I still think ‘smelling’ is bogus, and borders on insulting, given the careful work that has gone into the alpha and mu results. Some types of new physics are more fashionable than others, that’s surely true, and the majority has the dubious privilege of saying that the 3.5 sigma deviations that the minority sometimes work on ‘smell wrong’. And the majority sometimes ends up working on the LEP so-called ‘Higgs’, or the muon magnetic moment, or CP asymmetries in B physics, all of which are (so far) not new physics either, by any sane definition.

Now most particle physicists are indeed looking towards LHC, which is a quite rational thing to do, but that doesn’t mean Nature must be generous enough to give us a nice new discovery there. The thing is to be as prepared as possible for whatever is going to be thrown at us, which may come in the LHC, or somewhere completely different. Since the LHC will throw out a lotttt of data, simply by power of numbers it requires the most preparation.

There is simply no reason why anyone should place weight on a theorist’s ‘intuition’ about debatable experimental results. The only way to find out if such a result is right or wrong is – do more experiments.

‘Smelling’ and ‘intuition’ about what are experimentally determinable facts are simply exhibitions of the theorist’s prejudices. Naturally the theorist is sometimes right and sometimes wrong… then he can repeat the story of when he was right, and forget the times he was wrong.

Remember the muon – ‘Who ordered that?’ The existence of three families is an awkward and messy fact that doesn’t explain anything nicely, and caused a lot of theoretical problems, most of which are still unsolved. Three families smells terrible from almost every angle – but it is an experimental fact.

The cosmological constant also smells awful theoretically, with our current level of (lack of) understanding, unless you are prepared to accept some rather shaky anthropic type reasoning.

Now, it is not so much work to read up about how the alpha and mu results were obtained and what the possible problems with them actually are, then you might come to some sort of informed opinion, using the brain rather than the nose.

E.g. http://www.physik.uni-bielefeld.de/igs/schools/cosmology/cosmo-schedule.html for an elementary start.

Now to work.

Comparison of alpha and mu variations is very model dependent. The mu data are only at two redshifts and don’t allow the drawing of any trend line. The alpha data don’t show a clear trend although their average is significantly different from null. There is no pattern given present data. A linear variation with time (assuming that the value is spatially homogeneous) doesn’t fit both Oklo and varying alpha. Neither does a linear variation with redshift. Anyway Oklo should be redone to take into account variation in nuclear physics parameters (not just alpha) but that is a mess because of nuclear physics being generally messy.

Thomas

Ah….that’s what happens when there is DATA!! Counting down desperately to the LHC….

if i understand this discussion at all, it may be the case that the universe has an inherent “handedness.”

what the cause may be is poorly understood (if at all), but this handedness exists, nonetheless.

is this the essence of the discussion?

Joshua, I haven’t been following the debates closely, although I have talked a bit with Jacobson about this. I also tend to worry about superluminal propagation, but someone needs to sit down and show what would actually go wrong. I think Eugene is working on this, actually.

http://arxiv.org/abs/astro-ph/9812088

Jacobson and Foster take this to mean that, in their “ae-theory,” the parameters should be chosen such that the effective graviton modes are all super-luminal. We discounted this possibility from the start, but I understand that some people are not so conventional.

Is that more clear? I am not really up on the current trends in spontaneous Lorentz breaking; are there any more plausable theories that you know of? Is superluminal propagation a very good out? I know its impossible to rule out, but I feel it is rather unattractive theoretically. Thanks.

Reading your remarks about quintessence generating
polarization I thought of an idea (which you may have
already thought of and discarded). Generally you improve
the bounds on such couplings when you have a long-baseline
for the photon. Now the longest baseline that is available
for observation is that traversed by CMB photons from the
LSS to us. The baseline is of the order of the age of the
universe. If there is some quintessence type field
with pseudosclar coupling to photons then it will
contribute to the polarizations of the CMB (on which there
are good constraints from WMAP-3). So using the WMAP
polarization results one would probably get the best
bounds on these type of couplings…?

Best wishes,
Subhendra

Joshua — I think I also agree that only spontaneously-broken models of Lorentz violation make sense, but there are plenty of such models. Unless I am misunderstanding what you mean.

In my first publication, me, Horace Stoica and my supervisor Guy Moore put some bounds on a class of spontaneous Lorentz violating vector-tensor theories that provide a cherenkov-type mechanism by which cosmic rays could cool off way too much on even galactic distance scales.

I think we assumed throughout that the vev of the vector field was time-like and I recall having some very good reason for doing so. Barring acausal dispersion relations (in the less than speed of light sense), we found that these theories were very tightly constrained.

I came away from that work distinctly sceptical of any Lorentz violating theories, since my impression was that the spontaneously broken models were really the only viable candidates. I’ve been told in rather passionate prose that this is too short sighted, but no-one can really tell me why. Any help?

Thanks.

Aaah, the sweet smell of ‘rightness’. Like pornography, we can’t define it but we know it when we …errr… see it.

An undergrad advisor of mine Tom Devlin , first pointed out such an effect to me, but maintained that it wasn’t a smell, but a sound. He called it the “‘ring’ of rightness.” Here, we know it when we hear it.

It’s probably also what we call physics intuition, and it really is amazing what a powerful force it can be. Frequently I think I’m right about something only to be later proved wrong, but when that ‘ding’ goes off after a thought that first glimpse usually turn out to be correct in the end.

http://arxiv.org/abs/astro-ph/0508378