In a seminar held at CERN today, physicists presented the latest results of their searches for the Standard Model Higgs boson – hinting at the possible nature of the elusive particle.
According to the researchers, it’s too early to say whether their experiments have discovered the Higgs boson, but the tentative findings of have been causing much interest in the scientific community.
The main conclusion is that the Standard Model Higgs boson, if it exists, is most likely to have a mass constrained to the range 116-130 GeV by the ATLAS experiment, and 115-127 GeV by CMS. Tantalising hints have been seen by both experiments in this mass region, but these are not yet strong enough to claim a discovery.
Links:
- A helpful backgrounder on the Higgs boson, supplied by the Canadian SMC
- Webcast of the entire seminar from CERN, explaining the latest results
- An extensive collection of press information, photos and video provided by CERN.
Our friends at the Australian, Canadian and UK Science Media Centres have collected the following reaction from leading physicists.
Feel free to use these quotes in your reporting. The New Zealand Science Media Centre has local experts available for comment, contact us for more info (04 4995476; smc@sciencemediacentre.co.nz).
From the AusSMC:
Associate Professor Kevin Varvell is from the School of Physics at the University of Sydney, and the Director of the Sydney node of the ARC Centre of Excellence for Particle Physics at the Terascale
“The results announced last night have the scientific community anticipating that the long search for the Higgs boson may soon bear fruit – by either seeing it emerge with more data in 2012 or by closing the window on its existence as predicted by our current standard theory. A big further step will have been taken towards a deeper understanding of the workings of the Universe at a fundamental level.”
from the UK SMC:
Dr Alan Barr of Oxford University’s Department of Physics, ATLAS UK physics coordinator, said:
“It is a testament to the superb performance of the LHC that we are already finding hints that might be indicative of Higgs bosons so early in the machine’s lifetime. The results are not yet conclusive, but during the next year we will know whether the Higgs boson exists in the form predicted by the “Standard Model” of particle physics. The analysis has to be done very carefully, since in scientific research the most interesting results are often found in unexpected places.’
“We must bear in mind that the Standard Model is known to be incomplete, since it describes only that 5% of the universe that is made of atoms. What the LHC will tell us about the other 95% of the universe is likely to be an open question for many years to come.”
Prof Dan Tovey, Professor of Particle Physics at the University of Sheffield and spokesman for ATLAS, said:
“While these results do not provide conclusive proof of the existence of the Higgs boson the fact that broadly similar hints have been seen by two competing experiments using several different complementary techniques is very suggestive. With much more data due next year it won’t be long before we can answer this question once and for all.”
Prof Geoff Hall, Professor of Physics at Imperial College London and UK spokesperson for CMS said:
“At the beginning of this year, we had little idea of what mass the Higgs boson might have, assuming it really existed. Now the situation is completely changed, as a result of less than one year of LHC data, and the region where the Higgs may be found has been narrowed from about 500 GeV to 10-20 GeV. There are also strong hints that the Higgs may really exist in that narrow range. This is quite remarkable. The successful and rapid analysis shows how well the experiments work and how ready for the complex studies the scientists are, after about twenty years of building and preparation. It has been a huge effort.
“It is too soon to draw conclusions but it certainly begins to feel as though we are on the verge of momentous progress, confirming the Standard Model and shedding new light on deeper ideas. Of course, it is tempting to speculate how particle physics will change with a Higgs discovery but most of us are still focused on verifying that it is really found and, if so, to prove what kind of Higgs it is – eg Standard Model or supersymmetric. This will require a lot more data in the coming year, and even after that for some years to come.”
Prof Themis Bowcock, Head OF Particle Physics at the University of Liverpool, said:
“The CERN results on the Higgs boson have the scientific world agog. Have they or have they not seen the elusive particle sometimes called the God Particle? First proposed in the 1960s, this particle plays a crucial role in the evolution of the Universe from the Big Bang to the way we see it today.
“Our understanding of nature and its fundamental forces is known as the Standard Model. 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.
“The Standard Model relies on a particle called the Higgs boson which interacts with other particles making some very heavy whilst leaving others light. This shapes the Universe we know today. However to date no-one has found direct evidence of the Higgs.
“The ATLAS and CMS experiments at the LHC have come as close as anyone to observing the Higgs and now both have presented small but significant signals. It is possible that each observation is simply a statistical fluke, a fluctuation in the background, mimicking a Higgs signal. But the fact that ATLAS and CMS independently agree on the possible Higgs mass substantially increases the overall significance of the results.
“If the Higgs observation is confirmed, through analysis of data to be collected next year, this really will be one of the discoveries of the century. Physicists will have uncovered a keystone in the makeup of the Universe – one whose influence we see and feel every day of our lives.”
Dr Alan Barr, physics coordinator of the ATLAS UK collaboration, said:
“Our understanding of physics at the microscopic level is described by a beautiful piece of mathematics known as the “Standard Model”. For that mathematical model to work correctly, various pieces must work together, like a well-engineered machine. The Higgs boson is a crucial part of the machinery of the subatomic world.
“This evidence of the existence of a Higgs boson suggests that the mathematically beautiful theory of the subatomic world is more than just an elegant model, and that it really does seem to describe the universe around us.”
Dr Stephen Haywood, Head of the Atlas Group at the STFC Rutherford Appleton Laboratory, said:
“This is what many of us have been working towards for the best part of 20 years. If the first inklings of the Higgs boson are confirmed, then this is just the start of the adventure to unlock the secrets of the fundamental constituents of the Universe.”
Dr Claire Shepherd-Themistocleus, Head of the CMS Group at the STFC Rutherford Appleton Laboratory, said:
“We are homing in on the Higgs. We have had hints today of what its mass might be and the excitement of scientists is palpable. Whether this is ultimately confirmed or we finally rule out a low mass Higgs boson, we are on the verge of a major change in our understanding of the fundamental nature of matter.”
Prof Stephan Söldner-Rembold, Head of the Particle Physics Group at the University of Manchester said:
“ATLAS and CMS have presented an important milestone in their search for the Higgs particle, but it is not yet sufficient for a proper discovery given the amount of data recorded so far. Still, I am very excited about it, since the quality of the LHC results is exceptional.
“The Higgs particle seems to have picked itself a mass which makes things very difficult for us physicists. Everything points at a mass in the range 115-140 GeV and we concentrate on this region with our searches at the LHC and at the Tevatron.
“The results indicate we are about half-way there and within one year we will probably know whether the Higgs particle exists with absolute certainty, but it is unfortunately not a Christmas present this year. The Higgs particle will, of course, be a great discovery, but it would be an even greater discovery if it didn’t exist where theory predicts it to be. This would be a huge surprise and secretly we hope this might happen. If this is case, there must be something else that takes the role of the “standard” Higgs particle, perhaps a family of several Higgs particles or something even more exotic. The unexpected is always the most exciting.”
Prof Paddy Regan, Department of Phys?cs, University of Surrey said:
“The identification of the Higgs Boson at CERN, if confirmed, would be the icing on the cake for the standard model of physics, which aims to explain how all the matter which make up the structure of the universe holds together and interacts. However, what I personally find most amazing is not necessarily the mathematical beauty which predicts the existence of the Higgs Boson, but the incredible 21st century technology which allows the search to be undertaken. The CERN scientists at ATLAS and the CMS try to pick out the weakest glimpses of the decays of the Higgs boson; to be able to select out these few, extra special decays from the overwhelming massive storm of residues from the multitude of other particle collisions and identify such a rare object is simply mindblowing.”
Professor Paul Newman, Professor of Particle Physics, University of Birmingham, said:
“There is immense excitement surrounding these seminars. We don’t expect to have a definitive answer to the Higgs boson question until sometime next year, but depending on how closely the two experiments agree, things could be about to get very interesting indeed.”
Prof John Womersley, STFC Chief Executive said:
“There is still some way to go before the existence of the Higgs boson can be confirmed or not, but excitement is mounting. UK physicists and engineers have played a significant role in securing today’s results, and will continue to be at the forefront of exploring the new frontiers of knowledge opened by the results coming from the LHC. This is an incredibly exciting time to be involved in physics!”
From the Canadian Science Media Centre:
Manuella Vincter, Carleton University Physics Professor and Canada Research Chair in Experimental Particle Physics. Member of the ATLAS Collaboration:
The outstanding performance of the Large Hadron Collider as well as of the ATLAS and CMS experiments this past year has made it possible to present to the scientific community today results of the search for the Higgs Boson. A long, collaborative chain of talented students and research scientists was required to pull this off so quickly after the end of the 2011 data-taking period and I am very proud to say that many Canadian scientists contributed to this success. Though it is still too early to claim a discovery, what I find most exciting is the possibility that, with another year’s worth of data, we may be able to make a definitive statement on the existence of a Standard Model Higgs Boson. Such a statement would help guide our theoretical and experimental efforts over the next decade.
*Oliver Stelzer-Chilton, TRIUMF scientist and collaborator on ATLAS:
“We live in exciting times! We are closing in on the long sought after Higgs boson. The search is now intensifying in the 115-130 GeV mass region. There are intriguing hints near 125 GeV seen by both experiments, but not statistically significant to draw any conclusions, yet. With the exceptional performance of the LHC, we will already have enough data next year to make more definite statements.”
Rob McPherson, ATLAS Canada spokesperson:
The performance of the LHC collider, and both the ATLAS and CMS experiments, in 2011 exceeded our wildest hopes. ATLAS and CMS see excesses consistent with a Standard Model Higgs boson with a mass at about 126 GeV. While not quite enough to discover the Higgs with the 1 in a million threshold that particle physics demands, it is tantalizingly close. I eagerly await the 2012 run where we will discover or exclude the Standard Model Higgs. The end of the nearly half a century journey for the Standard Model is finally in sight!
Isabel Trigger, research scientist at TRIUMF national particle physics laboratory:
This is the first hint of the direction our careers will take over the next decades. Knowing for sure that there is a Higgs, and knowing its mass, will tell us what else to look for, what kind of experiments will need to be built in the future. This is the first tentative cry of “land ahead!” that lets us chart a course for discovery.
Nigel Lockyer, director of TRIUMF national particle physics laboratory:
We have the last hiding place of the Standard Model Higgs completely surrounded! It’s either going to be in there or we’re going to have to revise everything we thought we knew. This type of scientific drama is thrilling to me; with thousands of scientists working on each team, you know they’ve been very thoughtful. The pressure is intense and yet the quest noble – to discover what is really going on in our world.
Dr. Philip Schuster, Faculty, Perimeter Institute for Theoretical Physics
“For 40 years, physicists have searched for the origin of the weak interactions, and the mechanism that generates mass for fundamental particles in the Universe. These phenomena are responsible for basic features of our world ranging from the long lifetime of the Sun to the very existence of atoms. Today, it looks like we have promising evidence that there is actually a Higgs mechanism in Nature, and the particle associated with that mechanism may finally be showing itself. Going forward, physicists will gather more evidence needed to prove that a Higgs particle exists. Understanding the properties of the Higgs mechanism and where it comes from will be an important goal for the next decade.”