The Higgs boson is a cornerstone of the Standard Model, a theory developed in the early 1970s to explain the five percent of the Universe composed of visible matter and energy, all carried by fundamental particles. Now, two years after making history by unearthing the Higgs boson, the particle that confers mass, physicists are broadening their probe into its identity, hoping this will also solve other great cosmic mysteries. The better they become acquainted with the Higgs at the infinitely small quantum level, the further the experts seem from explaining certain cosmic-scale questions, like dark matter.
From next year, scientists will smash sub-atomic particles at ever higher-speeds in the upgraded Large Hadron Collider (LHC) near Geneva, which announced the Higgs discovery on July 4, 2012. Not only will they hope for new particles to emerge, but also for the Higgs to show signs of, well, weirdness.So far, the Higgs has conformed well to the traits predicted in the Standard Model of particle physics, the mainstream theory of how our Universe is constructed.
The model has weaknesses in that it doesn't explain dark matter or dark energy, which jointly make up 95 percent of the Universe. Nor is it compatible with the theory of gravity. Scientists have proposed alternative theories to explain the inconsistencies -- like supersymmetry which postulates the existence of a "sibling" for every particle in the Universe and may explain dark matter and dark energy.
No proof of such symmetric particles has been found at the LHC, currently in sleep mode for an 18-month overhaul to super-boost its power levels.
Supersymmetry, additionally, predicts the existence of at least five types of Higgs boson, and physicists will thus be watching the LHC Higgs closely for signs of behaviour inconsistent with the Standard Model. "It would give us a very good hint that there is physics there beyond the Standard Model and that there's new, additional physics coming soon," said Dave Charlton, who heads the ATLAS experiment at the LHC, a facility of the European Organisation for Nuclear Research (CERN) which celebrated its 60th anniversary on Tuesday. "It could help to explain many of the other problems we have in physics at the moment," he added.
For starters, they don't understand how it [the Higgs Boson] can have such a small mass. Nor is the evidence consistent for the role it played in the development of the early Universe after the Big Bang -- issues that may be resolved by so-called New Physics the experts hope will follow soon.
When the LHC fires up again next year, scientists will be on the lookout for new particles, including other types of Higgs, and possible "invisible decays" of the boson to indicate the presence of dark matter.
"All of the particles of the Standard Model have now been discovered," said Charlton."If we see new particles, it's something new... if we see new particles, it will point to something whether it is supersymmetry or some other new theory. "It will tell us that the Standard Model is broken, that there is something else."
Charlton said we may never know if the Higgs found at the LHC was exactly the Standard Model version or something that just resembles it.
Themis Bowcock, particle physics head at the University of Liverpool, said confirmation of several Standard Model predictions over the past two years have placed a new focus on what is not yet known. "It allows us to step back and view the boundaries of our knowledge with a keener eye," he told AFP. "We realise we have mastered our closest and most obvious challenges, but like a 15th century navigator we are motivated to venture beyond our mapped lands to discover the missing 95 percent -- the New World."
In the summer of 2012, scientists hailed the announcement of the Higgs discovery, speculating that it could one day make light speed travel possible by "un-massing" objects or allow huge items to be launched into space by "switching off" the Higgs.* CERN scientist Albert de Roeck likened it to the discovery of electricity, when he said humanity could never have imagined its future applications.
"What's really important for the Higgs is that it explains how the world could be the way that it is in the first millionth of a second in the Big Bang," de Roeck told AFP.* "Can we apply it to something? At this moment my imagination is too small to do that."
Physicist Ray Volkas said "almost everybody" was hoping that, rather than fitting the so-called Standard Model of physics -- a theory explaining how particles fit together in the Universe -- the Higgs boson would prove to be "something a bit different".
"If that was the case that would point to all sorts of new physics, physics that might have something to do with dark matter," he said, referring to the hypothetical invisible matter thought to make up much of the universe.
"It could be, for example, that the Higgs particle acts as a bridge between ordinary matter, which makes up atoms, and dark matter, which we know is a very important component of the universe."
"That would have really fantastic implications for understanding all of the matter in the universe, not just ordinary atoms," he added.* De Roeck said scrutinising the new particle and determining whether it supported something other than the Standard Model would be the next step for CERN scientists.
Definitive proof that it fitted the Standard Model could take until 2015 when the LHC had more power and could harvest more data.
The LHC went offline for a two-year refit in December, 2012 that will see its firepower doubled to 14 trillion electronvolts -- a huge step forward in the search for new particles and clues about what holds them all together. De Roeck said he would find it a "little boring at the end if it turns out that this is just the Standard Model Higgs".
Instead, he was hoping it would be a "gateway or a portal to new physics, to new theories which are actually running nature" such as supersymmetry, which hypothesises that there are five different Higgs particles governing mass.
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 Daily Galaxy via AFP (PARIS), CMS, and CERN
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