Particle physics includes the study of fundamental subatomic particles for matter as well as antimatter, and their interactions. Subatomic particles of matter include electrons, protons and neutrons, and those of antimatter include positron, antiproton and antineutron. While electrons and positrons are elementary particles, which means that they are not made up of a combination of smaller particles, and do not have a substructure, protons, neutrons, antiprotons and antineutrons have an internal structure, and are made up of elementary particles called quarks and antiquarks. 


The Higgs Boson, also known as the God Particle, was discovered on July 4, 2012, at the CERN Laboratory in Geneva, Switzerland, and is an elementary particle. All elementary particles of matter can be divided into two broad categories: fermions and bosons. Fermions include quarks and leptons. An electron is a lepton. Meanwhile, the Higgs Boson is a boson. 


ALSO READ | What Are Matter And Antimatter? We Don’t Disappear As There Is A ‘Little More’ Matter Than Antimatter, A CERN Physicist Says


The Higgs Boson, identified after over 40 years of research, is considered one of the most important scientific discoveries of the modern era, because it provides evidence for the Standard Model of Particle Physics, which describes how various particles make the universe. The Higgs Boson is known as the God Particle because without it, the Standard Model would fail. 


All the elementary particles are the building blocks of nature, and are governed by four types of forces — gravitation, electromagnetism, the weak force, and the strong force. The Standard Model of Particle Physics unites the building blocks of nature, and three of the fundamental forces. Gravitation remains outside the model, because graviton is yet to be discovered. 


MUST READ | EXCLUSIVE: India Has A Very Long Tradition Of Particle Physics, Says CERN Physicist Archana Sharma


Not only gravitons, but also several other elementary particles  believed to exist in the universe have not been discovered. On the sidelines of a physics conclave held at Shiv Nadar School, Gurgaon, ABP Live spoke to Dr Archana Sharma, a principal scientist at CERN, and asked her about the mysteries in the world of particle physics, and if more particles, apart from the graviton, are yet to be discovered. Dr Sharma is also the Head of the Engagement Office at the Compact Muon Solenoid (CMS) Experiment, CERN. She was recently awarded the Pravasi Bharatiya Samman Award, the highest award conferred on Indians living abroad by the President of India. 


Dr Sharma is also a recipient of the Bharat Gaurav Award. She has performed groundbreaking research in particle physics, and was a part of the team involved in the discovery of the Higgs Boson. 


However, according to Dr Sharma, the discovery of the Higgs Boson is “not the complete story”, because there could be "other particles that mimic the Higgs Boson", and it is not known "if we will see particles of dark matter". She said that since there could be new particles, “we need an all-encompassing theory”.


Here are excerpts from the interview:


You said that 63 new particles were found at CERN since the discovery of the Higgs Boson. What kinds of particles are these?


Archana Sharma: Particles are resonances. They form and then decay. They are new kinds of formation of the basic quarks. There could be new particles. Since we founded the Large Hadron Collider (LHC), every year or two, we find these new particles.


When will we know that this is the complete set of particles that describes all matter and the formation of the universe?


 



"We do not know if we will see particles of dark matter," CERN physicist Dr Archana Sharma told ABP Live.


This is a quest that has been ongoing for a century. In the 1930s, particle physics started, and we slowly unpacked what is inside the atom, inside the nucleus, inside the proton, and eventually, the quarks. The Higgs Boson was postulated in 1964, and found in 2012. This decades-long search gave us the Standard Model of Particle Physics. However, this is not the complete story. There are still many mysteries that are open. There are too many constraints that we give, which is why the model works. First of all, we will study the Higgs Boson. Then, there are questions whether there are more Higgs Bosons. There could be other particles that mimic the Higgs Bosons. Those are the kinds of studies we are going to do on the high luminosity Large Hadron Collider. Of course, there is a quest for dark matter and dark energy. We do not know if we will see particles of dark matter. Of course, gravity is not included in the Standard Model of Physics. This is because, on the energy scale, the graviton has to be discovered. So, we need to have an all-encompassing theory.


How will it be possible for new particles to be discovered?


In 1940, when the first computer was invented, the Chairman of IBM said ‘maybe the world needs two computers’. More than a hundred years ago, someone had said that all that was to be invented has been invented. We are in another world after that was said. There are all sorts of discoveries including ChatGPT and other artificial intelligence technologies. There were floppy discs at some point of time. Now, nobody even thinks of them. We now have a computer in our hands fitted into a mobile phone. Therefore, we need technologies and higher energies to probe further and discover new particles.


Can particle physics help search for intelligent life?


We do not exist in a silo. Particle physics has many technologies like magnets, radiation detectors and imaging applications. Magnets and detectors are probes that can be used to track particles. On the International Space Station, there is a particle detector. It is a CERN experiment. It is looking for cosmic rays. So, who knows, in the future, our technologies can definitely be used in missions that go beyond the Earth and look at alien life.