159 research outputs found
A Polarized HERA Collider
A brief review is given of the status of nucleon spin structure functions as
determined from polarized deep inelastic lepton-nucleon scatttering, including
current outstanding problems. The characteristics of a polarized HERA collider,
some of the particle physics topics it could address, and the accelerator
physics challenges it must meet are discussed.Comment: 5 Pages, 6 Figures, To be published in the Proceedings of the DIS99
Conference April 1999, DESY Zeuthen, German
Recommended from our members
Internal spin structure of the proton from high energy polarized e-p scattering
A review is given of experimental knowledge of the spin dependent structure functions of the proton, which is based on inclusive high energy scattering of longitudinal polarized electrons by longitudinally polarized protons in both the deep inelastic and resonance regions, and includes preliminary results from our most recent SLAC experiment. Implications for scaling, sum rules, models of proton structure, and the hyperfine structure interval in hydrogen are given. Possible future directions of research are indicated
Overview of the SME: Implications and Phenomenology of Lorentz Violation
The Standard Model Extension (SME) provides the most general
observer-independent field theoretical framework for investigations of Lorentz
violation. The SME lagrangian by definition contains all Lorentz-violating
interaction terms that can be written as observer scalars and that involve
particle fields in the Standard Model and gravitational fields in a generalized
theory of gravity. This includes all possible terms that could arise from a
process of spontaneous Lorentz violation in the context of a more fundamental
theory, as well as terms that explicitly break Lorentz symmetry. An overview of
the SME is presented, including its motivations and construction. Some of the
theoretical issues arising in the case of spontaneous Lorentz violation are
discussed, including the question of what happens to the Nambu-Goldstone modes
when Lorentz symmetry is spontaneously violated and whether a Higgs mechanism
can occur. A minimal version of the SME in flat Minkowski spacetime that
maintains gauge invariance and power-counting renormalizability is used to
search for leading-order signals of Lorentz violation. Recent Lorentz tests in
QED systems are examined, including experiments with photons, particle and
atomic experiments, proposed experiments in space and experiments with a
spin-polarized torsion pendulum.Comment: 40 pages, Talk presented at Special Relativity: Will it Survive the
Next 100 Years? Potsdam, Germany, February, 200
Magnetic Field Stimulated Transitions of Excited States in Fast Muonic Helium Ions
It is shown that one can stimulate, by using the present-day laboratory
magnetic fields, transitions between the sub-levels of fast
ions formating in muon catalyzed fusion. Strong fields also cause the
self-ionization from highly excited states of such muonic ions. Both effects
are the consequence of the interaction of the bound muon with the oscillating
field of the Stark term coupling the center-of-mass and muon motions of the
ion due to the non-separability of the collective and internal
variables in this system. The performed calculations show a possibility to
drive the population of the sub-levels by applying a field of a few
, which affects the reactivation rate and is especially important to the
-ray production in muon catalyzed fusion. It is also shown that
the splitting in due to the vacuum polarization slightly
decreases the stimulated transition rates.Comment: 5 figure
The Definition of Mach's Principle
Two definitions of Mach's principle are proposed. Both are related to gauge
theory, are universal in scope and amount to formulations of causality that
take into account the relational nature of position, time, and size. One of
them leads directly to general relativity and may have relevance to the problem
of creating a quantum theory of gravity.Comment: To be published in Foundations of Physics as invited contribution to
Peter Mittelstaedt's 80th Birthday Festschrift. 30 page
Probing Lorentz and CPT violation with space-based experiments
Space-based experiments offer sensitivity to numerous unmeasured effects
involving Lorentz and CPT violation. We provide a classification of clock
sensitivities and present explicit expressions for time variations arising in
such experiments from nonzero coefficients in the Lorentz- and CPT-violating
Standard-Model Extension.Comment: 15 page
The Muonium Atom as a Probe of Physics beyond the Standard Model
The observed interactions between particles are not fully explained in the
successful theoretical description of the standard model to date. Due to the
close confinement of the bound state muonium () can be used as
an ideal probe of quantum electrodynamics and weak interaction and also for a
search for additional interactions between leptons. Of special interest is the
lepton number violating process of sponteanous conversion of muonium to
antimuonium.Comment: 15 pages,6 figure
Study of the radiative decay with CMD-2 detector
Using the of data collected with the CMD-2 detector at VEPP-2M
the decay mode , has been
studied. The obtained branching ratio is B(.Comment: 13 pages, 5 figures, LaTex2e, to be published in Phys. Lett.
Thermodynamic Gravity and the Schrodinger Equation
We adopt a 'thermodynamical' formulation of Mach's principle that the rest
mass of a particle in the Universe is a measure of its long-range collective
interactions with all other particles inside the horizon. We consider all
particles in the Universe as a 'gravitationally entangled' statistical ensemble
and apply the approach of classical statistical mechanics to it. It is shown
that both the Schrodinger equation and the Planck constant can be derived
within this Machian model of the universe. The appearance of probabilities,
complex wave functions, and quantization conditions is related to the
discreetness and finiteness of the Machian ensemble.Comment: Minor corrections, the version accepted by Int. J. Theor. Phy
Measurement of omega meson parameters in pi^+pi^-pi^0 decay mode with CMD-2
About 11 200 e^+e^- -> omega -> pi^+pi^-pi^0 events selected in the center of
mass energy range from 760 to 810 MeV were used for the measurement of the
\omega meson parameters. The following results have been obtained: sigma
_{0}=(1457 \pm 23 \pm 19)nb, m_{\omega}=(782.71 \pm 0.07 \pm 0.04) MeV/c^{2},
\Gamma_{\omega}=(8.68 \pm 0.23 \pm 0.10) MeV,
\Gamma_{e^+e^-}\cdot Br (\omega -> pi^+pi^-pi^0)=
(0.528 \pm 0.012 \pm 0.007) \cdot 10^{-3} MeV.Comment: 8 pages, 4 figure
- …