Updated parameter limits of the left-right symmetric model

Abstract Bounds of the neutral current sector parameters of the left-right symmetric model are investigated taking into account the low-energy data, LEP-data and CDF-result for the top mass m t = 174 ± 10 −12 +13 . It is found that in the case of the minimal scalar sector with a left- and a right-handed triplet and a bidoublet Higgses the mass of the heavy neutral gauge boson M Z ′ should be larger than 1.2 TeV, assuming equal left- and right-handed gauge couplings and a negligible VEV of the left-handed triplet. For larger values of the ratio g L g R smaller values of M Z ′ are allowed.