These processes represent the production of a pair of Higgs bosons. The production proceeds through gluon-fusion one-loop diagrams involving loops of top quarks. The formulae implemented in the code are taken from ref. [1], where the two Higgs bosons are treated as being on-shell. To enforce this condition, the code sets zerowidth to true, overriding the value set in the input file. The calculation can be performed at LO only, (i.e. one-loop order only). Two decays of the Higgs bosons are currently foreseen, although other decays can easily be implemented. In process 601, one Higgs boson decays to a pair of b-quarks, and the other decays to a pair of τ’s. In process 602, one Higgs boson decays to a pair of b-quarks, and the other decays to a pair of photons.
nplotter˙auto.f is the default plotting routine.
[1] E.W.N. Glover and J.J. van der Bij, Higgs boson pair production via gluon fusion, Nucl. Phys. B309 (1988) 282.