“The pentaquark is not just any new particle,” said LHCb spokesperson Guy Wilkinson. “It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.”
Here’s the paper, with more than 680 authors. Between New Horizons zipping past Pluto earlier today (look at this pic!) and this, what a day for science.
Last year (spoilers!), CERN confirmed the discovery of the Higgs boson. Physicist-turned-filmmaker Mark Levinson has made a film about the search for the so-called God Particle. Particle Fever follows a group of scientists through the process of discovery and the construction of the mega-machine that discovered the Higgs, the Large Hadron Collider. Here’s a trailer:
Two additional data points: the movie is holding a 95% rating on Rotten Tomatoes and legendary sound designer and editor Walter Murch edited the film. Particle Fever is showing at Film Forum in New York until March 20. (thx, james)
“We observe in our data clear signs of a new particle, at the level of 5 sigma, in the mass region around 126 GeV. The outstanding performance of the LHC and ATLAS and the huge efforts of many people have brought us to this exciting stage,” said ATLAS experiment spokesperson Fabiola Gianotti, “but a little more time is needed to prepare these results for publication.”
“The results are preliminary but the 5 sigma signal at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” said CMS experiment spokesperson Joe Incandela. “The implications are very significant and it is precisely for this reason that we must be extremely diligent in all of our studies and cross-checks.”
How sure are they that they’ve found the Higgs? Brian Cox notes on Twitter:
5 sigma is the usual particle physics threshold for discovery. It roughly means that you’re 99.9999% sure
As a naturalist, da Vinci probed, prodded, and tested his way to a deeper understanding of how organisms work and why, often dissecting his object of study with this aim. “I thought, why not present the idea of data analysis to the world within the naturalist world of Leonardo?” Cittolin says. In the drawing below, the CMS detector is the organism to be opened; the particles passing through it and the tracks they leave behind are organs exposed for further investigation.
Cittolin brings a sense of humor to his work. For example, after betting CMS colleague Ariella Cattai that he could produce a quality drawing for the cover of the CMS tracker technical proposal by a given deadline, he included in the drawing a secret message in mirror-image writing-which was also a favorite of da Vinci’s. The message jokingly demanded a particular reward for his hard work. The completed picture was delivered on time and within a few hours Cattai cleverly spotted and deciphered the message. She promptly presented him with the requested bottle of wine.
The teams are sworn to secrecy, but various physics blogs, and the canteens at Cern, are alive with talk of a possible sighting of the Higgs, and with a mass inline with what many physicists would expect.
Since the Higgs’ nickname is the God particle, does this count as the Second Coming? (@gavinpurcell)
“We are now entering a very exciting phase in the hunt for the Higgs boson,” Sharma said. “If the Higgs boson exists between 114-145 GeV, we should start seeing statistically significant excesses over estimated backgrounds, and if it does not then we hope to rule it out over the entire mass range. One way or the other we are poised for a major discovery, likely by the end of this year.”
By smashing together lead ions instead of protons, researchers at the Large Hadron Collider have produced a “mini-Big Bang”.
The collisions obtained were able to generate the highest temperatures and densities ever produced in an experiment. “This process took place in a safe, controlled environment, generating incredibly hot and dense sub-atomic fireballs with temperatures of over ten trillion degrees, a million times hotter than the centre of the Sun.
“At these temperatures even protons and neutrons, which make up the nuclei of atoms, melt resulting in a hot dense soup of quarks and gluons known as a quark-gluon plasma.” Quarks and gluons are sub-atomic particles — some of the building blocks of matter. In the state known as quark-gluon plasma, they are freed of their attraction to one another. This plasma is believed to have existed just after the Big Bang.
“If you want to discover new particles, you have to produce them; and these new particles are massive. To produce them, you need higher energies. For the first time [on Tuesday], we will be producing particles that have energy 3.5 times higher than the maximum energy achieved so far. […] At the end of the 7 TeV (3.5 TeV per beam) experimental period, the LHC will be shut down for maintenance for up to a year. When it re-opens, it will attempt to create 14 TeV events.
However, if the theorists are right, before it ever finds the Higgs, the LHC will see the first outline of something far bigger: the grand, overarching theory known as supersymmetry. SUSY, as it is endearingly called, is a daring theory that doubles the number of particles needed to explain the world. And it could be just what particle physicists need to set them on the path to fresh enlightenment.
If you haven’t been keeping up with particle physics for the past few years (as I haven’t), this will bring you up to speed a bit.
Are the problems that have plagued the Large Hadron Collider and previous high-energy efforts (SSC, I’m looking at you here) a result of the Higgs boson travelling back from the future to meddle in its own discovery? A pair of scientists think it’s a possibility.
“It must be our prediction that all Higgs producing machines shall have bad luck,” Dr. Nielsen said in an e-mail message. In an unpublished essay, Dr. Nielson said of the theory, “Well, one could even almost say that we have a model for God.” It is their guess, he went on, “that He rather hates Higgs particles, and attempts to avoid them.”
This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an “anti-miracle.”
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 list also functions as a nice overview of what’s happening at the edges of our physics understanding. (via 3qd)
A pair of articles on the Large Hadron Collider at CERN: A Giant Takes On Physics’ Biggest Questions and Crash Course. The LHC will hopefully provide the 1.21 gigawatts 7 trillion electron volts needed to uncover the Higgs boson, aka, The God Particle. “What we want is to reduce the world to objects that have no structure, that are points, that are as simple as we can imagine. And then build it up from there again.”
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