Wave-function-based characteristics of hybrid mesons

We propose some extensions of the quark potential model to hybrids, fit them to the lattice data and use them for the purpose of calculating the masses, root mean square radii and wave functions at the origin of the conventional and hybrid charmonium mesons. We treat the ground and excited gluonic field between a quark and an antiquark as in the Born-Oppenheimer expansion, and use the shooting method to numerically solve the required Schrödinger equation for the radial wave functions; from these wave functions we calculate the mesonic properties. For masses we also check through a Crank Nichelson discretization. For hybrid charmonium mesons, we consider the exotic quantum number states with J ^PC = 0^+?, 1^?+ and 2^+?. We also compare our results with the experimentally observed masses and theoretically predicted results of the other models. Our results have implications for scalar form factors, energy shifts, magnetic polarizabilities, decay constants, decay widths and differential cross-sections of conventional and hybrid mesons.     

Nuclear mass formula with a Yukawa-plus-exponential macroscopic model and a folded-Yukawa single-particle potential

We use a Yukawa-plus-exponential macroscopic model and a folded-Yukawa single-particle potential to systematically calculate the ground-state masses of 4023 nuclei ranging from ¹⁶O to {279}112. The method is also used to calculate the fission-barrier heights of 28 nuclei ranging from ¹⁰⁹Cd to ²⁵²Cf. We introduce several previously neglected physical effects, including a smaller nuclear radius constant, a proton form factor, an exact diffuseness correction, an A⁰ term, a chargeasymmetry term, and microscopic zero-point energies. The nuclear radius constant is determined from elastic electron scattering and microscopic calculations of nuclear density distributions, the range of the Yukawa-plus-exponential folding function is determined from heavy-ion elastic scattering, the surface-energy constant and surface-asymmetry constant are determined from the fission-barrier heights of the 28 nuclei that are considered, and the remaining constants are determined from the ground-state masses of 1323 nuclei ranging from ¹⁶O to ²⁵⁹No for which experimental values are known with experimental errors less than 1 MeV. For the final formula, the root-mean-square error in the ground-state masses is 0.835 MeV and the root-mean-square error in the fission-barrier heights is 1.331 MeV. Some of the remaining discrepancies in the groundstate masses can be understood in terms of instabilities with respect to ε₃ and ε₆ deformations.     

W pair production by Z0 pair fusion

Using the effective gauge boson approximation we calculate the invariant mass distribution and longitudinal polarization fraction for the production of W⁺W⁻ pairs by Z⁰ pair fusion at a collider energy of 40 TeV. The mass distribution is compared with the case where the production is by W⁺W₋ pair fusion. Results are presented for Higgs masses of 0.5 and 1 TeV.     

Study of hadrons using the Gaussian functional method in the O(4) linear σ model

We study properties of hadrons in the O(4) linear σ model, where we take into account fluctuations of mesons around their mean field values using the Gaussian functional(GF) method. In the GF method we calculate dressed σ and π masses, where we include the effect of fluctuations of mesons to find a better ground state wave function than the mean field approximation. Then we solve the Bethe-Salpeter equations and calculate physical σand π masses. We recover the Nambu-Goldstone theorem for the physical pion mass to be zero in the chiral limit.The σ meson is a strongly correlated meson-meson state, and seems to have a two meson composite structure. We calculate σ and π masses as functions of temperature for both the chiral limit and explicit chiral symmetry breaking case. We get similar behaviors for the physical σ and π masses as the case of the mean field approximation, but the coupling constants are much larger than the values of the case of the mean field approximation.     

Calculation of the glueball mass spectrum ofSU (2) andSU (3) non-abelian lattice gauge theories II:SU (3)

We calculate the glueball mass spectrum in theSU (3) lattice regularized gauge theory. We find fourlight glueballs: the 0⁺⁺, 2⁺⁺, 0^?+ and, most interestingly from the experimental point of view, the oddball 1^?+. We calculate the 0⁺⁺ and 2⁺⁺ masses over a range of β values and find thatboth states conform to continuum renormalization group behaviour to a very significant degree. The question of metastable states and temperature is addressed in detail. Finally we discuss and resolve contrary claims in the recent literature.     

Meson properties in an extended non-local NJL model

We consider a non-local version of the NJL model, based on a separable quark-quark interaction. The interaction is extended to include terms that bind vector and axial-vector mesons. The non-locality means that no further regulator is required. Moreover the model is able to confine the quarks by generating a quark propagator without poles at real energies. Working in the ladder approximation, we calculate amplitudes in Euclidean space and discuss features of their continuation to Minkowski energies. Conserved currents are constructed and we demonstrate their consistency with various Ward identities. Various meson masses are calculated, along with their strong and electromagnetic decay amplitudes. We also calculate the electromagnetic form factor of the pion, as well as form factors associated with the processes γγ^* → π⁰ and ω → π⁰γ^*. The results are found to lead to a satisfactory phenomenology and lend some dynamical support to the idea of vector-meson dominance.     

Perturbative QCD calculation of jet cross sections in e+e− annihilation

We calculate the α_s² to three-jet cross sections in e⁺e^? annihilation in a scheme that uses regulator masses for the infrared and collinear divergences. Using various methods to define the three-jet region, we find that the corrections to the O(α_s) cross sections are large.     

Inclusive processes and shadow effects in deuteron

Using the data on inclusive spectra we analyze the contribution of inelastic intermediate states to the shadow correction Δ for high-energy (E > 10 GeV) hadron-deuteron scattering. We note that the intermediate states with large masses M² ～ ER^?1 may contribute appreciably to the shadow correction, but the estimate of this contribution in the framework of the Regge-pole model for inclusive processes shows that it is small. The main contribution to the Δ is due to the small masses M < 2 GeV, which are produced by diffraction dissociation. We calculate the value Δ_inel for pd, πd and Kd scattering and estimate the energy dependence of Δ. The results are in agreement with the existing experimental data.     

Electromagnetic mass shift of pions in unified gauge field theories and the light-cone

The electromagnetic mass shift of pions is discussed in unified gauge field theories of weak and electromagnetic interactions to second order of the electric charge and the pion mass, respectively. We calculate the contributions of the next to leading light-cone singularities (quark mass terms) and it is found that these do not contribute to the divergences in the mass shift provided the masses of the bare proton quark and neutron quark are equal. γ, Z, W, φ exchanges are taken into account. Different bare quark masses in general make the mass shift divergent. In the tadpole contribution, the Born term causes a divergence unless we extrapolate first to q² = 0.     

The ferromagnetic phase of quark matter in the framework of one gluon exchange and thermodynamics with the density-temperature-dependent particle mass model

In the current work we examine the possibility of ferromagnetism phase of quark matter by using the one gluon exchange interaction and the thermodynamics with the density-temperature-dependent particle masses as well as the normal thermodynamics (with constant masses). We calculate the free energy per particle of the polarized and unpolarized states to discuss the difference between these two phases at various densities and temperatures. In our calculations we assume that the QCD coupling, α_c, is constant (the simple model) or varies with the temperature and the density (the asymptotic freedom); but we keep α_c less than one, because we intend to use the perturbation method to calculate the exchange energy. We also assume that the up and down quarks are massless and do not interact. Only the strange quarks interact with each other via the one gluon exchange interaction. The free and internal energies as well as the effective masses and the pressure are calculated at different densities and temperatures. The results are discussed and a comparison is made with those of Tatsumi. Finally it is shown that the present models do not predict any transition for the strange quark matter to its ferromagnetic phase.     

Renormalisation group behaviour of 0+ and 2+ glueball masses inSU(2) lattice gauge theory

We calculate the 0⁺ and 2⁺ glueball masses at several values of the coupling and verify compatibility with the desired renormalisation group behaviour. The calculation uses momentum smeared glueball wave functions on a large 8⁴ lattice and confirms our previous results obtained on smaller lattices.     

Mass Measurements at the Wright Nuclear Structure Laboratory

A program to measure masses along the astrophysical rp-process path in the A～60–80 region is underway at the Wright Nuclear Structure Laboratory, Yale University. The classic technique of end-point determinations for β⁺ spectra measured in coincidence with daughter γ-rays is used to determine Q _EC which, in turn, is used to calculate the mass. Several innovations have been incorporated to increase the sensitivity and selectivity of the method. Results of recent experiments are reported.     

Excited baryons in the bag

We calculate the negative parityN ^* andΔ ^* states in the chiral bag model. After projecting out spurious center of mass states we reproduce the known masses reasonably well. Both the colour gluon exchange diagrams and the quark-quark spindependent forces due to the presence of Goldstone pions give important contributions to the ordering of the states. Previous calculations are examined and we conclude that the chiral bag models can sucessfully account for the negative parity states as well as the baryon ground states.     

Equilibrating of 15N-Gases by Electrodeless Discharge: A Method of Indirect Mass Spectrometric Analysis of 30N2 for Denitrification Studies in Soils

Abstract

The estimation of denitrification in soil by the ¹⁵N tracer technique includes isotope analysis of gas samples with a nonrandom distribution of the N₂ mole masses of 28, 29 and 30. In that case the emission of total ¹⁵N is underestimated by calculating ¹⁵N atom fractions from the ²⁹N₂/²⁸N₂ ratio if ³⁰N₂ is not considered. ³⁰N₂ can be measured indirectly in N₂ enriched with ¹⁵N with nonrandom distribution of mole masses by mass spectrometric analysis. The nitrogen fraction of gas samples was transferred to discharge tubes. Microwaves (60 sec) generated an electrodeless discharge of the gas which caused a temporary split-up of N₂ molecules and thus established an equilibrium distribution of the mole masses. The ²⁹N₂/²⁸N₂ ratio was measured in equilibrated and in untreated samples to calculate the real emission of ¹⁵N. The measurements of ¹⁵N standard gases by this method satisfactorily coincided with calculated values for ¹⁵N atom fraction above a concentration of 50 δ‰.     

Atomic masses above146Gd derived from a shell model analysis of high spin states

From a shell model analysis of high-spin states in neutron deficient nuclei above¹⁴⁶Gd we have derived the ground state masses of theN=82 and 83 isotones of Eu, Tb, Dy, Ho, and Er. The results can be used to calculate the energies of aligned multiparticle yrast configurations. They also link ten α-decay chains to the nuclei with known masses, providing many new absolute mass values which are compared with predictions. An examination of the two-proton separation energies atN=82 shows an 0.5 MeV break in the nuclear mass surface atZ=64.     

Glueball spectrum and Pomeron in the Wilson loop approach

Using a nonperturbative method based on the asymptotic behavior of Wilson loops, we calculate the masses of glueballs and the corresponding Regge trajectories. The only input is the string tension fixed by the meson Regge slope, while perturbative contributions to spin splittings are defined by standard α_s values. The masses of the lowest glueball states are in a perfect agreement with lattice results. The leading glueball trajectory, which is associated with the Pomeron is discussed in detail, and its mixing with f and f′ trajectories is taken into account.     

The parallelizing S7 torsion in gauged N=8 supergravity

Using the parallelizing S⁷ torsion as an ansatz we investigate two solutions of gauged N=8 supergravity with SO(7) invariance. Supersymmetry is uniformly broken. We calculate the masses for these solutions which are both unstable. Certain apparent discrepancies with the results obtained by spontaneous compactification of d=11 supergravity are discussed. We establish that the compactification on the parallelized S⁷ has an SO(7) invariance and clarify the issue of supersymmetry breaking. The lack of stability in d=4 indicates that this d=11 solution is unstable.     

Baryon production by primordial black holes

The evaporation of primordial black holes (PBH's) by the Hawking process can produce an excess of baryons over anti-baryons. Assuming a power-law form of the initial mass spectrum of PBH's and taking into account the observational constraints on that spectrum we calculate the baryon excess produced. We find that if the spectrum is steep ($\text{α?3.5}$) or cut off for masses above ～ 10⁹ g, the observed baryon/photon ratio of ～ 10^?9 can be produced by PBH evaporations.