The Large Hadron Collider Discovers New Pentaquark Particle

14/07/2015 14:47 BST | Updated 14/07/2015 14:59 BST

Scientists at the Large Hadron Collider have discovered an entirely new form of particle known as a pentaquark.


The discovery of this new class of particle proves right a theory that was first proposed in 1964 when American physicist, Murray Gell-Mann put forward the idea that particles must be composed of charged objects known as quarks.

Gell-Mann would go on to win the Nobel prize in 1969 for his work however up until this point the model has featured one key gap, the existence of pentaquarks.

The group of scientists involved published their findings in the journal Physical Review Letters.

Guy Wilkinson, a spokesperson for the LHCb team that carried out the research 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. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.”


The LHCb detector is just one of seven major experiments that are going on simultaneously at the LHC.

Pentaquarks have been notoriously difficult to prove as physics co-ordinator for LHCb Patrick Koppenburg points out to the BBC.

"There is quite a history with pentaquarks, which is also why we were very careful in putting this paper forward,"

"It's just the word 'pentaquark' which seems to be cursed somehow because there have been many discoveries that were then superseded by new results that showed that previous ones were actually fluctuations and not real signals."


The team discovered the particle by closely examining how a sub-atomic particle called Lambda b decayed over time. They found that as it went through the process of decaying it went through a number of different states.

It was within these states that the scientists discovered what they believe to be conclusive proof of the pentaquark.

Due to the high-precision of the LHC's sensors the team were able to see the process at a level of clarity that hadn't previously been possible.


The LHC has recently undergone a major two year upgrade.

In a statement, CERN explains the scale of the difference between the research that had been done before to the new research that has just been published.

"It’s as if the previous searches were looking for silhouettes in the dark, whereas LHCb conducted the search with the lights on, and from all angles."

The next step in the process will be examining how the pentaquarks interact with the quarks.

This new research comes during the LHC's second run after it was closed down for a two year update. Now the update has finished the LHC is able to smash particles at twice the speed it had previously, giving scientists an even greater breadth of evidence to examine.