Model Of Elementary Particles Research Articles

Classical model of an elementary particle with a Bertotti-Robinson core and extremal black holes

We discuss the question, whether the Reissner-Nordstr\"om (RN) metric can be glued to other solutions of Einstein-Maxwell equations in such a way that (i) the singularity at $r=0$ typical of the RN metric is removed, and (ii) matching is smooth. Such a construction could be viewed as a classical model of an elementary particle balanced by its own forces without support by an external agent. One choice is the Minkowski interior that goes back to the old Vilenkin and Fomin's idea who claimed that in this case the bare deltalike stresses at the horizon vanish if the RN metric is extremal. However, the relevant entity here is the integral of these stresses over the proper distance which is infinite in the extremal case. As a result of the competition of these two factors, the Lanczos tensor does not vanish and the extremal RN cannot be glued to the Minkowski metric smoothly, so the elementary-particle model as an empty ball inside fails. We examine the alternative possibility for the extremal RN metric---gluing to the Bertotti-Robinson (BR) metric. For a surface placed outside the horizon there always exist bare stresses but their amplitude goes to zero as the radius of the shell approaches that of the horizon. This limit realizes the Wheeler idea of ''mass without mass'' and ''charge without charge.'' We generalize the model to the extremal Kerr-Newman metric glued to the rotating analog of the BR metric.

Light cone quantization, Heterotic strings and E–infinity derivation of the number of Higgs bosons

Abstract Using light cone quantization as well as a variety of super and Heterotic string theories in conjunction with E –infinity theory we show that while a minimum of one Higgs particle is absolutely necessary for a consistent standard model of elementary particles, the number could be as large as 12 particles and include one or more graviton.

Effects of confinement on the permanent electric-dipole moment of Xe atoms in liquid Xe

Searches for permanent electric-dipole moments (EDM) of atoms provide important constraints on competing extensions to the standard model of elementary particles. Recently proposed experiment with liquid {sup 129}Xe [M.V. Romalis and M.P. Ledbetter, Phys. Rev. Lett. 87, 067601 (2001)] may significantly improve present limits on the EDMs. To interpret experimental data in terms of CP-violating sources, one must relate measured atomic EDM to various model interactions via electronic-structure calculations. Here we study density dependence of atomic EDMs. The analysis is carried out in the framework of the cell model of the liquid coupled with relativistic atomic-structure calculations. We find that compared to an isolated atom, the EDM of an atom of liquid Xe is suppressed by about 40%.

Generation and applications of slow polarized muons

The muon is an elementary particle and, as such, forms a fundamental building block of the Standard Model of elementary particles. At the same time, the muon, especially the positively charged muon, when implanted in matter has established itself as a magnetic spin microprobe and hydrogen-like probe to study a variety of static and dynamic phenomena in superconductivity, magnetism, radical chemistry, semiconductor physics and many other fields. The limitation of this technique has been up until recently that it is restricted to investigation of bulk properties, because muons are generated from pion decay as high-energy particles with a broad stopping depth profile. This article describes recent developments of so-called ‘slow muon’ beams, where the energy is reduced down to the electronvolt to kiloelectronvolt range, thus making the probe depth sensitive on the nanometre scale. Some recent applications of this novel probe are described, such as the measurement of magnetic field profiles at the surface of superconductors and the measurement of the spatial variation in the polarization of conduction electrons in magnetic/non-magnetic multilayers. The generation of slow negative muons and possible applications of low-energy muons in the design of future muon colliders and neutrino sources are also briefly discussed.

Quark mixing, CKM unitarity

In the Standard Model of elementary particles, quark-mixing is expressed in terms of a 3 x 3 unitary matrix V, the so called Cabibbo-Kobayashi-Maskawa (CKM) matrix. Significant unitarity checks are so far possible for the first row of this matrix. This article reviews the experimental and theoretical information on these matrix elements. On the experimental side, we find a 2.2 sigma to 2.7 sigma deviation from unitarity, which conflicts with the Standard Model.

CP Violations in the Universe

The origin of the asymmetry between matter and antimatter that is evident in our part of the Universe is one of the open questions in cosmology, because the CPT symmetry between matter and antimatter seems to be absolutely conserved at microscopic level. We repeat here the classical proofs which exclude the viability of a Universe baryon symmetric on the average, or the observed asymmetry as an initial conditions. The current understanding is that the asymmetry should have been dynamically generated before nucleosynthesis, by B, C, and CP violating processes, acting out of thermodynamical equilibrium, as suggested by Sakharov in the 70's. The physical realizations of these conditions would be possible, in principle, also in the framework of the Standard Model of elementary particles, but the present limits on the mass of the higgs particle exclude this possibility. Finally we present the model of baryogenesis through leptogenesis, which is allowed by a minimal extension of the Standard Model, which has the appeal of being testable in future long-baseline neutrino oscillation experiments.

Dark matter annihilation in the halo of the Milky Way

If the dark matter in the Universe is made of weakly self-interacting particles, they may self-annihilate and emit γ-rays. We use high-resolution numerical simulations to estimate directly the annihilation flux from the central regions of the Milky Way and from dark matter substructures in its halo. Although such estimates remain uncertain because of their strong dependence on the structure of the densest regions, our numerical experiments suggest that less direct calculations have overestimated the emission both from the centre and from the halo substructure. We estimate a maximal enhancement of at most a factor of a few with respect to a smooth spherical halo of standard Navarro–Frenk–White (NFW) structure. We discuss detection strategies for the next generation of γ-ray detectors and find that the annihilation flux may be detectable, regardless of uncertainties about the densest regions, for the annihilation cross-sections predicted by currently popular elementary particle models for the dark matter.

Neutrino masses and mixings: What do they mean?

Neutrino masses show that the standard model of the elementary particles and interactions is incomplete and suggest the existence of physics at high mass scales. Furthermore, the difference between quark and lepton mixing raising new questions. We discuss some theoretical attempts to address these questions emphasizing their limitations and the potential. PACS: 14.60.Pq Neutrino mass and mixing – 12.10.-g Unified field theories and models

The Search for a Permanent Electric Dipole Moment

Small-scale experiments sensitive to tiny effects could offer profound insights into what lies beyond the standard model of elementary particles.

Resource Letter: SM-1: The standard model and beyond

This Resource Letter provides a guide to literature on the standard model of elementary particles and possible extensions. In the successful theory of quarks and leptons and their interactions, important questions remain, such as the mechanism of electroweak symmetry breaking, the origin of quark and lepton masses, the source of the baryon asymmetry of the Universe, and the makeup of its matter and energy density. References are cited for quarks and leptons, gauge theories, color and chromodynamics, weak interactions, electroweak unification, CP violation, dynamics of heavy quarks, Higgs bosons, precision electroweak measurements, supersymmetry, dynamical electroweak symmetry breaking, composite quarks and leptons, grand unification and extended gauge groups, string theories, large extra dimensions, neutrino masses, cosmic microwave background radiation, dark matter, dark energy, accelerator facilities, and non-accelerator experiments.

First-principles study of illite-smectite and implications for clay mineral systems.

Illite-smectite interstratified clay minerals are ubiquitous in sedimentary basins and they have been linked to the maturation, migration and trapping of hydrocarbons, rock cementation, evolution of porewater chemistry during diagenesis and the development of pore pressure. But, despite the importance of these clays, their structures are controversial. Two competing models exist, each with profoundly different consequences for the understanding of diagenetic processes: model A views such interstratified clays as a stacking of layers identical to endmember illite and smectite layers, implying discrete and independently formed units (fundamental particles), whereas model B views the clays as composed of crystallites with a unique structure that maintains coherency over much greater distances, in line with local charge balance about interlayers. Here we use first-principles density-functional theory to explore the energetics and structures of these two models for an illite-smectite interstratified clay mineral with a ratio of 1:1 and a Reichweite parameter of 1. We find that the total energy of model B is 2.3 kJ atom(-1) mol(-1) lower than that of model A, and that this energy difference can be traced to structural distortions in model A due to local charge imbalance. The greater stability of model B requires re-evaluation of the evolution of the smectite-to-illite sequence of clay minerals, including the nature of coexisting species, stability relations, growth mechanisms and the model of fundamental particles.

Radiative muon capture by3He

The rate of the nuclear reaction $^3He+\mu^- \to ^3H+\gamma+\nu_{\mu}$ has been calculated using both the elementary particle model (EPM) approach and the impulse approximation (IA) approach. Using the EPM approach, the exclusive statistical radiative muon capture (RMC) rate for photon energy greater than 57 MeV is found to be $0.245 s^{-1}$ and the ordinary muon capture (OMC) rate to be $1503 s^{-1}$. The IA calculation exhibits a slight dependence on the type of trinucleon wave functions used. The difference between the IA and EPM calculation is larger for RMC than for OMC. To resolve the difference between the two approaches a more detailed investigation including meson exchange corrections will be required.

Infinitely Many Solutions for Derrick’s Equation

Abstract In this paper we study a class of field equations, in several space dimensions, which admits solitary waves. The equation is a vector-valued version of a field equation proposed by Derrick in 1964 as model for elementary particles. We show the existence of infinitely many solutions with arbitrary topological charge.

Correlated many-body treatment of the Breit interaction with application to cesium atomic properties and parity violation

Corrections from the Breit interaction to basic properties of atomic ${}^{133}\mathrm{Cs}$ are determined in the framework of third-order relativistic many-body perturbation theory. The corrections to energies, hyperfine-structure constants, off-diagonal hyperfine $6S\ensuremath{-}7S$ amplitude, and electric-dipole matrix elements are tabulated. It is demonstrated that the Breit corrections to correlations are comparable to the Breit corrections at the Hartree-Fock level. Modification of the parity-nonconserving (PNC) $6S\ensuremath{-}7S$ amplitude due to Breit interaction is also evaluated; the resulting weak charge of ${}^{133}\mathrm{Cs}$ shows no significant deviation from the prediction of the standard model of elementary particles. The neutron skin correction to the PNC amplitude is also estimated to be -0.2% with an error bound of 30% based on the analysis of recent experiments with antiprotonic atoms. The present work supplements publication [A. Derevianko, Phys. Rev. Lett. 85, 1618 (2000)] with a discussion of the formalism and provides additional numerical results and updated discussion of parity violation.

CP violation in B meson decays

The Universe exhibits a remarkable asymmetry without which we could not exist: it contains large quantities of matter but almost no antimatter. Yet in the interactions of elementary particles at high energy as much antimatter as matter is produced. While it is clear that this asymmetry occurred in the very early evolution of the Universe the mechanism is not understood. However one key element is the phenomenon of CP violation, which results in a small difference in the way in which particles and their antiparticles decay. CP violation was discovered in 1963 in the decays of K mesons and has been investigated in detail since then in these decays. During the 1990s new projects were developed to extend these measurements to the decay of B mesons. Two major projects, Belle at KEK in Japan and BABAR at SLAC in the USA, began operation in 1999 and reported first results in 2000. This paper reviews the phenomenon of CP violation in the decays of elementary particles and demonstrates the basis for the measurements of CP violation parameters in B meson decays. A description is given of the BABAR detector together with an outline of the procedure for analysing the data. First results are consistent with predictions of the Standard Model of elementary particles but during the coming years additional data will provide more stringent tests that could reveal new phenomena.

Lochlainn O’Raifeartaigh

Lochlainn O’Raifeartaigh

Dynamical structure of space-time discontinuum and spin [formula omitted

It seems that spin 1 4 was recently observed in so called deep inelastic scattering experiments [1]. Apparently its explanation is not packed in the frame of quark-gluon model of elementary particles. However the new theory [2] surely contains these objects with spin 1 4 . Such objects appear if we consider our space-time at very small distances as a discontinuum. Thus, two things are connected: spin 1 4 and space-time discontinuum.

Examples of Gamow vectors

We present three selected physical examples of Gamow vectors to illustrate their physical significance, namely, central potential scattering, one-dimensional lattice with impurities in electric field (Stark) and a simple model for unstable elementary particles (Friedrichs).

Comment on Formulating and Generalizing Dirac's, Proca's, and Maxwell's Equations with Biquaternions or Clifford Numbers

Many difficulties of interpretation met by contemporary researchers attempting to recast or generalize Dirac's, Proca's, or Maxwell's theories using biquaternions or Clifford numbers have been encountered long ago by a number of physicists including Lanczos, Proca, and Einstien. In the modern approach initiated by Gursey, these difficulties are solved by recognizing that most generalizations lead to theories describing superpositions of particles of different intrinsic spin and isospin, so that the correct interpretation emerges from the requirement of full Poincare covariance, including space and time reversal, as well as reversion and gauge invariance. For instance, the doubling of the number of solutions implied by the simplest generalization of Dirac's equation (i.e., Lanczos's equation) can be interpreted as isospin. In this approach, biquaternions and Clifford numbers become powerful opportunities to formulate the Standard Model of elementary particles, as well as many of its possible generalizations, in very elegant and compact ways.

Fermion masses in a model for spontaneous parity breaking

In this paper we discuss a left-right symmetric model for elementary particles and their connection with the mass spectrum of elementary fermions. The model is based on the group $SU(2)_L\otimes SU(2)_R\otimes U(1)$. New mirror fermions and a minimal set of Higgs particles that breaks the symmetry down to $U(1)_{em}$ are proposed. The model can accommodate a consistent pattern for charged and neutral fermion masses as well as neutrino oscillations. An important consequence of the model is that the connection between the left and right sectors can be done by the neutral vector gauge bosons Z and a new heavy Z'.