Nuclear structure function at large x and ΛQCD

We explain that due to the presence of the short-range nucleon correlations in nuclei the theoretical pattern of Bjorken scaling violation at x > 0.7 is expected to be simpler here than in lepton-nucleon scattering. Consequently, lepton-nucleus scattering is better suited for the accurate determination of Λ_QCD if nuclear effects are properly accounted for. On the contrary if they are ignored (as it is often done at present) Λ_QCD is considerably underestimated.     

Nuclear spin-orbit interaction and T-odd angular correlations in ternary fission

T-odd angular correlations in ternary fission of ²³³U and ²³⁵U nuclei by slow polarized neutrons are not related to TRI (time reversal invariance) violation, but are caused by an effective spin-orbit interaction in the final state.     

T-odd asymmetries for products from the spontaneous fission of oriented nuclei

The problem of describing T-odd asymmetries in ternary fission reactions of oriented nuclei is solved for the first time on the basis of quantum theory. Estimates of the T-odd asymmetry coefficients in the angular distributions of the reaction products are obtained using the spin density matrix of the oriented fissioning nucleus. It is demonstrated that experiments on observing T-odd asymmetries in the spontaneous fission of oriented nuclei are of interest because the T-odd asymmetry coefficients can be around an order of magnitude greater than similar coefficients in the fission of unoriented target nuclei induced by polarized neutrons.     

Prediction of hyperdeformed nuclear states at very high spins

Calculations based on the generalized cranking-Strutinsky method with the deformed Woods-Saxon potential predict the existence of extremely elongated hyperdeformed nuclear shapes with the axis ratios significantly exceeding2:1. The strongest effect is expected to take place for nuclei around ¹⁶⁶Er, ¹⁶⁸Yb, and ¹⁷⁰Hf (Z = 68, 70, 72; N = 98) for spins as high as the fission limit down to I ∼ 10–20. The chances for observing those states in nature are discussed in detail. Systematic occurrences of the superdeformed and hyperdeformed states also in lighter (A ∼ 70, and A ∼ 100) nuclei are suggested as a consequence of the approximate pseudo-oscillator (or pseudo-SU(3) symmetries of the realistic nuclear mean field.     

Non-decoupling of heavy neutrinos and lepton flavour violation

We consider a class of models predicting new heavy neutral fermionic states, whose mixing with the light neutrinos can be naturally significant and produce observable effects below the threshold for their production. We update the indirect limits on the flavour non-diagonal mixing parameters that can be derived from unitarity, and show that significant rates are in general expected for one-loop-induced rare processes due to the exchange of virtual heavy neutrinos, involving the violation of the muon and electron lepton numbers. In particular, the amplitudes for μ-e conversion in nuclei and for μ → ee⁺e⁻ show a non-decoupling quadratic dependence on the heavy neutrino mass M, while μ → eγ is almost independent of the heavy scale above the electroweak scale. These three processes are then used to set stringent constraints on the flavour-violating mixing angles. In all the cases considered, we point out explicitly that the non-decoupling behaviour is strictly related to the spontaneous breaking of the SU(2) symmetry.     

On the deexcitation of phonon excitations in nonspherical even-even nuclei by <Emphasis Type="Italic">M</Emphasis>1 transitions

The reasons for the violation of sign invariability for the parameter of mixture of M1 and E2 multipoles in the deexcitation of levels of the β-and γ-rotational bands to levels of the ground-state rotational band are considered for N = 90–114 nonspherical even-even nuclei.     

The strong CP problem revisited

The strong CP-violating θ parameter, the problem of strong CP violation and their status are reviewed. Among all possibilities, two natural solutions to the strong CP puzzle are thoroughly discussed and emphasized: the axion-type mechanism for hard CP violation and the non-Peccei-Quinn scheme for spontaneous CP nonconservation. Basic properties of the axion are derived from the modified Peccei-Quinn symmetry. Astrophysical and cosmological constraints are described for two different types of invisible axions. In nonaxion solutions, CP is spontaneously broken at the grand-unification scale and the CP phase is transmitted down to the low energy sector by quantum effects or by fermion mixing effects. As a by-product, the cosmological baryon asymmetry, which is caused by the same source of CP violation ultimately responsible for the kaon ε parameter, is generated adequately at the one-loop level.     

Quark-flavor symmetries and their violation in quantum chromodynamics

In Quantum Chromodynamics, the hadrons consisting of light (u, d, s) and heavy (c, b) quarks are subject to approximate flavor symmetries, providing the basis for powerful effective theories. I will briefly overview the origin of these symmetries and the scale of their violation. The current precision tests of Standard Model in the electroweak decays of hadrons demand an accurate quantitative account of flavor-symmetry violation effects. I will discuss the continuum (non-lattice) QCD calculation of these effects in hadronic matrix elements, taking as an example the decay constants of heavy–light hadrons.     

From a new smell to a new flavour −BdBd mixing,CP violation and new physics

Using the preliminary data on B_dB̄_d mixing from ARGUS, and the standard model with three families, we infer a lower bound on the top quark mass of 50–70 GeV; also, B_sB̄_s mixing has to be close to maximal. We discuss how the prospects for observing CP violation in B⁰ decays are enhanced and sketch alternative scenarios for new physics.     

T-violation experiments using Mössbauer transitions

We analyse the effects of time-reversal (T) violation on the transmission of photons through a system of magnetized foils that have a Mössbauer transition with comparableM1 andE2 strength (e. g.⁹⁹Ru or¹⁹⁷Au). We consider experiments that are true tests of T violation and therefore are not subject to effects from final-state interactions, discussing observables that probe either parity-violating or parity-conserving T-odd interactions. We propose a novel three-foil experiment sensitive to a T-odd, P-odd multipole admixture. This experiment should be insensitive to most systematic problems faced by the earlier experiments.     

Li7 self diffusion in LiAl—An NMR study

The self diffusion of Li⁷ in near stoichiometric LiAl has been investigated by observing the Li⁷ and Al²⁷ NMR relaxation rates. The diffusivity for a Li⁷ atom is determined to be D = 9 × 10^?6 exp (?0.12 eV/kT) cm²/sec. Both the Li⁷ and Al²⁷ rates show the effects of quadrupole relaxation. The electric field gradients from the moving defects in LiAl are a factor of 37 ± 5 stronger at the Al nuclei suggesting covalent character to the bonding.     

Explicit R-parity breaking in supersymmetric models

Supersymmetric models generally invoke R parity to ensure that baryon and lepton numbers are symmetries of the renormalizable operators of the low-energy effective theory. The phenomenology of lepton-number violation is analyzed in low-energy models in which R parity is explicitly broken by superrenormalizable operators. Constraints on lepton-number violating parameters are found to be mild. The photino is able to decay, avoiding a stringent cosmological lower bound on its mass. Alternatives to R parity are considered in the context of an SU(5) grand unified model coupled to N=1 supergravity. One possibility, θ parity, leads to new mechanisms for baryon- number violation in addition to lepton-number violation.     

Current status of research on <Emphasis Type="Italic">T</Emphasis> invariance in neutron-nuclear reactions

In this work, the current state of research on T invariance in neutron-nuclear reactions is considered. The promising character of investigations in this field related to possible enhancement of T-invariance violation in compound states of medium and heavy nuclei is underlined. Progress in preparation of experimental tests of T invariance using three-and five-vector correlations in cross sections of interaction of polarized neutrons with aligned nuclei is described in detail. T-invariance tests in reactions of radiative neutron capture and in coherent scattering of polarized neutrons on crystals are also considered.     

Spontaneous breakdown of CP symmetry,cabbibo angle in nuclear and hypernuclear physics

Following a suggestion of Salam and Strathdee that CP violation disappears and the Cabbibo angle vanishes at high magnetic fields we infer that no CP (or T) violation should be observed in nuclear beta decays and that stable hypernuclei are in principle possible.     

Scaling violation in electroproduction at large ω'

The GVD predictions for scaling violation in electroproduction at ω'?5 are presented and agree with data. The effects of charm are included and found negligible in the ω′?q² domain of present experiments, but appreciable at higher ω' and (or)q².     

Decay of heavy and superheavy nuclei

We present here, an overview and progress of the theoretical works on the isomeric state α decay, α decay fine structure of even–even, even–odd, odd–even and odd–odd nuclei, a study on the feasibility of observing α decay chains from the isotopes of the superheavy nuclei Z = 115 in the range 271 ≤A ≤ 294 and the isotopes of Z = 117 in the range 270 ≤A ≤ 301, within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The computed half-lives of the favoured and unfavoured α decay of nuclei in the range 67 ≤Z ≤ 91 from both the ground state and isomeric state, are in good agreement with the experimental data and the standard deviation of half-life is found to be 0.44. From the α fine structure studies done on various ranges of nuclei, it is evident that, for nearly all the transitions, the theoretical values show good match with the experimental values. This reveals that CPPMDN is successful in explaining the fine structure of even–even, even–odd, odd–even and odd–odd nuclei. Our studies on the α decay of the superheavy nuclei ^271?294115 and ^270?301117 predict 4 α chains consistently from ^284,285,286115 nuclei and 5α chains and 3α chains consistently from ^288?291117 and ²⁹²117, respectively. We thus hope that these studies on ^284?286115 and ^288?292117 will be a guide to future experiments.     

Nuclear electric dipole moment of He

A permanent electric dipole moment (EDM) of a physical system requires time-reversal (T) and parity (P) violation. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Here we calculate the magnitude of the P-, T-violating EDM of ³He and the expected sensitivity of such a measurement to the underlying P-, T-violating interactions. Assuming that the coupling constants are of comparable magnitude for π-, ρ-, and ω-exchanges, we find that the pion-exchange contribution dominates. Our results suggest that a measurement of the ³He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion–nucleon P-, T-violating interaction.     

Some problems in the generalized theory of finite Fermi systems

A realistic version of the generalization of the theory of finite Fermi systems to the case where some complex configurations involving phonons are explicitly taken into account is proposed. Secular equations describing the fragmentation of simple states in odd and even-even nuclei over complex configurations that belong to, respectively, the quasiparticle ? phonon + quasiparticle ? phonon ? phonon and the two quasiparticles ? phonon type and which are presently of greatest interest are derived on the basis of general relations for nuclei that involve pairing (nonmagic nuclei). These equations take into account effects associated with ground-state correlations due to complex configurations and with the additional quasiparticle-phonon mechanism of Cooper pairing in nuclei. The effects in question were disregarded previously, but they are of interest since they can be observed in present-day experiments.     

CP violation in a multi higgs doublet model

We study CP violation in a multi-Higgs doublet model based on aS ₃×Z ₃ horizontal symmetry. We consider two mechanisms for CP violation in this model: a) CP violation due to complex Yukawa couplings; and b) CP violation due to scalarpseudoscalar mixings. We find that the predictions for ε′/ε, CP violation in B decays and the electric dipole moments of neutron and electron are different between these two mechanisms. These predictions are also dramatically different from the minimal Standard Model predictions.     

Mass and energy dependence of pion-induced fission

Data for fission induced by pi meson beams from 80 to 500 MeV are presented for nuclei from Fe through Pu as measured by solid state track detectors. The general trends for binary fission withπ ⁺ are reproduced fairly well by a calculation in the ‘high excitation’ limit with standard level density and fission barrier parameters, butπ ^? data are underpredicted. A universal dependence of the binary fission probabilities with the fissility (Z±1)²/A is found to be valid for both pion beam charges for all beam energies below the delta resonance. Probabilities for observing three fragments withπ ⁺ are not reproduced by a ternary fission application of the model found to work for binary fission.