New success in Higgs search
There is more and more evidence: today, at the Moriond Conference in La Thuile (Italy), scientists of both LHC experiments CMS and ATLAS announced that the particle discovered last year at the world’s largest particle accelerator is looking more and more like a Higgs particle. Analyses of both collaborations show that the particle very probably has no spin, as it is postulated for the Higgs particle. Whether this is the Higgs boson of the Standard Model of particle physics or possibly one of several Higgs particles predicted in other theories, physicists cannot yet determine. Additional intensive analyses are necessary to find the answer.
In July 2012, scientists announced the discovery of a particle with a mass of about 125 GeV. The physicists were sure that this was a so-called boson but they did not know whether this was the long-sought Higgs boson. After the discovery, the physicists immediately switched to another experimental mode: from “searching” to “investigating”. The scientists frantically scrutinised the collisions to find the properties of the newly found particle. They identified the particles according to their decay products trapped in the detector. Indeed, only very few of the trillions of collisions registered at the large LHC detectors actually produce a Higgs particle. These have to be identified and most meticulously evaluated.
The results of this true Sisyphean task and the current status of investigations were presented at the Moriond Conference today. For this aim, the scientists were able to analyse two and a half times as many collisions as available at the discovery in 2012. "We can now be pretty sure that it is a Higgs particle," said DESY particle physics director Professor Joachim Mnich. “I eagerly wait to know whether this is the Standard Model Higgs or the first experimental hint of a theory that goes beyond.” However, for this statement, the LHC scientists will certainly require additional years and more data.
The LHC accelerator was shut down beginning of this year to prepare it for operation at maximum energy levels. With its restart planned in 2015, the LHC will be able to produce even more particle collisions at higher collision energies to further advance into so far unexplored territories. The journey of discovery has only just begun.