We investigated mu(+) decays at rest produced at the ISIS beam stop target. Lepton flavor (LF) conservation has been tested by searching for nu(e) via the detection reaction p(nu(e),e(+))n. No nu(e) signal from LF violating mu(+) decays was identified. We extract upper limits of the branching ratio (BR) for the LF violating decay mu(+)-->e(+)+nu(e)+nu(-) compared to the standard model (SM) mu(+)-->e(+)+nu(e)+nu(mu) decay: BR<0.9(1.7) x 10(-3) (90% C.L.) depending on the spectral distribution of nu(e) characterized by the Michel parameter rho=0.75(0.0). These results improve earlier limits by one order of magnitude and restrict extensions of the SM in which nu(e) emission from mu(+) decay is allowed with considerable strength. The decay mu(+)-->e(+)+nu(e)+nu(mu) often proposed as a potential source for the nu(e) signal observed in the LSND experiment can be excluded.

The KARMEN experiment at the spallation neutron source ISIS used \numub from \mup--decay at rest in the search for neutrino oscillations \numubnueb in the appearance mode, with p(\nueb,e+)n as detection reaction of \nueb. In total, 15 candidates fulfill all conditions for the \nueb signature, in agreement with the background expectation of 15.8+-0.5 events, yielding no indication for oscillations. A single event based likelihood analysis leads to upper limits on the oscillation parameters: sin^2(2theta) 100 eV^2 and Dm^2<0.055 eV^2 for sin^2(2theta)=1 at 90% confidence. Thus, KARMEN does not confirm the LSND experiment and restricts significantly its favored parameter region for \numubnueb.

The KARMEN experiment at the spallation neutron source ISIS used ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ from ${\ensuremath{\mu}}^{+}$ decay at rest for the search of neutrino oscillations ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ in the appearance mode, with $p({\overline{\ensuremath{\nu}}}_{e}{,e}^{+})n$ as a detection reaction of ${\overline{\ensuremath{\nu}}}_{e}.$ In total, 15 candidates satisfy all conditions for the ${\overline{\ensuremath{\nu}}}_{e}$ signature, in agreement with the background expectation of $15.8\ifmmode\pm\else\textpm\fi{}0.5$ events, yielding no indication for oscillations. A single event based likelihood analysis leads to upper limits on the oscillation parameters ${\mathrm{sin}}^{2}(2\ensuremath{\Theta})<1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ for $\ensuremath{\Delta}{m}^{2}>~100 {\mathrm{eV}}^{2}$ and $\ensuremath{\Delta}{m}^{2}<0.055 {\mathrm{eV}}^{2}$ for ${\mathrm{sin}}^{2}(2\ensuremath{\Theta})=1$ at 90% confidence. Thus, KARMEN does not confirm the LSND experiment and restricts significantly its favored parameter region for ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}.$

The neutrino experiment KARMEN is situated at the beam stop neutrino source ISIS. It provides nu(mu)'s, nu(e)'s and <(nu)over bar>(mu)'s in equal intensities from the pi(+)-mu(+)-decay at rest (DAR). The oscillation channel <(nu)over bar>(mu) --> <(nu)over bar>(e) is investigated in the appearance mode with a 56 t Liquid scintillation calorimeter at a mean distance of 17.7 m from the nu-source looking for p(<(nu)over bar>(e), e(+))n reactions. The cosmic induced background for this oscillation search could be reduced by a factor of 40 due to an additional veto counter installed in 1996. In the data collected through 1997 and 1998 no potential oscillation event was observed. Using a unified approach to smalt signals this leads to an upper limit for the mixing angle of sin(2)(2 Theta) < 1.3 10(-3) (90% CL) at large Delta m(2). The excluded area in (sin(2)(2 Theta),Delta m(2)) covers almost entirely the favored region defined by the LSND <(nu)over bar>(mu) --> <(nu)over bar>(e) evidence.

The EAS experiment KASCADE [1] has been installed at the laboratory site of the Reasearch Center Karlsruhe. It contains an extended array of electron detectors and muon detectors as well as a compact and complex central detection system including muon detectors and a large hadron calorimeter. The first aim of the KASCADE project is the determination of the chemical composition in the energy range at and above the "knee" of the primary cosmic ray spectrum. The main advantage of the new installation is the simultaneous measurement of a large number of observables for each individual event. This is achieved by the combination of various advanced detection techniques for the electromagnetic, the muonic, and the hadronic component of the air showers and by extensive simulation work on air shower properties and on the detector response. Data taking with a large part of the experiment has started in 1996. The reconstruction accuracy of air shower events is discussed for the various detector components of KASCADE and examples of data are presented.

The neutrino experiment KARMEN is situated at the beam stop neutrino source ISIS. It provides νμ's, νe's and νμ's in equal intensities from the π+-μ+-decay at rest (DAR). The oscillation channels νμ → νe and νμ → νe are investigated in the appearance mode with a 56t liquid scintillation calorimeter at a mean distance of 17.7m from the ν-source. Analyses of experimental data from the measuring period 1990–1995 corresponding to 9122 C protons on target or 2.52 · 1021μ+ DAR are presented. No evidence for oscillations could be found with KARMEN, resulting in 90% CL exclusion limits of sin2(2θ) < 8.5·10−3 (νμ → νe) and sin2(2θ) < 4.0·10−2 (νμ → νe) for Δm2 ≥ 100 eV2 in a simple 2 flavor description of ν-oscillations.

KARMEN, the Karlsruhe-Rutherford Medium Energy Neutrinoexperiment at the pulsed spallation neutron facility ISIS uses the beam stop neutrinos νμ, νe and νμ from π+ and μ+ decay at rest to search for neutrino oscillations in the appearance channels νμ → νe and νμ → νe. The signature for both oscillations is based on charged current neutrino nuclear interaction spectroscopy in a high resolution 56 t liquid scintillator calorimeter. The detector system has been upgraded with an additional veto layer during 1996 to eliminate cosmogenic background and to enhance its sensitivity in the oscillation channels. This report describes the results based on data acquired from June 1990 to August 1995 and the first data of 1997 with the new veto system in operation.

The 56 ton high resolution liquid scintillation calorimeter KARMEN at the beam stop neutrino source ISIS has been used to search for neutrino oscillations in the disappearance channel ${\ensuremath{\nu}}_{e}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{x}.$ The ${\ensuremath{\nu}}_{e}$ emitted in ${\ensuremath{\mu}}^{+}$ decay at rest are detected with spectroscopic quality via the exclusive charged current reaction ${}^{12}\mathrm{C}({\ensuremath{\nu}}_{e}{,e}^{\ensuremath{-}}{)}^{12}{\mathrm{N}}_{\mathrm{g}.\mathrm{s}.}$ almost free of background. Analysis of the spectral shape of ${e}^{\ensuremath{-}}$ from the ${\ensuremath{\nu}}_{e}$-induced reaction as well as a measurement of the absolute ${\ensuremath{\nu}}_{e}$ flux allows one to investigate oscillations of the type ${\ensuremath{\nu}}_{e}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ and ${\ensuremath{\nu}}_{e}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{\ensuremath{\mu}}.$ The flux-independent ratio ${R}_{\mathrm{C}\mathrm{C}/\mathrm{N}\mathrm{C}}$ of charged current events ${}^{12}\mathrm{C}({\ensuremath{\nu}}_{e}{,e}^{\ensuremath{-}}{)}^{12}{\mathrm{N}}_{\mathrm{g}.\mathrm{s}.}$ to neutral current events ${}^{12}{\mathrm{C}(\mathrm{\ensuremath{\nu}},\mathrm{\ensuremath{\nu}}}^{\ensuremath{'}}{)}^{12}{\mathrm{C}}^{*}$ provides additional information in the oscillation channel ${\ensuremath{\nu}}_{e}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{x}.$ All three analysis methods show no evidence for oscillations. For the ${\ensuremath{\nu}}_{e}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ channel 90% confidence limits of ${\mathrm{sin}}^{2}(2\ensuremath{\Theta})<0.338$ for $\ensuremath{\Delta}{m}^{2}>~100{\mathrm{eV}}^{2}{/c}^{4}$ and $\ensuremath{\Delta}{m}^{2}<0.77{\mathrm{eV}}^{2}{/c}^{4}$ for maximal mixing in a simple two-flavor oscillation formalism are derived. A complete three-flavor analysis of the experimental data from 5 years of measurement with respect to ${\ensuremath{\nu}}_{e}\ensuremath{\leftrightarrow}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ and ${\ensuremath{\nu}}_{e}\ensuremath{\leftrightarrow}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ mixing is presented.

The weak neutral current reaction 12C(νμ,νμ′)12C∗ (1+,1; 15.1MeV) has been observed for the first time in the KARMEN experiment. Neutrino events were separated from background using two different analysis methods. The measured cross section σNC=(3.2 ± 0.5stat. ± 0.4syst.) × 10−42 cm2 for monoenergetic νμ from π+-decay at rest is in good agreement with the standard model, the isovector-axialvector coupling constant of weak hadronic current deduced from this experiment is |β|=1.11±0.13.