54 research outputs found
Late Cenozoic deformation of the Gavrovo and Ionian zones in NW Peloponnesos (Western Greece)
No full textThe structural deformation of Mesozoic-Tertiary sediments of the Ionian and Gavrovo zones in NW Peloponnesos is related to the propagation of a fold-thrust system during the Cenozoic. The sediments of the Gavrovo zone have been deformed by high angle reverse faulting generating an imbricate fan. Skolis mountain represents the Gavrovo thrust front. The detachment occurred in the underlying flysch of the Ionian zone. The Ionian zone has also been affected by shortening above a detachment horizon situated in the lower horizons of Triassic evaporites. The main compressional structure of the Ionian zone is a broad anticline revealed by a seismic survey west of Skolis mountain. The Gavrovo-sheet emplacement caused the downthrow and bending of the eastern part of the Ionian zone followed by halokinesis of Triassic evaporites to the west. Post-compressional normal faulting has predominated since the Pliocene, resulting in the formation of the Kato Achaia and Simopoulo basins in the peripheral area of Skolis mountain. Diapirs of Triassic evaporites occur in the mentioned basins that complicate the tectonic pattern in front of the Skolis thrust
Late Cenozoic deformation of the Gavrovo and Ionian zones in NW Peloponnesos (Western Greece)
No full textThe structural deformation of Mesozoic-Tertiary sediments of the Ionian and Gavrovo zones in NW Peloponnesos is related to the propagation of a fold-thrust system during the Cenozoic. The sediments of the Gavrovo zone have been deformed by high angle reverse faulting generating an imbricate fan. Skolis mountain represents the Gavrovo thrust front. The detachment occurred in the underlying flysch of the Ionian zone. The Ionian zone has also been affected by shortening above a detachment horizon situated in the lower horizons of Triassic evaporites. The main compressional structure of the Ionian zone is a broad anticline revealed by a seismic survey west of Skolis mountain. The Gavrovo-sheet emplacement caused the downthrow and bending of the eastern part of the Ionian zone followed by halokinesis of Triassic evaporites to the west. Post-compressional normal faulting has predominated since the Pliocene, resulting in the formation of the Kato Achaia and Simopoulo basins in the peripheral area of Skolis mountain. Diapirs of Triassic evaporites occur in the mentioned basins that complicate the tectonic pattern in front of the Skolis thrust.JCR Journalope
First study of rapidity gaps in e+ e- annihilation
No full textWe present the first study of rapidity gaps in e(+)e(-) annihilations, using Z(0) decays collected by the SLAG Linear Collider Large Detector experiment. Our measured rapidity gap spectra fall exponentially with increasing gap size over five decades, and we observe no anomalous class of events containing large gaps. This supports the interpretation of the large-gap events measured in and ep collisions in terms of exchange of color-singlet objects. The presence of heavy flavors or additional jets does not affect these conclusions
Search for a nonminimal Higgs boson produced in the reaction e+ e- ---> h Z*
No full textA data sample corresponding to 1.23 million hadronic Z decays collected by the ALEPH detector at LEP has been searched for signals of the production of a non-minimal CP-even Higgs boson h in the reaction e+e- --> hZ*. The h decay modes considered were: those of the minimal standard model Higgs boson, with modified branching ratios; decays into a pair of CP-odd Higgs bosons A; and decays into invisible final states. Only one event was found, a very acoplanar e+e- pair which could originate from the standard model background process e+e- --> e+e- nu (nu) over bar. Upper limits for the cross-section of the reaction e+e- --> hZ* have been derived as a function of m(h), the mass of the Higgs boson h. In the case of invisible decays, the 95% CL lower limit on m(h) is 65 GeV/c(2) for a production cross-section equal to that of a minimal standard model Higgs boson. When combined with previous ALEPH results on the reaction e+e- --> hA, these cross-section upper limits exclude a domain in the (m(h), M(A)) plane of the MSSM such that, if invisible h and A decays can be neglected, 95% CL lower limits of 44 and 21 GeV/c(2) result for m(h) and m(A), respectively, independent of the other parameters of the model
Measurement of the tau-neutrino helicity and the Michel parameters in polarized e+ e- collisions
No full textWe present a new measurement of the tau neutrino helicity h(nu tau) and the tau Michel parameters rho, eta, xi, and the product delta xi. The analysis exploits the highly polarized SLC electron beam to extract these quantities directly from a measurement of the tau decay spectra, using the 1993-1995 SLD data sample of 4328 e(+)e(-) --> Z(0) --> tau(+)tau(-) events. From the decays tau --> pi nu(tau) and tau --> rho nu(tau) we obtain a combined value h(nu tau) = -0.93 +/- 0.10 +/- 0.04. The leptonic decay channels yield combined values of rho = 0.72 +/- 0.09 +/- 0.03, xi = 1.05 +/- 0.35 +/- 0.04, and delta xi = 0.88 +/- 0.27 +/- 0.04
Comparison of a new calculation of energy-energy correlations with e+ e- ---> hadrons data at the Z0 resonance
No full textWe have compared a new QCD calculation by Clay and Ellis of energy-energy correlations (EEC's) and their asymmetry (AEEC's) in e(+)e(-) annihilation into hadrons with data collected by the SLD experiment at SLAG. From fits of the new calculation, complete at O(alpha(s)(2)), we obtained alpha(s)(M(Z)(2)) = 0.1184 +/- 0.0031 (expt) +/- 0.0129 (theory) (EEC) and alpha(s)(M(Z)(2)) = 0.1120 +/- 0.0034 (expt) +/- 0.0036 (theory) (AEEC). The EEC result is significantly lower than that obtained from comparable fits using the O(alpha(s)(2)) calculation of Kunszt and Nason
Precise measurement of the left-right cross-section asymmetry in Z boson production by e+ e- collisions
No full textWe present a precise measurement of the left-right cross section asymmetry (A(LR)) for Z boson production by e+e-. The measurement was perfomed at a center-of-mass energy of 91.26 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (63.0 +/- 1.1)%. Using a sample of 49392 Z decays, we measure A(LR) to be 0.1628 +/- 0.0071 (stat) +/- 0.0028 (syst) which determines the effective weak mixing angle to be sin2 theta(W)eff = 0.2292 +/- 0.0009 (stat) +/- 0.0004 (syst)
Study of the structure of e(+)e(-)-> b(b)over-bar-g events and first limits on the anomalous chromomagnetic coupling of the b quark
No full textThe structure of e(+) e(-) --> g events was studied using Z(0) decays recorded in the SLC Large Detector experiment at SLAC. Three-jet final states were selected and the charge-coupled device-based vertex detector was used to identify two of the jets as b or (b) over bar. Distributions of the gluon energy and polar angle were measured over the full kinematic range for the first time, and compared with perturbative QCD predictions. The energy distribution is potentially sensitive to an anomalous b chromomagnetic moment kappa. We measured kappa to be consistent with zero and set the first limits on its value: -0.17<kappa<0.11 at 95% C.L. [S0556-2821(99)01121-2]
Measurement of j / psi production in continuum e+ e- annihilations near s**(1/2) = 10.6-GeV
No full textThe production of J/ψ mesons in continuum e<sup>+</sup>e<sup>-</sup> annihilations has been studied with the BABAR detector at energies near the ϒ(4S) resonance. The mesons are distinguished from J/ψ production in B decays through their center-of-mass momentum and energy. We measure the cross section e<sup>+</sup>e<sup>-</sup>→J/ψX to be 2.52±0.21±0.21 pb. We set a 90% C.L. upper limit on the branching fraction for direct ϒ(4S)→J/ψX decays at 4.7×10<sup>-4</sup>
Measurement of the branching fractions for psi(2S) ---> e+ e- and psi(2S) ---> mu+ mu-
No full textThis is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APS.We measure the branching fractions of the ψ(2S) meson to the leptonic final states e+e- and μ+μ- relative to that for ψ(2S)→J/ψπ+π-. The method uses ψ(2S) mesons produced in the decay of B mesons at the Υ(4S) resonance in a data sample collected with the BABAR detector at the Stanford Linear Accelerator Center. Using previous measurements for the ψ(2S)→J/ψπ+π- branching fraction, we determine the e+e- and μ+μ- branching fractions to be 0.0078±0.0009±0.0008 and 0.0067±0.0008±0.0007, respectively.This work was supported by the DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the A.P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation
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