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Particle physics: CERN's LHCb experiment raises eyebrows, here's all you need to know

Particle Physicists Have Raised An Eyebrow Following An LHCb Experiment By The European Organisation For Nuclear Research (CERN). A Frail But Persistent Sign Of Physics Has Been Revealed By The LHCb Experiment In CERN.

News Nation Bureau | Edited By : Bindiya Bhatt | Updated on: 19 Apr 2017, 05:27:18 PM
Particle physics: CERN's LHCb experiment raises eyebrows

New Delhi:

Particle physicists have raised eyebrows following an LHCb experiment by the European organisation for nuclear research (CERN). A frail but persistent sign of physics has been revealed by the LHCb experiment in CERN.

The result of the experiment contradicts a basic assumption of the Standard Model and hints that this theory, which has been considered since time immemorial, may not be complete in itself.

Here is all you need to know:

Understanding the Standard Model of particle physics

Four fundamental forces – electromagnetic, strong, weak and gravitational – govern the nature. To merge these fundamental forces and have one equation to describe everything – the theory of everything is one of the major programmes in physics.
So far, a theory that has been devised by the scientists only gives a unified description of the first three forces and it is called the Standard Model (SM).

Understanding the particles in particle physics

All subatomic particles are composed of quarks and they are available in sex flavours or types - Up, Down, Truth, Beauty, Charm and Strange. They do not take place as singles but come in pairs forming the mesons (e.g. pions and kaons), or triplets, to form the Baryons (e.g. protons and neutrons).  

All particles are subject to gravity but here is the list of elementary particles:

-Low-mass  leptons (electron, muon, tau) are not made up of quarks. They interact only through electromagnetic and weak interactions.

-The heavy-mass baryons (protons neutrons etc) perform all types of interactions. These are all fermions, or spin ½ particles.

-Mesons (pions, kaons etc) are bosons. Highly unstable, they are short-lived. They interact through strong interactions.

-Gauge bosons mediate the various forces. While gluons mediate the strong interactions, the W and Z bosons mediate the weak interaction and the photons, the electromagnetic interactions.

Researchers have been observing all these particles. Higgs particle was the last particle to be seen experimentally. This is a boson and is involved in the mechanism by which the baryons get their mass.

Understanding the gaps in the Standard Model

Anything such as the description of the dark matter particles is not included in the Standard Model. An experimental discovery of a dark matter particle such as a WIMP (weakly interacting massive particle) would see physics beyond the standard model.

Because quarks come in flavours, the standard model doesn’t let these to be changed in processes that are observed strongly. So, flavour-changing neutral currents’ experimental evidence would also go beyond the Standard Model.

‘Indication’ found by LHCb experimen

LHCb has revealed an “indication” saying a difference in the behaviour of electrons and muons has been observed.

Two types of reactions have been observed. In one, B meson decays to an excited K Meson and a muon-plus and muon-minus pair. Unlike the prediction of the standard model that these two reactions should have the same rate, the experimentalists have found a significant difference in the rates. Hence, indications are that there is something different from the prediction of the Standard Model.

Though a massive announcement, experimentalists are still cautious to say that the statistical significance is not sufficient for it to be termed a discovery.

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First Published : 19 Apr 2017, 04:18:00 PM

Related Tags:

Particle Physics CERN Physics