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Large Hadron Collider

GS Paper 3

Syllabus: Science and Technology



The world’s most powerful particle collider, the Large Hadron Collider (LHC), will begin smashing protons into each other at unprecedented levels of energy beginning July 5.

  • It is expected to throw up evidence of “new physics” — or physics beyond the Standard Model of Particle Physics, which explains how the basic building blocks of matter interact, governed by four fundamental forces.


What is LHC?

The Large Hadron Collider is a giant, complex machine built to study particles that are the smallest known building blocks of all things.

  • Structure: LHC is a 27-km-long track-loop buried 100m underground on the Swiss-French border.
  • Operation: In its operational state, it fires two beams of protons almost at the speed of light in opposite directions inside a ring of superconducting electromagnets.
    • Guided by magnetic field: The magnetic field created by the superconducting electromagnets keeps the protons in a tight beam and guides them along the way as they travel through beam pipes and finally collide.
    • High precision: The particles are so tiny that the task of making them collide is akin to firing two needles 10 km apart with such precision that they meet halfway.
    • Supercooled: Since the LHC’s powerful electromagnets carry almost as much current as a bolt of lightning, they must be kept chilled. It uses liquid helium to keep its critical components ultracold at minus  271.3 degrees Celsius, which is colder than interstellar space.
  • Experiments:
    • ATLAS is the largest general-purpose particle detector experiment at the LHC
    • Compact Muon Solenoid (CMS) experiment is one of the largest international scientific collaborations in history, with the same goals as ATLAS, but which uses a different magnet-system design.)


Latest upgrade: After its maintenance and upgrades, the collider was switched back on this April. This is the LHC’s third run.



  • ‘God Particle’ discovery: In scientists at CERN had announced the discovery of the Higgs boson or the ‘God Particle’ during the LHC’s first run.
    • This led to Peter Higgs and his collaborator François Englert being awarded the Nobel Prize for physics in 2013.
  • The Higgs boson is the fundamental particle associated with the Higgs field, a field that gives mass to other fundamental particles such as electrons and quarks.
  • ‘New Physics’ beyond Standard Model: After the discovery of the Higgs boson, scientists have started using the data collected as a tool to look beyond the Standard Model, which is currently the best theory of the most elementary building blocks of the universe and their interactions.


New quest: To further the understanding of so-called “dark matter”: Dar matter is a hard-to-detect, the hoped-for particle is believed to make up most of the universe, but is completely invisible as it does not absorb, reflect, or emit light.


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Practice Questions

Q. Enumerate the main goals of the Large Hadron Collider (LHC). How will it help us to understand the evolution of the universe? (250 words)

Q. Recently, Scientists observed the merger of giant blackholes’ billions of light-years away from the Earth. What is the significance of this observation? (UPSC CSE 2019)

(a) ‘Higgs boson particles’ were detected.

(b) ‘Gravitational waves’ were detected.

(c) Possibility of intergalactic space travel through ‘wormhole’ was confirmed.

(d) It enabled the scientists to understand ‘singularity’.

Answer: B

The merger of large heavenly bodies creates gravitational waves.


Q. Consider the following pairs: (UPSC CSE 2018)

Terms sometimes                         Context/Topic
seen in news

  1. Belle II experiment       —         Artificial Intelligence
  2. Blockchain technology —       Digital/Cryptocurrency
  3. CRISPR – Cas9             —        Particle Physics

Which of the pairs given above is/are correctly matched?

(a) 1 and 3 only

(b) 2 only

(c) 2 and 3 only

(d) 1, 2 and 3

Answer: B

The Belle II experiment is a particle physics experiment designed to study the properties of B mesons and other particles. CRISPR is used for gene editing.


Q. The efforts to detect the existence of Higgs boson particle have become frequent news in the recent past. What is/are the importance (s) of discovering this particle? (UPSC CSE 2013)

  1. It will enable us to understand as to why elementary particles have mass.
  2. It will enable us in the near future to develop the technology of tranferring matter from one point to another without traversing the physical space between them.
  3. It will enable us to create better fuels for nuclear fission.

Select the correct answer using the codes given below.

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Answer: A

Higgs boson is related to particle physics.

Statement 2 and 3 are incorrect: No such evidence has been found.

Source: Indian Express