 When Burhop took charge of the Bubble Chamber Group at University College in 1967 , he was quick to grasp the advantages of heavy liquid bubble chambers for studying neutrino interactions , and steered the group towards participation in joint European ventures , using the <unk> . The group 's discovery of neutral currents in 1973 was a milestone on the road to the theoretical unification of electromagnetism with the weak force . In 1974 and 1975 , with the help of Robert R. Wilson , the director of the Fermilab in the United States , an international team from Fermilab and seven European laboratories under Burhop 's leadership carried out a search for a new particle , the existence of which Burhop had predicted in 1963 . He had suggested that neutrino interactions could create short @-@ lived ( perhaps as low as 10 − 14 s ) particles that could be detected with the use of nuclear emulsion . Experiment <unk> at Fermilab successfully detected particles with a lifetime of the order of 10 − 13 s . A follow @-@ up experiment <unk> with the SPS confirmed the existence of the Λ + 
