Search

The effective mass spectrum of two protons from the reactionp+n→pp+π−(backward) was investigated. The work was carried out at ITEP using a 3-meter magnet spectrometer and a proton beam of 1.98GeV/cmomentum. Liquid deuterium was used as a target. The presented mass spectrum includes about 34000 events. No statistically significant signals from narrow dibaryons were found in the mass region 1.89–2.17GeV/c2; the upper limits on narrow dibaryon production cross-section are given. At a mass of 1.8775GeV/c2a narrow enhancement was found. A more detailed investigation of the observed phenomenon is needed.

For the first time an electrostatic method of wire tension measurement (WTM) is used for drift chamber construction. It became possible due to the use of a digital approach to sense the wire oscillations induced by an alternating potential. The method has excellent signal-to-noise ratio, high accuracy which is well above the stringing requirements and reasonable measuring time. The WTM system implemented in a CAMAC–Machintosh–Labview environment is now in use for the KLOE drift chamber stringing control and for monitoring the end-plate deformation.