04 July 2012

CERN Announces Discovery of Higgs Boson

An example of simulated data modeled for the CMS particle detector on the Large Hadron Collider (LHC) at CERN. Here, following a collision of two protons, a Higgs boson is produced which decays into two jets of hadrons and two electrons. The lines represent the possible paths of particles produced by the proton-proton collision in the detector while the energy these particles deposit is shown in blue.
The European Organization for Nuclear Research (CERN) has announced the discovery of the Higgs Boson with a discovery level of 4.9 sigma. The Large Hadron Collider has been conducting the ATLAS experiment and the CMS Experiment.

A 5 sigma certainty means that it has just a 0.00003% probability that the result is due to chance. This is why most report the discovery as 99.9999% sure.

The announcement was done in Melbourne, Australia at the opening of the 2012 International Conference on High Energy Physics (ICHEP). The 2012 ICHEP is this year's major particle physics conference.

The A Toroidal LHC Apparatus (ATLAS) and Compact Muon Solenoid (CMS) experiments are the largest international scientific collaborations in history, involving more than 3000 scientists, engineers, and students from 172 institutes in 40 countries.

The CMS has the Higgs boson at a mass of 125.3 +/- 0.6GeV at 4.9 Sigma. ATLAS discovers the Higgs Mass at 126.5 GeV at 5 sigma. Previously, multiple independent measurements point to the region of 124 to 126 GeV. As such, the particle has been independently discovered by both ATLAS and CMS experiments.

As physicist Brian Cox puts it, "In simple language, CMS have discovered a new boson, and it behaves like the Standard Model Higgs... ATLAS and CMS have independently discovered a new particle mass ~ 126 GeV which behaves like SM Higgs"

"We have restricted the most likely mass region for the Higgs boson to 116-130 GeV, and over the last few weeks we have started to see an intriguing excess of events in the mass range around 125 GeV," explained ATLAS experiment spokesperson Fabiola Gianotti last December 2011.

The existence of the Higgs particle is a step towards the theory of the Standard Model. The Standard Model is a mathematical model that describes or explains all particle physics observed so far by physicists.

The Higgs boson within the Standard model explains why other elementary particles, except the photon and gluon, are massive. In particular, the Higgs boson would explain why the photon has no mass, while the W and Z bosons are very heavy.

A diagram summarizing the tree-level interactions between elementary particles described in the Standard Model. Vertices (darkened circles) represent types of particles, and edges (blue arcs) connecting them represent interactions that can take place. The organization of the diagram is as follows: the top row of vertices (leptons and quarks) are the matter particles; the second row of vertices (photon, W/Z, gluons) are the force mediating particles; and the bottom row is the Higgs boson.
The Higgs Boson is theorized to be the particle that determines the mass of an object. A boson is a class of particles and these particles form a field; the Higgs field. This is similar to how photons comprise the electromagnetic field.

By discovering the Higgs Boson, scientist may then understand how mass is obtained and why some elements have more mass than others.

Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity. Unlike weight, mass is not affected by gravity. An object has no weight in space but still has mass.

The Higgs Mechanism as proposed by Peter Higgs is that there is a Higgs field that are attracted to objects which slows them down, giving them mass. The more particles (Higgs Boson) of the field that the object attracts, the more mass it has. Furthermore, as the mass of an object approaches zero, the closer it gets to accelerating to the speed of light. This can be seen with light, since light has no mass and travels at that speed.

Regarding the discovery of the Higgs like particle, "It's an incredible thing that has happened in my lifetime," says Higgs

Video: What is the Higgs Boson?

CERN experiments observe particle consistent with long-sought Higgs boson

Geneva, 4 July 2012. At a seminar held at CERN1 today as a curtain raiser to the year’s major particle physics conference, ICHEP2012 in Melbourne, the ATLAS and CMS experiments presented their latest preliminary results in the search for the long sought Higgs particle. Both experiments observe a new particle in the mass region around 125-126 GeV.

“We observe in our data clear signs of a new particle, at the level of 5 sigma, in the mass region around 126 GeV. The outstanding performance of the LHC and ATLAS and the huge efforts of many people have brought us to this exciting stage,” said ATLAS experiment spokesperson Fabiola Gianotti, “but a little more time is needed to prepare these results for publication.”

"The results are preliminary but the 5 sigma signal at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” said CMS experiment spokesperson Joe Incandela. “The implications are very significant and it is precisely for this reason that we must be extremely diligent in all of our studies and cross-checks."

“It’s hard not to get excited by these results,” said CERN Research Director Sergio Bertolucci. “ We stated last year that in 2012 we would either find a new Higgs-like particle or exclude the existence of the Standard Model Higgs. With all the necessary caution, it looks to me that we are at a branching point: the observation of this new particle indicates the path for the future towards a more detailed understanding of what we’re seeing in the data.”

The results presented today are labelled preliminary. They are based on data collected in 2011 and 2012, with the 2012 data still under analysis. Publication of the analyses shown today is expected around the end of July. A more complete picture of today’s observations will emerge later this year after the LHC provides the experiments with more data.

The next step will be to determine the precise nature of the particle and its significance for our understanding of the universe. Are its properties as expected for the long-sought Higgs boson, the final missing ingredient in the Standard Model of particle physics? Or is it something more exotic? The Standard Model describes the fundamental particles from which we, and every visible thing in the universe, are made, and the forces acting between them. All the matter that we can see, however, appears to be no more than about 4% of the total. A more exotic version of the Higgs particle could be a bridge to understanding the 96% of the universe that remains obscure.

“We have reached a milestone in our understanding of nature,” said CERN Director General Rolf Heuer. “The discovery of a particle consistent with the Higgs boson opens the way to more detailed studies, requiring larger statistics, which will pin down the new particle’s properties, and is likely to shed light on other mysteries of our universe.”

Positive identification of the new particle’s characteristics will take considerable time and data. But whatever form the Higgs particle takes, our knowledge of the fundamental structure of matter is about to take a major step forward.


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