快猫短视频

EVEN physicists get their sums wrong. A glimpse of the eagerly sought
particle known as the Higgs boson, reported last year, was revealed last week to
be just a mathematical slip.

快猫短视频s at CERN in Geneva reported seeing signs of the elusive Higgs last
September, just as their LEP accelerator was due to be demolished to make way
for a more powerful machine. In a flurry of excitement, they persuaded their
managers to let them run LEP for an extra month to gather more data
(快猫短视频, 9 September 2000, p 4).
The Higgs boson is believed to endow
other particles with mass, and physicists are desperate to find it.

Researchers studying data from collisions in two of LEP鈥檚 four detectors
found a bigger signal than they expected in the area where the Higgs should
appear. This signal stuck out above the noise by as much as three standard
deviations鈥攎eaning there was 0.3 per cent chance it was due to random
noise. CERN policy says you need five standard deviations to claim a discovery,
though three is strong evidence. With an extra month鈥檚 data, the evidence was
not much stronger and LEP was closed, to the anger of many physicists.

Now a re-analysis of last autumn鈥檚 results shows that some of the
calculations were wrong. 鈥淎t the beginning of November they were doing analysis
very quickly,鈥� a CERN spokesman told 快猫短视频.

The new analysis shows researchers overestimated the collision energy of the
particles, so the level of noise relative to signal was higher than expected.
The correction means the relative size of the excess signal is just two standard
deviations, giving it a five per cent chance of being due to noise. That鈥檚 still
enough to be tantalising, says Chris Tully of Princeton University, who is
responsible for data analysis on one of the detectors. But it鈥檚 not enough for
LEP to go down in history as the accelerator that discovered the Higgs, he says.