Getting to Higgs
Where's Higgs?
| Physicists think the Higgs is very heavy and very weakly-interacting. Very few will be produced even at the correct mass-energy. It will be difficult to pick them out of all the other particles produced at the same time. | ||||
|
What is the correct mass-energy? Physicists get a lower mass limit by direct observation and an upper limit from theory. At the end of the Large Electron Positron Collider run at CERN, one of the experiments, ALEPH, may have data that indicate the presence of a Higgs.
The mass was around 114 GeV/c2. That is in the range of the mass of the "Supersymmetric Standard Model Higgs." The mass of the "Standard Model Higgs" is near that of the top quark (175 GeV/c2).
Why haven't we seen Higgs at Fermilab? The Higgs mass is probably less than that of the top so Run I had enough energy. That wasn't the problem. The upgrade to Run II increased twenty-fold the "luminosity," which indicates the number of protons and antiprotons colliding per second. It really is the quarks and gluons inside the protons that collide. Many other particles are produced by other quarks and gluons, in addition to the particles that we are hoping to find. Fermilab physicists think that Run II could produce the Higgs in sufficient numbers to be detected. This would be big news! We don't have real Higgs data. Our other analyses used real Fermilab data for known particles, B mesons and W and Z bosons. Finding new particles like Higgs in the data is not so easy because those data are mixed in with background data from many other particles. For the Higgs data analysis we will use "Monte Carlo" Higgs data mixed in with background. Monte Carlo data are simulated, computer-generated data based on theories of what the actual results will be. Physicists use Monte Carlo data to test detectors and software, and as in this case, to see how they could identify a new particle if it had given mass and characteristics. Higgs events are extremely rare, so we must increase the number of Higgs events in our dataset if we expect to determine the mass. | |||||
| Higgs Mass Calculation » |