Possible Consequences of Parity Conservation

It has been shown that parity may be an exact unbroken symmetry of nature. This requires a doubling of the number of physical particles, although only two parameters beyond those in the Standard Model are introduced. We show that the Lagrangian describing parity conserving models can be reformulated in terms of a basis in which each term of the Lagrangian is parity invariant, although gauge invariance is not manifest. We then examine some further experimental signatures of parity conservation. We point out that, in the simplest case, there is one parity-even and one parity-odd physical neutral Higgs mass eigenstate, whose Yukawa coupling constants are Formula: see text-that of the Standard Model Higgs boson. Furthermore, half of their widths are generated by almost invisible decay modes. Also, if neutrinos are massive then the ordinary and mirror neutrinos will, in the minimal case, be maximally mixed due to parity conservation. This means that vacuum oscillations can be large, thus providing a possible solution to the solar neutrino problem.