The latest research findings from the Large Hadron Collider (LHC) at CERN show that the CMS and ATLAS experiments are now reporting that the significance of their observation of the Higgs-like particle is standing close to the 7 sigma level, well beyond the 5 required for a discovery, and that the new particle's properties appear to be consistent with those of a Standard Model Higgs boson.
The CMS and ATLAS representatives went on to report that further analysis of the data, and a probable combination of both experiments' data next year, will be required before some key properties of the new particle, such as its spin, can be determined conclusively. The focus of the analysis has now moved from discovery to measurement of the new particle in its individual decay channels.
The measurements reported by both experiments show that the new Higgs-like particle is in good health with a mass of around 125 GeV, but much further analysis is needed to reveal the full details of its identity. The next update is scheduled for the spring 2013 conferences, but for the final word before the LHC resumes running in 2015, we'll probably have to wait some time longer.
Other highlights from CERN included the LHCb experiment reporting on a measurement of one of the rarest processes so far observed in particle physics, the decay of a Bs (pronounced B-sub-s) meson into two muons. Measurements of rare decays provide important tests of the Standard Model of particle physics, and are good places to look for new physics beyond the Standard Model.
The highlights from the ALICE experiment's first three years are detailed studies of the quark-gluon plasma, QGP, the matter of the primordial universe. Measurements from the TOTEM experiment give insights on the structure of the proton and provide input to the analyses of the other LHC experiments.
Physicists hope that a "new physics" will provide a more straightforward explanation for the characteristics of the Higgs boson than that derived from the current Standard Model. This new physics is sorely needed to find solutions to a series of yet unresolved problems, as presently only the visible universe is explained, which constitutes just four percent of total matter.
"The Standard Model has no explanation for the so-called dark matter, so it does not describe the entire universe – there is a lot that remains to be understood," said Dr. Volker Büscher of Johannes Gutenberg University Mainz (JGU).
"Almost half a century has passed since the existence of the Higgs boson was first postulated and now it seems that we at last have the evidence we have been looking for. What we have found perfectly fits the predicted parameters of the Higgs boson," says Büscher.
The Higgs boson is important to our current fundamental theory of physics as it explains why the elementary building blocks of matter have a mass at all.
The existence of the Higgs boson was predicted in 1964 and it is named after the British physicist Peter Higgs. It is the last piece of the puzzle that has been missing from the Standard Model of physics and its function is to give other elementary particles their mass. According to the theory, the so-called Higgs field extends throughout the entire universe. The mass of individual elementary particles is determined by the extent to which they interact with the Higgs bosons.
On the one hand, the Higgs particle is the last component missing from the Standard Model of particle physics. On the other hand, physicists are struggling to understand the detected mass of the Higgs boson. "Using our theory as it currently stands, the mass of the Higgs boson can only be explained as the result of a random fine-tuning of the physical constants of the universe at a level of accuracy of one in one quadrillion," explained Matthias Neubert, of the Institute of Physics at Johannes Gutenberg University Mainz (JGU).
The image at the top of the page is galaxy cluster Abell 520 — 2.4 billion light-years away — may challenge some of our basic theories about Dark Matter. It is overlaid with false-color maps showing concentrations of starlight (orange), hot gas (green) and mass (blue). The mass is mostly Dark Matter.
More on the subject:
The Daily Galaxy via CERN and Johannes Gutenberg University Mainz (JGU).
Image Credit: M.J. Jee and A. Mahdavi/NASA/ESA/CFHT/CXO