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Working hard at Canada’s Perimeter Institute, that is.   Longer posts are on hold for a couple of days while some friends and I stuff our brains with the details of as many ATLAS and CMS papers as we can handle.  We’ve gotten through fifteen or so, I suppose, on several topics.  Already I have learned a lot about the Higgs searches and the supersymmetry-like searches, which eventually will make their way onto these pages.   There are many devils in the details…  In the meantime, in case you’re interested, I did a small update to the article on the  implications of current data for Higgs particles of various types.

I’ve started a new article [click here] that tries to lay out the scientific implications of the Large Hadron Collider searches for the Higgs particle, as of early September 2011.   It’s a work in progress, so there will be more to come.  So far I’ve considered the implications for the Standard Model itself [recall the Standard Model consists of the known elementary particles and the simplest possible Higgs field and particle], and for variations on the Standard Model in which nature has a few extra types of particles that we don’t know about yet.  I’ll get to more complex cases, including supersymmetry and its five Higgs particles, later.  But I’ll bet that you will already be shocked at how different is the case of the Standard Model itself, which is easy to discuss succinctly, from even the simplest variants of the Standard Model.

The Lepton-Photon 2011 conference in Mumbai is just getting ready to start.  Unlike the EuroPhysics conference in Grenoble last month, the number of experimental talks is small — and the talks are short.   So it’s all going to go by very fast.  We’ll get our full dose of Higgs searches at the  Large Hadron Collider (LHC) and Tevatron this morning (Monday), and searches for other types of novel phenomena (including top quark physics, supersymmetry, extra dimensions, etc.) tomorrow.  And then the topics will switch to other types of experiments (neutrinos, dark matter, collisions of heavy ions, and cosmic rays), until Saturday.

Although in principle the amount of data collected at the LHC has roughly doubled between Grenoble and Mumbai — a great achievement — you should not assume that the LHC experimentalists have had sufficient time to analyze it all.   In fact many studies presented in Grenoble did not use anywhere near the full amount of data that they had back then — I expect we will see many of those studies updated in Mumbai, but probably only for half the current data.  So there will be only a few results, I suspect, that use all the data.  Some of the Higgs studies might be among them, so that will be quite interesting.  We are likely, if Higgs results with more data are presented, to see more of the heavy-Higgs region excluded by the data than we saw at Grenoble.  We are unlikely to see anything clearly pointing toward discovery at this point — the hints will probably shift but remain hints for now.  I think we would probably need to double the data again first before things become clear.  But that will happen soon enough; by the end of the fall, perhaps?

Stay tuned for more news today….

8/21/11

Once you’ve read about the elementary particles of the Standard Model of particle physics — what we know about the world so far — you might want to learn something about supersymmetry — a speculative idea, whose proponents hope it will resolve several important puzzles about our world.   I’ll get back to the puzzles, and whether and how supersymmetry might solve them, soon.  Today’s article talks a bit about what this symmetry is, what its consequences are for particle physics, why an important bit of trickery is needed to hide the symmetry from obvious view, and how that trickery changes the particle physics implications.

As part of this article, I’ve put up a post about the difference between fermions and bosons.  So those of you who have wondered Why is the Higgs particle called the `Higgs boson’?  now get a chance to find out!

A couple of days ago I posted an elementary article on the elementary particles — an introduction to the particles of the Standard Model of Particle Physics, focusing on how they interact with one another.

Now I have an article for you on how drastically the particles and forces would be rearranged if the Higgs field were zero  in nature.   It’s pretty remarkable, actually, if you’ve never seen it before!  A surprising underlying organization emerges in this imaginary zero-Higgs-field world.  And by looking at how things differ between the real world and this imaginary one, it is possible to glean some insights into how the Higgs field is able to give mass to the known particles, and how it thereby determines the properties of the weak nuclear force.    And you can also learn about a number of interesting issues that continue to puzzle particle physicists.

Hope you enjoy it!

Today’s new article on the known types of particles attempts to set forth the particles of nature in a couple of different ways, ones that I hope will give you insights into why particle physicists categorize the particles the way they do.

The article describes the particles of the Standard Model of Particle Physics, which consists of all the known apparently-elementary particles and the simplest possible Higgs particle.   The name Standard Model just means: this is the simplest set of equations that can fit all the data we have gathered over decades, and that repeatedly makes correct detailed predictions for new experiments (despite occasional hints to the contrary, for instance this one, which unfortunately have tended to vanish over time.)

Sometimes this collection of types of particles is called the Particle Zoo.    Is there some hidden structure that underlies it?

Soon I’ll provide another post showing how this somewhat disorganized array of particles would have been much more simply organized were it not for the Higgs field.  What is the secret story behind this wily Higgs field?!

Correction below — a couple of readers pointed out that I had read a misquote of what Rolf Heuer, director general of CERN, had actually said.  I’ve updated the post to reflect what he said and why he said it, though the main point of the post doesn’t change at all.

I’ve left the EuroPhysics conference … With 400 talks, and a hundred or so from the Tevatron and the Large Hadron Collider, it was information overload.

There are two more days of summary talks at the conference, and tomorrow (Wednesday) afternoon there will be a bit more on the Higgs particle search.  A combination of the DZero and CDF Tevatron results will be presented, and perhaps a preliminary combination of the ATLAS and CMS results at LHC.  [I won’t be there, so don’t look for the update as it happens…]  The combinations can be done roughly in your head by looking at the various experiments separately, so there should be no surprises.

The one thing I want to remind you, in case the press makes a big deal out of what is said on Wednesday, is that what has been done so far to obtain a hint of a Higgs signal involves a very difficult measurement.   [Soon I’ll write an explanation of what I mean by this, but for now you can read more about this here. ]  The experimentalists are well aware of that, and say so both in public and in private.   I believe I saw the director general of the CERN laboratory quoted as saying this will all be cleared up by the end of the year.  UPDATE: This was indeed what I saw, but what I saw was itself a misquote; Heuer actually said “it” will be cleared up by the end of next year.   Either statement is true, depending on what “it” is.

• If “it” means finding or excluding the Standard Model Higgs particle (remember that’s not the most general Higgs particle, see the Higgs FAQ) then that may not be fully settled until late next year — though in saying “end of next year” Heuer is being suitably conservative.
• If “it” means figuring out if the current hint of a Higgs particle signal is a mirage or something real, that is probably something that will start to be settled between this December and next June.

Either way, [and here we return to the original post]  notice what this also implies: this [meaning the current hints] will not be cleared up much before the end of the year.  Science requires patient work, especially when the methods are challenging and fraught with subtleties. (more…)

A second video excerpt from my public talk “A Ring of Truth”, given last March, is now available.  I have put a link to it on the “Movie Clips” page.  This excerpt explains briefly why the Higgs is important (even to you), what the Higgs field does in nature, and how particle physicists make and detect rare particles.   [Things will be clearer if you watch excerpt 1 before watching excerpt 2.]