The standard model of particle physics gets a jolt

What is the News? 

Researchers from the Collider Detector at Fermilab(CDF) Collaboration in the U.S announced that they have made a precise measurement of the mass of the so-called W boson. 

They stated that the W boson is slightly heavier than that predicted by the so-called Standard Model of particle physics. This result is highly significant because this implies the incompleteness of the Standard Model of Elementary Particles.

However, the mass discrepancy of the W boson needs to be checked and confirmed to the same accuracy by other facilities, for example, the Large Hadron Collider (LHC).

What is the Standard Model of Elementary Particles?

The Standard Model of Elementary Particles is a theoretical construct in physics that describes particles of matter and their interaction. 

It is a description that views the elementary particles of the world as being connected by mathematical symmetries, just as an object and its mirror image are connected by a bilateral (left-right) symmetry.

These are mathematical groups generated by continuous transformations from, say, one particle to another. 

What are the Fundamental Particles described by this Model?

This model describes the universe in terms of the following 17 fundamental particles: six quarks (three families of two each), six leptons (three families of two each), the massless photon (carrier of the electromagnetic force), the massive W (charge neutral), Z0 bosons (carriers of the weak nuclear force), massive Higgs boson (which endows mass to all massive particles) and massless gluons (carriers of the strong nuclear force) and their antiparticles. 

Why is the standard model believed to be incomplete?

Firstly, the standard model is thought to be incomplete because it gives a unified picture of only three of the four fundamental forces of nature — electromagnetic, weak nuclear, strong nuclear and gravitational interactions — it totally omits gravity.

Secondly, the model does not include a description of dark matter particles. So far these have been detected only through their gravitational pull on surrounding matter.

What is W Boson?

Discovered in 1983, the W boson is a fundamental particle. Together with the Z boson, it is responsible for the weak force, one of four fundamental forces that govern the behavior of matter in universe.

The W boson, which is electrically charged, changes the very make-up of particles. It switches protons into neutrons, and vice versa, through the weak force, triggering nuclear fusion and letting stars burn.

Source: The post is based on the article “The standard model of particle physics gets a jolt” published in The Hindu on 10th May 2022