original: the higgs boson is the only standard model particle that has not yet been observed .
simplifications: the higgs boson is the only standard model particle that has not yet been watched . the higgs boson is the only standard model particle that has not yet been seen . the higgs boson is the only standard model particle that is still unobserved . the higgs boson is the only standard model particle that has not so far been discovered . the higgs-boson is the only standard model particle that has n't been seen yet . the higgs boson is the only normal modle object which has not yet been seen . the higgs boson is the only standard model particle that has not been seen . the higgs-boson is the only standard model particle that has not yet been seen .