17 June 2015

Evidence of left-handed cosmic magnetic field provides clues for why the universe contains more matter than antimatter

Giant screw-like magnetic fields in space could offer clues to why there is something rather than nothing in the universe.
According to cosmologists, the Big Bang should have produced equal amounts of matter and antimatter that would almost immediately annihilate each other, leaving a universe that was practically empty. Yet, here we are.
But where is the cosmic antimatter?
Tanmay Vachaspati, a physics professor at Arizona State University, and colleagues at ASU, Washington University and Nagoya University, think they have found a clue to this mystery.
They say that a signal in NASA's Fermi Gamma ray Space Telescope data suggests an overwhelming production of matter in the early universe. They detailed their findings in a paper published May 14 in the journal Monthly Notices of the Royal Astronomical Society.
Finding the signal wasn't an accident.
In 2001, Vachaspati had predicted that the genesis of matter in the very early universe would also generate a `left-handed' screw-like magnetic field everywhere in space.
"The surprising connection between matter-antimatter asymmetry and left-handed magnetic fields arises from a detailed theoretical study of how particles interact a billionth of a second after the big bang," he explained.
Later, Vachaspati and his postdoctoral fellow, Hiroyuki Tashiro, showed that the screw-like magnetic field would imprint a spiral pattern in gamma rays emitted from distant supermassive black holes as they propagate through intergalactic space to Earth.
Describing his recent paper with Francesc Ferrer and Wenlei Chen at Washington University, and ASU Cosmology Initiative postdoctoral fellows, Borun Chowdhury and Hiroyuki Tashiro, Vachaspati said:
"We decided to finally test these theoretical ideas with real data, not expecting to see anything. We were blown away when we observed the predicted spiral pattern in gamma ray data taken by the Fermi Telescope. It is breathtaking that our theoretical ideas might actually have played out in the very early universe, and that we are now beginning to see the effects."

Image: An artist's impression of the Fermi Gamma ray Space Telescope (FGST) in orbit.