On Tuesday, Geneva-based physicists announced the discovery a new class of particle, dubbed a “pentaquark,” according to a press release earlier today by CERN (the French acronym for the European Organization for Nuclear Research), the world’s leading laboratory for particle physics.
The pentaquark discovery was made at LHCb, one of four experiments at CERN’s Large Hadron Collider.
“The pentaquark is not just any new particle,” said LHCb spokesperson Guy Wilkinson.
“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.
More precisely the states must be formed of two up quarks, one down quark, one charm quark and one anti-charm quark.”
So, what exactly is a pentaquark?
Ordinary quarks make up protons or neutrons. A proton or neutron is comprised of three quarks, and these are the ingredients of subatomic particles, so it is easy to appreciate the difficult nature of studying them, and it was by studying the decay of unstable quark particles that scientists hoped to discover the pentaquark.
Take four quarks, bind them together with an anti-quark, and voila! The pentaquark is explained.
But what makes a pentaquark “not just any new particle?”
“Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted…,” added Wilkinson. “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.”
The existence of the pentaquark was just a hypothesis, literally, just yesterday. Past experiments searching for pentaquarks had proven inconclusive, even disproved, according to a statement from CERN. The LHCb has allowed physicists to look for evidence of pentaquarks from many perspectives not previously available before the Large Hadron Collider.
Imagine that previous searches for the pentaquark were being conducted in the dark, and the LHCb turned on the lights for research, literally, “illuminating all angles” for research of the microscopic components, according to CERN.
If this discovery is verified, this will be a second landmark finding for the Large Hadron Collider in Geneva. LHC scientists were responsible for the Higgs-Boson discovery two years ago, per Science News.
“We’re recreating temperatures that were last seen billionths of a second after the Big Bang,” Professor Tara Shears, a particle physics professor from the University of Liverpool, explained to BBC News. “When you get to this hot temperature, matter dissociates into atoms, and atoms into nuclei and electrons.”
“Everything unravels to its constituents. And those constituents are what we study in particle physics.”
This pentaquark is elusive.
Previous experiments thought to have proven the existence of the pentaquark were later disproven.
Other states of quarks have been studied, as well. As previously reported by the Inquisitr, tetraquarks were discovered in April by the Large Hadron Collider, and just after the LHC had been shut down for two years of repairs and upgrades.
The next step in the analysis will be to study how the quarks are bound together within the pentaquarks.
[Image courtesy of CERN]