The KARMEN experiment at the pulsed neutron facility ISIS is investigating neutrino-nucleus reactions and neutrino oscillations. In this paper we present cross sections for neutrino induced charged and neutral current reactions on C-12. These results allow a precision test of the standard model of weak interaction by imposing new limits on the neutral current isovector axial vector coupling strength beta(A), the strength parameter rho measuring the universality of W+/- and Z(0) coupling in the low energy regime and by investigating the Lorentz, structure of muon decay. Neutrino oscillations (v) over bar (mu)-->(v) over bar (e) are investigated in the appearance mode by looking for p((v) over bar (e), e(+))n reactions. An analysis of 3 years running time with the KARMEN2 setup reveals no indication of an oscillation signal excluding most parts of the LSND oscillation evidence.

The KARMEN experiment at the pulsed spallation neutron facility ISIS uses the beam stop neutrinos nu(mu), nu(e) and <(nu)over bar>(mu) from pi(+) and mu(+) decay at rest to search for neutrino oscillations in the appearance modes nu(mu) --> nu(e) and <(nu)over bar>(mu) --> <(nu)over bar>(e). A high resolution 56 ton liquid scintillation calorimeter located at a mean distance of 17.5 m from the proton beam stop allows identification of nu(e) and <(nu)over bar>(e) with spectroscopic quality. We report the status of our search for neutrino oscillations after four years of running. No positive evidence for neutrino oscillations has been observed in both appearance channels. The 90 % CL Limits of this experiment exclude mixing angles sin(2)2 Theta greater than or equal to 0.0062 in the <(nu)over bar>(mu) --> <(nu)over bar>(e) channel and sin(2)2 Theta greater than or equal to 0.048 in the nu(mu) --> nu(e) channel for the region Delta m(2) > 1 eV(2)

The KARMEN experiment at the pulsed spallation neutron facility ISIS studies the charged and neutral current reactions C-12 (nu(e),e(-)) N-12 and C-12 (nu,nu') C-12* (1(+)1) in the astrophysical important energy range up to 50 MeV. Neutrinos are detected by a 56 ton high resolution Liquid scintillation calorimeter with spectroscopic quality. Efficient background rejection results in clear neutrino signatures and allows reliable cross section measurements down to 10(-42) cm(2) We present cross section results for nu-induced reactions on carbon with special emphasis on their implications for neutrino astrophysics and weak nuclear formfactors and report a new flux-independent test of the equality of the couplings of nu(e) and <(nu)over bar>(mu) to the weak neutral current at low energies.

The charged and neutral current reactions 12C(νe, e−) 12Ng.s. and 12C(ν, ν') 12C∗[1+, 1; 15.1 MeV have been studied with cumulative neutrino fluxes an order of magnitude greater than reported previously. Flux-averaged cross sections of [9.1±0.5stat±0.8syst]×10−42 cm2 and [10.4±1.0stat±0.9syst]×10−42 cm2 respectively are in excellent agreement with theoretical calculations. The energy dependence of the charged current reaction has also been measured. The ratio of cross sections provides a flux-independent test of equality of the couplings of νeandνμ to the weak neutral current for |q2|<8×10−3 (GeVc)2, and is in good agreement with the universality postulate.

The KARMEN experiment at the pulsed neutron facility ISIS is investigating neutrino properties and interactions by measuring neutrino-induced charged current (CC) 12C(νe,e−)12N reactions and, for the first time, neutral current (NC) 12C(ν,ν′) 12C∗ excitations of nuclei. We present cross section results for these reactions in the energy range of beam dump neutrinos Eν ≤ 52.8MeV with emphasis on weak nuclear form factors and μ - e - universality of neutral currents.

KARMEN denotes an experimental program of neutrino physics using a pulsed source of neutrinos νμ, νeandνμ with energies up to 52.8 MeV and a 56 t scintillation calorimeter. Major physics aims are the measurement of charged current (CC) as well as neutral current (NC) neutrino nucleus interactions on 12C with their implications for specific weak couplings, nuclear formfactors, μ-e universality and the search for neutrino oscillations νμ → νeandνeandνμ → νe. We present the results of the KARMEN experiment from its first two years of data taking.

The charged current nuclear transition C-12(nu(e), e-) N-12(g.s.) has been observed in the KARMEN experiment. The flux average cross section for nu(e) from mu+ decay at rest is determined to be [sigma] = [8.1 +/- 0.9(stat.) +/- 0.75(syst.)] x 10(-42) cm2. For the first time also the energy dependence of the cross section has been measured for neutrino energies up to 50 MeV.

KARMEN is a 56 t scintillation calorimeter designed for beam dump neutrino experiments at the neutron spallation facility ISIS of the Rutherford Appleton Laboratory. The calorimetric properties are demonstrated by cosmic muons and laser calibration. The measured energy resolution of the detector is σE/E ≈ 11.5%/√E[MeV], the position resolution σx = 5 cm and the timing resolution σt ≈ 350 ps.

An anticounter for the KARMEN experiment was built for effective suppression of background induced by cosmic muons. A special arrangement of 136 plastic scintillator sheets (NE 110, 3 cm thick) with 180° light coupling provides tight enclosure of the 56 t central calorimeter, reducing the leakage of the anticounter for cosmic muons to less than 1.5%.