Entering Higgs habitat

A powerful new collider will allow scientists to explore the territory where the long-sought Higgs particle-maybe even a whole family of them-resides.

Illustration: Sandbox Studio

They sound like Zen koans: The Higgs field bestows mass on other particles, but its own mass is unknown. It pervades the universe, but no one has seen its physical manifestation, the Higgs particle. It's the only missing piece of the Standard Model of particles and forces, but the model accounts for just four percent of the universe.

Less puzzlingly, but just as important, physicists think the Higgs field is responsible for giving mass to some particles but not others. It acts like a gooey, universe-sized bucket of molasses. As particles travel through the field, some interact with the molasses more strongly than others. Those that interact most become heaviest, while those that don't interact at all are left without mass. Without this fundamental phenomenon, the world would be a different place: heavy atoms wouldn't hold together; all elementary particles would be massless, zipping around at the speed of light; the reactions that stoke stars would go faster, slower, or not at all.

Discovering the Higgs particle and pinning down how much it weighs will ultimately make or break theories that explain, for example, the nature of the dark matter that makes up nearly a quarter of the universe.

After more than 20 years of searching, physicists think they will finally find this elusive particle at the Large Hadron Collider, now being set up in an underground tunnel near the Geneva, Switzerland, headquarters of CERN, the European particle physics lab.

Why is this omnipresent entity so hard to find? What makes the search different this time?

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-- Heather Rock Woods

Eleventh annual URA Thesis Award Competition underway

Fermilab and the Universities Research Association invite submissions for the 11th annual URA Thesis Award Competition. The award recognizes the most outstanding thesis related to work conducted at Fermilab or in collaboration with Fermilab scientists. Work must have finished in the 2007 calendar year.

Nominations must be submitted to Richard Tesarek by March 1, 2008, and should include at least two letters supporting the merits of the nominated thesis. The Ph.D. granting institution should provide at least one letter. The Thesis Awards Committee will make the selection. Judges will look for clarity of presentation, originality and physics content. To qualify, the thesis must have been submitted as partial fulfillment of the Ph.D. requirements in the 2007 calendar year, be written in English and it must have been submitted in electronic form to the Fermilab Publications Office in accordance with Fermilab policy.

Latest supercomputer calculations support the six-quark theory

From Brookhaven National Laboratory,
Feb. 8, 2008

A new calculation, reported in the January 25, 2008 issue of Physical Review Letters, confirms the six-quark theory of particle-anti-particle asymmetry. This is the first complete calculation of this phenomenon to employ a highly accurate description of the quarks that adds a fifth dimension beyond those of space and time.

This result allows recent experiments studying the decays of bottom quarks to be compared with earlier, strange quark experiments. This comparison agrees with the predictions of the Standard Model of particle physics and implies that the particle-anti-particle asymmetries (technically known as "CP-symmetry violation") seen in these two different decay processes have a common origin.

This research was carried by physicists from the U.S. Department of Energy's Brookhaven National Laboratory, Columbia University, the University of Connecticut, Edinburgh University, University of Southampton, and the RIKEN BNL Research Center (RBRC) using powerful, massively parallel supercomputers specially constructed to perform these calculations and capable of tens of trillions of arithmetic operations per second. The work was funded by the Particle Physics and Astronomy Research Council in the UK (now the Science & Technology Facilities Council), the RIKEN Laboratory in Japan, and the Office of High Energy Physics within the U.S. Department of Energy's Office of Science.

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