Can you explain the Higgs?

April 10, 2008 | 6:23 am

Explaining the Higgs concept-how elementary particles acquire mass-and how this relates to the Higgs field and the Higgs particle is difficult. It is such a challenge that in 1993 former British science minister William Waldegrave announced a competition and offered a bottle of vintage champagne to anyone who could explain the Higgs mechanism on a single sheet of paper.

This week, Time magazine rose to the challenge. Reporter Eben Harrell wrote:

Working from Higgs’ theory, scientists postulate that initially weightless particles move through a ubiquitous quantum field, known as a Higgs field, like a pearl necklace through a jar of honey. Some particles, such as photons–weightless carriers of light–can cut through the sticky Higgs field without picking up mass. Others get bogged down and become heavy; that is the process that creates tangible matter.

I think this is pretty good! Compare this with our own 60-second explanation by Howard Haber of the University of California, Santa Cruz. And if you are curious: here are the winning page-long entries of Waldegrave’s contest.

Do you have your own explanation? Post it here!

Kurt Riesselmann

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Pier Oddone has a posse

April 9, 2008 | 5:03 am

A few months ago, two-inch by two-inch stickers containing the likeness of Fermilab Director Pier Oddone and the words “Pier Oddone has a posse” were found in the Wilson Hall parking lot, the elevators, and other inconspicuous areas.

The strategically placed stickers are a spinoff of a mid-1980s street art campaign featuring Andre the Giant. Originally begun as sort of an inside joke, the stickers were later disseminated by the skater community and became a curious phenomenon done just to get people talking about it. Later spinoffs were created to show support of a theory or a personality, including Darwin and the process of evolution.

Oddone was flattered when notified of the sticker art.

Rhianna Wisniewski

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End of PEP-II and BaBar runs at SLAC

April 8, 2008 | 11:17 am

Last night, the beams were dumped for the final time from the PEP-II rings and the BaBar experiment took its last data. It was the end of nine years of operation in which the design specifications were more than tripled. SLAC and BaBar staff and collaborators commemorated the last day of running with a set of short speeches on the SLAC green, followed by ice cream for everybody.

Read some comments on the final operations of PEP-II by Jonathan Dorfan, director of SLAC during most of PEP-II/BaBar running. Here is an extract:

Unseen by us except through the myriad of electronic signals shipped from the accelerator control system and displayed on a series of monitors at Babar, the PEP-II operators diagnose the fault, thrust the HER injection system into high gear and begin refilling the 1,760 electron bunches. Notwithstanding the violent loss of the electron beam, the 2.6 amperes of positrons have remained orbiting stably in the low energy ring. A scant 10 minutes after the beam loss, data-taking has recommenced at maximum luminosity and low backgrounds. The two Babar Run Coordinators, Georg Marks from Germany and Jacques Chauveau from France, smile-their admiration for what the PEP-II operations staff has just done, and do day-in-day-out, is clearly reflected on their faces. Data taking has been restored-PEP-II and Babar are ticking away in perfect unison, each executing an enormously complex set of technical feats, pushed up hard against the edge of feasibility. Clearly I am observing “factory” performance.

Below are some photos taken by Brad Plummer of the main control center in the last days of operation.

David Harris

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New congressman speaks on Fermilab and Argonne

April 8, 2008 | 6:32 am

Freshman Congressman Bill Foster, a Democrat from the 14th District in Illinois, gives a nice Q&A about his priorities, first days in office, and whether he can help his old employer Fermilab. The Northern Star newspaper, a student publication from Northern Illinois University, which works closely with Fermilab, published the story.

Here’s an excerpt from the article:

NS: What are the issues you feel most strongly about and how do you plan to approach them? And how will you face opposition?

BF:Well, there are a range of issues that do address on different time scales. Well, the things that I am hoping to immediately work on is that I am going to make a serious attempt to see if we can get some financial relief because of the funding cuts at the Fermilab and Argonne and I am going to make an effort, that’s all I can promise.

That’s going to be tough, that’s a very short term priority.

Tona Kunz

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Packing them in at the world’s largest particle accelerator

April 7, 2008 | 12:48 pm

Tens of thousands of visitors, hours-long lines, shuttle buses between major sights–a typical day at Disneyland, perhaps, but a very atypical day at CERN, the European Organization for Nuclear Research.

This past weekend, more than 70,000 visitors flocked to the European particle physics laboratory for the LHC 2008 Open Days, the last opportunity to view the massive underground installations of the Large Hadron Collider. The LHC, which will become the world’s highest energy particle accelerator when it starts running later this year, is located in a 27-kilometer ring 100 meters underground near Geneva, Switzerland.

“People started lining up at 7:30 a.m. for tickets to visit ATLAS, and even the small visit points were flooded,” said CERN’s Paola Catapano, one of the event organizers. “It was beyond expectations.”

More than 30,000 visitors packed into elevators to visit the LHC accelerator, the smaller SPS accelerator, or the four huge LHC experiments: ALICE, ATLAS, CMS and LHCb. For those who preferred to stay aboveground, or who didn’t arrive early enough to score tickets for a subterranean tour, there were dozens of activites available: exhibits on all aspects of LHC construction, superconductivity and superfluidity, computing center and control room tours, and even an LHC-experiment rugby tournament.

For kids, the most popular activities were the presentations and broadcasts by Fred, a host of the popular French children’s show “C’est pas sorcier” (It’s not magic). Fred traveled to each of the CERN visit points, often filling up assembly halls hours in advance. In one location, Fred’s admirers arrived early enough to happen upon a lecture by two winners of the Nobel Prize in Physics, listening politely and then quizzing the eminent scientists about their career paths and what puts the “3” in helium-3.

While the weekend was geared towards members of the surrounding French and Swiss communities, visitors and journalists came from across Europe and even farther afield. A team of 1500 volunteers was there to greet them, giving up their weekend to explain the technical aspects of antimatter production or hand out balloons.

Katie Yurkewicz

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Transition: What is it?

April 7, 2008 | 7:22 am

This is not rocket science but it is pretty close. Every day the accelerators running at Fermilab handle complex beam tuning, steering, and correcting quite routinely and with little fanfare. Tens of thousands of details about the particle beam and its position are checked, modified, and monitored in real time.

As the accelerator increases the energy of the beam, the beam becomes “relativistic”. As particles become relativistic, their speed changes little and they start gaining effective mass at a faster rate. Eventually the particles gain so much effective mass that at a certain point, an increase in energy does not significantly change how fast the particles travel around the accelerator. This is called the “transition energy” of the accelerator.

During transition, the controls of the accelerator must perform an intricate minuet to guide the particles. Large accelerators like the Tevatron choose not to handle transition; they leave it to their smaller cousins; the Booster and Main Injector. Dave McGinnis, a scientist in the Accelerator Division and one of the experts of the Fermilab accelerator complex explains transitions in this video clip.

Fred Ullrich

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LIGO gets upgrade go-ahead

April 4, 2008 | 7:45 am

Einstein’s general theory of relativity predicts that moving massive bodies will send out gravitational waves. As they pass through the Earth, they will cause the lengths of objects to change very slightly and so should be detectable. The problem is that they will change the lengths of objects by only one part in 10²⁰ (100 billion billion). That’s about one billionth of the width of a typical atom for a one meter object!

Very few scientists doubt that they exist but the challenges in observing them are so great that they haven’t been observed directly yet. (There have been indirect observations.)

During the week, the LIGO gravitational wave observatory was approved for the upgrade to Advanced LIGO that will give it the power to actually detect gravitational waves. Wasn’t that what LIGO was for? Well, not exactly. The technology is so challenging to implement that LIGO needed to run at a lower sensitivity first to ensure that everything was operational and to learn more about how it would run.

The transition to Advanced LIGO will increase the sensitivity of the instruments by a factor of 10, enough to detect the incredibly faint signals of gravitational waves roughly once per week.

The new observatory will be ready for operation in 2014 but you can get involved in the preliminary data analysis through the Einstein@home project.

For more information about the Advanced LIGO funding, see the news story in New Scientist.

And if you want a completely different take on the project, you can see and read about a 7-year-old’s impression of LIGO in a previous story from symmetry.

For a last piece of trivia, there is a difference in physics terminology between gravitational waves and gravity waves. Gravitational waves are the waves predicted by Einstein but gravity waves are the everyday kind of waves like ocean waves that occur in a fluid when gravity is present.

David Harris

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Your doodles may vary

April 4, 2008 | 4:54 am

I always wished I could draw. Part of this longing came from a desire to be an artist, and thus really, really cool. But a lot of it was boredom. As a biology student, and later as a newspaper reporter, I spent endless hours in lectures and meetings, where bursts of frantic, can’t-do-it-fast-enough note-taking gave way to long sleepy stretches of waiting for the next interesting thing. If only I could draw, I thought, I could replace those squiggles in the margins of my notebook with fantastic creatures or rude portraits of the guy behind the podium. Waiting would be fun.

Chris Ing, a computational physics student at the University of Waterloo and half of the Jacks of Science blog, has no such problem. His third-year physics notes are full of whimsical drawings, from a lollipop dog to a pig-turtle hunter, a gambling bear, his PHYS359 prof, and birds describing strange formulas.

Ing wrote:

Even in my mathiest courses I find it irresistible to doodle in the margins of my notes. I like to think of it as balancing the left and right sides of my brain but that’s just sugar coating my short attention span.

My first reaction: This guy has a whole lot more spare brain power than I do. My second: Mathiest? What a great word!

My own doodling opportunities aren’t what they used to be. I sit in fewer meetings and take notes almost exclusively on my laptop. But a week or so ago, well into my fifth decade, I started taking drawing lessons from my good friend Cathy Lyn Harrison, who runs an art school for kids. Here’s one of my first efforts:

It’s a start. And on that fine day when my laptop allows me to doodle in the margins, I’ll be ready.

Glennda Chui

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New director announced for Jefferson Lab

April 3, 2008 | 3:22 pm

Hugh Montgomery, associate director for research at Fermilab, has just been announced as the new director of Jefferson Lab in Virginia, to succeed current director Christoph Leeman.

Details in a press release here (PDF). Text is included below.

Read the rest of this entry »

David Harris

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A crack in the Standard Model?

April 3, 2008 | 1:21 pm

Our current framework of particle theory cannot explain why all antimatter disappeared after the big bang while some matter survived the big annihilation battle. Today Scientific American highlighted results obtained with the Fermilab collider experiments that might open the door to finding a new force that creates a matter-antimatter imbalance beyond the Standard Model.

While it is far too early to call this a discovery, it is intriguing that both the CDF and the DZero experiments at Fermilab hint at this. In the story, Luca Silvistreni, a member of the team that found the new results, is quoted saying, “Everything points in the same direction, and so I think it’s rather unlikely this is a statistical fluke.” CDF cospokesperson Jacobo Konigsberg (photo) points out that “if it is a fluke, that should become clear by the end of the summer as the Fermilab teams analyze more data.”

The analysis itself was carried by a group of European physicists known as the UTfit Collaboration. New Scientist reported in more detail on their work a couple of weeks ago.

The quest to understand the matter-antimatter asymmetry is one of the nine big questions of the Quantum Universe report. Here is a 2-minute video in which physicist Persis Drell, now director of the Stanford Linear Accelerator Center, explains why we wouldn’t exist if the early universe hadn’t found a way to favor matter over antimatter.

Kurt Riesselmann

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