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Higgs Boson Particle Discovered

By Various experts

CERN (the European Organization for Nuclear Research) has announced that the long-sought Higgs boson exists after experiments conducted in the Large Hadron Collider yielded results that are consistent with its existence. The Higgs boson is the final particle in the Standard Model of physics, and has remained hidden from scientists’ reach until a series of experiments confirmed its presence.

“Today's announcement that the Higgs boson has been discovered at CERN represents the most important and profound discovery in particle physics in almost 30 years. The Higgs represents the key missing piece of the jig-saw puzzle that is the famous Standard Model of nuclear and particle physics. It has been anticipated for more than four decades and were it not there theorists all over the world would have been back to their drawing boards in desperation. Now that it has been found, there is not only a palpable sense of relief but a great deal of excitement as we begin to pore over the details of the various experimental results to see what hints they may have for completely new physics which goes beyond the Standard Model.”

Professor Anthony Thomas is Director of the Adelaide Node of the ARC Centre of Excellence in Particle Physics at the Terascale. He is based at the University of Adelaide’s School of Chemistry and Physics

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“The existence of the Higgs boson is a cornerstone of Einstein's dream. In 1955 Albert Einstein died without fulfilling his lifelong dream: the unification of all physical laws in a single equation. Since then thousands of physicists have pursued the quest for unification. Various theories have been worked out that might realise the dream, however we do not know which one, if any, is correct.

In 1983 a glimpse of hope for unification emerged in the form of the discovery of two particles called the W and Z bosons. The existence of these particles proved that the unification of two out of four fundamental forces is possible. However, the unification was not complete without the existence of a hypothetical third particle: the Higgs boson. So the existence of the Higgs particle became one of the cornerstones of unification.

In 1991 the construction of the Superconducting Super Collider started. This machine was going to be powerful enough to find the Higgs boson. Unfortunately, in 1993 the project was cancelled by the US Congress, and Einstein's dream once again was fading away. Today, after 50 years of its theoretical introduction, we have learned that the Higgs boson probably exists! This is a tremendous step ahead in our fundamental understanding of unification and in realizing Einstein's dream.”

Dr Csaba Balazs is Director of the Monash Node of the Centre for Particle Physics at the Terascale, Monash University, Melbourne

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“This could hardly be a more exciting time for our field of research. The Higgs boson has been searched for using progressively larger and more sophisticated accelerators and detectors for 30 or 40 years now. Whilst it is too early to say yet whether the new particle which has been seen is the Higgs predicted by our Standard Model of Particle Physics, or something even more interesting, it is fair to say that we have taken a very big step forward today. Now the hard work begins to flesh out what this new thing really is.

Here at the conference centre in Melbourne leading up to the broadcast from CERN, I was struck by the buzz going around the place. Some knew what one of the two large experiments ATLAS and CMS would say, some knew nothing, and many had heard rumours or even seen leaks. What everyone had in common was a sense of anticipation and the feeling that the field may not be the same come the evening.”

Associate Professor Kevin Varvell is Director of the Sydney Node of the ARC Centre of Excellence for Particle Physics at the Terascale. He is based in the School of Physics at the University of Sydney

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“The Higgs boson gives each type of particle its own mass. Its existence is required to explain several features of our current model of particle physics, and evidence for the Higgs will further validate this model. Hints from data at the Large Hadron Collider collected in 2011 pointed to a region in mass at about 125 GeV (equivalent to about 125 proton masses) where some anomalous activity may be occurring. The data collected in 2012 so far have been analysed and are demonstrating excesses consistent with a signal which at first glance looks consistent with the expectation of a Standard Model Higgs Boson. If confirmed to be the Standard Model Higgs this will provide a crucial piece in our understanding of how particles in the Universe are assigned masses. Its measurement could have far reaching effects on research in fundamental particle physics.”

Dr Paul Jackson is a lecturer in high energy particle physics in the School of Chemistry and Physics at the University of Adelaide and works with the ARC Centre of Excellence in Particle Physics at the Terascale. He is also team leader of the Adelaide group on the ATLAS experiment at the CERN LHC

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“This is a historic day for science. After a 50 year quest to find the particle that explains the origin of mass, two independent experiments have finally uncovered definitive evidence for a new particle with exactly the properties required. Thousands of physicists, computer scientists and engineers have chased this result for decades, working tirelessly to build ever more complex machines capable of glimpsing this most elusive of subatomic particles. The really great thing is that this is just the beginning of a wild adventure to discover if the particle is the simplest type of Higgs boson, or a more exotic variety that will contain clues to even greater cosmic mysteries. Australian researchers have played a significant role in this research and, through the Centre of Excellence for Particle Physics, will continue to make major discoveries at the highest level in international science.”

Dr Martin White is a Research Associate in the University of Melbourne with the ARC Centre of Excellence for Particle Physics at the Terascale (CoEPP).

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“This is a very exciting time for physicists. Physicists are not normally very effusive but we are at this time. This is a milestone for the physics community, and for human understanding of the fundamental laws that govern the universe. As scientific discoveries go, this is up there with finding a way to split the atom. People have been working towards this for many years, and Australian groups have been part of this from the beginning so for the best part of 25 years. And to now be part of the reportage is a real privilege.”

Professor Geoff Taylor is the Director of the ARC Centre of Excellence for Particle Physics at the Terascale (CoEPP) and chair of the 36th International Conference on High Energy Physics (ICHEP 2012) in Melbourne.

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“Scientists at CERN are to be congratulated on today’s results, which are a great achievement for the Large Hadron Collider and other experiments leading up to this.

“I am astounded at the amazing speed with which these results have emerged. They are a testament to the expertise of the researchers and the elaborate technologies in place.

“I never expected this to happen in my lifetime and shall be asking my family to put some champagne in the fridge.”

Professor Sir Timothy O’Shea, Principal of the University of Edinburgh

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“We are delighted at this significant development in the search for the Higgs boson, and congratulate Professor Peter Higgs on this.

“This particle is integral to our understanding of the physical world and evidence of its existence is a testament to Professor Higgs and to all the scientists who are working to uncover it.

“Professor Higgs has inspired many colleagues and students over the years, some of whom have also gone on to become involved in the Large Hadron Collider experiments. His legacy will continue to inspire future generation of physicists, at Edinburgh and beyond.”

Professor Peter Higgs of the University of Edinburgh

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"Today we have witnessed a discovery which gives unique insight into our understanding of the universe and the origin of the masses of fundamental particles. There is no doubt that the Higgs particle exists and we now have to understand its properties and whether it behaves exactly as predicted by theory.

“This discovery is the first milestone of the LHC physics programme and opens the door to many more exciting discoveries by the LHC experiments in the next decade.

“Particle physicists at the University of Manchester's play a leading role on the ATLAS experiment and have built part of the ATLAS detector. “

Prof Stefan Söldner-Rembold, Professor of Particle Physics at the University of Manchester

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“Today is a historic day. A new heavy particle, the first of its kind, has been observed in CMS. It took 20 years to build the CMS detector, arguably the most complex scientific instrument ever built. This result is a tribute to the talent and dedication of thousands of scientists and engineers from about 40 countries that built and now operate CMS. Within the experimental precision achieved so far the results appear consistent with expectations for a standard model Higgs boson.

“The Higgs boson is the last and key missing element of the highly successful standard model, one of the great achievements of 20th century science. More data are required to reveal whether it has all the properties of the standard model Higgs boson or whether some do not match, implying new physics beyond the standard model. I believe this observation opens the door to a new vista of physics that will take many more years to explore.”

Professor Tejinder Virdee FRS, Imperial College London

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"Many people have been working night and day to analyse the fresh data from the LHC which has been pouring in this year, which has allowed us to reveal these exciting preliminary results today. The tantalising hints we saw in December are repeated and strengthened in the new ATLAS data, so we're now quite confident that we're seeing a new particle. Finding out if it's got all the properties of the Standard Model's Higgs boson will need a lot more data and painstaking work. We're now opening a new chapter of fundamental physics, as the LHC was designed to do."

Professor Dave Charlton, Deputy Spokesperson for the ATLAS project from the University of Birmingham’s School of Physics and Astronomy

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“This is cast-iron proof that a new particle has been discovered. It looks like the Higgs.

“For physicists the dice are definitely now loaded in favour of a discovery. Based on the CERN results alone there appears to be less than one chance in a million that this is fake, which is roughly the same probability as flipping a coin heads-up 21 times in a row. Very few physicists would privately argue that this is not a Higgs particle.

“Half a century after it was first proposed, and after a monumental effort by generations of physicists around the world, the discovery of the Higgs represents a major breakthrough in our fundamental understanding of nature. For physicists, this is the equivalent of Columbus discovering America.

“Each of the two experiments (ATLAS and CMS) searching for the Higgs have presented data which, independently, surpass the ‘gold-standard’ for discovery which they themselves have set. Although the ATLAS and CMS teams are keen to point out the preliminary nature of this data, newly released data from the Tevatron at Fermilab in the US seem to support the Higgs hypothesis.

“Our perception of the Higgs is that it is like no other fundamental object in nature. Our modern understanding of physics – known as the Standard Model – relies on the existence of the Higgs boson, which interacts with other particles making some very heavy whilst leaving others light. This shapes the Universe we know today.

“For the last 40 years it has allowed us to understand phenomena such as light, the way the sun burns, and how atoms and nuclei are held together. Without the Higgs there would be no stars and ultimately no life.

“Physicists have laboured for decades to reach this goal but a huge task still awaits them. Mapping out the properties of this new particle is the next step, it opens a new era in Particle Physics and will take years more painstaking work. But the stakes could not be higher. The Higgs offers humanity, for the first time, a unique glimpse into why nature is the way it is.”

Prof Themis Bowcock, Head of Particle Physics at the University of Liverpool

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Questions:

Q. I understand that it is the Higgs field that confers mass but what is the relationship of the Higgs boson to the field? And if it is the field that confers mass, what does the Higgs boson do?

SS: “In quantum theory all fields have "quanta" associated with them. As an example, the photon is the quantum of the electromagnetic field. In analogy, the Higgs boson is the particle related to the Higgs field.”

JG: “The Higgs field permeates throughout the whole universe. A Higgs boson can be thought of as a little ripple of the Higgs field. It is the smallest ripple allowed by quantum mechanics.”

Q. I understand that the field is around us all the time. Are Higgs bosons there too? I.e. are they being made in nature all the time or were they only made in the fraction of the second after the Big Bang, hence the need to recreate these conditions?

SS: “Higgs particles are very heavy and it therefore requires a lot of energy to produce them. This is the reason we need high-energy accelerators like the LHC.”

JG: “It takes a lot of energy to create real Higgs bosons. Also they are very short lived and decay rapidly into other particles. It is this process that is being observed at LHC.”

Q. if the field is there all the time, why not just look for it? Or is it even harder to detect?
SS: “The Higgs field interacts with the fundamental particles that make up the world around us and it gives them their mass. When measuring particle masses we see the Higgs field at work. However, to get a positive proof that this theory is really correct we need to find the Higgs particle which comes with the field. Peter Higgs actually postulated the existence of the Higgs particle as an afterthought to his original paper as a possible experimental signature of his theory.”

JG: “The Higgs field provides a mechanism to generate mass in various elementary particles. In particular, the fact that the W-bosons and the Z-bosons have mass is good indirect evidence for the Higgs field. Detecting the Higgs boson will provide a direct test for the existence of the Higgs field itself.”

SS = Stefan Söldner-Rembold at the University of Manchester
JG = Prof Jerome Gauntlett, Head of Theoretical Physics at the Blackett Laboratory, Imperial College London

Source: AusSMC, UKSMC