EVEN from beyond the grave it is possible to help
tease apart the nature of matter. Newly processed measurements from the
now defunct Tevatron particle collider have led to the most precise
estimate yet of the mass of the W boson. That in turn constrains the
mass of the long-sought Higgs boson.
The Tevatron was housed at Fermilab in
Batavia, Illinois, and turned off in September 2011, but researchers
are still combing through the data it produced.
Their latest sums, combined with
earlier data from other detectors, place the W boson's mass at 80.385
gigaelectronvolts, plus or minus 0.015 GeV. The previous estimate was
80.4 GeV, give or take 0.045 GeV.
Thanks to relationships laid out in
the standard model of physics - our best picture of the menagerie of
particles and forces that make up the universe - the improved W boson
mass hones estimates for the mass of the Higgs, the missing piece of the
standard model.
Last December, physicists at the Large
Hadron Collider at CERN, near Geneva, Switzerland, announced hints of a
Higgs with a mass of about 125 GeV. The new W boson mass boosts
confidence in that result, as it is consistent with a Higgs weighing
between 115 and 127 GeV. "It's all fitting together nicely," says Dmitri
Denisov of DZero, one of the Tevatron's two main detectors.
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