The reason of the asymmetry between electromagnetic and weak interactions is (hypothetical) particle called Higgs's boson. Photon has no weight, so electromagnetic interaction, like the gravitational one, has an infinite range. The weak interaction, with a range of about quark size (if we can say anything about their dimensions at all) - it means less than 10-16 cm, has as agents (i.e. intermediators) massive bosons: two charged (W+ i W-) with a mass 81 GeV/c2 and one neutral Z0 (m=93 GeV/c2).
Mass of bosons W i Z mass, according to the most probable theories, result from their interaction with Higgs boson. Higgs also delivers mass to quarks and leptons (different, for different families of quarks and leptons). In vacuum, after Higgs' disappearing, remains a hole, called Higgs' ghost.
Leon Lederman's book "Divine particle" ( Nobel Prize, for discovering mionic neutrino ) is a dream about Higgs, if it is only one - like he adds honestly.
Experiments performed at CERN in 2001, shortly before closing electron-positron accelerator (LEP) suggested a possibility that higgs (maybe two of them) appeared at about 114 GeV energy. Theory does not reject this value neither confirms it. To catch higgs at CERN, a more powerful device, a hadronic collider LHC is under construction (its start is predicted for 2007).
"To define in complete way standard model we need twenty or even more parameters and constants, not defined by a theory: among the others the force of coupling between strong, weak and electromagnetic interactions, masses of quarks and leptons and other parameters which define interactions with Higgs boson. Besides there exist at least 34 components of the matter, which seem to be elementar particles of interactions agents: 15 quarks [18 today, 2003] (five [six] tastes of each one in three colors), six leptons, eight gluons, three bosons of the weak interactions and a hypothetical Higgs' boson.
In the matter of the simplicity, standard model seems to be no progress in comparison to ancient visions ot the matter consisting with earth, water, air and fire, interacting by friendship and conflict."
Chris Quigg, Scientific American, June 1985.
Chris Quigg, in time of writing of that text was and director faculty of theoretical physics in Fermilab in Baravia (Illinois) and physics proffesor at University of Chicago.