The ICHEP Effect

I created a tool that watches how many plots DZERO, CDF, ATLAS, and CMS release as a function of time. Here are the results for this year (each little square is a plot):

I’m going to call that bump in July there the ICHEP effect.

How can there be no questions?

I’m sitting here, on the last day of ICHEP, listening to some excellent summary talks. One of the experimental neutrino talks just went by – excellent (sorry, no link because I don’t have internet as I write this). But there were no questions. I’ve noticed this for many of the talks at the plenary. Or if there is a question, it is the “if you doubled your dataset what would happen to that 2 sigma excess?”

How can this be? There are almost 1000 people watching these talks, many of them experts in the topics being discussed. And no questions? Physics is built on questions! This is how we learn – almost never is something so clear that we don’t need questions! Heck, the whole field is structured around this. We invite experts to our University to give a seminar so we can have their undivided attention for a whole day to ask them questions. We go to workshops so we can ask each other questions and learn. We write papers and then respond to the papers with letters and more papers which are basically a slow version of Q&A. So what is going on here?

I don’t know, of course, however I’m going to take a stab:

• Exhaustion. It is the end of a full week of conference. We’ve all be talking, discussing, and thinking about these topics for a solid week and we need a break for our brains to process everything.
• Embarrassment. There are 1000 people here. Many of them very important people in the field (i.e. they think you are stupid and your chances of funding go down). So you’d better make sure you have a good question before you ask it.
• These are summary talks. The speaker is often presenting a huge amount of information in a very short amount of time. It is likely they are an expert in the topic they are presenting, but given the volume of information discussed in such a short amount of time, it is not likely they know all the details. The people who are experts on each topic gave talks in the plenary sessions. Indeed, there were lots more questions there than there are in the plenary sessions.

I’m sure there are other possibilities as well.

A fun way to browse ICHEP talks

One of my hobbies is better ways to visualize information with modern computers. Those of you that have followed me know about my efforts with DeepZoom. So, ICHEP is being rendered this way as we speak.

If you click on the link above your browser will load up a very large image using Sliverlight (which you’ll need to have installed: Windows and Mac computers only, I’m afraid). You’ll see about 400 talks all displayed at once. You can then use your mouse and mouse wheel to zoom in to see a particular talk. Your browser should load up the bits of the talk you are looking. You can click on a slide to bring it full screen and use the back and forward arrow keys to move around.

BUT: you need a decent computer, decent graphics card, and, above all, a decent internet connection. In short, no one at ICHEP can look at this display because the internet connection is not robust enough (I’d add a picture here but I’m at ICHEP and can’t load it up right now!).

The display is updated about once every 4 hours, so as the plenary talks continue they should slowly show up there in that display.

Enjoy!

A Big Day

I was going to post this before anything started this morning, however the ICHEP committee decided not to purchase wifi in the main conference hall, so it took until now for me to have time to post this….

Today is the first day of plenary talks at ICHEP. Up to now it has all been plenary sessions – and there have been a lot of talks. Now everything collapses into one room. And it is a very big room. I don’t think I’ve ever been in a room this big for a physics conference before.

Several things happen today – but two I’m particularly interested in seeing are the final combination of the Tevatron Higgs searches and a speech by the president of France, Sarkozy.

Sarkozy's speech was much better than I was expecting! He and his speech writers had worked together to craft a quite good message. One part was a vigorous defense of why it is a good idea to invest in science now even though there is a financial crisis on. Basically, his message boiled down to: a country can not ignore the future for the crisis of the present – there is always a crisis of the present. A message I wish more of the legislators in the state of Washington would get. The second half of his message was the details of the investments that France is making. You can’t always trust the numbers that politicians give you in settings like this, but one stuck out: a reinvestment in Saclay – one billion Euros in the next 10 years.

The second thing I’m looking forward to are the combined results from the Tevatron. You can guess what will happen when you look at the CDF and DZERO higgs talks (which I’d link to if there was any wireless at all here!). Both experiments are basically excluding the region around 160 GeV on their own, and both have a downward fluctuation at low mass.

Update from the Higgs talk:

Ben’s fashion choice: Tour de France yellow tee shirt along with a suit jacket. Nice!

High mass region: from 158 – 175 GeV is now excluded (about x4 bigger than before).

Low mass region: Starting to exclude the really low mass region as well now. Expected limit is around 1.2 or 1.4 or so. But the exclusion right now looks like a fluctuation low, so it will be very interesting to watch the next update 6 months from how. The expected is getting quite close to expected SM cross section! Sweet!

The Practice Talk

ICHEP is tomorrow, and I write this just as I’m about to jump on a TGV to transport me from the South of France (Marseille) to Paris. For an experimentalist the last several days have been full of practice talks (and they will continue to go on past the start of ICHEP). Everyone gives them from the most senior person on down.

That might seem funny… Even senior well established people give them. The reason is pretty simple: often it saves your bacon! This is especially true for the large overview talks that many people have to give. These are long – sometimes as long as 45 minutes, and frequently cover material that the person given the talk is not expert in. See the many CDF/DZERO combined talks that will occur at ICHEP. Since you can’t be a member of both experiments there is no way one person can possibly be an expert in both experiments! The practice talk is a chance for the two experiments to sit in the same room and give the speaker advice, tell them extra information in case they get a tricky question, etc.

The other thing it does is teach. This is especially true when you are just starting out. In experimental particle physics we are constantly giving talks to our colleagues – those on ATLAS or perhaps on CMS, depending on which experiment we work. But these talks are full of jargon (“B layer”, “layer zero-zero”, etc. – who is going to guess what those are and what experiment??). Sometimes we get so used to the jargon we forget it is jargon. When I was a graduate student and beginning post-doc I had a lot of trouble with this. Practice talks were a great way to have people spot it.

Another thing is TIME. Ugh. The clock. When you are giving a talk about 50% of your concentration is focused on delivering the material, watching the audience to see if they are falling asleep, or they looked confused or puzzled. The other half is constantly checking the clock and the slide number to make sure you are still in sync. The good folks who run the session are charged with one thing above all: keep it on time. And if you go over, they can get pretty aggressive. This can be difficulty because usually the most interesting slides are the ones that come last – they contain the punch-line, the measurement, THE PLOT. So, it sucks to have to rush through that!

Finally, the old maxim: practice makes perfect. By forcing you to have a draft of the talk several days ahead of time, you have several days to do polish work. Rather than just getting the major parts of the talk up the night before you have to give it.

I remember when we started doing practice talks in DZERO – the average quality of our presentations at conferences went way up! I don’t know of any large experiment that doesn’t do this now.

How about theorists? What do they do…? :-)

Rumors

Who doesn’t love a little gossip every now and then? Tommaso, as is usual for his style, started one the other day – that the Tevatron claims to have seen a light standard model Higgs. For whatever the reasons (both positive and negative) this one caught like wildfire. You know its big when it shows up on this site!

But to make this really work – and I mean really work in that rumors provide some sort of science payback – you need a conversation. Someone has to say the rumor (to start it). Then someone else picks it up and perhaps spreads it. But then people want to join in on the conversation. For example - “there is no way that can be true because of x, y, and z”, and then someone else says “ah – but you forgot that x can be zero, and if that happens then y and z don’t matter, and this becomes possible once more! Ha!” And so on.

That part of the rumor and gossip conversation I do consider useful. For one thing, it makes the gossipers smarter. Assembling the set of critical arguments to work out the possibility that a rumor is true or not often takes some pretty deep knowledge of the field. And from this discussion new ideas can come as well. For example, I learned quite a bit by watching the gossip and speculation after the CDF forward muon results (shoot, I can’t find a link for that result!) and DZERO same sign asymmetric muon results were released.

Which brings me to the real reason I’m writing this result. That conversation. Currently I see it on Facebook. Seriously! In my circle of friends there are a bunch of experimentalists and theorists who get into some pretty serious discussions using nothing more than one or two lines of text – or perhaps a paragraph. It is excellent. Facebook does an excellent job of re-creating the water cooler – a bunch of people standing around. Though it is better – even if you have to be busy in a meeting or teaching a class you can skip out and rejoin the conversation and read up on what everyone said! This style of conversation is also very important for someone like me: who is constantly traveling and can’t always drop by an office to catch up on the latest.

Before Facebook this happened mostly in blog comments. It still does, and the quality is quite high there, but it seems like it moves more slowly. How about twitter? I did a search over there, and there is lots of chat. But the quality level is pretty low – it is mostly people riffing of the idea or pointers to articles, etc. Are there other places people discuss this sort of thing, but at a physics level? Or perhaps better ways to use tools like twitter to find good conversation? Where else do these conversations occur in the modern digital world?

Favorite Higgs joke seen on twitter. :-)

P.S. It is almost impossible for me to participate in this particular rumor/gossip because I am an active member of DZERO, one of the two Tevatron experiments. No matter what I say, I’m screwed. So, best not to say anything. Sorry if you came to this post expecting something else!

The ICHEP Shuffle

Or maybe it should be called the ICHEP Crunch. We are one week out now. And from an experimentalist at-a-large-collider-experiment’s point-of-view, ICHEP is almost settled. The almost-final versions of all the plots are prepared, the supporting text sanitized of jargon is being fine-tuned, and the large collaborations are getting their last review in of the results. Heck, even some early results are staring to trickle out (CDF has released a two mass Higgs searchs: WH and ZH associated production (no excess!!) and a search for a standard model higgs decaying to taus (find all CDF results here), and DZERO has a search for a t’ quark (find all DZERO results here).

It feels a little bit like the ‘night before Christmas. It is the calm that is so spooky… Which is in direct contrast, of course, to what is going on outside the experiments in the papers and other blogs…

I’m fortunate enough to be on two of the experiments, ATLAS and DZERO, and on each experiment I’m participating in two sides of the shuffle. On DZERO I have a student working on getting one of the results ready. I bet that the “ICHEP deadline” was first talked about almost 6 months ago. That is about the time that the pressure started building for the folks doing the real work in the experiments. Ever since then each time someone wants to add something new, or spend the time to better understand and reduce a systematic error, they have to ask themselves “does this mean not releasing it for ICHEP?”*

In ATLAS I help run one of the groups producing results. This is management, not physics I’m doing there. The goal for people doing this task is to make sure that all the results are high enough quality to enter the review process. Sometimes this means convincing people to drop a plot, or add an extra plot. By the time someone like me gets heavily involved in the day-to-day of the analyses being prepared we are getting very close to the internal review process.

Back on DZERO I’m also helping out with one of the reviews of an analysis. Once the analyzers have put the finishing touches on their analysis, and the people running their physics group give the ok, the analysis is handed off to an internal review group. These people are meant to be independent reviewers of the analysis, and are supposed to go over it with a fine-toothed comb. Unlike external reviewers, they have access to all the internal information of the experiment. The review is based on an “analysis note” and supporting documentation. Just the note can be 100’s of pages long in case of a complex analysis (Like the Higgs searches from CDF I mentioned above). If no problems are found this review probably takes about a week. But a fresh set of eyes always turns up new problems. It is very intense time for the reviewers and the analyzers: the reviewers send questions, and the analyzers respond as fast as they can so that the review doesn’t get stuck and miss ICHEP. BTW, if you watch the experiments you’ll often see one or two or three analyses come out just after ICHEP – these are the ones where an issue was raised and couldn’t be addressed in time to make it for the conference.

Finally, with that done, the ICHEP shuffle enters its last phase: collaboration review. The now perfected analysis along with documentation suitable for everyone to read (which may be a journal paper draft) is thrown up on an internal web page and a message is broadcast to the complete collaboration (all 600 for DZERO or 3000 for ATLAS): “Our experiment is going to release this work – this week is the last chance to raise issues before it is made public!”

At the same time this review is on going everyone is putting together their ICHEP talks, running practice talks to make sure they are high quality, and answering questions that come in from the collaboration. A popular analysis can get 100’s of comments, for example (an unpopular one might get just a few). Each comment must be reviewed and answered by the analyzers and the answers cross-checked by the internal review. At the same time public web pages are being prepared with high quality versions of all the plots and links to the supporting text and documents.

And then ICHEP starts!

So… you might ask… what defines the length of the ICHEP Shuffle? Which is about 6 months? At the two ends of the year there are two large sets of conferences. ICHEP this year is in the summer, and in the winter is the Morriond series. I’ll bet you good money that I’ll see emails with the title “Morriond Analysis Planning” hitting my Inbox the week after ICHEP is over.

But, for us in these large collider experiments, ICHEP is the breather between the dances. A chance to relax, look around, see what everyone else is doing, get some new ideas, and maybe even explore Pairs!

Physics at the LHC – What did Guido mean!?

My summer has started. And the first stop is the conference Physics at the LHC 2010 conference (or pLHC as it has been known internally by the experiments).

As Barbara already mentioned, this conference, occurring this week in Hamburg, Germany, is a preview of results we might expect at ICHEP.

It is Wednesday morning and all the LHC experiments have big plenary talks discussing overviews of their physics current results. One of the CMS results has already been discussed by Tommaso. The results all show the first time the experiments are gingerly dipping their foot into the pool of physics. Ok, so it is the shallow end right now. Observation of many quark-onia bumps, but some real new measurements not done at the LHC’s new higher-than-ever energy, 7 TeV. But they also include the first observation of the W boson and the Z boson at the LHC. Now we’re talking!

One fascinating conversation occured right at the start of the meeting. It was a discussion that occurred during the introductory talk by Guido Tonelli, the spokesperson for CMS (video available). Sitting in the audience was Steven Myers from CERN, who runs the LHC (who also gave a talk on the present and near future of the LHC machine). Both Guido and Fabiola Gianotti (ATLAS spokesperson) pleaded with Steve to give them more luminosity. Guido went one step further and said that if they can give CMS enough luminosity in the next month they will measure the Standard Model for ICHEP.

What does that mean? Both experiments have observed the W boson now. Does that mean measuring its cross section? Or an observation of top quark production? Is there any reasonable plan for the LHC that would give it enough luminosity to observe top quark production!? Or was it just a flashy statement made to urge Steve to give the experiments more data? Does CMS have something up their sleeve? I guess time will tell… And both CMS and ATLAS will do push their data as far as they can.

Update: at the end of the CMS talk, slide 54, there is the statement “100 nb-1, 380 W and 35 Z”, and the speaker said “this we can be sure of.” So, that gives the scale of the CMS plans. And lets hope the LHC can actually give us that 100 np-1 of data!

Late to the party…

Hi all! We are now about 6 weeks out from the start of ICHEP, and this is my first blog post. So introductions are in order. I’m a professor at the University of Washington, located in fantastic Seattle (we only tell people it is raining…). I’m an experimentalist working on the DZERO experiment at the Tevatron and the ATLAS experiment at the LHC.

I maintain another blog (sporadically). If you read through it you’ll quickly discover my main interests. I love high-pT physics. DZERO’s recent B’s mixing result (see Jester’s earlier posts on it here and here) is fascinating, but sadly aren’t things I work on. I tend to be more interested in top, Higgs physics, and, recently exotic physics. On the flip side I’ve long been fascinated with computing in HEP, having started in high school programming a LeCroy FASTBUS microcontroller (yeah, yeah, tell me about it, I didn’t get out much).

This year’s ICHEP should be special for the LHC and the Tevatron experiments. I know this because of how busy everyone is in the experiments… More on that in a future post.