CERN boffins to lift LHC beam power

CERN has announced that it’s going to boost the beam energy of the Large Hadron Collider by 0.5 TeV this year in a bid to pull more data out of the micro-universe before the machine takes a break at the end of the year.

The CERN management says running the LHC at 4 TeV per beam will help it meet a data target of 15 inverse femtobarns* for the ATLAS and CMS experiments, with LHC bunch spacing to remain at 50 nanoseconds.

Citing “tantalising” results out of 2010 and 2011’s particle gun shots, CMAC (the CERN Machine Advisory Committee) has decided that the lift in operating power could help pin the Higgs boson butterfly into the physicists’ collection once and for all.

“Two good years of operational experience with [the] beam and many additional measurements made during 2011 give us the confidence to safely move up a notch, and thereby extend the physics reach of the experiments before we go into the LHC’s first long shutdown,” Seven Myers, CERN director for accelerators and technology, in a statement.

CERN believes another years’ worth of data at the 2012 target could either identify the Higgs boson’s mass within its current window of 124-126 GeV, or rule out a standard model Higgs particle “altogether”.

The machine will run at its higher energy until November before taking a 20-month break. During the break, the LHC will be prepped to resume operation at even higher energies, reaching its full design power of 7 TeV per beam in 2015. ®

Bootnote: *A barn is a unit of area. Wikipedia says it is of “whimsical” origin, originally being a Manhattan Project euphemism for the cross-sectional area of a uranium atom. So why is data-gathering expressed in units of area instead of, for example, more IT-familiar terms like terabytes, high-resolution DVDs, or entire copies of the Encyclopedia Britannica?

The (very small) areas the LHC works with help define the probability of an interaction, so the unit of area – the femtobarn – happens to predict how many interactions you’ll get when you fire the beam. So in the world of particle physics, cross-sectional area is a predictor of data collection. In other words, how many barns are your particles going to hit?

If you want an explanation with the maths and without my bad puns, there’s a good outline on Quora. ®