In the Reader Request Thread, Ian asks:
I'd like to hear what you think we'll learn (if anything!) when the LHC comes online next month.
Well, that sort of depends on the time scale. I'm not a big accelerator guy, but my sense from reading the blogs of people who are is that we're not likely to learn anything at all this year, other than the answer to the question "do the components of the LHC work?" They've got a few weeks of preliminaries before they start any particles going through, and then a whole bunch of sanity checks and calibration tests to do, and a scheduled shut-down in December. It's unlikely that any actual science will be done in the short term.
As for what they'll learn in the longer term...
I really don't have the background to have an educated opinion about what they'll find when they start getting real collisions. As I understand it, it would be really shocking if they didn't find the Higgs boson-- if the Higgs mass isn't in the region that the LHC can explore, then something is drastically, devastatingly wrong with the Standard Model.
Beyond that, I don't have any way to evaluate the claims of different things that might be detected. In a perverse sort of way, I'm actually kind of rooting for "nothing." As someone outside of high-energy physics, I think it would be kind of amusing if they completely failed to detect any sort of supersymmetric partner particles, or any of the other things that they're hoping they might see.
It wouldn't be funny to people in those fields, but as an experimentalist, I enjoy watching theorists squirm.
Actually, the most fun possible result would be for Fermilab to scoop them on the Higgs, and one of the low-energy AMO-based methods to detect something (PNC transitions, a non-zero electron EDM, some departure from theory in the g-factor measurements) that would constrain the range of new physics enough for the LHC results to be anti-climactic. That would be fabulous.
What can I say? I'm a schadenfreude kind of guy...
Physical Science
Comments
# 1 | ian | July 29, 2008 10:43 AM
YEAYYYY! You're a good man, Chad. I've always said so. All Hail Chad the Great!
Seriously, thanks for blogging.
# 2 | John Novak | July 29, 2008 11:03 AM
Damned if you do, damned if you don't: The failure to find anything will be interpretted as a requirement to build an even bigger and more expensive one and find out what went wrong....
# 3 | Chris Granade | July 29, 2008 11:09 AM
You know, it's not just experimentalists who like to watch theorists squirm... sometimes it's other theorists. After all, if we figured everything out, then us theorists (I hope it isn't too conceded to count myself amongst them) would be bored and jobless!
# 4 | peter | July 29, 2008 11:29 AM
#3- only if you misspell 'conceited'...
-the no(i)sy pedant...
# 5 | CCPhysicist | July 29, 2008 12:27 PM
I strongly disagree with #2. The day they build The Next Big Machine and find nothing is the day that higher energy physics comes to an end. The temptation will be to say, "Well, that must be all there is. Figure it out."
Theorists may not be out of business if they can redirect attention to the low energy high intensity regime such as AMO, but exactly how do you sell that big collider if the predictions turn out to be useless?
# 6 | island | July 29, 2008 1:07 PM
if the Higgs mass isn't in the region that the LHC can explore, then something is drastically, devastatingly wrong with the Standard Model.
Maybe not so devastating. It might even be as simple as the nature of the cosmological model that has been wrongly *assumed*:
http://www.lns.cornell.edu/spr/2006-02/msg0073320.html
John Conway talked about the absurdity that the modern interpretation of the negative energy states derives in his post to CV:
http://cosmicvariance.com/2007/11/06/higgs-101/#comment-321311
John said:
I talked about this stuff on Dorigo's blog, as it pertains to Dirac's Hole Theory and the rationalization of the negative energy states. The missed clue came when Dirac failed to unify GR and QM as he had done with SR and QM, but the mistake was made when they misinterpreted the negative mass solutions that fall out of the Dirac Equation:
http://dorigo.wordpress.com/2007/10/18/
It's really very simple:
What happens to a finite vacuum when you rip a huge hole in it?
This is an extremely simple example that you can see was followed by several more relevant posts that went typically unchallenged in the research group:
http://www.lns.cornell.edu/spr/2005-06/msg0069755.html
Too bad that theorists won't "squirm" as long as they can divide by two, because they should have been doing this ever since the smaller colliders failed to find the SM higgs as expected around 160 GeV.
Luckily for science, there won't be funding for any more colliders if the LHC turns up nothing.
THEN sanity in science might actually have a chance.
# 7 | Ron | July 29, 2008 1:21 PM
You're a bad, bad man.
# 8 | Sean Carroll | July 29, 2008 2:11 PM
Unfortunately, if the LHC does not find the Higgs, it will not squeeze theorists into a corner. (Being squeezed into a corner and forced to be clever is the most fun place to be.) The LHC was never guaranteed to find the Higgs; the energy reach just isn't up to it. That's what the SSC was supposed to be for. There is a good chance that the LHC will find it, but it's far from a given, even within reasonable theoretical ranges. It will actually be much easier to find superpartners if they are there than to find the Higgs. (But it will take a long time to be sure they are really superpartners.)
# 9 | Coriolis | July 29, 2008 2:19 PM
I think you're quite wrong on that point CCphysicist. If anything, as a condensed matter guy I find this whole business of particle physicists finding what they look for (and seemingly only what they look for) pretty boring. I think some big failures might shake things up and make it fun ;).
It's not like anybody in congress who gives them money actually understands anything when they succeed, or will understand anything if they fail, so I think the money will flow (or not) regardless. The predictions are and have been "useless" in terms of the "how to build a better lightbulb" type of thinking for a long time anyways, and that hasn't stopped high energy people before (and rightfully so I think).
# 10 | Andrew Foland | July 29, 2008 2:28 PM
If the LHC doesn't find the next big thing, you can rest assured there will be a lot of Congressmen asking US lab directors:
"You mean you paid the French all this money and you've got nothing to show for it?"
The US government is running massive structural deficits and every day another program gets eaten by that wolf. If LHC finds nothing, US high energy physics will end. It might well end even if LHC does find something.
And condensed-matter types won't get any of that money. Don't cheer too hard.
# 11 | Jonathan Vos Post | July 29, 2008 3:45 PM
I went on record more than 4 years ago with what is not even the most Sci-Fi prediction for LHC observation. Now that Sean Carroll has upheld the highest traditions of Caltech, I can uphold the lower traditions...
http://necsi.org/events/iccs/openconf/author/papers/211.doc
IMAGINARY MASS, FORCE, ACCELERATION, AND MOMENTUM:
PHYSICAL OR NONPHYSICAL?
Jonathan Vos Post
Andrew Carmichael Post
Christine M. Carmichael
Physics Department
Woodbury University
Burbank, California
... This paper makes two bold predictions, one of which is experimentally testable by contemporary and near-future equipment, the other of which is more speculative, but may have observable cosmological implications. The detailed derivations of these predictions will presented in subsequent paper, and must be omitted here due to page count constraints.
The first prediction is that an event of at least 100 GeV might cause the creation of an imaginary mass particle, or "imaginon." Further, that particle, by gravitational interaction with other particles, will experience imaginary force, and accelerate in a direction orthogonal to normal 4-space, thus disappearing from our observable cosmos (or from our brane). This process would take at least one Planck Time 5.4 × 10^(-44) seconds. How long depends on the speed of the imaginon (real magnitude of imaginary
velocity vector) and the "brane thickness" of normal 4-space along the 5th (or higher) dimensions. That thickness may well be one Planck Length 1.6 × 10^(-35) meters. Travel of one Planck Length in one Planck Time would mean that the imaginon's speed is that of light, which is infeasible by Special Relativity for a non-zero imaginary mass. The imaginon thus either travels sub-luminally, the "thickness" of normal 4-space is more than one Planck Length, or the "disappearance" takes longer than one Planck Time. We shall return to the questions of observability of this process.
The second, hazier prediction, is that an entirely imaginary mass universe exists, with at least 3 spacial dimensions of its own, adjacent and/or orthogonal to normal 4-space. This is what Isaac Asimov has predicted (in the fictional context of Nemesis). However, Professor Asimov neglected to think through the properties of that Imaginary Cosmos.
In such a cosmos, all particles are of imaginary mass. Hence all pairs of particles have, as previously discussed, antigravitational repulsion from each other. Thus, at first blush, no large cosmological structures would be produced, i.e. no stars, no galaxies, no supergalaxies. However, oppositely charged imaginons can orbit each other in pairs, so long as the electromagnetic attraction exceeds the antigravitational repulsion. Various interactions between imaginon pairs are possible, including Bose-Einstein condensation. Hence imaginary mass universe cosmological structures may be possible after all. The equivalents of fission may be possible (if the Weak Force operates similarly), and fusion (if the Strong Force operates similarly). The imaginary universe would be, in some sense, dual to our 4-space, but neither identical nor opposite in behavior.
The creation of imaginons may only happen in pairs, for events of at least 200 GeV (or double whatever the minimum energy needed to create a single imaginon). If so, the pairs would be expected to be of equal and opposite charge, thus conserving charge. CPT symmetry would be expected to apply, with similar violations. Such pairs might always be bound, and isolated imaginons not possible, just as isolated quarks are unlikely. Compex-conjugate mass imaginon pairs have a far-field gravitational effect on real mass particles that is asymptotic to zero.
Specific numerical prediction regarding imaginary mass: as seen from our 4-space, a particle of imaginary mass leaving the brane appears as a violation of conservation of energy and conservation of momentum. That IS allowed by QM, for very small distances and times. By Heisenberg [derivation omitted] we find that the energy needed to kick the imaginon out of the brane is roughly 10-to-the(-8) Joules = a tenth of an erg = 100 GeV This is, not coincidently, the same order of magnitude as the predicted minimum energy of a Higgs boson; was exceeded by the LEP, and will be exceeded by CERN next year (LHC). [Bagger, 2003] Note that NO experiment to date has shown any violation of conservation of momentum. When Pauli proposed the neutrino to explain an apparent violation, Born offered that for subatomic scales, maybe sometimes there could be a violation. As to my suggestion for a super-sensitive Eotvos experiment, see: [Will 1993], [Will, 1998]...
# 12 | perry | July 29, 2008 10:02 PM
Can't we always pawn everything on a new particle that has a mass too large to detect now? Hell its worked for 50 years or more!
If we get a closeup of the "desert" it will be boring, I hope for some new cool physics. Maybe it can be like the 20's, when Dirac said "first rate physics was done by second rate men"
# 13 | Coriolis | July 30, 2008 11:53 AM
Man Andew, you must have had alot of bad experience with condensed matter people. I'm in favor of LHC and whatever the next big accelerator is, whether they find what they are looking for with the LHC or not. I just think it would be more interesting if they don't find what they're looking for and it leads to some big changes in the theories ;). If anyone in condensed matter wants to steal particle physics money at this point in time they're crazy.
# 14 | JTankers | July 31, 2008 2:53 AM
Professor Otto Rossler compellingly argues that if the Large Hadron Collider creates a micro black hole it may likely destroy Earth, contrary to safety arguments made by CERN.
http://www.wissensnavigator.com/documents/spiritualottoeroessler.pdf A Rational and Moral and Spiritual Dilemma
# 15 | island | July 31, 2008 11:25 AM
Professor Otto Rossler compellingly argues that if the Large Hadron Collider creates a micro black hole it may likely destroy Earth...
And you see this as a bad thing?... ;)