Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!genrad!decvax!decwrl!sun!megatest!yin From: yin@megatest.UUCP Newsgroups: net.physics Subject: Re: Z0 particle discovered? - (nf) Message-ID: <203@megatest.UUCP> Date: Tue, 14-Jun-83 19:26:44 EDT Article-I.D.: megatest.203 Posted: Tue Jun 14 19:26:44 1983 Date-Received: Wed, 15-Jun-83 20:08:23 EDT Lines: 45 #R:ihlts:-14600:megatest:10300001:000:2178 megatest!yin Jun 14 19:13:00 1983 The Z0 particle is the neutral intermediate vector boson. It, along with the W+ and W- particles (the charged IVB's), are believed to be mediators of the weak force (one example of the weak force in action is beta decay). The Glashow-Salam-Weinberg (GSW) theory of electroweak interactions, whose originators won the Nobel Prize back in 1980(?), along with other theories, predicts the existence of Z0, W+ and W- and gives some of their expected physical characteristics. By considerations of beta decay amplitudes and widths, a lower bound of 30 Gev can be put on the mass of these particles. If the additional constraints of the GSW theory are considered as well, then the predicted mass of these particles is - M(Z0) = 90 Gev M(W+) = M(W-) = 80 Gev As you can see, these are very massive particles. Their large mass accounts for the weakness of the weak force as well as for their rare appearances, which had to wait for the recent generation of particle accelerators to come on line. The existence of the Z0 particle is a major step in the verification of these electroweak theories. The GSW theory is a gauge field theory that attempts to unify the weak force and the electromagnetic force, much the same way that quantum electrodynamics (QED) unified quantum mechanics and electrodynamics. It is a major step toward grand unified field theories, which would include the strong force. I do not believe that the existence of Z0 helps the grand unified theories as much as it does the electroweak theories, beyond the verification gained because grand unified theories tend to build on electroweak theories. An interesting prediction of the grand unified theories is that hadron number should not always be conserved. Since protons are known to have a lifetime >10^30 years, it is necessary to postulate the existence of a proton decay mediator with extremely large mass, i.e. the X particle where - M(X) = 10^14 to 10^15 Gev It will be a while before a particle accelerator exists which can produce something that massive. yin shih, megatest corp (...!lbl-csam!megatest!yin)