LHC is back

Magnet quenches are fairly common. The problem last year was the failure of the system that protects the machine when they happen.

This just improves the bad odds a bit for the 170 GeV prediction of Connes from 5% to something a bit bigger.

Martin,

There aren’t many examples I know of of this kind, so hard to say. In principle, one time in 20 this should happen. There’s also the phenomenon to keep in mind that when experimentalists err, it generally is on the side of thinking their results are more accurate than they really are…

I have heard of particles with a signal at the 5 sigma significance level disappearing into noise.
How often in your experience does it happen that a particle is found in its (e.g. 2 sigma) exclusion zone?

Cheers,
Martin

If we wanted to use advanced potentials, or mixed advanced / retarded potentials, the boundary conditions on the Cauchy surface would have to include carefully set up incoming spherical waves for the moving charged particles to absorb, and these would have to be correlated with the future motions of the charged particles. Thus Minkowski signature field equations automatically create correlations away from the Cauchy surface, if there are no correlations on the Cauchy surface.

Furthermore, if the boundary conditions on the Cauchy surface are random, the state of a memory device at any time will in general be correlated with events in its past light cone, and in particular, with events on its past worldline, going back to the Cauchy surface, but cannot be correlated with events on its future worldline except under special conditions of shielding, since events on its future worldline will in general depend on the boundary conditions on the Cauchy surface outside its current past light cone, which have not yet had any impact on the memory device.

Thus the fact that we remember the past but not the future points to nothing more than that the boundary conditions of physical fields have been specified in the simplest possible way, namely randomly on a Cauchy surface, with no correlations.

The reason we can’t unscramble an egg is different. First, we have to get the ordered state, i.e. the yolk separated from the albumen. Such locally highly nonrandom states can arise out of initially random states by a long series of ratchet-like processes such as evolution, or by forces that tend to separate the components of a mixture such as a colloid, due for example to differing densities, or high interface energies. Once we have the egg, it is easy to scramble it, because a wide variety of crude driving motions, such as shaking or stirring, can all effectively turn the initial ordered state into a disordered state, via chaotic motions. However the fact that it is difficult to unscramble an egg is a specific property of the yolk / albumen mixture, and tells us nothing at all about other systems. For example, if we “scramble” oil and water together, the mixture will soon separate, due to the differing densities of oil and water, and the relatively high surface energy at the oil / water interface.

IRONY

In a rather ironical manner the first Higgs mass that is now excluded by the Tevatron latest results is precisely 170 GeV, namely the one that was favored in the NCG interpretation of the Standard Model, from the unification of the quartic Higgs self-coupling with the other gauge couplings and making the “big desert” hypothesis, which assumes that there is no new physics (besides the neutrino mixing) up to the unification scale. My first reaction is of course a profound discouragement, mixed with an enhanced curiosity about what new physics will be discovered at the LHC.
I’ll end with these verses of Lucretius:
Suave, mari magno turbantibus aequora ventis,
e terra magnum alterius spectare laborem;
non quia vexari quemquamst jucunda voluptas,
sed quibus ipse malis careas quia cernere suave est.
———————————————–
[Pleasant it is, when over a great sea the winds trouble the waters, to gaze from shore upon another's tribulation: not because any man's troubles are a delectable joy, but because to perceive from what ills you are free yourself is pleasant.]
Posted by AC at 3:57 PM 20 comments

Monday, August 4, 2008