Posted: July 7th, 2010
Pop-Up Particle Physics from the Large Hadron Collider

Alan Alda moderates as leading physicists Lisa Randall (Harvard) and Michael Tuts (Columbia), join CERN’s Emma Sanders to explain new science coming from the Large Hadron Collider in Geneva, Switzerland. In particular, they share details of the ATLAS Experiment, a particle physics experiment that began earlier this year searching for new discoveries in the head-on collisions of protons of extraordinarily high energy.

ATLAS will learn about the basic forces that have shaped our Universe since the beginning of time and that will determine its fate. Among the possible unknowns are the origin of mass, extra dimensions of space, unification of fundamental forces, and evidence for dark matter candidates in the Universe.

Voyage to the Heart of Matter is a pop-up book that Sanders has authored with pop-up engineer and illustrator Anton Radevsky about the science of CERN’s Large Hadron Collider, focusing on the ATLAS experiment. In this unique collaboration, 7,000 tons of metal, glass, plastic, cables, and computer chips leap from the page in miniature pop-up, to tell the story of CERN’s quest to understand the birth of the universe.

This event is presented with the support of the Consulate General of Switzerland. Deputy Consul General Sabine Ulmann Shaban, representing the home country of the Large Hadron Collider, will make opening remarks.

Recorded on May 25 at the New York Academy of Sciences.  Total runtime: 98 minutes.

  • Andrian

    We think this is the Higgs . They chose not to. If you look at Matt’s posting on the Chi_b(3P) today, it tells us that the exnerimepts are not afraid to announce a discovery, provided they believe the case is solid. Second, it is hard to underepmhaisze how fast this turnaround is. Run II of the Tevatron began on March 1st, 2001. Their first paper was submitted on July 29th, 2003. The 2011 LHC proton run ended on October 30th. That leaves ten weeks for the data to be reconstructed, calibrated and aligned, analyzed, compared with Monte Carlo, cross-checked and discussed. I get the feeling that people think that once the data is collected the exnerimepts have their answer. Nothing could be further from the truth it takes hundreds of people to ensure that by the time they make their final plots, the data, calibration and analysis is all understood and can be trusted.In a related point, the exnerimepts continue to make progress in calibration, alignment and analysis. These improvements will mean there will be events that are in the plot that will move out, events that are out of the plots that will move in, and events that stay in may move to somewhat different masses. With a robust signal, on average this will improve things. With a small number of events, tiny changes in where and how many the events are can make substantial changes to the significance. If I paraphrase the argument as follows: ATLAS has a large excess (indeed, larger than one would expect from a SM Higgs, by about a factor of 2), and while not convincing in and of itself, just look at all the statistically marginal effects in the exact same spot. What are the chances of that? The odds of the statistically marginal effects moving around may be higher than you think. We don’t know, and won’t know until the exnerimepts apply the latest calibrations, but it would not surprise anyone on the experimental side to see substantial effects in the significance plots from these small changes to the analysis. Anyone in this field long enough has seen this happen time and again. This is part of what Preliminary means. To stretch an analogy, just as nine women can’t have a baby in one month, you can’t make a significant and credible peak by combining a lot of marginal ones. And, like the baby, you can’t rush things it will take time for the final calibrations to be done, it will take time for all the channels to be included, it will take time for a proper combination between both exnerimepts to be done, and in all probability it will take more data. We know how much data on average it should take for a discovery in this mass region, and it’s quite a bit more than what’s been collected.Third, Matt is absolutely right that one should distinguish between evidence and expectation. And finally, one needs to remember what a sigma it is. It is a measure of how consistent one’s data is with the null hypothesis, which in this case is there is no Higgs, only a background that is perfectly predicted by theory and perfectly simulated in our software . Statistically rejecting the null hypothesis is a necessary but not sufficient condition for discovery, and the question how many sigmas is only part of the story.Give it time. By 2012 we will have a much clearer picture of what is going on. We’ve waited more than 30 years, a few more months or a year won’t kill us.