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- From: matt@physics.berkeley.edu (Matt Austern)
- Newsgroups: sci.physics
- Subject: Re: SU(5) GUT (was Re: Superbashing ...)
- Date: 18 Aug 92 17:44:35
- Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
- Lines: 31
- Distribution: usa
- Message-ID: <MATT.92Aug18174435@physics.berkeley.edu>
- References: <92218.094826DOCTORJ@SLACVM.SLAC.STANFORD.EDU> <phfrom.238@nyx.uni-konstanz.de>
- <12AUG199219583210@zeus.tamu.edu> <phfrom.245@nyx.uni-konstanz.de>
- <18AUG199200471328@zeus.tamu.edu> <mcgrew.714174409@skid.ps.uci.edu>
- Reply-To: matt@physics.berkeley.edu
- NNTP-Posting-Host: physics.berkeley.edu
- In-reply-to: mcgrew@skid.ps.uci.edu's message of 18 Aug 92 22:11:12 GMT
-
- In article <mcgrew.714174409@skid.ps.uci.edu> mcgrew@skid.ps.uci.edu (Clark McGrew) writes:
-
- > Minimal-SUSY SU(5) does predict that 10^30<tau(p->e+pi0)<10^34 years,
- > but it has problems because extra Higgs are introduced leading to
- > decay modes such as nucleon goes to lepton and strange quark. While
- > life time predictions are difficult for these modes due to "dimension
- > five operators" (Don't ask me why, I'm just quoting review papers, see
- > the literature if you're really interested), the predicted lifetimes
- > are around tau(Nuc->Lep K)<10^30 years. This is ruled out by both the
- > IMB-1 and Kamioka and will be further constrained by new IMB-3 data.
-
- What most people who construct SUSY SU(5) models do is to come up with
- some kind of symmetry principle which forces these dimension-five
- operators to be absent from the theory.
-
- To me, at least, this seems a bit ad-hoc; that is, these symmetries
- aren't something that anyone would have thought were particularly
- natural if they hadn't known ahead of time that they had to do
- something to avoid making disastrously wrong experimental predictions.
-
- (If I get very energetic, I'll post an article explaining what that
- phrase "dimension-five operator" means. It comes from effective field
- theories, which are the most natural way of looking at problems like
- this. Read Georgi's book, _Weak Interactions and Modern Particle
- Theory_, if you get impatient while waiting for me to post.)
- --
- Matthew Austern I dreamt I was being followed by a roving band
- (510) 644-2618 of young Republicans, all wearing the same suit,
- matt@physics.berkeley.edu taunting me and shouting, "Politically correct
- austern@theorm.lbl.gov multiculturist scum!"... They were going to make
- austern@lbl.bitnet me kiss Jesse Helms's picture when I woke up.
-