Precision measurement indicates lighter Higgs particle
A high-precision mass determination of the W boson at the Fermi National Accelerator Laboratory (Fermilab) suggests a lower mass of the previously undiscovered Higgs boson.
In the Tevatron, currently the world's most energetic accelerator, the researchers analyzed collisions between protons, the nuclei of hydrogen atoms, and their antiparticles. The collisions give rise to numerous subatomic processes and, among hundreds of particles, also give rise to the W boson, the carrier particle of the weak nuclear force. The mass of the W boson has now been determined in the most precise individual measurements to date to be 80.413 GeV/c² with an accuracy of 0.06 percent. Based on physical models, an upper limit for the mass of the hypothetical Higgs boson was calculated, which at 153 GeV/c² is lower than the previously assumed 166 GeV/c².
The Higgs boson is an interaction particle predicted in the physical standard model, but it is the only one that has not yet been proven. While the other bosons, such as the photon, the gluon, and the W and Z bosons mediate the electromagnetic and nuclear forces, the Higgs boson is held responsible for the particle masses. At the same time, it is said to represent the most massive boson and can therefore only be produced in very high-energy collisions.
Although the energies that can be generated in the Tevatron should be sufficient for the discovery of the Higgs particle, there has been no success so far. Researchers at the European nuclear research center CERN hope to finally achieve the necessary collision energies with the new particle accelerator LHC. According to plans, what will then be the most energetic accelerator is to go into operation before the end of this year. (vs)
