The smallest building blocks of matter were the focus of a panel discussion held yesterday at the 66th Lindau Nobel Laureate Meeting.
In particular, laureates Steven Chu, David J. Gross, Takaaki Kajita and Carlo Rubia together with three young scientists working at the European nuclear research centre CERN in Geneva spoke about recent experiments designed to detect hitherto unknown particles. The Director General of CERN, Fabiola Gianotti, was also present via live video stream.
The standard model incorporates the current state of knowledge about matter particles and force particles, including the Higgs boson, which was not experimentally detected until 2012. However, it fails to explain numerous phenomena; for example, the theory does not include gravitation. Moreover, knowledge is lacking about the composition of dark matter and dark energy, which make up a large part of the universe. Supersymmetric particles, which may provide an explanation, do not figure in the standard model. Also, the standard model is at odds with the finding that neutrinos have mass, as explained during the panel discussion in Lindau by Takaaki Kajita, who was awarded the 2015 Nobel Prize for this observation.
ATLAS and CMS, the two large detectors of the Large Hadron Collider (LHC) particle accelerator at CERN, presented data in December last year that might suggest the existence of another massive particle. Both experiments measured a small surplus of photon pairs -- tandem light particles -- with a combined mass of around 750 giga-electron volts in the debris of particle collisions. Now that the power of the LHC has been significantly boosted once again, researchers hope that new measurements will shed light on this phenomenon. They have already collected more data than during the whole of last year.
"We're analysing these data very carefully at the moment, but we do not yet have any official findings to announce," reported Fabiola Gianotti. There was some speculation as to whether news of the discovery of the suspected new elementary particle might be expected at the beginning of August, when the 38th International Conference on High Energy Physics (ICHEP) is held in Chicago. Four years ago, the discovery of the Higgs boson was presented at this same conference series.
Besides particle physics, quantum physics and cosmology are focal topics within the programme of the 66th Lindau Nobel Laureate Meeting. It was inaugurated on Sunday and runs until Friday, 1 July. 29 Nobel Laureates and 400 undergraduates, PhD students and postdocs from approximately 80 countries take part.