sparticles

Micro black holes could form at lower-than-expected energies

New simulations of head-on collisions of particles travelling at nearly the speed of light show that black-hole formation can occur at lower collision energies than expected, according to a team of researchers in the US. The researchers attribute this to a “gravitational focusing effect” whereby the two colliding particles act like gravitational lenses, focusing the energy of the collision into two distinct light-trapping regions that eventually collapse into a single black hole. Although the work shows that black holes can form at lower collision energies than expected, the team says that the result has no impact on real particle collisions taking place at the Large Hadron Collider (LHC) at CERN.

From 2008 onwards, when the LHC was first scheduled to be switched on, there were rumours about what the experiment might create – extra dimensions, sparticles and strangelets, vacuum bubbles and, of course, planet-destroying black holes. Although the experiment ran seamlessly from November 2009 for more than two years and scientists found no evidence whatsoever for the formation of micro black holes, the fascination with black-hole formation and evaporation continues – among researchers and the media.

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Ten Lessons from the Standard Model

The most recent Nobel Prize in physics, awarded to Francois Englert and Peter Higgs for the prediction of the Higgs boson, marks the apotheosis of the Standard Model in two ways. First, the Higgs particle is a milestone in itself: It is the last ingredient required to complete the Standard Model. But second, and more profoundly, the discovery process bore witness to the extraordinary power of the Standard Model. Higgs particles are rare and fleeting visitors to our world. Even at the Large Hadron Collider (LHC), where the discovery was made, they are produced in less than a billionth of all collisions. When they are produced, they quickly decay, leaving behind just a few extra tracks among hundreds of others from more conventional sources. It is only because physicists can so reliably predict such “backgrounds,” as well as the rate of Higgs particle production and the modes of its decay, that the discovery experiments could be planned and their results interpreted.

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