The Catholic University of America

Nov. 1, 2010

CUA Physicist Wins Grant to Unlock Mysteries of Subatomic Particles

Tanja Horn  

Tanja Horn, a CUA assistant physics professor since 2009, has been awarded a $467,982 federal grant to build and develop a detector that will help unlock the mysteries of the smallest particles of matter.

Over the course of two years, the funding from the National Science Foundation will enable Horn to work with two undergraduate or graduate students per semester at the Thomas Jefferson National Accelerator Facility in Newport News, Va.
“This is a grant from the NSF’s Major Research Instrumentation program, whose purpose is to increase research opportunities at major scientific research facilities,” says L.R. Poos, dean of the School of Arts and Sciences. “It is an extremely competitive grant process and receiving this award is a very strong testimony to Professor Horn’s accomplishments already in her career.”
With the help of the same two students, Horn will construct the particle detector, a 3-foot by 3-foot device made of aerogel, the lightest known substance in existence, at the nuclear physics lab on campus. It will then be transported to and mounted onto a spectrometer, a 400-ton super microscope.
By the time the spectrometer is built and installed in 2014, it will examine two types of particles that are too small to be observed even under high-powered microscopes. Still a mystery to physicists, one particle is a kaon, a subatomic object made of a quark and strange quark, so called because it interacts with particles differently from others. The other is a pion, composed of two regular quarks. The detector will measure how quarks form to bind subatomic particles.
“The ultimate goal of this research is unveiling the mysteries of the strong force, which is one of the four basic forces of nature, along with gravity, electromagnetism, and the less-familiar weak force,” Horn says.
The strong force binds quarks into protons and neutrons. It also binds together simpler particles such as kaons.
According to Horn, “The field generated by the presence of the strong force also gives rise to additional, short-lived particles inside the kaon: a bevy of quarks and gluons [particles that bind together quarks] that constantly blink into and out of existence. This group of extra particles generated by the strong force is called the quark-gluon sea. By measuring the quark-gluon sea, scientists can study the strong force at its most basic level.”

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