No abstract

The CPLEAR collaboration has constructed a detector at CERN for an extensive programme of CP-, T-and CPT-symmetry studies using K and K 0 produced by the annihilation of p's in a hydrogen gas target. The K 0 and K 0 are identi ed by their companion products of the annihilation K which are tracked with multiwire proportional chambers, drift chambers and streamer tubes. Particle identi cation is carried out with a liquid Cherenkov detector for fast separation of pions and kaons and with scintillators which a l l o w the measurement o f t i m e o f i g h t and energy loss. Photons are measured with a lead/gas sampling electromagnetic calorimeter. The required antiproton annihilation modes are selected by fast online processors using the tracking chamber and particle identi cation information. All the detectors are mounted in a 0.44 T uniform eld of an axial solenoid of diameter 2 m and length 3.6 m to form a magnetic spectrometer capable of full online reconstruction and selection of events. The design, operating parameters and performance of the sub-detectors are described.

The yields of the atomic 4--*3 transitions in antiprotonic 14N, 16'17'180, 19F, and 2aNa were measured at the CERN antiproton facility, LEAR. From these, the widths F~p of the 4f levels were determined to be 136_+19meV (14N); 603_+22meV (160); 731 _+35 meV (~vO); 795+23 meV (xso); 2.79_+0.16 eV (19F); and 23.8_+7.4 eV (23Na).

We present a new measurement of the K L -K S mass difference (m) using semileptonic decays of neutral kaons. The measurement yields m = ( 0 : 5274 0:0029 stat: 0:0005 syst: ) 10 10 h=s.

We present a new measurement of the K L -K S mass difference (m) using semileptonic decays of neutral kaons. The measurement yields m = ( 0 : 5274 0:0029 stat: 0:0005 syst: ) 10 10 h=s.