreement with the equivalent parameter inferred from Stanford electron scattering. An effont is made to relate the Weiszacker equation directly to potentials obtained from scattering and shell models. (W.D.M.)

Generalized mass formula for non-strange and hypernuclei with SU(6) symmetry breaking

Abstract: A simultaneous description of non-strange nuclei and hypernuclei is provided by a single mass formula inspired by the spin–flavour SU(6) symmetry breaking. This formula is used to estimate the hyperon binding energies of lambda, double lambda, sigma, cascade and theta hypernuclei. The results are found to be in good agreement with the available experimental data on 'bound' nuclei and relativistic as well as quark mean-field calculations. This mass formula is useful to estimate binding energies over a wide range of masses including the light mass nuclei. It is not applicable to a repulsive potential.

Softly broken N=2 QCD

Abstract: We analyze the possible soft breaking of $N=2$ supersymmetric Yang-Mills theory with and without matter flavour preserving the analyticity properties of the Seiberg-Witten solution. We present the formalism for an arbitrary gauge group and obtain an exact expression for the effective potential. We describe in detail the onset of the confinement description and the vacuum structure for the pure $SU(2)$ Yang-Mills case and also some general features in the $SU(N)$ case. A general mass formula is obtained, as well as explicit results for the mass spectrum in the $SU(2)$ case.

Nuclear deformations in the A≈80-100 region

Abstract: The occurrence of highly deformed nuclei in the A approximately=80 and A approximately=100 mass regions has been investigated in the framework of the Strutinsky approach with a Nilsson-type potential and the Yukawa-plus-exponential macroscopic mass formula, including elongation, necking and gamma deformation. Special emphasis was given to the spin-orbit potential parameters, which have large variations at the magic numbers and also depend on the shell filling. Good reproduction of the masses, deformations and shape transition was achieved in both mass regions. The phenomena of shape coexistence are also supported by the calculated potential energy surfaces. The odd-particle influence in driving the nucleus to deformed shapes is demonstrated. The results obtained are rather similar to those of the more elaborated Yukawa shell-model calculations, and show for the first time that a Nilsson-type model can also account for the large deformations of the light Kr, Sr and Zr nuclei.