HIGGS BOSON

Presented by Abhijeet Das

M.Sc. (4th Semester) ID- BS13MP0360

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PARTICLE PHYSICS

It is the branch of physics that studies the nature of the particle which are the constituents of matter (particle with mass) and radiation ( massless particle).e.g., Proton, Neutron, Photon

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STANDARD MODELIt is a theory which deals with the description of the three fundamentals forces of nature i.e., electromagnetic, weak and strong forces using gauge bosons. It is still unable to explain the gravitational force.The species of gauge bosons are W-, W+ and Z bosons and gluons and photons.This model predicted the existence of higgs boson.

3Reference: Google Images

NON-TECHNICAL SUMMARY

1. Symmetries and forces: According to Standard Model the fundamental forces arise from symmetry and are transmitted by particles called gauge bosons.

The weak force symmetry should cause its gauge bosons (W and Z boson) to have zero mass but experiments show that the gauge bosons are very massive and short ranged.

2. Higgs Mechanism: It is a mathematical model which was devised by 3 group

of physicist (Higgs, Englert and Brout, Guralnik, Hagen and Kibble) almost at the same time to describe why and how gauge bosons could be massive in spite of their symmetry.

They showed that the symmetry would be broken if an unusual type of field exist throughout the space which would enable particles to have mass.

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NON-TECHNICAL SUMMARY

3. Higgs Field: According to Standard Model a field (Higgs field) is necessary to exist throughout the space and should break the symmetry laws of electroweak interaction.The existence of this field triggers the Higgs mechanism causing the gauge bosons to be massive.

4. Higgs Boson: The existence of the Higgs field could be confirmed if a particle (Higgs Boson) associated with this field could be found.

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MEN BEHIND HIGGS MECHANISM

Peter Higgs Englert

Reference: Google Images 6

MEN BEHIND HIGGS MECHANISM

Brout Kibble, Hagen and Guralnik (from right to left)

Reference: Google Images

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OVERVIEW

In particle physics, elementary particles give rise to the world around us.

Physicists tries to explain the behaviour of these elementary particles and their interaction using The Standard Model which believes to explain everything other than gravity.

Around 1960 all attempts to create a gauge invariant theory for two of the four fundamental forces of nature failed at a point. They demand that either particles with mass were massless or massless particles had to exist.

In 1964 three group of researchers independent of each other showed that the problem could be resolved if an unusual kind of field exist throughout the space which would cause existing particles to acquire mass.

The simplest way to find the existence of this field was to find a particle which would give rise to that field.

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DISCOVERY

On 4th April 2012 morning the ATLAS and CMS detectors each observed a new particle in the mass region of 126GeV . This particle is consistent with the Higgs boson as predicted by the Standard Model.

Reference: Google Images9

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PROPERTIES

1. It is a boson.2. Mass = 125.09(+-)0.21(stat)(+-)0.11(syst)3. Mean Lifetime = 1.56*10-22 sec4. Electric Charge = 05. Color charge = 06. Spin = 07. Parity = positive

SIGNIFICANCE

Validating the standard model

Explain symmetry breaking

Explain how particles acquire mass

Existence of a scalar field in the universe

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THE LARGE HADRON COLLIDER

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THE LARGE HADRON COLLIDER

It is the world’s largest and most powerful particle collider built by CERN from 1998 to 2008. It is built in collaboration with 10,000 scientists and engineers. It has a tunnel with 27km in circumference and as deep as 175m (574 ft) beneath the Franco-Swiss border near Geneva Switzerland. Its synchrotron is made to collide two opposite particle beams of either proton at up to 4TeV or lead nuclei (574TeV per nucleus or 2.76 per nucleon) with energies increased to around 6.5Tev (13TeV collision energy) in 2015. The data is anticipated to be produced at the rate of tens of petabytes per year which is analyzed by a grid based computer network connecting 140 computer centers in 35 countries. It went live on 10th September 2008. There are 1,232 dipole magnets to keep the beam at circular path and 392 quadrapole magnets to keep the beam focused. Approximately 96 tones of superfluid He-4 is needed to keep the magnets made of copper-clad niobium-titanium at the operating temperature of 1.9K (-271.25°C) making it the largest cryogenic facility in the world. The speed of the proton is 3 m/s slower than the speed of light.

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DETECTORS IN LHC

ATLAS (A toroidal LHC apparatus) and CMS (Compact MUON solenoid): They are used for detecting things like new mass and extra dimensions

ALICE (A large ion collider experiment): It is built to study a fluid form of matter called quark-gluon plasma that existed shortly after the big-bang.

LHCb (Large hadron collider beauty): It is built to study the anti-matter.

TOTEM (Total elastic and diffractive crossection measurement): It aims to measure the total crossection, elastic scattering etc.

MoEDAL (Monopole and exotic detectors at the LHC): It aims to directly search for magnetic monopole or dyon and other highly ionizing stable massive particles.

LHCf (Large Hadron Collider forward): It aims to study the particles in the forward region of collision. It intends to study the energy of neutral pions which can explain the origin of the ultra high energy cosmic rays.

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APPLICATION

For now there are no technological applications of the Higgs boson.

When fundamental discoveries are made there application in the real world takes times but when they do they have a big impact on the world.

e.g., “www” was created at CERN to share the results of experiments by Sir Timothy John Tim Berners-Lee

CERN- Conseil European pour la Recherche Nucléaire OR European Organization for Nuclear Research

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THANK YOU