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At least one massive neutrino, with mass greater than 1 MeV, can provide an explanation of the residual Goldberger-Treiman discrepancy (1938). Agreement with the π → eν branching ratio requires either one massive neutrino with mass between 34 and 139 MeV, or a number of massive neutrinos with appropriately chosen masses and mixing angles.

We show that, when nucleon-nucleon correlations are taken into account using correlation functions derived. from the Reid soft core potential, the contribution of three body forces to the binding energy of nuclear matter is enhanced. The two pion exchange three body forces contributes 6 MeV attraction.

In a recent letter, Nardulli et al. have derived a low energy potential representing the parity violating nucleon-nucleon interaction induced by parity non-conservation in the nucleon wavefunction. I point out that this potential is in conflict with the data on parity non-conservation in s-d shell nuclei.

It is shown that the rho -exchange isovector parity-violating potential is constrained by PCAC to be much weaker than the pi -exchange potential, and much weaker than recently proposed by Galic et al. (1979). This potential does not therefore provide a mechanism for suppressing enhanced neutral-current effects in the pi -exchange potential.

We study an invisible axion model in which the Higgs particles consist of only one isodoublet, one isosinglet and a pair of colortriplets. At the tree level only the up-type quarks obtain masses. The down-type quark masses result from one-loop radiative correction. We also discuss some of the related phenomenology.

The calculation of short-distance gluon exchange corrections to the ΔS = 0 weak interaction at the quark level is described. Results are given for the coefficients of the 36 independent four-quark operators involving u, d, and s quarks explicitly, and for the 16 independent operators, which remain when s quarks are eliminated and only u and d quarks explicitly occur in the operators.

The coupling to inelastic channels is shown to transfer about 10% of the single particle strength to inelastic continuum states, where it is difficult to observe it directly. However it is pointed out that such a depletion of the single particle strength is consistent with recent analyses of stripping reactions on doubly magic nuclei.

The parity-nonconserving nucleon-nucleon potential is calculated from the Oakes theory of weak interactions on the assumption that $\ensuremath{\pi}$ and $\ensuremath{\rho}$ exchange terms dominate. It is found that this theory predicts a circular polarization of \ifmmode\pm\else\textpm\fi{}(1.8\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ for 482-keV $\ensuremath{\gamma}$ ray from $^{181}\mathrm{Ta}$. The observed polarization is -(0.06\ifmmode\pm\else\textpm\fi{}0.01)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$.

The possibility of quantizing the electric charge in supersymmetric, technicolor, and composite models is examined by studying some specific examples. By requiring an anomaly-free theory, the appropriate symmetry-breaking pattern of the gauge group, and mass generation, the electric charges may be determined.

We show that it is possible for neutrino oscillations to create a state of the universe in which the net lepton numbers are appreciable and different for each species at the time of nucleosynthesis. Under these conditions mixing induced by the oscillations can influence the abundances of the light elements.

Publisher Summary This chapter explores the possible evidence for enhanced Δ S = 0, Δ T = 2 weak interaction in parity mixing in nuclei. The experiment on the α decay of the 2 − state at 8.88 MeV in 160 is in essential agreement with the calculations using a standard potential. This experiment is sensitive only to the Δ T = 0 term in the potential and, therefore, fixes it to be in the vicinity of that of the standard potential. Obtaining agreement with the datum by enhancement of the Δ T =0 term requires an enhancement of 10 3 .However, the Δ T = 2 part by a factor of about 30 can be enhanced and agreement for n + p → d + γ can be obtained without disturbing the agreement found in 16 0 and 19 F. The Δ T = 2 potential can be adjusted to obtain the correct sign for the circular polarization. There is an experimental limit on the parity mixing in p–p scattering at 15 MeV. This is just consistent with enhanced Δ T =2 potential, but if lowered significantly, it would exclude the potential in its present form.

A calculation is made of the parity-violating contributions of hypothetical excited quarks and leptons to two examples of low-energy phenomena. In particular, the contributions to polarized-electron--deuteron scattering and the parity-violating nuclear potential are studied. The parity-violating contributions are induced by the magnetic coupling of photons or gluons with virtual excited fermions and left-handed ordinary fermions. It is concluded that the mass of an excited quark, if it exists, must be larger than approx.3 TeV. The restriction on the mass of an excited lepton is less stringent.

Publisher Summary This chapter describes the three nucleon potential in nuclear matter. It presents a calculation of the two-pion exchange three nucleon potential for use in nuclear matter calculations. The new potential is based on a scattering amplitude, which was constructed to satisfy the constraints imposed by current algebra and the most scattering data. There is a significant s wave πN amplitude, although the well-known cancellation at the Adler point was imposed. A potential in nuclear matter where one will eventually average over the spins and isospins of the nucleons in computing the energy was constructed. The chapter presents the resulting amplitude in the rest frame of the incident nucleon. The background term F -(+) is required to satisfy the current algebra constraints when one pion is soft and the other is on the mass shell and when both pions are soft. This enables the determination of the coefficients in the expansion.

Publisher Summary This chapter describes the solvable few-body models as laboratories for nuclear reaction theories. It is found that the study of simple solvable models of a nuclear reaction process is a very useful technique for obtaining insight into the process and for testing the validity of the necessarily approximate theories which can be applied to real reaction processes. All of the models are of the separable potential type, applied in progressively more complex situations, namely, single channel scattering, many channel scattering, and three-body many channel scattering. The three-body problem with separable potentials has long been used as a test piece for theories of rearrangement collisions. One of the interesting questions in the theory of reactions is the reliability with which the theory can extract spectroscopic factors. This cannot be tested in the usual calculations, because the spectroscopic factors are always unity. The chapter highlights the construction of the three-body equations for energy dependent potentials. A possible future application of the model is the comparison of results obtained using exact multichannel n-target and p-target potentials and those obtained using the optical potentials in the formalism.

Publisher Summary This chapter discusses the different aspects of three-body forces in nuclei. There is a clear discrepancy of about 1 MeV between the calculated and observed binding energy of the triton. It seems impossible to move the binding energy curve of nuclear matter or finite nuclei away from the Coester Line. Almost as soon as the meson theory of nuclear forces was proposed, attempts were made to calculate three nucleon potentials arising from multiple pion exchange. There is a possible empirical need for many-body forces of weaker strength exchanged pions. As the three-body force does not open any new channels, the introduction of additional Lovelace type amplitudes is an unnecessary complication. The equation is a well-defined integral equation for three-body matrix, which can serve as the basis of a systematic perturbation expansion.

Publisher Summary This chapter discusses the three-body problem with energy-dependent potentials. Investigations of the nucleon–nucleon potential have emphasized that the energy dependence of the potential cannot be ignored. This makes it important to generalize the formulation of the many-body problem and in particular the three-body problem, to handle such energy dependent potentials. Such a generalization is presented in this chapter, and it is anticipated that this generalization will be useful in extending three-body models of nuclear reactions to include energy dependent optical model potentials. The chapter discusses the Faddeev equations for the three-body problem. It presents an argument that the two-body t matrices ti(s) are required for a range of energies below the elastic threshold, where the energy dependence of the potential is usually not defined. This demonstrates the need for a generalization of these equations to include energy dependent potentials. The chapter describes the complementary biorthogonal set. It also presents an energy-independent but non-Hermitian Hamiltonian operator.

The difficulties in computing the parity violating nucleon‐nucleon interaction from an underlying weak interaction theory are reviewed, and the extent to which the parameters of the interaction can be determined by the available data is discussed. A possible experiment in 21Ne which can provide useful constraints on the parameters is outlined.

Large-basis meson wave functions, built from static cavity quarks and gluons, are used in conjunction with a simple plane-wave projection prescription to calculate meson charge radii with /ital O/(/ital g//sup 2/) corrections. After fitting to the light-meson mass spectrum the pion charge radius is used to constrain the remaining degree of freedom of the model parameters. The resulting large-basis model is found to give the following mass predictions in the light-quark sector: /ital K//sup */(892)=904.4/plus minus/0.1 MeV, /phi/(1020)=1040.6/plus minus/0.1 MeV. For the kaon charge radius we obtain /l angle//ital r//sup 2//r angle//sub K/=0.35/plus minus/0.040 fm/sup 2/ (/l angle//ital r//sup 2//r angle//sub K//sup expt/=0.34/plus minus/0.05 fm/sup 2/).

The classic paper of Feynman and Gell Mann [1] on the current x current theory of the weak interaction pointed out that on this picture one would expect self interaction terms like $$H_{np}^{W}=\frac{1}{\sqrt{2}}G\left\{ {{{\bar{\psi }}}_{n}}{{r}_{u}}\left( 1+i{{r}_{5}} \right){{\psi }_{p}} \right\}\left\{ {{{\bar{\psi }}}_{n}}{{r}_{u}}\left( 1+i{{r}_{5}} \right){{\psi }_{n}} \right\}$$ to appear in the weak interaction a weak force between neutrons and swamped by the strong force, were conserve parity.. Such a term would give rise to protons, which would be completely it not for the fact Hnp w does not conserve parity.

The weak parity — violating nucleon — nucleon potential may be regarded as a meson exchange potential arising from the reactions $${\rm{N\bar N}}\,\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{{\rm{P}}{\rm{.v}}{\rm{.}}}^{{\rm{weak}}}} \,{\rm{mesons}}\,\left( {\pi ,\rho ,2\pi ,{\rm{etc}}.} \right)\,\buildrel {{\rm{strong}}} \over \longrightarrow \,{\rm{N\bar N}}$$ The main problem in calculating the single meson exchange terms is in the calculation of the weak meson — nucleon vertex. For 2π exchange the strong amplitude is no longer trivial, introducing additional complications. I now wish to discuss the π, ρ, and 2π potentials in turn.

We present the results of a calculation of the recently measured asymmetry of the 110-keV $\ensuremath{\gamma}$ ray emitted in the ${\mathrm{\textonehalf{}}}^{\ensuremath{-}}$ \ensuremath{\rightarrow} ${\mathrm{\textonehalf{}}}^{+}$ transition in $^{19}\mathrm{F}$. Our results, for the usual choice of parity nonconserving potential, are consistent with the observed asymmetry.

It is shown that neutrino mixing, of the type required for neutrino oscillations, will complicate efforts to determine the electron neutrino mass from β decay spectra. The shape of the spectra will depend on the masses and mixing angles of all neutrinos which couple to the electron neutrino.

The one pion exchange contribution to the weak parity violating nucleon-nucleon potential is calculated by relating the weak NNπ vertex to the nonleptonic hyperon decays by the Suzuki-Sugarawa method. It is also shown that the G parity odd part of the weak Hamiltonian cannot contribute to the potential.

The methods used recently to obtain analytic inversion formulas for inversion of multispectral extinction data on scattering by spheres in the anomalous diffraction approximation are extended to the case of scattering by a polydispersion of parallel cylinders at normal incidence in the same approximation. It is shown that a one-parameter family of inversion formulas exists in this case.

Amplitudes for the mixing of the meson valence ground state with O(g) states, I qqG}, are calculated using 51/2 quarks and 1+ (TE) gluon wavefunctions from perturbative c cavity dynamics. Bag parameters are obtained for increasing basis size by fitting to 7T-p and� K spectroscopy. The expected self-energy divergence appears to be regulated primarily by the strong coupling approaching zero. The K* and cf> masses are also calculated.

Corrections to the eey and qqy vertices, at the one loop level, from intermediate supersymmetric (SUSY) states are calculated. The induced parity-violating interaction between electrons and nucleons is applied to the calculation of the lowest order SUSY contribution to the asymmetry in deep inelastic e + deuteron scattering in both the 'tree-breaking' (TB) and 'renormalisation-group' (RG) supergravity models. The results indicate that, for a wide range of sparticle masses, the SUSY contributions lie well within constraints implied by present measurements.

We generalize our earlier result on forward scattering of light by polydisperse hazes of uniform spheres to include nonuniform particles of arbitrary shape. The forward scattering determines a (polarizability)(2) weighted mean mean-square radius of the haze.

Recent hints in experimental data of a fJ.1T resonance at 429 MeV have led us to speculate about the possibility of meson-lepton and dilepton resonances. We show that the proposed fJ.7T resonance at 429 MeV is not in conflict with the muon g-2 measurements, and that it could be interpreted as a partner of the excited charged leptons possibly seen at CERN. Moreover, a composite model by Fritzsch and Mandelbaum predicts not only a flavour octet of meson-muon resonances of which this could be one, but also dilepton resonances which were suggested by Ramm as an explanation of the lobe structure in the fJ.7T data. The observed widths and branching ratios of the resonances can be interpreted to suggest that the colour-octet states are considerably smaller than the colour singlets.

We show how the usual results of formal scattering theory should be modifted when the two particle potential is energy dependent.

Two-body decays of the charmed mesons to both PP and PV final states are discussed, employing an effective Lagrangian formalism. We show that a hybrid model combining the pole model and the c-quark decay model provides a reasonable description of the amplitudes for these processes.

We show that nuclear physics provides evidence against the existence of hadronic Van der Waals forces between nucleons.

It is shown that the cross section for scattering in the long-wavelength limit from a lossy dielectric sphere varies as λ−2 and not as λ−1, as is suggested in standard treatments of the subject. The λ−1 variation is in conflict with the analytic properties of the scattering amplitudes as a function of k = 2πλ−1, and this conflict is resolved when the wavelength dependence of the dielectric constant is taken into account.

Large-basis O(g) static cavity wavefunctions, containing bremsstrahlung and quark-sea states, previously fitted to the light quark meson sector, are applied to the ground-state meson spectrum in general. The only parameters of the model in the heavy quark sector are the quark masses me and mb which we fit to D and B states. Predictions for the meson mass spectrum are given and are found to be a significant improvement over the predictions of the original. MIT model.

The asymptotic form of the Mie-scattering amplitude is of interest for a number of reasons, perhaps the most important of which is to reduce significantly the computational effort involved when the size parameter becomes large. Recently, Nussenzveig and Wiscombe [ Phys. Rev. Lett.45, 1490 ( 1980)] published an asymptotic expansion for the Mie extinction efficiency based on complex-angular-momentum theory. In this paper, we show how this result may be generalized to the full forward-scattering amplitude.

We utilise the light-front dynamical formalism to compute the magnetic moments of baryons in a relativistic constituent quark model, investigating the dependence of the results on the mass of the constituent quarks and on the size of the hadron.

As a result of discussions which one of us (B.H.J.McK.) has had with B. Desplanques and H. J. Pimer, we have discovered an error in sign in some of our results: all numerical values of As, At, C, Py and Q( are of the wrong sign: This error is due, in part, to a misunderstanding of Danilov's (1965) paper, in which his relative momenta are defined as