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Radiation spectrum of extreme relativistic electrons and a probability of electron-positron pair production by energetic photons in a strong plasma wakefield are derived in the framework of a semiclassical approach. It is shown that that the radiation losses of the relativistic electron in the plasma wakefield scale as $ \propto \epsilon ^{2 / 3}$ in the quantum limit when the energy of the radiated photon becomes close to the electron energy, $\epsilon $. The quantum effects will play a key role in future plasma-based accelerators operating at ultrahigh energy of the electrons.

Radiation spectrum of extreme relativistic electrons and a probability of electron-positron pair production by energetic photons in a strong plasma wakefield are derived in the framework of a semiclassical approach. It is shown that that the radiation losses of the relativistic electron in the plasma wakefield scale as $ \propto \epsilon ^{2 / 3}$ in the quantum limit when the energy of the radiated photon becomes close to the electron energy, $\epsilon $. The quantum effects will play a key role in future plasma-based accelerators operating at ultrahigh energy of the electrons.

The hot gas in clusters of galaxies emits thermal bremsstrahlung emission that can be probed directly through measurements in the X-ray band with satellites like ROSAT and ASCA. Another probe of this gas comes from its effect on the cosmic microwave background radiation (CMBR): the hot cluster electrons inverse Compton scatter the CMBR photons and thereby distort the background radiation from its blackbody spectral form. In the last few years, the development of sensitive new instruments for measuring this distortion, called the Sunyaev-Zel'dovich (SZ) effect, has sparked a revolution in the field. Current radio interferometric arrays can now detect and map the SZ effect in even distant (z ~ 1) clusters. It is well known that one of the purposes of conducting such measurements is to determine the Hubble constant. In this review I report on the progress that has been made in this area, quote the current best estimate of Ho from the SZ effect of 8 galaxy clusters (44 - 64 km/s/Mpc +/- 17%), discuss important systematic uncertainties, and highlight what else has been learned about galaxy clusters from these investigations.

The hot gas in clusters of galaxies emits thermal bremsstrahlung emission that can be probed directly through measurements in the X-ray band with satellites like ROSAT and ASCA. Another probe of this gas comes from its effect on the cosmic microwave background radiation (CMBR): the hot cluster electrons inverse Compton scatter the CMBR photons and thereby distort the background radiation from its blackbody spectral form. In the last few years, the development of sensitive new instruments for measuring this distortion, called the Sunyaev-Zel'dovich (SZ) effect, has sparked a revolution in the field. Current radio interferometric arrays can now detect and map the SZ effect in even distant (z ~ 1) clusters. It is well known that one of the purposes of conducting such measurements is to determine the Hubble constant. In this review I report on the progress that has been made in this area, quote the current best estimate of Ho from the SZ effect of 8 galaxy clusters (44 - 64 km/s/Mpc +/- 17%), discuss important systematic uncertainties, and highlight what else has been learned about galaxy clusters from these investigations.

We consider the production of ultrarelativistic positronium (Ps) in $\gamma A \to Ps + A$ and $e A \to Ps + e A$ processes where $A$ is an atom or a nucleus with charge $Ze$. For the photoproduction of para- and ortho-Ps and the electroproduction of para-Ps we obtain the most complete description compared with previous works. It includes high order $Z \alpha$ corrections and polarization effects. The accuracy of the obtained cross sections is determined by omitted terms of the order of the inverse Ps Lorentz factor squared. The studied high order multi-photon electroproduction of ortho-Ps dominates for the collision of electrons with heavy atoms over the bremsstrahlung production from the electron via a virtual photon proposed by Holvik and Olsen. Our results complete and correct the studies of those authors.

The theoretical foundations of quantum mechanics and de Broglie-Bohm mechanics are analyzed and it is shown that both theories employ a formal approach to microphysics. By using a realistic approach it can be established that the internal structures of particles comply with a wave-equation. Including external potentials yields the Schrodinger equation, which, in this context, is arbitrary due to internal energy components. The uncertainty relations are an expression of this, fundamental, arbitrariness. Electrons and photons can be described by an identical formalism, providing formulations equivalent to the Maxwell equations. Electrostatic interactions justify the initial assumption of electron-wave stability: the stability of electron waves can be referred to vanishing intrinsic fields of interaction. Aspect's experimental proof of non-locality is rejected, because these measurements imply a violation of the uncertainty relations. The paper finally points out some fundamental difficulties for a fully covariant formulation of quantum electrodynamics, which seem to be related to the existing infinity problems in this field.

The theoretical foundations of quantum mechanics and de Broglie-Bohm mechanics are analyzed and it is shown that both theories employ a formal approach to microphysics. By using a realistic approach it can be established that the internal structures of particles comply with a wave-equation. Including external potentials yields the Schrodinger equation, which, in this context, is arbitrary due to internal energy components. The uncertainty relations are an expression of this, fundamental, arbitrariness. Electrons and photons can be described by an identical formalism, providing formulations equivalent to the Maxwell equations. Electrostatic interactions justify the initial assumption of electron-wave stability: the stability of electron waves can be referred to vanishing intrinsic fields of interaction. Aspect's experimental proof of non-locality is rejected, because these measurements imply a violation of the uncertainty relations. The paper finally points out some fundamental difficulties for a fully covariant formulation of quantum electrodynamics, which seem to be related to the existing infinity problems in this field.

The theoretical foundations of quantum mechanics and de Broglie-Bohm mechanics are analyzed and it is shown that both theories employ a formal approach to microphysics. By using a realistic approach it can be established that the internal structures of particles comply with a wave-equation. Including external potentials yields the Schrodinger equation, which, in this context, is arbitrary due to internal energy components. The uncertainty relations are an expression of this, fundamental, arbitrariness. Electrons and photons can be described by an identical formalism, providing formulations equivalent to the Maxwell equations. Electrostatic interactions justify the initial assumption of electron-wave stability: the stability of electron waves can be referred to vanishing intrinsic fields of interaction. Aspect's experimental proof of non-locality is rejected, because these measurements imply a violation of the uncertainty relations. The paper finally points out some fundamental difficulties for a fully covariant formulation of quantum electrodynamics, which seem to be related to the existing infinity problems in this field.

The production of ultrahigh energy photons, electrons and neutrinos as the decay products of pions produced in photomeson interactions between cosmic ray nucleons and the blackbody microwave background is discussed in terms of the resultant energy spectra of these particles. Simple asymptotic formulas are given for calculating the ultrahigh energy photon spectrum predicted for the universal cosmic ray hypothesis and the resulting spectra are compared with those obtained previously by numerical means using a different propagation equation for the photons. Approximate analytic solutions for the photon spectra are given in terms of simple power-law energy functions and slowly varying logarithmic functions.

For additional meeting information, visit the MRS Web site at www.mrs.org/meetings/ or contact: Member Services, Materials Research Society, 506 Keystone Drive, Warrendale, PA 15086-7573 Tel 724-779-3003 • Fax 724-779-8313 • [email protected] MRS Symposium PP: Frontiers of Chemical Imaging—Integrating Electrons, Photons, and Ions Direct imaging and spectroscopy are powerful means to develop an atomistic understanding of scientific issues associated with knowledge gaps and problems in energy, environment, and national security. For example, identification of mechanisms associated with chemical, material, and biological transformations requires the direct observation of structural and chemical process that happens at atomic scale. It has been generally realized that any single imaging and spectroscopic method can only yield a small subset of available information. In many cases, a thorough understanding of materials’ behavior relies on collective information captured with different imaging and spectroscopy methods, which normally correspond to different spatial, energy, and temporal resolutions. Therefore, one of the great challenges for the scientific community is to find paths that can uniquely integrate results from multiple imaging and spectroscopy capabilities to analyze a specific region within the same sample without modifying it. Although there are certain degrees of success in understanding fundamental physical, chemical, and biological processes, the ability to obtain in-situ data in complex processes continues to pose challenges. Advances in chemical imaging will hold the potential for fundamental breakthroughs in understanding the mechanisms involved in these processes, which in turn will guide the designing and discovering of new materials. The purpose of this symposium is to bring together scientists and engineers working in the field of imaging using electrons, photons, and ions to discuss the frontier of the integrated chemical imaging across different platforms. The symposium will showcase the revelation of atomic- and molecular-level building blocks through multimodal chemical imaging capabilities. Interdisciplinary topics related to dynamic imaging and spectroscopy of nanostructured materials, catalytic process, and energy harvesting and storage will be highlighted. Session topics will include:  Frontiers in chemical imaging and analysis using electrons, photons, and ions  In situ imaging and spectroscopy in catalysis and energy harvesting and storage materials  Imaging beyond normal conditions, which include, but are not limited to, liquid, gas, high-pressure, and high-temperature environment  Phenomena across the boundary of soft and hard materials  New instruments and data visualization, analysis, and modeling tools for chemical imaging Invited speakers include: Larry Allard (Oak Ridge National Lab), Joy Andrews Hayter (Stanford Synchrotron Radiation Lightsource), Simon Bare (UOP/Honeywell), Raphaëlle Dianoux (Nanoscan, Switzerland), Peter Fischer (Lawrence Berkeley National Lab), Brian Gorman (Colorado School of Mines), Wayne D. Kaplan (Technion–Israel Inst. of Technology, Israel), Scott Lea (Pacific Northwest National Lab), David Muller (Cornell Univ.), Markus Raschke (Univ. of Colorado), Peter Schattschneider (Vienna Univ. of Technology, Austria), Eric Stach (Brookhaven National Lab), Louis Terminello (Pacific Northwest National Lab). Symposium Organizers Chongmin Wang Pacific Northwest National Laboratory Environmental Molecular Sciences Laboratory MSIN K8-87, 3335 Q Ave., Richland, WA 99352 Tel 509-371-6268, Fax 509-371-6242, [email protected] Jane Y. Howe Oak Ridge National Laboratory Bldg. 4515, MS 606 1 Bethel Valley Rd., Oak Ridge, TN 37831-6064 Tel 865-574-4487, Fax 865-241-3650, [email protected] Artur Braun Empa, Swiss Federal Laboratories for Materials Testing and Research Laboratory for High Performance Ceramics Überlandstr. 129, CH-8600 Dübendorf, Switzerland Tel 41-58-765-4850, Fax 41-58-765-4150, [email protected] Jigang Zhou Canadian Light Source Inc. 101 Perimeter Rd., Saskatoon, SK, S7N 0X4, Canada Tel 306-657-3587, [email protected]

We present a full ab-inito description of the coupled out-of-equilibrium dynamics of photons, phonons, and electrons. In the present approach the quantised nature of the electromagnetic field as well as of the nuclear oscillations is fully taken into account. The result is a set of integro-differential equations, written on the Keldysh contour, for the Green's functions of electrons, phonons, and photons where the different kind of interactions are merged together. We then concentrate on the electronic dynamics in order to reduce the problem to a computationally feasible approach. By using the Generalised Baym-Kadanoff ansatz and the Completed Collision approximation we introduce a series of efficient but controllable approximations. In this way we reduce all equations to a set of decoupled equations for the density matrix that describe all kind of static and dynamical correlations. The final result is a coherent, general, and inclusive scheme to calculate several physical quantities: carrier dynamics, transient photo-absorption and light-emission. All of which include, at the same time, electron-electron, electron-phonon, and electron-photon interaction. We further discuss how all these observables can be easily calculated within the present scheme using a fully atomistic ab-initio approach.

Book Source: Digital Library of India Item 2015.60140 dc.contributor.author: Robert Andrews Millikan dc.date.accessioned: 2015-06-29T20:21:16Z dc.date.available: 2015-06-29T20:21:16Z dc.date.copyrightexpirydate: 0000-00-00 dc.date.digitalpublicationdate: 2003-12-20 dc.date.citation: 1947 dc.identifier: RMSC, IIIT-H dc.identifier.barcode: 111049 dc.identifier.origpath: /data6/upload/0155/121 dc.identifier.copyno: 1 dc.identifier.uri: http://www.new.dli.ernet.in/handle/2015/60140 dc.description.numberedpages: 642 dc.description.numberedpages: 22 dc.description.scanningcentre: RMSC, IIIT-H dc.description.main: 1 dc.description.tagged: 0 dc.description.totalpages: 664 dc.format.mimetype: application/pdf dc.language.iso: English dc.publisher.digitalrepublisher: Universal Digital Library dc.publisher: The University Of Chicago Press dc.rights: Copyright Protected dc.title: Electrons (+and -) Protons Photons Neutrons Mesotrons And Cosmic Rays dc.rights.holder: The University Of Chicago Press

We show that when an electron or photon propagates in a cylindrically symmetric waveguide, its spin angular momentum (SAM) and its orbital angular momentum (OAM) interact. Remarkably, we find that the dynamics resulting from this spin-orbit interaction are quantitatively described by a single expression applying to both electrons and photons. This leads to the prediction of several novel rotational effects: the spatial or time evolution of either particle's spin/polarization vector is controlled by the sign of its OAM quantum number, or conversely, its spatial wavefunction is controlled by its SAM. We show that the common origin of these effects in electrons and photons is a universal geometric phase. We demonstrate how these phenomena can be used to reversibly transfer entanglement between the SAM and OAM degrees of freedom of two-particle states.

In 1998, the detector H1 at HERA has been equipped with a small backward spectrometer, the Very Low Q^2 (VLQ) spectrometer comprising a silicon tracker, a tungsten - scintillator sandwich calorimeter, and a Time-of-Flight system. The spectrometer was designed to measure electrons scattered under very low angles, equivalent to very low squared four - momentum transfers Q^2, and high energy photons with good energy and spatial resolution. The VLQ was in operation during the 1999 and 2000 run periods. This paper describes the design and construction of the VLQ calorimeter, a compact device with a fourfold projective energy read-out, and its performance during test runs and in the experiment.

In 1998, the detector H1 at HERA has been equipped with a small backward spectrometer, the Very Low Q^2 (VLQ) spectrometer comprising a silicon tracker, a tungsten - scintillator sandwich calorimeter, and a Time-of-Flight system. The spectrometer was designed to measure electrons scattered under very low angles, equivalent to very low squared four - momentum transfers Q^2, and high energy photons with good energy and spatial resolution. The VLQ was in operation during the 1999 and 2000 run periods. This paper describes the design and construction of the VLQ calorimeter, a compact device with a fourfold projective energy read-out, and its performance during test runs and in the experiment.

Nonperturbative coupling of light with condensed matter in an optical cavity is expected to reveal a host of coherent many-body phenomena and states. In addition, strong coherent light-matter interaction in a solid-state environment is of great interest to emerging quantum-based technologies. However, creating a system that combines a long electronic coherence time, a large dipole moment, and a high cavity quality ($Q$) factor has been a challenging goal. Here, we report collective ultrastrong light-matter coupling in an ultrahigh-mobility two-dimensional electron gas in a high-$Q$ terahertz photonic-crystal cavity in a quantizing magnetic field, demonstrating a cooperativity of $\sim$360. The splitting of cyclotron resonance (CR) into the lower and upper polariton branches exhibited a $\sqrt{n_\mathrm{e}}$-dependence on the electron density ($n_\mathrm{e}$), a hallmark of collective vacuum Rabi splitting. Furthermore, a small but definite blue shift was observed for the polariton frequencies due to the normally negligible $A^2$ term in the light-matter interaction Hamiltonian. Finally, the high-$Q$ cavity suppressed the superradiant decay of coherent CR, which resulted in an unprecedentedly narrow intrinsic CR linewidth of 5.6 GHz at 2 K. These results open up a variety of new possibilities to combine the traditional disciplines of many-body condensed matter physics and cavity-based quantum optics.

#Why is #glass and a lot of #matter (like #air) #transparent The #electrons don't #eat those #photons and let them pass through, unchanged.-O7pUj20HQPr.mp4 Why is glass and a lot of matter like air transparent The electrons dont eat those photons and let them pass through unchanged O7pUj20HQPr mp4 Why glass matter air transparent electrons eat photons

The theoretical foundations of quantum mechanics and de Broglie--Bohm mechanics are analyzed and it is shown that both theories employ a formal approach to microphysics. By using a realistic approach it can be established that the internal structures of extended particles comply with a wave-equation. Including external potentials yields the Schrodinger equation, which, in this context, is arbitrary due to internal energy components. The statistical interpretation of wave functions in quantum theory as well as Heisenberg's uncertainty relations are shown to be an expression of this, fundamental, arbitrariness. Electrons and photons can be described by an identical formalism, providing formulations equivalent to the Maxwell equations. Electrostatic interactions justify the initial assumption of electron-wave stability: the stability of electron waves can be referred to vanishing intrinsic fields of interaction. The theory finally points out some fundamental difficulties for a fully covariant formulation of quantum electrodynamics, which seem to be related to the existing infinity problems in this field.

This is an attempt to construct a classical microscopic model of the electron which underlies quantum mechanics. An electron is modeled, not as a point particle, but as the end of an electromagnetic string, a line of flux. These lines stretch across cosmic distances, but are almost unobservable because they condense into pairs--which form the ether. Photons are modeled to propagate on these line pairs, which act effectively as wave guides. These line pairs are also responsible for the force of gravity--which is electromagnetic in character.

Entanglement is a fundamental feature of quantum theory as well as a key resource for quantum computing and quantum communication, but the entanglement mechanism has not been found at present. We think when the two subsystems exist interaction directly or indirectly, they can be in entanglement state. such as, in the Jaynes-Cummings model, the entanglement between an atom and light field comes from their interaction. In this paper, we have studied the entanglement mechanism of electron-electron and photon-photon, which are from the spin-spin interaction. We found their total entanglement states are relevant both space state and spin state. When two electrons or two photons are far away, their entanglement states should be disappeared even if their spin state is entangled.

The particle Fock space of the matter fields in QED can be constructed using the free creation and annihilation operators. However, these particle operators are not, even at asymptotically large times, the modes of the matter fields that enter the QED Lagrangian. In this letter we construct the fields which do recover such particle modes at large times. We are thus able to demonstrate for the first time that, contrary to statements found in the literature, a relativistic description of charged particles in QED exists.

The particle Fock space of the matter fields in QED can be constructed using the free creation and annihilation operators. However, these particle operators are not, even at asymptotically large times, the modes of the matter fields that enter the QED Lagrangian. In this letter we construct the fields which do recover such particle modes at large times. We are thus able to demonstrate for the first time that, contrary to statements found in the literature, a relativistic description of charged particles in QED exists.

We study quantum systems of interacting electrons, magnetic monopoles, and electromagnetic field. We formulate a convenient field theory, in which the electron-photon, monopole-photon, and electron-monopole interactions take simple forms.

This report describes research on nuclear photodisintegration carried out with the University of Melbourne 35 MeV betatron. It is divided into four sections. The first of these reports on (gamma,n) cross section measurements which comprise the major part of the work. Photoneutron cross sections are reported for 16O, 9Be, 10B, 11B, 12C, 13C, 45Sc and natural osmium. The motivation for each of these studies is given, as are the results of the measurements. Parts II through IV are briefer, and describe respectively measurements of photoproton energy spectra from the zirconium isotopes, measurements and calculations regarding de-excitation gamma-ray measurements in 19F, 31p, and 39K, and finally the last stages of work on the determination of cross sections for K-shell ionization in nickel, silver and gold. (Author)

The CERN-NA-59 experiment examined a wide range of electromagnetic processes for multi-GeV electrons and photons interacting with oriented single crystals. The various types of crystals and their orientations were used for producing photon beams and for converting and measuring their polarisation. The radiation emitted by 178 GeV unpolarised electrons incident on a 1.5 cm thick Si crystal oriented in the Coherent Bremsstrahlung (CB) and the String-of-Strings (SOS) modes was used to obtain multi-GeV linearly polarised photon beams. A new crystal polarimetry technique was established for measuring the linear polarisation of the photon beam. The polarimeter is based on the dependence of the Coherent Pair Production (CPP) cross section in oriented single crystals on the direction of the photon polarisation with respect to the crystal plane. Both a 1 mm thick single crystal of Germanium and a 4 mm thick multi-tile set of synthetic Diamond crystals were used as analyzers of the linear polarisation. A birefringence phenomenon, the conversion of the linear polarisation of the photon beam into circular polarisation, was observed. This was achieved by letting the linearly polarised photon beam pass through a 10 cm thick Silicon single crystal that acted as a "quarter wave plate" (QWP) as suggested by N. Cabibbo et al.

We study the electronic band structure and optical conductivity of an array of tunnel-coupled array of graphene nanoribbons. We show that due to the coupling of electronic edge states for the zigzag nanoribbon structure, the Fermi surface can become a hyperbola similarly to the case of the layered metal-dielectric structures, where the hyperbolic isofrequency contours originate from the coupling of localized surface plasmon polaritons. Moreover, we show that for both types of the ribbon edge, the optical response of the structure can be characterized by a uniaxial conductivity tensor, having principal components of the different signs. Therefore, the tunnel-coupled nanoribbon array can be regarded as a tunable hyperbolic metasurface.

A representation of the quadratic Dirac equation and the Maxwell equations in terms of the three-dimensional universal complex Clifford algebra $\bar{\bfa{C}}_{3,0}$ is given. The investigation considers a subset of the full algebra, which is isomorphic to the Baylis algebra. The approach is based on the two Casimir operators of the Poincar\'e group, the mass operator and the spin operator, which is related to the Pauli-Lubanski vector. The extension to spherical symmetries is discussed briefly. The structural difference to the Baylis algebra appears in the shape of the hyperbolic unit, which plays an integral part in this formalism.

The wave-structure of moving electrons is analyzed on a fundamental level by employing a modified de Broglie relation. Formalizing the wave-function $\psi$ in real notation yields internal energy components due to mass oscillations. The wave-features can then be referred to physical waves of discrete frequency $\nu$ and the classical dispersion relation $\lambda \nu = u $, complying with the classical wave equation. Including external potentials yields the Schr\"odinger equation, which, in this context, is arbitrary due to the internal energy components. It can be established that the uncertainty relations are an expression of this, fundamental, arbitrariness. Electrons and photons can be described by an identical formalism, providing formulations equivalent to the Maxwell equations. The wave equations of intrinsic particle properties are Lorentz invariant considering total energy of particles, although transformations into a moving reference frame lead to an increase of intrinsic potentials. Interactions of photons and electrons are treated extensively, the results achieved are equivalent to the results in quantum theory. Electrostatic interactions provide, a posteriori, a justification for the initial assumption of electron-wave stability: the stability of electron waves can be referred to vanishing intrinsic fields of interaction. The concept finally allows the conclusion that a significant correlation for a pair of spin particles in EPR--like measurements is likely to violate the uncertainty relations.

The coupled system of Boltzman equations for the interacting system of electrons, positrons and photons in high external electric, E, and arbitrary magnetic, H, fields is solved. The consideration is made under the conditions of arbitrary heating and the mutual drag of carriers and photons. The non-stationary and non-uniform distribution function of photons for the all considered cases is obtained. It is shown that the distribution function of photons has the stationary limit for the drift velocities $(\vec{u}\vec{q}/ \hbar \omega_q)

We consider the production of ultrarelativistic parapositronium and orthopositronium atoms in collisions of high energy electrons with laser photons. Our results demonstrate the opportunity of intensive positronium beam formation with Lorentz-factor 10^6 using laser beam conversion on high energy electrons at the future Electron Linear Accelerators.

We consider the production of ultrarelativistic parapositronium and orthopositronium atoms in collisions of high energy electrons with laser photons. Our results demonstrate the opportunity of intensive positronium beam formation with Lorentz-factor 10^6 using laser beam conversion on high energy electrons at the future Electron Linear Accelerators.

We give an example of a purely bosonic model -- a rotor model on the 3D cubic lattice -- whose low energy excitations behave like massless U(1) gauge bosons and massless Dirac fermions. This model can be viewed as a ``quantum ether'': a medium that gives rise to both photons and electrons. It illustrates a general mechanism for the emergence of gauge bosons and fermions known as ``string-net condensation.'' Other, more complex, string-net condensed models can have excitations that behave like gluons, quarks and other particles in the standard model. This suggests that photons, electrons and other elementary particles may have a unified origin: string-net condensation in our vacuum.

We give an example of a purely bosonic model -- a rotor model on the 3D cubic lattice -- whose low energy excitations behave like massless U(1) gauge bosons and massless Dirac fermions. This model can be viewed as a ``quantum ether'': a medium that gives rise to both photons and electrons. It illustrates a general mechanism for the emergence of gauge bosons and fermions known as ``string-net condensation.'' Other, more complex, string-net condensed models can have excitations that behave like gluons, quarks and other particles in the standard model. This suggests that photons, electrons and other elementary particles may have a unified origin: string-net condensation in our vacuum.

The connected system of Boltzman equations for the interacting system of electrons, positrons and photons in high external electric E and arbitrary magnetic H fields is solved. The consideration is made under the conditions of arbitrary heating and the mutual drag of carriers and photons. The non-stationary and non-uniform distribution function (DF) of photons for the all considered cases is obtained. It is shown that the DF of photons have the stationary limit for the drift velocities $(\overset{\to }\to{u}\overset{\to}\to{q}/\hbar \omega_q)

It is shown that electrons and photons can be considered as composities of particles representating the fundamental representation of the extended Lorentz group $SU(3)\otimes SU(3)$ in (8+1) dimensional space-time which are held together by force mediated by gauge particles belonging to the regular representation. In this theory, spin states of electron, positron and photon belong to the $8\otimes 8$ representation of the group. The fine structure constant of the fundamental gauge interaction is found to be unity from the fact that the photon is massless. The mass of the fundamental particles constituting the electron and the photon is estimated to be $\geq 10^{21}$ GeV from the experimental limit for the life-time of electron decay into neutrino and photon which is a consequence of the model. This corresponds to distances of less than $10^{-35}$ cm which is smaller than the Planck length indicating thereby that the composite nature of electrons and photons will be revealed when we go to Planckian energies.

For the 1994 Tevatron collider run, CDF has upgraded the electron and photon trigger hardware to make use of shower position and size information from the central shower maximum detector. For electrons, the upgrade has resulted in a 50\% reduction in backgrounds while retaining approximately 90\% of the signal. The new trigger also eliminates the background to photon triggers from single-phototube discharge.

Binary mixtures of electrons with protons and of electrons with photons subjected to external electromagnetic fields are analyzed by using the Anderson and Witting model equation. The relativistic laws of Ohm and Fourier are determined as well as general expressions for the electrical and thermal conductivities for relativistic ionized gas mixtures. Explicit expressions for the transport coefficients are given for the particular cases: a non-relativistic mixture of protons and non-degenerate electrons; an ultra-relativistic mixture of photons and non-degenerate electrons; a non-relativistic mixture of protons and completely degenerate electrons; an ultra-relativistic mixture of photons and completely degenerate electrons and a mixture of non-relativistic protons and ultra-relativistic completely degenerate electrons.

Journal of Research of the National Bureau of Standards

Heavy particle, electron, and UV photon bombardment of solid surfaces has been recently observed to result in the emission of infrared, visible, and ultraviolet radiation. This effect occurs over a wide range of incident projectile energies. Line radiation arising from transitions between discrete atomic or molecular levels may be attributed to the decay of excited particles which have been sputtered or electronically/chemically desorbed from the surface. Broadband continuum radiation, which is also observed, is believed to arise either from fluorescence of the near surface bulk or from the radiative decay of desorbed excited clusters. Spacecraft, in the ambient near Earth environment, are subject to such bombardment. The dynamics of energetic particle and photon beam interactions with surfaces which lead to surface erosion and glow phenomena will be treated. In addition, projected experimental and theoretical studies of oxygen and nitrogen beam surface interactions on materials characteristic of spacecraft surfaces will be discussed.

Recent advances in condensed matter theory have revealed that new and exotic phases of matter can exist in spin models (or more precisely, local bosonic models) via a simple physical mechanism, known as "string-net condensation." These new phases of matter have the unusual property that their collective excitations are gauge bosons and fermions. In some cases, the collective excitations can behave just like the photons, electrons, gluons, and quarks in our vacuum. This suggests that photons, electrons, and other elementary particles may have a unified origin -- string-net condensation in our vacuum. In addition, the string-net picture indicates how to make artificial photons, artificial electrons, and artificial quarks and gluons in condensed matter systems.

We present new results regarding the features of high energy photon emission by an electron beam of 178 GeV penetrating a 1.5 cm thick single Si crystal aligned at the Strings-Of-Strings (SOS) orientation. This concerns a special case of coherent bremsstrahlung where the electron interacts with the strong fields of successive atomic strings in a plane and for which the largest enhancement of the highest energy photons is expected. The polarization of the resulting photon beam was measured by the asymmetry of electron-positron pair production in an aligned diamond crystal analyzer. By the selection of a single pair the energy and the polarization of individual photons could be measured in an the environment of multiple photons produced in the radiator crystal. Photons in the high energy region show less than 20% linear polarization at the 90% confidence level.

We present new results regarding the features of high energy photon emission by an electron beam of 178 GeV penetrating a 1.5 cm thick single Si crystal aligned at the Strings-Of-Strings (SOS) orientation. This concerns a special case of coherent bremsstrahlung where the electron interacts with the strong fields of successive atomic strings in a plane and for which the largest enhancement of the highest energy photons is expected. The polarization of the resulting photon beam was measured by the asymmetry of electron-positron pair production in an aligned diamond crystal analyzer. By the selection of a single pair the energy and the polarization of individual photons could be measured in an the environment of multiple photons produced in the radiator crystal. Photons in the high energy region show less than 20% linear polarization at the 90% confidence level.

Book Source: Digital Library of India Item 2015.176777 dc.date.accessioned: 2015-07-07T04:59:29Z dc.date.available: 2015-07-07T04:59:29Z dc.date.digitalpublicationdate: 0000-00-00 dc.date.citation: 1935 dc.identifier.barcode: 99999990012872 dc.identifier.origpath: /data/upload/0012/877 dc.identifier.copyno: 1 dc.identifier.uri: http://www.new.dli.ernet.in/handle/2015/176777 dc.description.scanningcentre: IIAp, Bangalore dc.description.main: 1 dc.description.tagged: 0 dc.description.totalpages: 517 dc.format.mimetype: application/pdf dc.language.iso: English dc.publisher.digitalrepublisher: Iiap dc.publisher: The University Of Chicago Press dc.rights: Out_of_copyright dc.source.library: Indian Institute Of Astrophysics dc.title: Electrons + And - Protons Photons Neutrons And Cosmic Rays dc.rights.holder: The University Of Chicago Press

The intent of this research program was to elucidate the microscopic mechanisms by which the energy of incoming beams of atoms, ions, electrons and photons is absorbed, localized and redirected to produce neutral-particle desorption from surfaces and subsequent surface modification of restructuring. The model system LiF was used, and the results compared with measurements of electronically desorbed Li-atoms adsorbed on other substrates. This study explored how the degree of surface metallization influences the choice of the final excitation state of the desorbing particle. Measurements were made to compare the desorption of excited state neutral lithium from lithium fluoride by electron, photon and ion bombardment and from lithium-dosed tungsten and lithium-dosed glass by electron and photon bombardment. In the electron and photon desorption experiments, only the first lithium resonance line is observed. These results contrast with the ion sputtering results, where emissions from higher excited states were observed. This suggests that the presence of a metal rich surface provides a channel for de-excitation of excited lithium states which are above the lithium metal Fermi energy.

Precision measurements of the structure of nucleons and nuclei in the regime of strong interaction QCD are now possible with the availability of high current polarized electron beams, polarized targets, and recoil polarimeters, in conjunction with modern spectrometers and detector instrumentation. The physics at JLab will be highlighted using two recent measurements of general interest. The ratio of the proton electric to magnetic form factors indicates the importance of the role of angular momentum in the structure of the nucleon. The existence of 5-quark configurations in the ground state wavefunctions of hadrons is confirmed by a narrow peak attributed to an exotic baryon with strangeness S=+1. These and other examples will be used to illustrate the capabilities and focus of the experimental program at JLab.

Heavy particle, electron, and UV photon bombardment of solid surfaces has been recently observed to result in the emission of infrared, visible, and ultraviolet radiation. This effect occurs over a wide range of incident projectile energies. Line radiation arising from transitions between discrete atomic or molecular levels may be attributed to the decay of excited particles which have been sputtered or electronically/chemically desorbed from the surface. Broadband continuum radiation, which is also observed, is believed to arise either from fluorescence of the near surface bulk or from the radiative decay of desorbed excited clusters. Spacecraft, in the ambient near Earth environment, are subject to such bombardment. The dynamics of energetic particle and photon beam interactions with surfaces which lead to surface erosion and glow phenomena will be treated. In addition, projected experimental and theoretical studies of oxygen and nitrogen beam surface interactions on materials characteristic of spacecraft surfaces will be discussed.

Fundamental solutions for the free Dirac electron and Einstein photon equations in position coordinates are constructed as matrix valued functionals on the space of bump functions. It is shown that these fundamental solutions are related by a unitary transform via the Cauchy distribution in imaginary time. We study the way the classical relativistic mechanics of the free particle comes from the quantum mechanics of the free Dirac electron.

Includes bibliographical references and indexes

Usually, the emission of low-energy photons in electron-positron (or electron-ion) bunch collisions is calculated with the same approach as for synchrotron radiation (beamstrahlung). However, for soft photons (E_gamma < E_c where E_c is a critical photon energy), when the coherence length of the radiation becomes comparable to the bunch length, the beamstrahlung approximation becomes invalid. In this paper, we present results of our calculation for this region based on approximation of classical currents. We consider several colliders with dense bunches. The number of low-energy photons dN_gamma emitted by N_e electrons per bunch crossing in the energy interval dE_gamma is dN_gamma = alpha g N_e dE_gamma/E_gamma, where alpha is the fine-structure constant, and the function g, which depends on the bunch parameters, typically is of order unity for modern colliders. In particular, for the ILC, we find that E_c = 83 keV and g=5.5 at a vanishing beam axis displacement, and g=0.88, E_c=0.24 keV for KEKB. We also calculate the specific dependence of dN_gamma on the impact parameter between the two beam axes. In principle, the latter aspect allows for online monitoring of the beam axis displacement.

Book Source: Digital Library of India Item 2015.212545 dc.date.accessioned: 2015-07-09T18:03:09Z dc.date.available: 2015-07-09T18:03:09Z dc.date.digitalpublicationdate: 0000-00-00 dc.date.citation: 1935 dc.identifier.barcode: 99999990082002 dc.identifier.origpath: /data_copy/upload/0082/007 dc.identifier.copyno: 1 dc.identifier.uri: http://www.new.dli.ernet.in/handle/2015/212545 dc.description.scanningcentre: IIAp, Bangalore dc.description.main: 1 dc.description.tagged: 0 dc.description.totalpages: 517 dc.format.mimetype: application/pdf dc.language.iso: English dc.publisher.digitalrepublisher: Iiap dc.publisher: The University Of Chicago Press dc.rights: Out_of_copyright dc.source.library: Indian Institute Of Astrophysics dc.title: Electrons + And - Protons Photons Neutrons And Cosmic Rays dc.rights.holder: The University Of Chicago Press