Weizmann Institute of Science astrophysicists have been prominent in
the experiments that have shown “promising signs” of the existence of
the Higgs boson – the “God particle” – that provides a framework for all
of the subatomic particles in nature and has been sought for decades.
Scientists at the Large Hadron Collider (LHC) and the CERN research
center in Switzerland said in an excited announcement on Tuesday that it
found some evidence in its experiments of the existence of the
elementary particle.
It was suggested in 1964 by six physicists, including University of
Edinburgh physicist Peter Higgs whom it was named after, as a way to
explain mass.
The sub-atomic particle called Higgs is the one piece of the Standard
Model of Particle Physics that has not been proven to exist, and some
scientists believe that the model will have to be rethought if the Higgs
is not found.
Prof. Giora Mikenberg of the Rehovot institute was the ATLAS Muon
Project leader for many years and now heads the Israeli LHC team.
Prof. Ehud Duchovni heads the Weizmann Atlas group, as well as a
small group looking for SUSY signals. Prof Eilam Gross is currently the
ATLAS Higgs physics group convener.
All are members of the Weizmann Institute’s Particle Physics and
Astrophysics Department, and they have been part of the effort to find
the Higgs since 1987.
ATLAS and its sister experiment in the LHC, CMS, have been searching for the Higgs boson together.
“In 2011, the LHC particle accelerator in Geneva collided over 300
trillion protons,” said Gross. “All of that enormous energy –
seven-trillion electron volts – went into the effort to produce the
Higgs boson.
But in each collision, other similar particles are created, and there
is no way to foresee what we will find. The chances of a collision
producing a Higgs boson are so small that only about 100 are expected to
be observed over the course of a year.”
Finding possible signs of a Higgs involved looking for statistical
anomalies in the data (compared to what the results would look like if
there were no Higgs) in the expected mass range.
The problem is that once these anomalies appear, the scientists had
to rule out statistical flukes. But several weeks ago, it was noticed
that “extra” events in the probable Higgs range had accumulated in the
experimental results during 2011.
“We couldn’t believe our eyes – we looked at the screen for ages
before we started to digest what we were seeing,” Gross continued.
“In the past three weeks, the entire Higgs search team in the ATLAS
experiment have checked and rechecked the results from every possible
angle. We checked for errors… for bugs in the program.”
The ATLAS results suggest that there could be a Higgs boson with a
mass of around 126 GeV, and that there is just a 1 in 5,000 chance that
the extra events they observed in this particular mass are the result of
a statistical fluke, and not the creation of a Higgs boson.
Such fluctuations might still disappear, so the proof is still not at
all conclusive, but scientists believe that it bodes well for the next
round of LHC collisions, which are due to begin in April 2012.
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