15 research outputs found
Study of Single W production in e-gamma collisions through the decay lepton spectrum to probe gamma-WW couplings
We investigate the effect of anomalous gamma-W-W couplings in e-gamma --> nu
W through the angular and energy spectrum of the secondary leptons. Within the
narrow-width approximation, a semi-analytical study of the secondary lepton
energy-angle double distribution is considered. Utility of observables derived
from this is demonstrated by considering the anomalous coupling,
delta-kappa-gamma. Results of our investigation for typical ILC machine
considered at Ecm = 300-1000 GeV re-affirms potential of this collider as a
precision machine.Comment: Typos corrected, discussion added in section 2 for clarity, error in
fig.2 corrected, figures 7 and 8 replaced with better resolutio
Lepton Number Violating Radiative Decay in Models with R-parity Violation
Models with explicit R-parity violation can induce new rare radiative decay
modes of the boson into single supersymmetric particles which also violate
lepton number. We examine the rate and signature for one such decay,
, and find that such a mode will be very difficult
to observe, due its small branching fraction, even if the lepton number
violating coupling in the superpotential is comparable in strength to
electromagnetism. This parallels a similar result obtained earlier by Hewett in
the case of radiative decays.Comment: 10 pages, 2 figures(available on request), LaTex, ANL-HEP-PR-92-8
Hadronic production and the Gottfried Sum Rule
The difference in production rate between and at hadron colliders
is very sensitive to the the difference between up- and down-quark
distributions in the proton. This sensitivity allows for a variety of useful
measurements. We consider the difference in the sea
distributions and the difference in the
polarized parton distribution functions. In both cases we construct an
asymmetry to reduce systematic uncertainties. Although we discuss measurements
at the Tevatron and future hadron colliders, we find that the Brookhaven
Relativistic Heavy Ion Collider (RHIC) is the most appropriate hadron collider
for these measurements.Comment: 19 pages (20 figures available from the authors), MAD/PH/74
Flavor Asymmetry of the Nucleon Sea and W Boson Production
The advantage and feasibility of using -boson production to extract unique
information on the flavor asymmetry of the and sea-quark
distributions in the proton are examined. The and production cross
section ratios in collisions are shown to be sensitive to the ratios, and they are free from charge-symmetry-breaking and
nuclear-binding effects. The feasibility for measuring these ratios at the RHIC
and LHC proton-proton colliders, as well as the expected sensitivity to the
ratios, are also presented.Comment: 7 pages, 4 figures (updated figures
Flavor Asymmetry of Antiquark Distributions in the Nucleon
1. Introduction
2. Possible violation of the Gottfried sum rule
2.1 Gottfried sum rule 2.2 Early experimental results 2.3 NMC finding and
recent progress 2.4 Small contribution 2.5 Nuclear correction: shadowing in
the deuteron 2.6 Parametrization of antiquark distributions
3 Expectations in perturbative QCD
3.1 Operator product expansion 3.2 Perturbative correction to the Gottfried
sum
4 Theoretical ideas for the sum-rule violation
4.1 Lattice QCD 4.2 Pauli exclusion principle 4.3 Mesonic models 4.3.1
Meson-cloud contribution 4.3.2 Chiral models 4.3.3 Anomalous evolution
4.4 Diquark model 4.5 Isospin symmetry violation 4.6 Flavor asymmetry ubar-dbar
in nuclei 4.7 Relation to nucleon spin 4.8 Comment on effects of quark mass and
transverse motion
5 Finding the flavor asymmetry ubar-dbar in various processes
5.1 Drell-Yan process 5.1.1 Fermilab-E866 results 5.2 W and Z production 5.3
Quarkonium production at large 5.4 Charged hadron production 5.5
Neutrino scattering 5.6 Experiments to find isospin symmetry violation
6 Related topics on antiquark distributions
7 Summary and outlookComment: 3+79 pages, LATEX2e, 29 eps figures. Physics Reports in press.
Complete postscript file is available at
http://www.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html Email:
[email protected]
Physics Opportunities of e+e- Linear Colliders
We describe the anticipated experimental program of an e+e- linear collider
in the energy range 500 GeV -- 1.5 TeV. We begin with a description of current
collider designs and the expected experimental environment. We then discuss
precision studies of the W boson and top quark. Finally, we review the range of
models proposed to explain the physics of electroweak symmetry breaking and
show, for each case, the central role that the linear collider experiments will
play in elucidating this physics. (to appear in Annual Reviews of Nuclear and
Particle Science)Comment: 93 pages, latex + 23 figures; typos corrections + 1 reference adde
CP-violating dipole form factors of the top quark and tau lepton in scalar leptoquark models
We calculate the CP-violating electric and weak dipole form factors of the
top quark and the tau lepton in models with scalar leptoquarks coupling only to
the third generation of quarks and leptons. We obtain numerical values of the
real and imaginary parts of these form factors at various energies for
different values of leptoquark masses and couplings. The existing limits on the
tau electric and weak dipole form factors allows us to put a limit on the
masses and couplings of such leptoquarks and therefore on the top electric and
weak dipole form factors. We also discuss constraints on the form factors
coming from indirect limits on leptoquark masses and couplings deduced from LEP
results on Z properties.Comment: 22 pages, LaTeX, includes 14 figures in postscript file
Atom Optics Quantum Pendulum
We explain the dynamics of cold atoms, initially trapped and cooled in a
magneto-optic trap, in a monochromatic stationary standing electromagnetic wave
field. In the large detuning limit the system is modeled as a nonlinear quantum
pendulum. We show that wave packet evolution of the quantum particle probes
parametric regimes in the quantum pendulum which support classical period,
quantum mechanical revival and super revival phenomena. Interestingly, complete
reconstruction in particular parametric regime at quantum revival times is
independent of potential height.Comment: 14 pages, 7 figure