SEARCH ON e~+- e~- PAIR AND OBSERVATION OF A NEW LIGHT NEUTRAL BOSON

摘要

We present a unified description of e e dilepton production in heavy ion collisions atrelativistic (3.7A GeV) and ultrarelativistic (200A GeV) energies. From theinteractions of [~(12)Cand ~(22)Ne] at 3.7A GeV and ~(32)Sat 200A with nuclearemulsion, 134 e~+ e~-pairs are observed. The differential distribution of the energyasymmetry of pairs is compared to a background observation at Bristol. The eventsare consistent in a way that, they scale well in a single curve of exponential decay.This ensures correct asymptotics and provides a unified description of mesonic decay.The existence of light neutral boson of mass (1.55±0.14 MeV/c~2) is questionable,because the candidate peak is seen in the invariant mass spectrum of its decay into e~+ e~-pairs. The data seem to suggest the production and subsequent decay of shortlived neutral boson with lifetime of the order of 10~(-16)S.