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Visiting the Big Bang

BU physicist on the new atom smasher that could unlock universal mysteries

Click on the audio player below to hear an interview with Andrew Cohen, a CAS professor of physics.

For decades, physicists have looked in very small spaces for answers to our universe’s biggest questions — inside atoms. Yet probing such small bits of matter requires enormous machines — particle accelerators and colliders that can stretch for miles.

ATLAS particle detector

Next May, the most powerful of these machines yet built, a 27-kilometer loop about 100 meters below ground in Switzerland called the Large Hadron Collider (LHC), will begin smashing proton beams together to create energy levels approaching what would have existed just after the big bang. The data the LHC produces could solve mysteries about the universe’s structure that have been unresolved for years. The big questions stem from shortcomings in the Standard Model of particle physics, which lists the most elementary particles (such as electrons and quarks) and describes how three fundamental forces — electromagnetism, the strong force that holds together atomic nuclei, and the weak force of radioactive decay — act on them. But the Standard Model neglects gravity, and it offers no explanation for dark matter, which is believed to make up most of the universe’s mass, but can’t be seen because it doesn’t emit light. Another major conundrum is why some particles (such as the W and Z bosons of the weak force) acquired mass after the big bang while others (such as photons) did not.

As the LHC nears readiness, the world of particle physics is abuzz with anticipation about what its experiments could reveal.

“The field has been very different in the past couple of years because everyone has been looking forward to an experiment that will finally give us serious evidence for or against our current theories,” says Andrew Cohen, a College of Arts and Sciences professor of physics, and a codeveloper of the Little Higgs theory, one of the most recent theories that goes beyond the Standard Model — other theories have names like supersymmetry and technicolor.

BU Today spoke with Cohen about the LHC and the discoveries about our universe waiting to be made.

Chris Berdik can be reached at cberdik@bu.edu. Ned Brown can be reached at ebrown@bu.edu.