Search for the Standard Model Higgs boson in e+e− collisions at

The reaction e(+)e(-) --> HZ is used to search for the Standard Model Higgs boson, The data sample consists of integrated luminosities of 10.9 pb(-1), 1.1 pb(-1), and 9.5 pb(-1) collected by the ALEPH experimentat LEP during 1996, at centre-of-mass energies of 161, 170 and 172 GeV, respectively. No candidate events were found, in agreement with the expected background of 0.84 events from all Standard Modelprocesses. This search results in a 95% C.L. lower limit on the Higgs bosonmass of 69.4 GeV/c(2). When combined with earlier ALEPHsearches performed at energies at and around the Z peak, this limit increases to 70.7 GeV/c(2). (C) 1997 Elsevier Science B.V.