67 research outputs found

    Quantum Interferometry, Measurement and Objectivity: Some Basic Features Revisited

    Get PDF
    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

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

    Full text link
    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

    A model independent and rephase invariant parametrization of CP violation

    Get PDF
    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

    Effective T-odd P-even hadronic interactions from quark models

    Full text link
    Tests of time reversal symmetry at low and medium energies may be analyzed in the framework of effective hadronic interactions. Here, we consider the quark structure of hadrons to make a connection to the more fundamental degrees of freedom. It turns out that for P-even T-odd interactions hadronic matrix elements evaluated in terms of quark models give rise to factors of 2 to 5. Also, it is possible to relate the strength of the anomalous part of the effective rho-type T-odd P-even tensor coupling to quark structure effects.Comment: 6 pages, 1 figure, RevTe

    Constraints on a Parity-Conserving/Time-Reversal-Non-Conserving Interaction

    Get PDF
    Time-Reversal-Invariance non-conservation has now been unequivocally demonstrated in a direct measurement at CPLEAR. What about tests of time-reversal-invariance in systems other than the kaon system? Tests of time-reversal-invariance belong to two classes: searches for parity violating (P-odd)/time-reversal-invariance-odd (T-odd) interactions, and for P-even/T-odd interactions (assuming CPT conservation this implies C-conjugation non-conservation). Limits on a P-odd/T-odd interaction follow from measurements of the electric dipole moment of the neutron (with a present upper limit of 6 x 10^-26 e.cm [95% C.L.]). It provides a limit on a P-odd/T-odd pion-nucleon coupling constant which is less than 10^-4 times the weak interaction strength. Experimental limits on a P-even/T-odd interaction are much less stringent. Following the standard approach of describing the nucleon-nucleon interaction in terms of meson exchanges, it can be shown that only charged rho-meson exchange and A_1 meson exchange can lead to a P-even/T-odd interaction. The better constraints stem from measurements of the electric dipole moment of the neutron and from measurements of charge-symmetry breaking in neutron-proton elastic scattering. The latter experiments were executed at TRIUMF (497 and 347 MeV) and at IUCF (183 MeV). Weak decay experiments may provide limits which will possibly be comparable. All other experiments, like gamma decay experiments, detailed balance experiments, polarization - analyzing power difference determinations, and five-fold correlation experiments with polarized incident nucleons and aligned nuclear targets, have been shown to be at least an order of magnitude less sensitive.Comment: 15 pages LaTeX, including 5 PostScript figures. Uses ijmpe1.sty. To appear in International Journal of Modern Physics E (IJMPE). Slight change in short abstrac

    Parity-Violating Interaction Effects I: the Longitudinal Asymmetry in pp Elastic Scattering

    Get PDF
    The proton-proton parity-violating longitudinal asymmetry is calculated in the lab-energy range 0--350 MeV, using a number of different, latest-generation strong-interaction potentials--Argonne V18, Bonn-2000, and Nijmegen-I--in combination with a weak-interaction potential consisting of rho- and omega-meson exchanges--the model known as DDH. The complete scattering problem in the presence of parity-conserving, including Coulomb, and parity-violating potentials is solved in both configuration- and momentum-space. The predicted parity-violating asymmetries are found to be only weakly dependent upon the input strong-interaction potential adopted in the calculation. Values for the rho- and omega-meson weak coupling constants hρpph^{pp}_\rho and hωpph^{pp}_\omega are determined by reproducing the measured asymmetries at 13.6 MeV, 45 MeV, and 221 MeV.Comment: 24 pages, 8 figures, submitted to Physical Review

    A Microscopic T-Violating Optical Potential: Implications for Neutron-Transmission Experiments

    Full text link
    We derive a T-violating P-conserving optical potential for neutron-nucleus scattering, starting from a uniquely determined two-body ρ\rho-exchange interaction with the same symmetry. We then obtain limits on the T-violating ρ\rho-nucleon coupling gρ\overline{g}_{\rho} from neutron-transmission experiments in 165^{165}Ho. The limits may soon compete with those from measurements of atomic electric-dipole moments.Comment: 8 pages, 2 uuencoded figures in separate files (replaces version sent earlier in the day with figures attached), in RevTeX 3, submitted to PR

    Parity nonconserving two-pion exchange in elastic proton-proton scattering

    Full text link
    Parity nonconserving two-pion exchange in elastic pp scattering is investigated in the presence of phenomenological strong distortions in various models. Parity violation is included in the nucleon-pion vertex considering NN and N Delta(1232) intermediate states in box and crossed box diagrams. Using the derived parity nonconserving two-pion exchange potential we calculate the longitudinal analyzing power A_L in elastic pppp scattering. The predicted effect is of the same order as vector meson exchanges.Comment: 13 pages, 8 eps figure

    Effective Lagrangians and Parity-Conserving Time-Reversal Violation at Low Energies

    Full text link
    Using effective Lagrangians, we argue that any time-reversal-violating but parity-conserving effects are too small to be observed in flavor-conserving nuclear processes without dramatic improvement in experimental accuracy. In the process we discuss other arguments that have appeared in the literature.Comment: Revised manuscript, 11 pages, RevTex, epsf.st

    Relationship between quantum decoherence times and solvation dynamics in condensed phase chemical systems

    Get PDF
    A relationship between the time scales of quantum coherence loss and short-time solvent response for a solute/bath system is derived for a Gaussian wave packet approximation for the bath. Decoherence and solvent response times are shown to be directly proportional to each other, with the proportionality coefficient given by the ratio of the thermal energy fluctuations to the fluctuations in the system-bath coupling. The relationship allows the prediction of decoherence times for condensed phase chemical systems from well developed experimental methods.Comment: 10 pages, no figures, late
    corecore