166 research outputs found

    Tests of the Equivalence Principle with Neutral Kaons

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    We test the Principle of Equivalence for particles and antiparticles, using CPLEAR data on tagged K0 and K0bar decays into pi^+ pi^-. For the first time, we search for possible annual, monthly and diurnal modulations of the observables |eta_{+-}| and phi_{+-}, that could be correlated with variations in astrophysical potentials. Within the accuracy of CPLEAR, the measured values of |eta_{+-}| and phi_{+-} are found not to be correlated with changes of the gravitational potential. We analyze data assuming effective scalar, vector and tensor interactions, and we conclude that the Principle of Equivalence between particles and antiparticles holds to a level of 6.5, 4.3 and 1.8 x 10^{-9}, respectively, for scalar, vector and tensor potentials originating from the Sun with a range much greater than the distance Earth-Sun. We also study energy-dependent effects that might arise from vector or tensor interactions. Finally, we compile upper limits on the gravitational coupling difference between K0 and K0bar as a function of the scalar, vector and tensor interaction range.Comment: 15 pages latex 2e, five figures, one style file (cernart.csl) incorporate

    Test of CPT Symmetry and Quantum Mechanics with Experimental data from CPLEAR

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    We use fits to recent published CPLEAR data on neutral kaon decays to π+π\pi^+\pi^- and πeν\pi e\nu to constrain the CPT--violation parameters appearing in a formulation of the neutral kaon system as an open quantum-mechanical system. The obtained upper limits of the CPT--violation parameters are approaching the range suggested by certain ideas concerning quantum gravity.Comment: 9 pages of uuencoded postscript (includes 3 figures

    The neutral kaon decays to π+ππ0\pi^+ \pi^- \pi^0: a detailed analysis of the CPLEAR data

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    A detailed analysis of neutral kaons decaying to \Pgpp \Pgpm \Pgpz\ is presented based on the complete data set containing half a million events. Time-dependent decay rate asymmetries are measured between initially tagged \PKz\ and \PaKz\ and for different regions of the phase space. These asymmetries, resulting from the interference between the CP-conserving decay amplitude of \PKzL\ and the decay amplitude of \PKzS\ -- either CP-violating or CP-conserving -- allow the determinationof the \PKzS\ parameters \etapmz\ (CP-violating) and \lampmz\ (CP-conserving), and also of the main i sospin components of the \PKzS\ decay amplitude. The branching ratio of \PKzS\ \rightarrow \Pgpp \Pgpm \Pgpz\ (CP-conserving) is deduced directly from \lampmz . In addition, we extract the slope parameters describing the energy dependence of the \PKzL \rightarrow \Pgpp \Pgpm \Pgpz Dalitz plot. The whole set of our results fits well within the current phenomenological picture of the neut ral-kaon system including CP violation and Chiral Perturbation Theory (ChPT)

    A determination of the CPT violation parameter Re(δ\delta) from the semileptonic decay of strangeness-tagged neutral kaons

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    We have improved by two orders of magnitude the limit currently available for the CPT violation parameter \red . To this purpose we have analyzed the full sample of neutral-kaon decays to \semi\ recorded in the CPLEAR experiment, where the strangeness of the neutral kaons was tagged at production and decay time. An appropriate function of the measured decay rates, including information from the analysis of \pip\pim\ decay channel, gives directly \red . The result =(3.0±3.3stat±0.6syst)×104\red = (3.0 \pm 3.3_\mathrm{{stat}} \pm 0.6_\mathrm{{syst}}) \times 10^{-4} is compatible with zero. Values for the parameters \imd, \rexm and \imxp were also obtained

    Contribution of CPLEAR to the physics of the neutral kaon system

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    We present the physics results of the CP-- and CPT--violation measurements performed by CPLEAR. CPLEAR has experimentally determined for the first time, the violation of T invariance and is able to disentangle all the CP-- and CPT--violating quantities from each other. This allows each of the CPT violating parameters to be determined with a precision of a few 10410^{-4} and, in particular, the mass and width equality between the \kn and \knb to be tested down to the level of 101910^{-19} GeV. Moreover, the precision of the CPLEAR measurements allows us to probe for the first time physics on a scale approaching the Planck mass

    Experimental tests of CPT symmetry and quantum mechanics at CPLEAR

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    We review a phenomenological parametrization of an open quantum-mechanical formalism for CPT violation in the neutral kaon system, and constrain the parameters using fits to recent CPLEAR data.We review a phenomenological parametrization of an open quantum-mechanical formalism for CPT violation in the neutral kaon system, and constrain the parameters using fits to recent CPLEAR data
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