229 research outputs found

    Constraints on Parity-Even Time Reversal Violation in the Nucleon-Nucleon System and Its Connection to Charge Symmetry Breaking

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    Parity-even time reversal violation (TRV) in the nucleon-nucleon interaction is reconsidered. The TRV ρ\rho-exchange interaction on which recent analyses of measurements are based is necessarily also charge-symmetry breaking (CSB). Limits on its strength gˉρ\bar{g}_\rho relative to regular ρ\rho-exchange are extracted from recent CSB experiments in neutron-proton scattering. The result gˉρ6.7×103\bar{g}_\rho\le 6.7\times 10^{-3} (95% CL) is considerably lower than limits inferred from direct TRV tests in nuclear processes. Properties of a1a_1-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

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    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

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    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

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    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 TT-matrix elements of a reaction of the type a+bc+d+...a+b\to c+d+.... 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

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    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

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    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

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    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

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    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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