0000000000387780
AUTHOR
J. Kemmer
showing 7 related works from this author
$$\bar K^{0*} (892)$$ andK 0*(892) production at lowp t and the quark parton model
1990
Data on the production of the neutralK*(892) resonances at lowpt by 200 GeVK− and π− is compared with the predictions of various models based on the quark parton model of hadrons.
Lifetimes of charged and neutralD mesons
1987
We have measured the lifetimes of hadronically produced charged and neutralD mesons using silicon microstrip detectors and an active silicon target in the NA32 spectrometer at the CERN SPS. We obtainτD± = (10.9±1.51.9)·10−13s andτD(−)10 = (4.2±0.5)·10−13s based on 59 and 90 fully reconstructed decays respectively, giving a ratioτD±/τD(−)10 of 2.6 ±0.5.
A giant exoplanet orbiting a very-low-mass star challenges planet formation models
2019
Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts con…
Breakthrough in pulse-shape based particle identification with silicon detectors
2000
Identification of charged particles is an important method in nuclear spectroscopy. We have achieved a major breakthrough that makes the pulse-shape discrimination (PSD) method with a single solid-state detector comparable to and sometimes better than the traditional telescope technique. By using rear-side injection in over-biased surface barrier n-type Si detectors made from homogeneously doped n-TD silicon, and extracting the pulse-shape information already at the preamplifier level we have reached improved Z and even A discrimination over a wide dynamic range. Previously good separation with the PSD technique required a major degradation of time resolution and inferior energy resolution.…
Novel digital K-edge imaging system with transition radiation from an 855-MeV electron beam
2001
A novel K-edge imaging method has been developed at the Mainz Microtron MAMI aiming at a very efficient use of the transition radiation (TR) flux generated by the external 855-MeV electron beam in a foil stack. A fan-like quasi-monochromatic hard X-ray beam is produced from the /spl plusmn/1-mrad-wide TR cone with a highly oriented pyrolytic graphite (HOPG) crystal. The absorption of the object in front of a 30 mm/spl times/10 mm pn charge-coupled device (pn-CCD) photon detector is measured at every pixel by a broad-band energy scan around the K-absorption edge. This is accomplished by a synchronous variation of the lateral crystal position and the electron beam direction which defines also…
Inclusive $$\bar K^{0*} (892)$$ andK 0*(892) production on silicon by 200 GeVK − andπ −
1990
The production of the neutralK− (892) resonances by 200 GeVK− andπ− has been studied over the kinematic range 0.0<xf<1.0 andpt2<5.0 GeV2. Longitudinal and transverse momentum distributions are presented. In addition the decay angular distributions inK− fragmentation to\(\bar K^{0*} \) have been investigated.
Production ofD, D * andD s mesons in 200 GeV/c ?? K ? andp-Si interactions
1988
The NA 32 experiment at the CERN SPS has collected 38 million hadronic interactions with incident 200 GeV/c π−,K− andp beam. Using a segmented silicon active target and a telescope of high resolution silicon microstrip counters we have selected fully reconstructedD0→K−π+,D0→K−π+π+π−,D+→K−π+π+,Ds+→K−K+π+π+ and charge conjugate decays. The integrated cross-sections forDo,D+D*+ andDs+ meson production and the dependence of the cross-section on longitudinal and transverse momentum of theD are presented.