HIGGS BOSON

HIGGS BOSON19 OCTOBER, 2012CONTENTSSTANDARD MODELWHAT IS HIGGS BOSON?HOW DOES THE HIGGS MECHANISM WORKS?WHY DO WE NEED HIGGS BOSON?THE HIGGS BOSON AND THE BIG BANGDETECTION OF HIGGS BOSONSTANDARD MODELgrew out of combining special relativity and quantum mechanicsdescribes our universe at the most fundamental leveldescribes the fundamental particles and how they interact via three of the four fundamental forces of naturestrong nuclearweak nuclearelectromagneticgravity is not includedSTANDARD MODELThe standard model asserts that the material in the Universe is made up of elementary fermions interacting through fields, of which they are the sources.

The particles associated with the interacting fields are bosons.

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5STANDARD MODELSpace consists of the Higgs field, with a non-zero value in all space.

There are two neutral and two charged components to the field.

One of the neutral and both of the charged components combine to create the W & Z bosons, which create the weak force, one of thefundamental forces of physics.

The remaining neutral charge creates the scalar Higgs boson, which has neither charge nor spin (thus causing it to followBose-Einstein statistics, and making it aboson).

Imagine an infinite field of snow.Empty space is like a medium, and as particles travel through this medium, some of them interact with it, some of them dont interact with it.The particles which do not interact with the medium is like a skier skimming across the top without sinking and fast.The ones that do interact with this medium, they acquire masses.A person walking on the snow with snow shoes with speed less than that of the skier is like a particle with mass interacting with the medium.The ones that pass through without interacting, those are our massless particles.If you have just boots on, then you will sink deeply into the snow like a particle with higher mass.

Like the snow-field is made up of snowflakes, Higgs field consists of Higgs Bosons.

The Higgs Boson has its job of giving masses to all the other elementary particles.

The elementary particles like electrons and neutrons are very symmetric. The way in which the different particles appear is the same.

The job of the Higgs boson is to distinguish between the two different types of particles.

Depending on how those different types of quark, or electron and the neutron, depending on how they connect to that Higgs field, that Higgs boson, they get different masses. The symmetry between these particles is broken.How the Higgs Mechanism Works Einstein AnalogyNumerous physicists chat quietly in a fairly crowded room.

Einstein enters the room causing a disturbance in the field.

3. Followers cluster and surround Einstein as this group of people forms a massive object.

Why Do We Need the Higgs?In order for the Standard Model to retain its symmetry, all particles would have to be massless. This is not possible since through experiments we know the weak force carriers have mass.

Yukawas formula states that force carrier mass is inversely proportional to force range. In this way, we can also deduce that weak force carriers have mass. (Because of the nature of the strong force, it is an exception to this rule).

The Higgs mechanism was originally introduced to allow the W and Z bosons to have mass. Physicists found to their delight that this was a way to give fermions mass as well.

The current Standard Model provides no explanation of how some particles come to have mass.

Without the Higgs mechanism, the SM remains symmetric only if mediators remain massless and produces nonsense results if weak force mediators have mass.

Developers of the Higgs mechanism used spontaneous symmetry breaking to introduce mass while retaining the SMs overall symmetry.

The SMs symmetry is broken only at a single point.Spontaneous Symmetry Breaking Analogies Dinner table analogyGlasses of water are placed between each plate at a circular dinner table. The arrangement is considered symmetric. The first person chooses a glass to take on their right or left. When that glass is chosen spontaneously, symmetry is broken, and everyone else at the table is forced to choose that side. Mexican hat analogySet a ball on the tip of a Mexican Hat the ball decides spontaneously where to fall. There is no influence on the balls path of choice.

Here the trough of the sombrero represents Higgs field lowest energy states. The chosen field is spontaneously chosen, breaking the symmetry.In the SM, the Higgs is introduced so that the physics and symmetry of the Standard model is retained.

What if the Higgs Boson did not exist?In view of the fact that mass would not exist in reality, physics' mechanic equations written by Newton (force = mass acceleration) and Einstein ( E = m C2) would have to be thought again!While our concept of mass would turn out to be fiction, these equations would still be valuable for real applications, but would be useless as far as telling us about the nature of Nature.The part of quantum theory that deals with the atomic number, coincidental to the atom's protons and their mass would have to be re-evaluated too with respect to reality!Physics whole concept of inertia would have to be re hauled too.

Should the Higgs boson be dismissed, entire sections of theoretical physics edifice would break apart and sink, just as the polar glaciers tumble and sink into the polar sea!And that cannot happen!The Higgs and the Big BangAt the instant of the Big Bang, the universe was comprised of particles of pure energy.Milliseconds after the event, the universe cooled and the Higgs field developed.Particles began to acquire mass as they cooled, slowed down and moved through the newly created Higgs field. Particles lost kinetic energy and gained mass (E=mc2).Elementary particles developed and the Higgs field continued to permeate space-time.In unification theory, physicists look to the big bang for evidence of a single super force. Each of the four fundamental forces is thought of as a manifestation of a single force at low energies.

detectionFirst theorized in 1964 by the British physicistPeter Higgs, who expanded on the ideas of American theoretical physicist Phillip Anderson

In May 2010, evidence came to light at Fermi lab which suggested there may be as many as 5 types of different Higgs bosons.

In 2012, CERN announced the existence of Higgs Boson.

Two laboratories working at theEuropean Organisation for Nuclear Research(CERN) had jointly announced on July 4 they had detected a newfundamental particlein experiments at theLarge Hadron Collidernear Geneva.The teams, from labs called Atlas and theCompact Muon Solenoid(CMS), on Monday each published their findings in the European journalPhysics Letters B.Although CERN's announcement was never doubted, it still had to be vetted by peers and then published in an established journal to meet benchmarks of accuracy and openness.The Large Hadron Collider (LHC)at the European Organization for Nuclear Research (CERN)One of the detectors used in the LHC is ATLAS (A Toroidal LHCApparatuS) was looking for the origin of mass in the form of the Higgs boson.ATLAS measures collisions between very fast moving protons. When these protons collide they create short-lived particles that ATLAS is designed to track in search of the Higgs.

In order to confirm a discovery of the Higgs particle, the CERN scientists must achieve two goals.Goal #1 is to verify that there is in fact a particle with the mass they expect the Higgs to have. They do this by firing particles at each other, carefully controlling the energy with which they collide, and measuring the results of the collision.

Goal #2 is to check that this particle behaves the way theory predicts i.e., whether theyve actually discovered the Higgs boson or some other particle that would call for a rethinking of the Standard Model of particle physics. This involves a lot more complex and long-winded analysis of data.The Higgs particle exists only fleetingly, and must be inferred from the presence of other particles it is likely to decay into.

Analysis of the Tevatron data showed unusually high numbers of these particles in certain regions, indicating a Higgs with a mass between 115-135 gigaelectronvolts (we use GeV, a unit of energy, to measure the mass of the particles because, by Einsteins famous equation, mass and energy are essentially the same quantity).

This was consistent with the narrower range of 124-126 GeV suggested by preliminary data from the Large Hadron Collider.The problem with the Tevatron result was that it was not statistically significant.

That means that, assuming the Higgs boson did not exist, the probability of seeing these results by random background fluctuation alone was unacceptably high.

The excesses measured by Tevatron were 2.2 standard deviations above background expectations.

The accepted threshold for a discovery in particle physics is five standard deviations, or approximately a one in three million chance of seeing these results in a world with no Higgs boson.On July 4 of this year, two CERN particle detecting experiments, ATLAS and CMS, made an announcement: they had discovered, with a significance of five standard deviations, a particle with a mass of around 125.3 GeV.

It was a landmark moment in the history of physics, but it is still only half the battle: they have only achieved goal #1.If the Standard Model is definitively confirmed or ruled out, the implications will take quite some time to become clear. Various theories will become more or less tenable, long unanswered questions will be solved or superseded, and new questions will arise.

The discovery of this particle, whatever it may turn out to be, is certainly important, but we should not blow it out of proportion.

No fundamental secrets of the universe have been discovered, no fields of knowledge have been instantly built up or toppled in one fell swoop, and life continues much as it had been.