With the Large Hadron Collider almost ready to turn on, it’s time to prepare ourselves for what it might find. (The real experts, of course, have been preparing themselves for this for many years!) Chad Orzel was asked what we should expect from the LHC, and I thought it would be fun to give my own take. So here are my judgments for the likelihoods that we will discover various different things at the LHC — to be more precise, let’s say “the chance that, five years after the first physics data are taken, most particle physicists will agree that the LHC has discovered this particular thing.” (Percentages do not add up to 100%, as they are in no way exclusive; there’s nothing wrong with discovering both supersymmetry and the Higgs boson.) I’m pretty sure that I’ve never proposed a new theory that could be directly tested at the LHC, so I can be completely unbiased, as there’s no way that this experiment is winning any Nobels for me. On the other hand, honest particle phenomenologists might be aware of pro- or con- arguments for various of these scenarios that I’m not familiar with, so feel free to chime in in the comments. (Other predictions are easy enough to come by, but none with our trademark penchant for unrealistically precise quantification.)
- The Higgs Boson: 95%. The Higgs is the only particle in the Standard Model of Particle Physics which hasn’t yet been detected, so it’s certainly a prime target for the LHC (if the Tevatron doesn’t sneak in and find it first). And it’s a boson, which improves CERN’s chances. There is almost a guarantee that the Higgs exists, or at least some sort of Higgs-like particle that plays that role; there is an electroweak symmetry, and it is broken by something, and that something should be associated with particle-like excitations. But there’s not really a guarantee that the LHC will find it. It should find it, at least in the simplest models; but the simplest models aren’t always right. If the LHC doesn’t find the Higgs in five years, it will place very strong constraints on model building, but I doubt that it will be too hard to come up with models that are still consistent. (The Superconducting Super Collider, on the other hand, almost certainly would have found the Higgs by now.)
- Supersymmetry: 60%. Of all the proposals for physics beyond the Standard Model, supersymmetry is the most popular, and the most likely to show up at the LHC. But that doesn’t make it really likely. We’ve been theorizing about SUSY for so long that a lot of people tend to act like it’s already been discovered — but it hasn’t. On the contrary, the allowed parameter space has been considerably whittled down by a variety of experiments. String theory predicts SUSY, but from that point of view there’s no reason why it shouldn’t be hidden up at the Planck scale, which is 1015 times higher in energy than what the LHC will reach. On the other hand, SUSY can help explain why the Higgs scale is so much lower than the Planck scale — the hierarchy problem — if and only if it is broken at a low enough scale to be detectable at the LHC. But there are no guarantees, so I’m remaining cautious.
- Large Extra Dimensions: 1%. The idea of extra dimensions of space was re-invigorated in the 1990’s by the discovery by Arkani-Hamed, Dimopolous and Dvali that hidden dimensions could be as large as a millimeter across, if the ordinary particles we know and love were confined to a three-dimensional brane. It’s a fantastic idea, with definite experimental consequences: for one thing, you could be making gravitons at the LHC, which would escape into the extra dimensions. But it’s a long shot; the models are already quite constrained, and seem to require a good amount of fine-tuning to hold together.
- Warped Extra Dimensions: 10%. Soon after branes became popular, Randall and Sundrum put a crucial new spin on the idea: by letting the extra dimensions have a substantial spatial curvature, you could actually explain fine-tunings rather than simply converting them into different fine-tunings. This model has intriguing connections with string theory, and its own set of experimental predictions (one of the world’s experts is a co-blogger). I would not be terribly surprised if some version of the Randall-Sundrum proposal turned out to be relevant at the LHC.
- Black Holes: 0.1%. One of the intriguing aspect of brane-world models is that gravity can become strong well below the Planck scale — even at LHC energies. Which means that if you collide particles together in just the right way, you could make a black hole! Sadly, “just the right way” seems to be asking for a lot — it seems unlikely that black holes will be produced, even if gravity does become strong. (And if you do produce them, they will quickly evaporate away.) Fortunately, the relevant models make plenty of other predictions; the black-hole business was always an amusing sidelight, never the best way to test any particular theory.
- Stable Black Holes That Eat Up the Earth, Destroying All Living Organisms in the Process: 10-25%. So you’re saying there’s a chance?
- Evidence for or against String Theory: 0.5%. Our current understanding of string theory doesn’t tell us which LHC-accessible models are or are not compatible with the theory; it may very well be true that they all are. But sometimes a surprising experimental result will put theorists on the right track, so who knows?
- Dark Matter: 15%. A remarkable feature of dark matter is that you can relate the strength of its interactions to the abundance it has today — and to get the right abundance, the interaction strength should be right there at the electroweak scale, where the LHC will be looking. (At least, if the dark matter is thermally produced, and a dozen other caveats.) But even if it’s there, it might not be easy to find — by construction, the dark matter is electrically neutral and doesn’t interact very much. So we have a chance, but it will be difficult to say for sure that we’ve discovered dark matter at the LHC even if the accelerator produces it.
- Dark Energy: 0.1%. In contrast to dark matter, none of the energy scales characteristic of dark energy have anything to do with the LHC. There’s no reason to expect that we will learn anything about it. But again, maybe that’s because we haven’t hit upon the right model. It’s certainly possible that we will learn something about fundamental physics (e.g. supersymmetry or extra dimensions) that eventually leads to a breakthrough in our understanding of dark energy.
- Strong Dynamics: 5%. Quantum Chromodynamics (QCD), the theory that explains the strong nuclear force as arising from strongly-interacting gluons coupled to quarks, is a crucial part of the Standard Model. An underappreciated feature of QCD is that the dynamics of quarks breaks the electroweak symmetry even without the Higgs boson — unfortunately, the numbers don’t work out for it to be the primary mechanism. However, an interesting alternative to the standard idea of a Higgs boson is to imagine a new “QCD-like” force that operates at even higher energies; one venerable idea along these lines is known as technicolor. For a long time now technicolor theories have been struggling to remain compatible with various experimental bounds; but theorists are clever, and they keep coming up with new ideas. I wouldn’t be completely surprised if a new strongly-interacting force was discovered at the LHC, although it’s a bit of a long shot.
- New Massive Gauge Bosons: 2%. Another Standard-Model-like thing that could show up is a massive gauge boson from a spontaneously broken symmetry (or more than one), similar to the W and Z bosons of the weak interactions — you will hear about searches for Z-prime bosons or W-prime bosons. As far as I know they don’t solve any pressing problems, but lots of things in the universe don’t solve any problems, and nevertheless exist.
- New Quarks or Leptons: 2%. The final Standard-Model-like thing we could find is a new “generation” of fermions (matter particles) — strongly-interacting quarks and non-strongly-interacting leptons. We don’t expect to, for the following indirect reason: each generation includes a neutrino, and neutrinos tend to be fairly light, and the existence of new light fermions is strongly constrained both by particle physics experiments and by Big Bang Nucleosynthesis. (If there are more light particles, the energy density of the universe is just a bit larger at any fixed temperature, and the universe therefore expands faster, and you therefore make a bit
less more Helium. [Shouldn't post late at night -- see below.])
- Preons: 1%. Historically, when we smash particles together at high energies, we find out that they were made of even smaller particles. The possibility that quarks and leptons are made of smaller constituents — preons — has certainly been taken very seriously, although none of the models has really caught on.
- Mysterious Missing Energy: 15%. Particles that are long-lived, neutral, and weakly interacting — including dark matter particles and gravitons — can only be found indirectly at a collider like the LHC. You are smashing things together, and if the total energy of the resulting particles you detect is less than that of the initial particles you smashed, you know that some invisible particles must have escaped as “missing energy.” But what? If you have a specific theory, you can match carefully to the expected dependence on the initial energy, the angle of scattering, and so forth. But if you don’t … it will be hard to figure out what is going on.
- Baryon-Number Violation: 0.2%. As Mark is explaining, there are more baryons than anti-baryons in the universe, and most of us think that the asymmetry must have been dynamically generated somehow. Therefore, some process must be able to change the number of baryons — but we’ve never observed such a process. And we probably won’t; in most models, violation of baryon number is far too rare to be visible at the LHC. But there is certainly no consensus about how baryogenesis happened, so we should keep an eye out.
- Magnetic Monopoles, Strangelets, Q-Balls, Solitons: 1%. These aren’t really new particles, but composite objects of one form or another. Even if they exist in nature, the violent inner chambers of a particle collider might not be the best environment in which to make them.
- Unparticles: 0.5%. One of the most recent hot topics in particle theory, unparticles are a suggestion from Howard Georgi that you could detect what looks like a fractional number of new particles, if there were a set of fields with perfect scale invariance (no masses or other parameters to judge their “size”). It’s undeniably clever, although the connection to reality still seems a bit tenuous. (Although.)
- Antimatter: 100%. We detected antimatter long ago! In 1932, to be precise. It is no longer a mystery.
- God: 10-20%. More likely than stable black holes, but still a long shot.
- Something that Has Never Been Predicted: 50%. Here is my favorite thing to root for. Particle theorists have been coming up with new models for so long without being surprised by new experimental results, some of them have forgotten what it’s like. Nature has a way of throwing us curve balls — which is not only something to be anticipated, it’s something to be very grateful for. Surprises are how we learn things.
- Something that Has Been Predicted, but Not Listed Above: 2%. I certainly haven’t included every idea ever proposed; if some model that not many people took seriously turns out to be right, someone will have some excellent gloating opportunities.
- Absolutely Nothing: 3%. It’s always possible that we won’t find anything really new, not even the Higgs. If that turns out to be the case — well, suffice it to say that there will be great wailing and gnashing of teeth. It’s not a prospect I am especially worried about, but reality is what it is, and I’m sure we will find a way to move forward if that’s the case.
Now let’s turn the damn machine on, already!
Update: pretty pictures! Via Swans on Tea.
three important points:
A) “there’s nothing wrong with discovering both supersymmetry and the Higgs boson.”
We better find more than one!
B) I would add the 10% from the warped models to the strongly coupled scenario, for which RS serves as a toy model via ADS/CFT. It would be a fantastic option, although it’s certainly constrained.
C) Absolutely nothing is not an option, we know field theory works well and something has to unitarize the theor. We already (indirectly) know the *Higgs*, or whatever works like it, is there. It’s certainly possible we have to completely overhaul our theories, and re-accomodate all our previous “knowledge”; but 3% is a bit too much, that’s not the way Science works, though nature is always another story ;p
G
I think there will be great wailing and gnashing of teeth if the result is, “Exactly what you would expect from the Standard Model, and nothing more.” Regardless of whether or not that includes the Higgs. I mean, what could be worse news for a theorist than, “The current model checks out, no tweaks needed.”
It seems to me that exclusion of the Higgs boson is far more interesting than it’s discovery at this point. With the constraints we have on likely Higgs masses, an exclusion will force us to rethink far more than a discovery will. Granted that it will mean countless bottles of champagne go unused in CERN, but I think we can take the hit if it means overthrowing a key element of the standard model.
I’m putting my money on the “Something that Has Never Been Predicted” option. It will be very interesting indeed if the Higgs boson is not found by the LHC.
I really wonder how you got number 10^(-25) .
It seems odd to me that most individuals accept the idea of entanglement but hardly any yet connect it to the idea of mass. It seems far more likely to me mass is just a form of very stable entanglement of all submicroscopic particles. And related to that was a previous comment that implied the only thing missing from the standard model. Far from it - think about that the fact that SM predicts if enough protons are observed one will be detected to decay - but that’s never occurred and they’ve had enough time to use that result to start drawing some conclusions about the standard model.
Eric Habegger, quantum opticians have made maximally (and less) entangled photons for decades, and there is no sign whatsoever that it has anything to do with mass. They don’t slow down, their frequency does not change, nothing.
Eric H,
The SM does NOT predict that the proton is unstable; this is a generic prediction of grand unified theories (GUTs).
Actually - the standard model does predict that the proton is unstable, through the baryon number anomaly. (But you certainly should never see this effect at colliders).
[...] A look at what the Large Hadron Collider will find. Hint - not a ginomous black hole that will kill us all. Probably. [...]
If you convert your percentages into betting odds, I’d bet against you on most of them. Supersymmetry at 60% seems like a particularly good one to bet against, for two reasons:
1. If TeV-scale SUSY really exists, it’s pretty surprising that we haven’t seen hints of it already.
2. Even if there are lots of SUSY events, convincing the physics community that it’s definitely SUSY–and not something else with new, heavy particles–won’t be easy. Measuring spin is hard at the LHC experiments, and I seem to recall that it will take more than the five years you’ve allowed.
On the bright side, I like your odds on “Something that Has Never Been Predicted.”
Where do you get your odds for Stable Black Holes? Many physicists believe that all black holes are stable.
Read Wikipedia article on Hawking Radiation. Hawking Radiation may not exist according to several peer reviewed papers.
The operators of the Large Hadron collider have a vested interest in propaganda that implies assured LHC safety.
Dr. Rossler theorizes that Hawking Radiation is not possible and if micro black holes are created they will destroy the planet in 50 months to 50 years.
LHCFacts.org
Sean, you seem to imply that finding nothing at all would be a very bad thing. I would have thought that ruling out a vast swathe of theories would be extremely interesting. Others have mentioned not finding the Higgs as an example of this, but there are certainly other theories which would also become unrealistically tightly constrained or squeezed out all together. Surely for theoretical physicists this is right up there with seeing something which has never been predicted.
My bet is for finding the Higgs, signatures of SUSY and the 50% “something not predicted.” As for black holes? — errmm, it would be interesting if there are some scattering amplitudes found which correspond to some dualality with black hole interiors via brane physics. I definately hope frankly that preons or related rishons are not found. That will really muck up the waters IMO. If missing energy is found it would appear that we are all in for some repeat of the history with neutrinos — maybe this will be dark matter.
Lawrence B. Crowell
Mark writes: Actually - the standard model does predict that the proton is unstable, through the baryon number anomaly.
Is this correct?
My recollection is that the standard model baryon number anomaly conserves baryon number modulo the number of fermion generations — presumably 3. A proton, with baryon number 1, could only “decay” to states with baryon number -2, 4, etc., all of which have higher energy than a single proton. So an isolated proton should be absolutely stable. (I suppose that a helium-3 or helium-4 nucleus could decay to a state with baryon number 0 or 1 respectively, and that we could call this “proton decay”, but I still wouldn’t say that this renders the proton unstable.)
The deuteron can decay in a positron and an anti-muon neutrino. The deuteron lifetime is about 10^(218) years.
Go warped extra dimensions! 10% chance, you say!?!
I’ve spent the total of about a couple days learning/thinking about this possibility, but that small amount of time in no way reflects my excitement for this possibility. The reason is, it seems to me, if warped extra dimensions are the explanation for hierarchy, this means that experimental verification of the fundamental theory is within our reach!
“Within our reach” is a vague term — surely it would take an enormous effort to sort things out, and probably it would take more powerful accelerators than we have in production. But I’m young, and I can hope that over the next 40 years I have to work on these things, the main gist of it might be sorted out. That hope is far more tenuous if quantum gravity sits at 10^18 GeV.
What probability would you give to the possibilty that whatever new physics comes out of the LHC will lead, however indirectly, to something uber-cool such as a solution to the world’s energy crisis, or warp drive?
As “Garbage” notes above, Randall-Sundrum is really a subset of strong dynamics. And while it’s great fun to play with, from a more theoretical point of view it’s not even clear that such theories exist; that is, they might just be effective theories with no good UV completion. The “landscape” of CFTs at strong ‘t Hooft coupling, with no supersymmetry, is pretty much completely mysterious. So I would put “strong dynamics” as significantly more likely than “warped extra dimensions.”
Incidentally, why is there a high energy threshold for producing gravitons? If they’re massless, like photons, they should exist at all energies.
Mark — re: your comment above: here’s a fun discussion — someday within the next 20-30 years, we’ll hopefully see sphaleron processes at colliders. As you know, one would “only” have to boost the energy of the LHC by a factor of 3-5 or so (although maybe “only” should be in two sets of quotes…), whereas to see the SM baryon number anomaly at a water cherenkov tank you would need to make a larger version of Super-K by 2 orders of magnitude or so. IMO, colliders (i.e. an energy-upgraded LHC) may get there first — and my opinion is the LHC probably will. Do you think a 100x SuperK (or alternative) will arrive before a 4x LHC?
JTankers,
Doubtful. But regardless, we’re not talking about stable black holes in general, just stable black holes produced in the LHC. That eventually is obscenely unlikely due to constraints from high-energy cosmic rays.
The basic argument is thus: if high-energy collisions can produce black holes, most of them will be charged (since the colliding particles won’t often have the same charge). As charged particles, they will experience copious amounts of friction in traveling through matter, and will come to rest within the Earth. And this will have been going on since the formation of the Earth some 4.5 billion years ago, many with masses in excess of a million times what the LHC is capable of producing. Therefore, the mere fact that the Earth still exists is strong evidence that such events simply do not occur. And if you want to throw anthropics into the mix, just bear in mind that other planets and stars still exist, too. Therefore the possibility that the LHC will produce anything dangerous (such as a stable black hole) is vanishingly small.
Something that could be filed under ‘nothing’, would be hidden sector proposals. Where you can hide all sorts of funky interactions in the strongly coupled sectors and the effects, if any, would be very indirect. They could look like dramatic violations of theory, even though secretely they are not.
I’d put the chances for ‘predicted but not listed above’ slightly higher as well. There are so many models!
How is there a 100% chance of antimatter, but a 3% chance of nothing? I though antimatter was not nothing. 103% ftw?
Unless you mean the nothing is actually on the “turn it on and have it blow up” scale instead of the “oh snap, stuff is coming out” scale.
Having worked on essentially every possibility on your list over the years, I also vote for `something we haven’t thought of yet’.
Sean forgot to include the latest hype in his list: unparticles
Eh… Unparticles are listed.
“God: 10-20%. More likely than stable black holes, but still a long shot.”
Sean, shouldn’t this make you an agnostic instead of an atheist?
Kenneth,
He meant that he places his confidence on nothing new at around 3%.
ree ree,
Atheist and agnostic are not mutually exclusive. Oh, and just for a bit of fun: 10^-20% probability of finding God is less of a probability than a planet-killing asteroid hitting the Earth in the next second (assuming no knowledge of such asteroids and their trajectories, just that they hit approximately once every 100 million years on average).
Sean, you give “evidence for or against string theory” only 0.1%, but wouldn’t either SUSY or warped extra dimensions constitute evidence for ST (or at the least, wouldn’t many physicists interpret those discoveries that way)? Yes, I understand that neither SUSY nor the existence of extra dimensions implies string theory (nor does the failure to find those things at LHC energies imply ST is false). But even knowing that some of the main aspects of string theory were on the right track would seem like incredibly valuable information to have, no?
Thus, I’m tempted to act as a Dutch bookie, betting against you regarding SUSY and warped extra dimensions but also betting for “evidence for or against string theory.”
Hello Jason,
Dr. Rossler appears to have invented the concept of charged micro black holes (mbh) earlier in 2008 (before release of the 2008 LHC Saftey Report) based on the mbh capturig a charged particle such as an electron in orbit around the mbh outside the event horizon.
This concept is unverifided and it is unknown if an mbh could capture a charged particle in orbit if the mbh and charged particle have a relativistic difference in velocity as a cosmic ray to Earth collision results may have. This may be one of the reasons that CERN’s SPC Comittee called cosmic ray and neutron star safety arguments “unverified”.
Jason,
“10^-20% probability of finding God is less of a probability than a planet-killing asteroid hitting the Earth in the next second (assuming no knowledge of such asteroids and their trajectories, just that they hit approximately once every 100 million years on average).”
Well, both probabilities are not zero. Thus, we cannot completely rule out something with the probability of 10^-20%. We just don’t know for sure (i.e. 0%). Hence my previous comment, which was just a joke in response to Sean’s joke. But strictly speaking, if you assign a nonzero probability to the existence of God, that means you don’t know if God exists or not. Hence, you’re agnostic (at least according to my understanding of the term).
Anyway, Jason, you are taking us way off topic here. I suggest you cut this nonsense out.
Scott, I’m sure many people would count susy or evidence for brane-world models as evidence for string theory, but for purposes of this classification I’m keeping them separate. Everyone admits that you could have either susy or branes without string theory (except for people who think that you can’t have anything without string theory).
But either discovery would definitely constitute “invaluable information”!
Sean:
More light particle species do make the Universe expand faster at a given temperature, but that makes for more helium, not less helium, since the weak interactions freeze at a higher temperature with a higher n/p ratio, and deuterium stabilizes sooner allowing more of the neutrons to survive without decaying.
At 19:1 odds I’d be happy to bet against the Higgs, and I’d be happy to lose.
Arrgh! I’ve even written papers about this, dammit. Encroaching senility.
[...] For some guess about what to expect at LHC, Sean Carroll has posted this. We are all eager to see. Bets are [...]
Hi Sean,
You must be nuts to give warped extra dimensions 10%. Would you like to bet something at those odds?
(This post is a fun read, thanks.)
-Sam
From the odds of Higgs vs. Dark Energy I can guess that these are completely unrelated. Too bad - it would be nice not to need two fields that pervades all of existence.
Any recommendations for websites with real (or nearly so)- time info, date, updates, reports on the LHC?
SUSY was discovered, let me check my notes, ah, yes, in 1947. The charged boson decayed into its fermionic partner, a particle discovered some years before, in 1937, with a mass about 15% lighter.
Regrettably it took 20 years to discover that it was, at all, a composite particle. And 10 years more to formulate, mathematically, the concept of supersymmetry.
JTankers,
You have misunderstood. The claim is not that it will capture charge, but that it will be charged from the time it is formed. The knowledge that black holes can potentially carry electromagnetic charge has been known for a long time now, and in this case, the only way the black hole produced during such collisions wouldn’t carry charge would be if it struck an opposite-charged particle on impact. As it turns out, this is highly, highly unlikely. So it will just slow down through friction until it can start accreting matter in significant amounts. Thus, since planets in our own solar system still exist, this process can’t occur.
ree ree,
Sorry for the aside, but I really think this point needs clarifying. I knew you were joking, but agnosticism and atheism are simply not mutually exclusive positions. An agnostic holds a stance that they either do not know or cannot know if a god or gods exist. An atheist simply lacks belief in a god or gods. One position is about knowledge, the other about belief. These are two different things, and it is entirely possible for a person to be both an agnostic and a theist, or an agnostic and an atheist.
But personally, I think a person who states, “Well, technically I can’t know for [i]certain[/i] that no god exists, but I know that it’s highly, highly unlikely,” would not count as an agnostic, but as a strong atheist.
Ned Wright:
I bet the question on everyone’s mind is what that does to the carbon abundance. . . .
Jason,
I understand what you’re saying. I guess it depends on distinguishing “I believe.” from “I know.”, where knowing is based on a sufficient amount of empirical evidence. I guess string theorists are agnostic M-theists.
By the way, the last sentence in my last comment was a joke. I, of course, took us off topic.
[...] Large Hadron Collider (LHC) expected to go online very soon, Sean Carroll of Cosmic Variance has posted his estimations of the likelyhood of various possible discoveries being made with the LHC. Meanwhile, The Boston [...]
http://www.lhcountdown.com/
Not to be to picky about your percentages, but you have 60% for supersymmetry, but
only 10% for dark matter. Standard Supersymmetry has a lightest supersymmetric particle
which is the main dark matter WIMP candidate. So unless your predicting we find a variant
R-party non-conversing, so no stable LSP, SUSY version: if the LHC finds SUSY it finds the
dark matter particle. Personnally i’d put SUSY a lot less likely to be found, but a stable WIMP
from some theory ought to be reasonably likely to be found.
Another good variant.
After 5 years we have evidence of new physics with 80% certainty, but have no idea which model it is exactly, due to lack of statistics.
[...] 5 times [↩]ah, gossip about other people’s professors [↩]the source of these is here [↩]i.e large extra dimensions, or warped dimensions, and there is only a combined 10% chance [...]
I know this probably isn’t hardcore enough for you all :), but I looked around and I can’t find anything on it:
To my lay man’s ears, it sounds like if these world-swallowing mini black holes exist and are easily created, then our solar system, and others, should have succumb to them already. And even if there’s a small chance that they do exist (catastrophic ones, that is), if its so small that we’re more likely to be obliterated by an asteroid, then I think it’s a risk we have to take.
Now that we’re clear: does anyone know of a (fictionalized) scientifically accurate description of what our planet being engulfed by a growing MBH might be like? Like would particles sent into the colliding chambers start disappearing? Eventually would Europe be stretched beyond habitability, while the rest of the earth’s peoples were huddled in South America (ie. as far away as possible)? Would it be able to destroy all life while still having an event horizon microscopically small? Would it be the size of a basketball or a city? Would our satellites in space look down at the dying earth and see a large part of the northern hemisphere totally “blacked out?”
I know this is pretty silly but it’s got me wondering. I would guess someone has already written something on this, but how about someone who really knows what he/she is talking about? Or, if world-eating mini black holes can actually be formed at the LHC, would that necessitate such significant changes to our current conceptions of physics as to render scenarios involving them impossible to realistically diagnose?
[...] Sean Carroll has been staking his bets on LHC discoveries over here at Cosmic Variance. « On tossing stuff into [...]
BDO Adams - it is true that SUSY with R-parity provides a natural excellent candidate for the dark matter. However, the devil is in the word “candidate”. Whether one gets the right relic abundance depends on the details of the parameters.
It would be possible for a given variant of SUSY (say the MSSM) to be right, and that the parameters be such that the LSP is overproduced - giving far more than we observe in dark matter. That possibility is therefore ruled out by cosmology.
It is also easily possible for the parameters to be such that the LSP abundance generated is negligible. Only special values give us what we see. So it is perfectly consistent to think that there is a higher chance of seeing SUSY than dark matter from the same model.
Elo:
David Brin’s Earth has a man-made black hole eating the planet as a plot driver. Available here. Or “How We Lost The Moon” by Paul J. McAuley, which apparently also features this kind of industrial accident - just Lunar-side this time. There’s also The Krone Experiment, written by someone who knows of what he speaks.
To add to Mark’s comment above, it’s also entirely possible that in discovering that some SUSY model is accurate, the LHC won’t be capable of nailing down the parameters of the model accurate enough to say whether or not it provides a dark matter candidate.
Personally I interpreted Sean’s comment, however, as stating that he feels the probability of directly detecting the dark matter particle in the LHC via observations of missing mass is quite small. Inferring the properties of the dark matter particle from other constraints on a SUSY model would be something else entirely, and personally I’d be rather surprised if it could be done.
I wouldn’t worry about black holes. At best we might get some small amplitude or channel production corresponding to some Brane duality or AdS/CFT type of duality to a black hole interior. A planet eating black hole is highly improbable.
As for SUSY, I suspect we might at best find broken SUSY. Dark matter might be something such as a photino or some SUSY pair of a known particle. Dark matter might also be strangelet matter, where the strange quark in a triplet can exist in a lower energy state than a triplet with ups and downs. Dark matter might be this stuff.
There have been worries about strangelets catalyzing everything into itself. Yet that worry is overblown. If dark matter is strangelet stuff clear this stuff is in the galaxy and comes down to stars and planets all the time. So far there is no evidence of planet eating strangelet activity out there.
BTW, an Earth mass black hole would be about the size of a glass marble ~ 1cm in diameter. If the moon were a black hole it would be about the size of a birdshot BB. Since black holes quantum decay a lunar mass black hole would emit some radiation with a black body temperature of around T = 3K, close to the CMB temperature. Any larger black hole has a colder temperature. Very small quantum black holes are hot and rapidly decay or explode — with the good news
this prevents any Earth gobbling black hole from taking root!
Lawrence B. Crowell
[...] a pretty interesting roundup of the things the nerds over at the Large Hadron Collider might find…you know if they can stop rapping for five [...]
Is it possible to compress a body like the Moon so that it becomes a black hole?
In principle maybe, but in practice I’d say no. There is a difference between gravity pulling matter in from the center (so to speak) and trying to implode something from outside. Trying to implode something results in Rayleigh-Taylor instabilities and shock wave deformation. This is the stuff nuclear weapons designers deal with, as well as with inertial confinement fusion.
A lunar mass mass black hole might only happen in the Hawking decay of a 10 or larger solar mass black hole some 10^67 years from now. It is safe to say we will not be around to “see” one.
Lawrence B. Crowell
To whom it may concern,
Unparticles were predicted few years before Georgi’s papers of 2007, see for example:
http://en.wikipedia.org/wiki/Unparticle
The Higgs mechanism is no longer needed to explain particle masses if one uses the framework of non-equilibrium field theory. For a Higgsless model in nice agreement with experimental data see:
http://www.iop.org/EJ/abstract/0295-5075/82/1/11001
Any odds on ‘discovering” an engineering flaw that fries the whole machine?
Yeah, but what are the evens and anti-odds? We look forward to updates annually…
Pleeeease let them find out that the extra dimensions predicted by string theory are used for various properties of matter, including mass…
What about Dragons? Any chance we will find some of them?
After about ten years of fruitless searching the theorists will be saying, “Well the energy range is too low - we never expected to discover anything about Higgs, DM or DE anyway.”
Garth
Hmmm, … the standard model predictions for the Higgs are pretty clear. It should be there. It can’t be pushed off to some higher energy domain so easily. If the Higgs fails to show up a central pillar of the standard model collapses and things become depressing for some, exciting for others.
Lawrence B. Crowell
[...] Sean Carroll, physicist at CalTech and blogger extraordinaire provides a list of things which will likely (or less likely) be found at the LHC Possibly related posts: (automatically generated)I am not the only one worried by thisWill the LCH [...]
[...] What Will the LHC Find? | Cosmic Variance. Stable Black Holes That Eat Up the Earth, Destroying All Living Organisms in the Process: 10-25%. So you’re saying there’s a chance? [...]
Hawking predicted a long time ago that the Higgs boson would never be observed, see here.
[...] Sean Carroll: What Will The LHC Find? Filed under: Current Events, Nature, Public Debate, Science — chr1 @ 7:22 pm Tags: Large Hadron Collider, LHC, Sean Carroll That’s the Large Hadron Collider. [...]
[...] of course been discussing these things for much longer.) Sean Carroll at Cosmic Variance has the most interesting take that I’ve seen for a semi-informed audience. He even gives odds on various discoveries that [...]
Secretly, I’m kind of hoping for a small black hole. Not a stable one, but one that evaporates. I think it would be interesting, don’t you? Can’t wait until the LHC is up and ready, it’ll be the 1st time in almost 10 years (exaggeration of course) since I’ve watched the news!
It never ceases to amaze me how string people can stay in their own little cocoons and keep floating away in unreality indefinitely. 10% chance for Warped Extra Dimensions?! You got to be kidding me.
There are several online exchanges that allow people to put their money where their mouths are. If Sean still wants to bid 10 cents a contract on the WED Futures, I will gladly hit him 10,000 right away. I will also be a seller on SUSY at 60 cents. Evidence for or against string? Half a penny may seem cheap, but it is really not if the thing is worth exactly zero.
Please do not bother to flame me, as my time is too valuable to be wasted in a flame-war. Go set up the futures on these bets and ask Sean to email me. Disagreement is human nature, and the best mechanism even invented to resolve it is the market. Unfortunately, there seems generally a negative correlation between the amount of one’s time spent on blogs (especially string blogs) and his ability to make the right call with real money on the line.
It would be nice to think that the LHC was last big experimental fling for a physics of matter, energy and forces alone.
Whereas next comes the physics of the real world of matter, energy, the forces and the nonlocally acting, matter and radiant energy form conserving cause.
Sean,
95% probability of seeing the Higgs, eh? So does that mean that you would be prepared to make a bet where I pay you $50 if it is not found & you pay me $950 if it is? If so, then you are on. Before you agree to this, though, please remember that (i) no fundamental scalars have ever been observed & (ii) the logic that leads one to the Higgs particle is not without flaw.
I love it how you injected humor into this semi-serious post.
When the LHC detects/fails to detect something, then the wavefunction then collapses and the probabilities listed here would cease to exist, right?
So how does one prove that God exists other than by not being able to prove he exists?
no ideas about the dragons eh?
[...] and hoping to find, and what they are looking for when TeV energies are reached, you should go read this comprehensive list at the (very cool) science blog, Cosmic Variance. It’s a nice collection of possible outcome [...]
[...] Large Hadron Collider will be turned on, with a 10-25% probability of making Stable Black Holes That Eat Up the Earth, Destroying All Living [...]
..what if the zlingblot contracongigulates into
+/- 983.0002, and the unstable inter-octa matrix falls over?
answer THAT Mr. Smarty pants scientist guys, you!…..
heh heh heh….ack.
So why don’t they collide small hadrons?
Are there any bookies publishing odds on what is expected to be found?
Chris Oakley,
You’ve got those numbers reversed. The bet would be $950 to you if the Higgs is not found, $50 to him if it is (assuming you’re betting that the Higgs won’t be found).
Well, a good start would be demonstrating that intercessory prayer works. Too bad it doesn’t. I don’t see how it’s possible to detect a deity in a particle accelerator, though, so I think that’s mostly a joke.
[...] Link (via Kottke) Tags: CERN, Physics, Science [...]
[...] list of what we might find when Cern turns on the LHC. Supposedly there’s a larger chance of finding God (10-20%) than [...]
People for the Ethical Treatment of Hadrons are at it again, protesting the atrocities high energy physicists commit every day with their holocaust of elementary particles.
–
http://www.bbspot.com/News/2008/08/group-protests-treatment-of-hardrons-at-cern.html
[...] Large Hadron Collider is almost complete, and many people are discussing what it might find. A list of the various things it may (or may not) uncover shows how many things there are out there, [...]
99% chance of a scientist gaining super-human powers.
Sean, you missed one possibility:
http://fqxi.org/community/forum/topic/230
The paper (or at least the first 10 pages that I managed to wade through) cracked me up regardless of its actual truth value. =)
[...] Here’s a rundown. [...]
Mr. Dick,
Duh, yes indeed, whatever I may have mis-typed before, I’m betting that there is no Higgs - apart from the white-haired emeritus professor.
The earth will stop spinning.
[...] of hadrons While we’re talking about the LHC, Sean at Cosmic Variance discusses some of the discoveries it might yield. After reading that I had to spend a good half hour on Wikipedia reminding myself what elementary [...]
Chris Oakley,
Thought so. But why do you think that the logic that leads to the Higgs is flawed?
Jason,
All documented on my web site. Spontaneously broken gauge theories are just smoke and mirrors, and the Higgs mechanism just a cheap trick. If you want to make a bet yourself, let me know.
WHAT would happen if I stood inside of the machine WHEN THEY SHOT THE beams around!
Thank you
Chris,
So, your problem is with renormalization? Why? It’s just a theory that states that the theories we have today don’t work to infinite energy, so we parameterize their behavior above some finite energy level, and as long as we can mathematically show that the energy level which we choose makes no difference for the dynamics, then the shell game works and we can measure the unknown behavior at high energies by comparing those amplitudes to experiment. Where is the problem?
Furthermore, I don’t see any specific argument against the Higgs, just a hand-wavy claim that the arguments are poor. If you want much more detailed explanations and arguments for these things, they are available. Your own ignorance of them does not mean that they don’t exist.
Joe,
Well, you’d be bombarded with high-energy protons and anti-protons that would likely cause lots of electrons in your body to get kicked out of their atoms, and would probably cause a number of nuclear reactions in various nuclei, effectively destroying atoms in your body. In short, it’d be bad. Standing next to a nuclear reactor with inadequate shielding would probably be safer.
Oh, I’d like to add a short disclaimer for the above statement: I don’t actually know much about the number of protons/anti-protons that would collide with your body in this scenario, so the intensity might potentially be low enough that it won’t actually be that bad for you. And if the beam is focused tightly enough, it may only be bad for a small area of your body.
Dear Chris,
I’ll take your bet regarding the existence or non-existence of the Higgs. I’ll wager you that the Higgs will be found within the next five years with a mass in the range 115-120 GeV. If I lose you’ll receive 40 virgins for eternity, whereas if you lose you immortal soul belongs to me. Sound fair?
[...] be turned on (but not quite doing the full work, which starts in September), and the former wrote a great post illustrating what it is physicists hope to discover with it, and what looks likely/possib…. With the Large Hadron Collider almost ready to turn on, its time to prepare ourselves for what [...]
Jason,
My problem with renormalization? I’d rather not have to do it, that’s what. Ever heard of renormalized thermodynamics? Or renormalized electromagnetism? Exactly. Also I don’t accept that if enough people believe in something that it must therefore be right. As for the Higgs, the whole VEV thing is classical and makes no sense in quantum field theory, so it just comes down to what is - according to ‘t Hooft and Veltman - renormalizable. Well - that’s not a criterion for me.
Lucifer,
This is unfair. If it is going to be an asymmetric bet then it should be asymmetric in my favour. Having to deal with the squabbling of what would in effect become forty wives for the rest of time does not sound attractive at all. That would in itself be like losing the bet. I would rather wager real money. Come back when you are willing to do this.
Chris,
Well, if we knew physics to infinite energies, presumably renormalization wouldn’t be necessary. But we don’t know physics to infinite energies, so we have a problem. Presumably any theory that is accurate to infinite energies would be capable of predicting the experimentally-derived parameters in renormalization theory. But until we have the experimental data to discern what that theory is, we’re just going to have to deal with renormalization. As long as we can show that the process is independent of the energy cutoff we choose, this just isn’t a problem. Presumably our experiments will start to go wrong once we go above the energies where the new physics comes in, but anywhere below that renormalization will work just fine.
As far as VEV being classical, why on Earth do you think a purely quantum-mechanical description is classical?
So, what are the odds that the collider produces something that leaves all yall cosmic physicist types speechless for at least 10^-10 seconds? And how many would agree that constitutes a miracle, thus proving the existance of God? Whatever. I know jack about this stuff but I find reassuring the idea that since naturally occurring radiation produces no serious calamities then the collider shouldn’t either. bb
It would probably be best if detailed discussion of Chris’ ideas about QFTs were carried out outside of the comments section here - his email is probably available on his web page, or he can provide it briefly here if he likes.
How clear will it be if these predictions are vindicated or not? That is, for example, how likely is it that it will be ambiguous whether the results should be interpreted as a Higgs particle, or as SUSY? I’d rather see predictions phrased in terms that could be more clearly verified, as in “settling a bet”.
Jason,
I am disappointed to hear you trot out the party line on this. It is of course very common in any area of science or engineering to have to work with ad hoc models whose connection with the underlying principles is difficult or impossible to discern, but that does not mean one should give up the search for something better. Neither should one dignify such models with labels that would suggest they are axiomatic when they clearly are not.
Mark,
With respect, the topic of the discussion is what the LHC will find, and the consensus is pretty clear: a Higgs boson is much the most likely candidate. I am arguing against this on the basis that - as Jason Dick rightly points out - the underlying theory is suspect, and I am not convinced of a need for a real, new scalar particle. I think that this is relevant to the post. I have said nothing about my alternative proposals here. Neither do I intend to. OTOH I am quite happy to correspond by e-mail with anyone who wants seriously to discuss the issues. Mine is coakley@cgoakley.demon.co.uk
Robin, you are right, which I why I specified the chances that 5 years down the road most particle physicists will agree that the thing had been discovered. It’s hard to be more objective than that, since the threshold of discovery/non-discovery will always depend on someone’s judgment about how likely a certain explanation is vs. some other explanation. (Some people still don’t believe the universe is expanding.)
Some things won’t be easy to identify — dark matter definitely won’t be, and the Higgs isn’t easy itself, but it’s been studied so thoroughly that we have a pretty good idea what the signals are. Supersymmetric particles are relatively easy to discover, but you won’t be able to call it “supersymmetry” with confidence until you get several particles following some pattern.
[...] out Cosmic Variance’s list of possible discoveries and the probability of each discovery being made in the next five years at the Large Hadron [...]
Renormalization from a physical point of view is simply rewriting the theory in terms of macroscopic observables, as explained by Wilson in the early 1970s. As Jason explained, in case of QFT we don’t know the theory at infinite energy (i.e. at zero length scale). The renormalized QFT is simply an effective theory in which you express everything in terms of physical observables. For renormalizable theories the details of what happens at small length scales drops out.
As such the remormalization process is not anything strange at all. You mentioned electromagnetism, but there you do work with coarse grained electromagnetic fields when considering dielectrics. In the late 1800s people like Lorentz tried to build a fully consistent classical theory of electromagnetism by taking into account the back reaction of radiation. They were led to consider renormalized mass etc. for electrons.
Renormalized thermodynamics? Well, that’s what we do when we describe critical phenomena, phase transitions etc. This in fact led to Wilson to his physical interpretation of the renormalization process, the renormalization group etc. etc.
It will be discovered that there is more unknown than ever before.
This has ever been so.
Hi Count,
(i) This is getting off-topic - see Mark’s comment above
(ii) I try not to get into arguments with people who will not identify themselves
Minor nitpick on Count Iblis’ post:
Renormalized QFT doesn’t express everything in terms of physical observables. It just expresses these high-energy/short-length parameters in terms of physical observables.
[...] science blog Cosmic Variance has a great rundown of what the LHC could find. At the top of this list is the Higgs boson, which is the only particle in the Standard Model (the [...]
Here is the calculation of the probability that you won’t find any of the stuff you listed before “absolutely nothing”:
Probability of *not* finding the Higgs Boson: 5%
Probability of *not* finding Supersymmetry: 40%
Probability of not finding either the Higgs Boson or Supersymmetry: 5% * 40% = 2%
Using the same general reasoning, we can compute
0.05 * 0.40 * 0.99 * 0.90 * 0.999 * 0.9999999999999999999999999 * 0.995 * 0.85 * 0.999 * 0.95 * 0.98 * 0.98 * 0.99 * 0.85 * 0.998 * 0.99 * 0.995 * 0.99999999999999999999 * 0.5 * 0.98 = 0.005 = 0.5%, which is pretty far from your listed 3%.
The moral of story? We’re gonna find something! (Assuming all those probabilities are independent, which is not strictly true. If the project gets shut down, then obviously none of that stuff will be found.)
@mark #9
actually, there are scenarios that sphaleron induced baryon number violation might be a feasible process in colliders (e.g. hep-ph/9601260)
Sean, I offer a snarky critique here.
Hi Chris. I know that paper, and it is careful work, if I recall correctly. But the results actually aren’t very encouraging. The main problem faced by any such question is that the sphaleron (or something close to it) is basically a highly coherent collection of something like 30 W bosons and phase space constraints mean that one doesn’t make it likely to see B-violation at colliders.
[...] 11th, 2008 What will the controversial Large Hadron Collider (particle accelerator) find? From Cosmic Variance: The Higgs Boson: 95%. The Higgs is the only particle in the Standard Model of Particle Physics [...]
Regarding a fictionalized account of a mini black-hole swallowing the earth, there’s ‘The Hole Man” a short story by Larry Niven:
http://www.ebookmall.com/ebook/89154-ebook.htm
This story was written before the concept of Hawking Radiation was popularized and wouldn’t be scientificially accurate by today’s standards, but it is fun nonetheless.
Incidentally, I completely agree with the idea that the odds of the LHC producing a black hole that would destroy the Earth are vanishingly small. The existence of Cosmic rays with energies far higher than what any Earthbound collider could impart clinches this for me.
[...] What Will the LHC Find? | Cosmic Variance What Will the LHC Find? | Cosmic Variance [...]
Para que va a servir el LHC [eng]…
y no es para acercar el fin del mundo. Un analisis detallado, interesante, bien explicado y muy completito de las cosas que nos puede mostrar el LHC con la probabilidad correspondiente. 100%: antimateria (hace mucho que esta descubierta, chicos); 95%: …
And Stargates? Will the LHC create a wormhole to another world?