Scientists find signs of missing 'god particle'

Rehovot scientists have had leading role in experiments that show long-sought Higgs boson may exist.

By JUDY SIEGEL-ITZKOVICH
CERN particle accelerator_311 (photo credit: reuters)
CERN particle accelerator_311
(photo credit: reuters)
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.
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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.