229 research outputs found
Constraints on Parity-Even Time Reversal Violation in the Nucleon-Nucleon System and Its Connection to Charge Symmetry Breaking
Parity-even time reversal violation (TRV) in the nucleon-nucleon interaction
is reconsidered. The TRV -exchange interaction on which recent analyses
of measurements are based is necessarily also charge-symmetry breaking (CSB).
Limits on its strength relative to regular -exchange are
extracted from recent CSB experiments in neutron-proton scattering. The result
(95% CL) is considerably lower than limits
inferred from direct TRV tests in nuclear processes. Properties of
-exchange and limit imposed by the neutron EDM are briefly discussed.Comment: RevTex, 8 pages. Factor ten error in cited neutron EDM corrected,
discussion and two references adde
Parity Violation in Proton-Proton Scattering
Measurements of parity-violating longitudinal analyzing powers (normalized
asymmetries) in polarized proton-proton scattering provide a unique window on
the interplay between the weak and strong interactions between and within
hadrons. Several new proton-proton parity violation experiments are presently
either being performed or are being prepared for execution in the near future:
at TRIUMF at 221 MeV and 450 MeV and at COSY (Kernforschungsanlage Juelich) at
230 MeV and near 1.3 GeV. These experiments are intended to provide stringent
constraints on the set of six effective weak meson-nucleon coupling constants,
which characterize the weak interaction between hadrons in the energy domain
where meson exchange models provide an appropriate description. The 221 MeV is
unique in that it selects a single transition amplitude (3P2-1D2) and
consequently constrains the weak meson-nucleon coupling constant h_rho{pp}. The
TRIUMF 221 MeV proton-proton parity violation experiment is described in some
detail. A preliminary result for the longitudinal analyzing power is Az = (1.1
+/-0.4 +/-0.4) x 10^-7. Further proton-proton parity violation experiments are
commented on. The anomaly at 6 GeV/c requires that a new multi-GeV
proton-proton parity violation experiment be performed.Comment: 13 Pages LaTeX, 5 PostScript figures, uses espcrc1.sty. Invited talk
at QULEN97, International Conference on Quark Lepton Nuclear Physics --
Nonperturbative QCD Hadron Physics & Electroweak Nuclear Processes --, Osaka,
Japan May 20--23, 199
Symmetries and Symmetry Breaking
In understanding the world of matter, the introduction of symmetry principles
following experimentation or using the predictive power of symmetry principles
to guide experimentation is most profound. The conservation of energy, linear
momentum, angular momentum, charge, and CPT involve fundamental symmetries. All
other conservation laws are valid within a restricted subspace of the four
interactions: the strong, the electromagnetic, the weak, and the gravitational
interaction. In this paper comments are made regarding parity violation in
hadronic systems, charge symmetry breaking in two nucleon and few nucleon
systems, and time-reversal-invariance in hadronic systems.Comment: 5 Pages, LaTeX, 2 PostScript figures. Talk at 17th International
IUPAP Conference on Few-body Problems in Physics, June 5-10, 2003, Durham,
North Carolina, US
On Complete Sets of Polarization Observables
A new criterion is developed which provides a check as to whether a chosen
set of polarization observables is complete with respect to the determination
of all independent -matrix elements of a reaction of the type . As an illustrative example, this criterion is applied to the
longitudinal observables of deuteron electrodisintegration.Comment: 8 pages revtex, final version, accepted for Nucl. Phys.
Extraction of bounds on time-reversal non-invariance from neutron reactions
Ratios involving on-resonance measurements of the three-fold and five-fold
correlation cross sections for which the dependence on some of the unknown
spectroscopic data is eliminated are considered. Closed form expressions are
derived for the statistical distributions of these ratios. Implications for
bounds on the variance of matrix elements of time reversal non-invariant
nucleon-nucleon interactions are considered within a Bayesian framework and the
competitiveness with bounds from other experiments is evaluated. The prospects
for null five-fold correlation measurements improving by an order of magnitude
or more upon the current bound on a parity-conserving T-odd interaction are
good.Comment: 14 pages, to be published in Physics Letters
A model independent and rephase invariant parametrization of CP violation
The phenomenological description of the neutral B meson system is proposed in
terms of the fundamental CP-violating observables and within a rephasing
invariant formalism. This generic formalism can select the time-dependent and
time-integrated asymmetries which provide the basic tools to discriminate the
different kinds of possible CP-violating effects in dedicated experimental
B-meson facilities.Comment: 19 pages, Plain Te
A Monitor of Beam Polarization Profiles for the TRIUMF Parity Experiment
TRIUMF experiment E497 is a study of parity violation in pp scattering at an
energy where the leading term in the analyzing power is expected to vanish,
thus measuring a unique combination of weak-interaction flavour conserving
terms. It is desired to reach a level of sensitivity of 2x10^-8 in both
statistical and systematic errors. The leading systematic errors depend on
transverse polarization components and, at least, the first moment of
transverse polarization. A novel polarimeter that measures profiles of both
transverse components of polarization as a function of position is described.Comment: 19 pages LaTeX, 10 PostScript figures. To appear in Nuclear
Instruments and Methods in Physics Research, Section
Quantum Interferometry, Measurement and Objectivity: Some Basic Features Revisited
The reduction paradigm of quantum interferometry and the objectivation
problem in quantum measurements are reanalyzed. Both are shown to be amenable
to straightforward mathematical treatment within "every-users" simple-minded
quantum mechanics without reduction postulate etc., using only its
probabilistic content.Comment: 5 pages, LaTeX, To be published in Proc. 2nd Interational Symposium
on Fundamental Problems in Quantum Physics, M. Ferrero and A. van der Merve
eds. (Kluwer Academic Publshers, 1997
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