A new particle called the pentaquark has been discovered by scientists at the Large Hadron Collider (LHC).
The previously unseen class of particle was first predicted to exist in the 1960s but has eluded physicists until now.
It was detected by Cern’s Large Hadron Collider beauty (LHCb) experiment at the LHC in Switzerland.
The LHCb experiment specialises in investigating the slight differences between matter and antimatter.
LHCb spokesperson Guy Wilkinson said: ‘The pentaquark is not just any new particle.
‘It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches.
The new class of particle was detected by Cern’s Large Hadron Collider beauty (LHCb) experiment at the LHC in Switzerland. The LHCb experiment (pictured) specialises in investigating the slight differences between matter and antimatter
‘Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.’
Back in 1964 American physicist, Murray Gell-Mann proposed the existence of sub-atomic particles called quarks. The work earned him the Nobel Prize in 1969.
He claimed that the properties of particles called baryons and mesons could be explained if they were made up of other even tinier particles – quarks.
The physicists studied the way in which an unstable sub-atomic particle called Lambda b turned into three other particles. They found that the production of the three new particles sometimes involved intermediate states, which have been named Pc(4450)+ and Pc(4380)+ (marked on this graph)
He also theorised that there could be a particle called a pentaquark, made up of four quarks and an antiquark, which is the anti-matter equivalent of a quark, the BBC reported.
It has taken until now to prove his idea true.
The findings have been submitted to the journal Physical Review Letters.
To come to their conclusions, the international team of physicists studied the way in which an unstable sub-atomic particle called Lambda b decayed into three other particles.
They found that the production of the three particles sometimes involved intermediate states, which have been named Pc(4450)+ and Pc(4380)+.
LHCb physicist Tomasz Skwarnicki of Syracuse University in New York, said: ‘We have examined all possibilities for these signals and conclude that they can only be explained by pentaquark states.’
‘More precisely the states must be formed of two up quarks, one down quark, one charm quark and one anti-charm quark.’
Scientists got excited that the particle had been found earlier in the millennium, but sightings proved to be inconclusive because they measured mass distribution against background noise to look for a pentaquark’s signature.
The experts described the previous searches as looking for silhouettes in the dark, whereas LHCb conducted the search with the lights on.
The experts described the previous searches as looking for silhouettes in the dark, whereas LHCb conducted the search with the lights on. This illustration shows an alternative layout for the pentaquark, showing a meson particle – one quark and one antiquark – and a baryon, made up of three quarks weakly bonded together
Using the LHC allowed experts to look at data from four different perspectives, giving them a multi-dimensional view of the transformation of sub-atomic particles.
All these perspectives pointed to the same conclusion – the presence of pentaquarks.
Wilkinson told The Guardian: ‘One place where pentaquarks may be relevant is when stars collapse and form neutron stars, the final stage of collapse before some go on to make black holes.
‘In that environment, it’s quite possible that pentaquarks are formed, and if that’s so, it could have significant consequences for what happens to the stars, what they look like and what is their ultimate fate.’
The discovery comes just four months after the LHC shut down for repairs and upgrades for two years.
LARGE HADRON COLLIDER: THE GREAT SWITCH ON
The LHC was restarted on April 5 this year, having been turned off for two years during a major renovation project that cost £100 million.
The world’s largest atom-smashing machine is most famous for proving the existence of the Higgs boson.
Physicists at Cern, the Geneva-based organisation which runs the LHC, are aiming to see dark matter for the first time ever thanks to the device’s upgrade.
Instead, they have discovered the pentaquark, for now.
The LHC is situated underground below the border between Switzerland and France, and consists of nearly 17 miles of circular tunnels.
It was shut down so that its energy levels could be almost doubled, allowing scientists to carry out more extreme experiments.
The LHC (pictured) was restarted on April 5 this year, having been turned off for two years during a major renovation project that cost £100 million
The LHC, which cost nearly £4 billion, ran at a low ‘injection’ energy of 450 giga-electron volts (GeV) when it restarted, but its power has now been increased to a record-breaking 13 tera-electron volts (TeV) – up from 7 TeV at the time it managed to detect the Higgs boson in 2013.
British scientist Peter Higgs was awarded the Nobel Prize after the discovery of the particle, which he and others predicted would exist but which had never been seen until the construction of the LHC.
Physicists have set their sights on finding dark matter, the undetectable material that makes up 84 per cent of matter in the universe and binds galaxies together yet whose nature is unknown.
If they are able to detect and describe dark matter, it will mark a huge leap forward in our understanding of the universe.
Cern spokesman Arnaud Marsollier said: ‘The LHC will be running day and night. When we will get results we don’t know. What is important is that we will have collisions at energies we’ve never had before.
‘…It took 50 years to find the Higgs boson and 20 years to build this machine, and it will be running at least until 2035, so we can be patient.’
Jasper and Sardine 