Particle Physics: Standard Model May Have To Be Revised

New data from the BaBar experiment shows a type of particle decay happens more often than the Standard Model predicts. The findings show that the Standard Model of particle physics might need to be revised.

The type of particle decay in question is called "B to D-star-tau-nu," and for some reason occurs more than it should. The "B to D-star-tau-nu" decay is when the B-bar meson decays into a D meson, an antineutrino, and a tau lepton. The level of certainty of the excess is 3.4 sigma in statistical terms, and is still too low to definitely break from the Standard Model. However, the results might mean something is amiss, and may be linked to the elusive Higgs bosons.

"The excess over the Standard Model prediction is exciting," said BaBar spokesperson Michael Roney, professor at the University of Victoria in Canada. The results are significantly more sensitive than previously published studies of these decays, said Roney. "But before we can claim an actual discovery, other experiments have to replicate it and rule out the possibility this isn't just an unlikely statistical fluctuation."

The BaBar experiment began in 1999 and ran until 2008. It collected particle collision data and helped two scientists win the Nobel Prize in Physics in 2008 for their work on matter-antimatter theory. Scientists are still sifting through the large amounts of data collected.

"If the excess decays shown are confirmed, it will be exciting to figure out what is causing it," said BaBar physics coordinator Abner Soffer, associate professor at Tel Aviv University. "We hope our results will stimulate theoretical discussion about just what the data are telling us about new physics."

Higgs bosons are thought to interact more strongly with heavier particles like B mesons and D mesons.

The   team presented their findings at the 10th annual Flavor Physics and Charge-Parity Violation Conference in Hefei, China, and submitted a paper to the journal Physical Review Letters.