The non-trivial effective potential of the ‘trivial’ λΦ4 theory: A lattice test

The strong evidence for the triviality of (⁴)₄ theory is not incompatible with spontaneous symmetry breaking. Indeed, for a trivial theory the effective potential should be given exactly by the classical potential plus the free-field zero-point energy of the shifted field; i.e., by the one-loop effective potential. When this is renormalized in a simple, but nonperturbative way, one finds, self-consistently, that the shifted field does become non-interacting in the continuum limit. For a classically scale-invariant (CSI) ⁴ theory one finds m _h ² , predicting a 2.2 TeV Higgs boson. Here we extend our earlier work in three ways: (i) we discuss the analogy with the hard-sphere Bose gas; (ii) we extend the analysis from the CSI case to the general case; and (iii) we propose a test of the predicted shape of the effective potential that could be tested in a lattice simulation.     

Is the physical vacuum a preferred frame?

It is generally assumed that the physical vacuum of particle physics should be characterized by an energy-momentum tensor in such a way as to preserve exact Lorentz invariance. On the other hand, if the ground state were characterized by its energy-momentum vector, with zero spatial momentum and a non-zero energy, the vacuum would represent a preferred frame. Since both theoretical approaches have their own good motivations, we propose an experimental test to decide between the two scenarios. PACS 11.30.Cp; 11.30.Qc; 03.30.+p     

Quantum-hydrodynamical picture of the massive Higgs boson

The phenomenon of spontaneous symmetry breaking admits a physical interpretation in terms of the Bose condensation process of elementary spinless quanta. In this picture, the broken-symmetry phase emerges as a real physical medium, endowed with a hierarchical pattern of scales, supporting two types of elementary excitations for : a massive energy branch , corresponding to the usual Higgs boson field, and a collective gapless branch . This is similar to the coexistence of phonons and rotons in superfluid ⁴He that, in fact, is usually considered the condensed-matter analog of the Higgs condensate. After previous work dedicated to the properties of the gapless phonon branch, in this paper we use quantum hydrodynamics to propose a physical interpretation of the massive branch. On the base of our results, M_H coincides with the energy gap for vortex formation and a massive Higgs boson is like a roton in superfluid ⁴He. Within this interpretation of the Higgs particle, there is no naturalness problem since M_H remains a naturally intermediate, fixed energy scale, even for an ultimate ultraviolet cutoff .Received: 24 November 2003, Published online: 29 January 2004     

Onset of sliding friction in incommensurate systems

Interstitial O3 molecules in 7.9 eV photon-irradiated silica are identified. Their optical absorption band at 4.8 eV nearly coincides with the 4.8 eV band of nonbridging oxygen hole centers. The O3-related band is distinguished by a smaller halfwidth (0.84 vs 1. 05 eV), by susceptibility to ultraviolet bleaching, by lack of correlation to the 1.9 eV luminescence band, and by rise of a singlet O2 luminescence band at 0.974 eV during photobleaching. This identification solves a long controversy on the nature of optical bands in silica and gives a tool for studying the mobility of atomic oxygen in SiO2.     

One-loop corrections to e+e− → e+e− in the weinberg model

Radiative corrections to Bhabha scattering are calculated in the simplest example of non-Abelian gauge theories. A detailed analysis of the higher-order effects is presented and the total differential cross section including weak corrections is evaluated at different angles in an energy range up to 70 GeV per beam. The effects of weak interactions appear to be negligible up to the production of the neutral vector boson.     

Synthesis and lectin binding ability of glycosamino acid-calixarenes exposing GlcNAc clusters

Novel calix[4 or 8]arene-based glycoconjugates exposing terminal N-acetyl-D-glucosamine clusters have been synthesized using amino acid-calixarenes as building blocks. The obtained glycosamino acid-calixarenes 9b-14b have lectin-binding ability and amplified inhibitory effects on erythrocyte agglutination induced by wheat germ (Triticum vulgaris) agglutinin (WGA). The inhibitory ability is dependent on the presence of the spacer and on the shape and rigidity of the calixarene skeleton.     

Renormalization of masslessλΦ 4 theories: Asymptotic freedom and spontaneous symmetry breaking

The implications of both one loop and gaussian approximation to the effective potential of masslessλΦ ⁴ theories are analyzed. By assuming only the unavoidable existence of a regularization scheme which preserves the variational inequality, it is possible to obtain an estimate of the weak coupling ß-function with is remarkably consistent with the Coleman-Weinberg one loop calculation. Both indicate that masslessλΦ ⁴ theories are asymptotically free, not in contradiction with any known rigorous result. The consequences of our analysis for the Standard Model of electroweak interactions are briefly illustrated.     

An approach to the nuclear many-body problem including virtual mesons (I). HF approximation in finite nuclei

A method is presented allowing a self-consistent treatment of meson dynamics in finite nuclei. The single-nucleon self-energy is derived in the framework of the HF approximation. The differences with respect to the usual (static) HF approach are the energy dependence of the self-energy and the appearance of a new term, and both are due to the time delay in meson propagation. The first effect introduces a double self-consistency condition on both the single-particle energies and wave functions. The reported results on the ¹²C and ¹⁶O nuclei show the importance of the correct treatment of meson degrees of freedom.     

Spontaneous self-assembly of water-soluble nucleotide-calixarene conjugates in small micelles coalescing to microspheres

Spontaneous self-assembly of calix[4]arenes bearing four 2'-deoxythymidine or 2'-deoxyadenosine nucleotide pendants is investigated using (1)H NMR, exchange NMR, and diffusion ordered NMR spectroscopies and dynamic light scattering. In aqueous medium, the nucleotide-calixarene conjugates, by noncovalent interactions involving both nucleobases and calixarene skeleton, form dimers which self-organize in micelles by increasing the concentration. Microscopic images (scanning electron microscopy and transmission electron microscopy) show that the nucleobase affects the aggregate morphology in the solid state.