dimensions volume 05 of particle physics symmetryA joint Fermilab/SLAC publication issue 05 november 08 volume 05 | issue 05 | november 08 On the cover In the last few months of the BaBar experiment at SLAC National Accelerator Laboratory, scientists pulled one last trick out of their bag and produced a new particle— the bottom-most bottomonium. In doing so, the 500-member symmetryA joint Fermilab/SLAC publication collaboration proved as agile as its cartoon namesake. Highlights from our blog, www.symmetrymagazine.org/breaking/ Crunch time for Joint First gamma-ray-only Large Hadron Collider’s Computing in a grid Dark Energy Mission pulsar observation ATLAS in Second Life or a cloud October 14, 2008: Last October 16, 2008: About October 22, 2008: A dedi- October 24, 2008: With month’s surprise cancella- three times a second, a cated LHC fan has recre- two relatively new models tion of the competition 10,000-year-old stellar ated the ATLAS experiment of computing floating about, to develop the Joint Dark corpse sweeps a beam of from the LHC in Second many commentators have Energy Mission left gamma-rays toward Earth. Life. This is done in the spirit been discussing the pros researchers stunned. Now This object, known as a of fan art, but I can tell you and cons of each, as if it the former competitors have pulsar, is the first one known from having been in the were a face-off with only less than two months to to “blink” only in gamma ATLAS cavern while it was one likely to be the victor come together and redefine rays, giving scientists new being built that this does a in a fight for dominance. what the mission should insights into how stars work. very good job of the look A new analysis argues that accomplish. and feel of the real detector. the two technologies are complementary. contents 02 Editorial: Starting up the Large Hadron Collider The Large Hadron Collider successfully circulated beams for the first time in September. That wonderful achievement moves the LHC toward first collisions and physics results, but other labs are still working hard in friendly competition. 03 Commentary: Kate McAlpine “I think rap is a good way to communicate. Rhyme has always helped embed words in my mind; hopefully science rap can help cement ideas in the minds of students and other interested people.” 04 Signal to Background Giving a hoot about restoration; open access to galaxies; ask a Nobel laureate; a collider inspires comic artists; Google commemorates the LHC first beam; eclipse chaser; letters. 08 BaBar and the Very Tiny Particle In which the 500 members of the BaBar experiment buy enough time for one last adventure: capturing the bottom-most bottomonium. 14 The Dark Universe Debate Who will be the first to prove the existence of dark matter and dark energy? A particle physicist and an astrophysicist go head to head. 20 Where Old Physics Stuff Goes to Live The Fermilab boneyard is no burial ground; it’s a place where unwanted parts find new homes and lives. They’re matched with scientists who can put them to good use, donated to local schools and parks, or sold for recycling. 28 Q&A With eta sub b symmetry’s Calla Cofield scores an exclusive interview with the particle…the ground state…the artist eta sub b, who recently emerged into the public spotlight after 30 years in hiding. 32 Essay: Robin Hanson “Today’s LHC forecasts are no easier to score than the typical horoscope.” C3 Logbook: LHC Startup On September 10, 2008, scientists at the European laboratory CERN attempted for the first time to send a beam of particles around a new particle accelerator, the Large Hadron Collider. C4 Explain it in 60 Seconds: Magnet Quench A magnet quench is a dramatic yet fairly routine event within a particle accelerator. In the case of a large superconducting magnet, such a quench generates as much force as an exploding stick of dynamite. from the editor failed, causing a magnet to quench and helium Starting coolant to leak. Although this is a setback, to be up the sure, there is nothing too surprising about an incident like this. Essentially all particle acceler- Large ators have suffered similar problems in the Hadron startup process. The LHC is a machine of unprecedented complexity, and no scientist ever Collider expected to just throw a switch and have the On September 10, machine operate. LHC engineers and scientists physicists and physics will repair this fault, start the machine up again, enthusiasts around probably deal with a number of other minor the world watched problems, and then, some time next year, see expectantly as CERN attempted to circulate first collisions. At that time, the science begins particle beams in the Large Hadron Collider for and theorists’ predictions will be under the the first time. Those of us watching from the microscope (see page 32). United States stayed up late and tried to get Meanwhile, there is a world of particle physics one of the precious Web connections to the going on outside the LHC. Over the summer, streaming broadcast of the event. the BaBar collaboration at SLAC released some Photo: Reidar Hahn, Fermilab In less than one hour—thereby winning LHC outstanding results. Physicists had been looking Project Leader Lyn Evans a bet—the first beam for the lowest-energy state of bottomonium, had made it, sector by sector, all the way around a particle with bottom and anti-bottom quarks, the 27-km tunnel and back to the starting point. for 30 years and finally nabbed it (see page 8). Never had two dots appearing on a computer The “eta sub b” might not have the name recog- screen so excited so many people. (See the log- nition of the Higgs boson, but the story of book in this issue of symmetry.) Later that finding it well illustrates just what it takes to morning, a beam was circulated in the opposite make a discovery in particle physics. direction and the first beam injection for the The answers to our scientific questions LHC was complete, more smoothly and rapidly won’t come only from energy-frontier machines. than most people expected. The successful Astrophysicists are good-naturedly racing to first beams are a testament to the immense beat particle physicists to the discovery of dark effort of a worldwide collaboration of scientists, matter and an understanding of the dark uni- engineers, and support staff. The whole team verse (see page 14). For those physicists trying deserves the flood of congratulations they to be the first to discoveries, the pressure is on received. while the LHC gets back on its feet. But they As symmetry readers are probably aware, had better hurry: The LHC will be up and running the LHC suffered an interruption to the smooth in no time. startup when a faulty electrical connection David Harris, Editor-in-chief Symmetry Editor-in-Chief Publishers Print Design and Production PO Box 500 David Harris Rob Brown, SLAC Sandbox Studio MS 206 650 926 8580 Judy Jackson, FNAL Chicago, Illinois Batavia Illinois 60510 Deputy Editor Art Director/Designer USA Contributing Editors Glennda Chui Roberta Antolini, LNGS Michael Branigan 630 840 3351 telephone Managing Editor Peter Barratt, STFC Design Assistant 630 840 8780 fax Kurt Riesselmann Romeo Bassoli, INFN Jared Scott www.symmetrymagazine.org Stefano Bianco, LNF [email protected] Senior Editor Illustrator Tona Kunz Kandice Carter, JLab Aaron Grant (c) 2008 symmetry All rights Lynn Yarris, LBNL reserved Staff Writers James Gillies, CERN Web Design and Production Elizabeth Clements Xeno Media symmetry (ISSN 1931-8367) Silvia Giromini, LNF Kelen Tuttle Youhei Morita, KEK Hinsdale, Illinois is published 6 times per Rhianna Wisniewski year by Fermi National Tim Meyer, TRIUMF Web Architect Accelerator Laboratory and Copy Editor Perrine Royole-Degieux, IN2P3 Kevin Munday symmetry | volume 05 issue november 08 SLAC National Accelerator Melinda Lee Yuri Ryabov, IHEP Protvino Web Design Laboratory, funded by the Interns Yves Sacquin, CEA-Saclay Karen Acklin US Department of Energy Calla Cofield Kendra Snyder, BNL Boris Starchenko, JINR Web Programmer Office of Science. Kathryn Grim Mike Acklin Jennifer Lee Johnson Maury Tigner, LEPP Michael Torrice Ute Wilhelmsen, DESY Photographic Services Tongzhou Xu, IHEP Beijing Fermilab Visual Media symmetry Gabby Zegers, NIKHEF Services 2 commentary: kate mcalpine in the universe that had been commissioned by Rapping NASA. It was also picked up by the press and physics has had tens of thousands of views on YouTube. Jonathan and I both hope to see more sci- A good portion of the ence rap. Maybe it’s just a flash in the pan, or public is curious about maybe this will become another way to get the what is going on in word out about scientific ideas and research. particle physics right One of the challenges in communication and now, and we have an outreach is that it’s often undervalued. Funding ever-longer list of ways can seem hard to justify because already-limited for them to find out— budgets are intended to support research. The from lab newsletters US LHC bloggers aren’t paid for the thought and to personal blogs, popular-level magazines, and time they put into posts. Volunteers often guide plain-language Web sites. public lab tours, and physicists involved in outreach CERN TV has been experimenting with work usually do it on their own time. YouTube since last October, and in late July, my This is part of the beauty of enthusiasm. colleagues and I put particles to music in the Nevertheless, it would be nice if scientists who “Large Hadron Rap,” a slightly goofy project aimed write about their work on blogs or craft articles at educating people about CERN’s Large for an outreach Web site could see those efforts Photo courtesy of Kate McAlpine Hadron Collider on the French-Swiss border (to valued on an equal footing with the hours they the extent that this is possible in five minutes!) spend coding software, for instance.