Higgs Boson Discovery Process
Date: Spring 2013
How do CERN physicists reach decision to declare detection of Higgs boson? What does raw data consist of? There are trillions of collisions, they pick out a "handful" of likely candidates and determine that there is enough confidence in those to confirm existence of the Higgs "particle". Can someone provide a hint of what went on?
Theoretical work must agree with the properties we know to be true. The effective mass of a Higgs boson, the energy required to produce one, has been estimated to keep the theory consistent with things we already know. Physicists at CERN cause protons to collide, two at a time. The extreme energy produces many different particles. Many different sensors and filters tell the computers which collisions produce what is not wanted. That data is not used. Collisions that pass all the sensor tests are recorded. The particles are absorbed, which measures the mass of the particles produced. There were some extra unidentified particles that passed all the filters and sensors. They were right at the energy expected for Higgs bosons. We do not know of any other particles that should be at this energy. Many different detectors, run by a variety of research groups, all saw the unidentified particles at that same energy, at that same mass. Nobody can say that these are for a fact and undeniably Higgs bosons. Nothing in scientific research is undeniable. Still, it agrees very well with what we would expect to see from Higgs bosons.
Dr. Ken Mellendorf
Illinois Central College
Thanks for the question. Yes, there are many collisions that are detected and recorded. Software is used to pick out certain collisions that have specific properties, such as charge, amount of energy dissipated, secondary particle production (and tracks). In essence, the software is used to sift through lots of data to look for correlations and patterns that are characteristic of a Higgs boson. I should stress that one does not "see" a particle, but only the effects of it or the other particles that it decays into.
I hope this helps. Please let me know if you have more questions.
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Update: November 2011