Context: The Large Hadron Collider(LHC) has observed three never-before-seen particles: a new kind of “pentaquark” and the first-ever pair of “tetraquarks”, which includes a new type of tetraquark. 

Large Hadron Collider(LHC)

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

• Located at: It is a 27-km-long track-loop buried 100 meters underground on the Swiss-French border. 

• Built by: European Organization for Nuclear Research(CERN) between 1998 and 2008 in collaboration with over 10,000 scientists from hundreds of universities and laboratories.

• Significance: It is the world’s largest and most powerful particle accelerator. 

• Experiments conducted at LHC: ATLAS is the largest general-purpose particle detector experiment at the LHC.

• The 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.

• Major Discovery: In 2012, scientists at CERN had announced to the world 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. 

• Note: 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.

What are Quarks, Pentakquark and Tetraquark?

• Quarks are elementary particles that come in six “flavours”: up, down, charm, strange, top, and bottom. They usually combine together in groups of twos and threes to form hadrons such as the protons and neutrons that make up atomic nuclei.

• But they can also combine into four-quark and five-quark particles called tetraquarks and pentaquarks. 

• These exotic hadrons were predicted by theorists about six decades ago — around the same time as conventional hadrons — but they have been observed by the Large Hadron Collider and other experiments only in the past 20 years.