Post image for A (physicist’s) dream come true

A (physicist’s) dream come true

July 11, 2012

The announcement that scientists have observed a new particle that may be the elusive Higgs boson spelled success for researchers at Indiana University Bloomington who have worked for years on a massive experiment that detected the particle.

On July 4 in Geneva Switzerland, representatives of two experiment teams, ATLAS and CMS, said that they had observed a new particle consistent with expectations for the Higgs boson. The experiments have been conducted over several years at the Large Hadron Collider operated by CERN, the European Organization for Nuclear Research.

Discovery of the Higgs boson would fill a crucial gap in the Standard Model, which describes the fundamental particles from which everything in the universe is made and the forces acting between them. The Higgs boson explains why fundamental particles have mass; without it, particles would whiz around at the speed of light and not be able to bind to form protons, neutrons, atoms, stars and the material of the universe, including human beings.

IU’s participation in the Large Hadron Collider includes leadership by IU physicists who designed and built a key component of the ATLAS detector mechanism and by information technologists who ensured the availability of vast computing resources used to analyze data from the experiment. The LHC facility is one of the largest experimental facilities ever built — 17 miles in circumference, 300 feet underground, lying beneath the territory of France and Switzerland.

“What ATLAS is seeing is a very strong indication that the Higgs boson exists at a mass of approximately 134 times that of the proton,” says physicist Harold Evans, principal investigator for IU’s ATLAS team. “This is interesting because it validates our current understanding of the micro-world of fundamental particles and the forces that govern them, and also because it may point us to a more complete theory that describes particle interactions at even higher energies and smaller distance scales.”

Researchers and staff from the Department of Physics in the IU College of Arts and Sciences, led by Professor Emeritus Harold Ogren, were responsible for the design and construction of a critical part of the ATLAS experiment’s equipment, called the Barrel Transition Radiation Tracker. This tracker is about as tall as a person and weighs almost a ton. It is part of the ATLAS detector, which like the CMS detector is installed in CERN’s massive LHC facility. Much of the Barrel Transition Radiation Tracker was constructed on the IU Bloomington campus.

“This is a proud day for all of the students, technicians and engineers who worked for many years in Bloomington on the TRT tracker,” Ogren said. “Finding the Higgs with the help of our tracker is a dream come true and a high point in my physics career.”

For Evans, who has been at CERN since mid-May, the build-up to last week’s announcement was the most exciting time in his career as a physicist.

“The level of anticipation and intensity at the lab has been simply incredible,” Evans says. “Meetings of the analysis teams at all times of the day and night, animated discussions over coffee, rumors and hints of what our competitors are seeing — all of these made CERN the best place in the world to be for me. I was very lucky to be there and to be a part of it all.”

IU physicist Sabine Lammers said the discovery announced last week is the beginning of a rich period of investigation for particle physics.

“It really is just the beginning of the Higgs era, even though it is the ‘final’ piece of the Standard Model puzzle,” she said. “We will be very eager to see what the properties of this new particle will be, and whether there is a single Higgs boson or several.”

As Harold Evans put it in an interview with the Bloomington Herald-Times, “You never know what one discovery will lead to. … You just never know, and that’s what makes it so exciting.”


IU scientists are among the primary authors of 16 peer-reviewed journal publications based on ATLAS data and about the computing systems that enable analyses of the data produced by the LHC. Members of the IU ATLAS group from the Department of Physics include faculty members Evans, Lammers, Ogren, and Rick Van Kooten as well as research scientists Pauline Gagnon, Vivek Jain, Fred Luehring and Daria Zieminska; postdoctoral researchers Sylvie Brunet, Darren Price and Ximo Poveda; graduate students Aparajita Dattagupta, KyungEon Choi, John Penwell, Ben Weinert, Denver Whittington and Yi Yang; engineer Kirill Egorov; and grant administrator Jenny Olmes-Stevens.

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