Large Hadron Collider may one day discover nature’s fifth force

April 29th, 2009 - 2:04 pm ICT by ANI  

Large Hadron Collider Washington, April 29 (ANI): A group of physicists at the University of Nevada, Reno has analyzed data from the Large Hadron Collider (LHC) that could ultimately prove or disprove the possibility of a fifth force of nature.

The LHC is an enormous particle accelerator whose 17-mile tunnel straddles the borders of France and Switzerland.

In a forthcoming Physical Review Letter article, the University of Nevada, Reno physicists are reporting an analysis of an experiment on violation of mirror symmetry in atoms.

Their refined analysis sets new limits on a hypothesized particle, the extra Z-boson, carving out the lower-energy part of the discovery reach of the LHC.

Andrei Derevianko, an associate professor in the College of Science’s Department of Physics, who has conducted groundbreaking research to improve the time-telling capabilities of the world’s most accurate atomic clocks, is one of the principals behind what is believed to be the most accurate to-date low-energy determination of the strength of the electroweak coupling between atomic electrons and quarks of the nucleus.

Derevianko and his colleagues have determined the coupling strength by combining previous measurements made by Dr. Carl Wieman, a Nobel laureate in physics, with high-precision calculations in a cesium atom.

The original work by Wieman used a table-top apparatus at the University of Colorado in Boulder.

The Boulder team monitored a “twinge” of weak force in atoms, which are otherwise governed by the electromagnetic force.

The Standard Model of elementary particles, developed in the early 1970s, holds that heavy particles, called Z-bosons, carry this weak force.

In contrast to the electromagnetic force, the weak force violates mirror symmetry: an atom and its mirror image behave differently.

This is known to physicists as “parity violation.”

The Boulder group’s experiment opened the door to new inquiry, according to Derevianko.

“It pointed out a discrepancy, and hinted at a possibility for new physics, in particular, extra Z-bosons,” he said.

In contrast to previous, less accurate interpretations of the Boulder experiment, Derevianko’s group has found a perfect agreement with the prediction of the Standard Model.

This agreement holds important implications for particle physics.

“Atomic parity violation places powerful constraints on new physics beyond the Standard Model of elementary particles,” Derevianko said. “With this new-found precision, we are doing a better job of ‘listening’ to the atoms,” he added.

By refining and improving the computations, Derevianko said there is potential for a better understanding of hypothetical particles (extra Z-bosons), which could be carriers of a so-far elusive fifth force of nature. (ANI)

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