Upper limits for neutrino oscillations (ν)over-barμ→(ν)over-bare from muon decay at rest -: art. no. 112001

The KARMEN experiment at the spallation neutron source ISIS used (nu) over bar (mu) from mu(+) decay at rest for the search of neutrino oscillations (nu) over bar (mu)-->(nu) over bar (e) in the appearance mode, with p((nu) over bar (e),e(+))n as a detection reaction of (nu) over bar (e). In total, 15 candidates satisfy all conditions for the (nu) over bar (e) 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)<1.7x10(-3) for Delta m(2)>= 100 eV(2) and Delta m(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 (nu) over bar (mu)-->(nu) over bar (e).