The Large Hadron Collider (LHC) may have not have succeeded in discovering particles that can “break” the Standard Model of particle physics, but that hasn’t dampened the enthusiasm of scientists associated with it. On Thursday, researchers working with the LHCb collaboration at LHC announced a unique discovery, all in a single analysis — a new system of five particles.
“The exceptionality of this discovery is that observing five new states all at once is a rather unique event,” CERN said in a statement.
The particles — described in a paper now available on the preprint server arXiv — are all excited states of a particle called Omega-c-zero (or Ωc0), which is a baryon containing two strange and one charm quark.
“From the analysis of the trajectories and the energy left in the detector by all the particles in this final configuration, the LHCb collaboration could trace back the initial event – the decay of the Ωc0 – and its excited states,” CERN said in the statement. “These particle states are named, according to the standard convention, Ωc(3000)0, Ωc(3050)0, Ωc(3066)0, Ωc(3090)0 and Ωc(3119)0.”
Quarks, the fundamental particles that make up protons and neutrons, come in six different “flavors” — up, down, strange, top, bottom and charm. Each quark has an antimatter equivalent known as antiquark. Both protons and neutrons — contained within the nucleus of an atom — are made up of three quarks bound together.
“The next step will be the determination of the quantum numbers of these new particles – characteristic numbers used to identify the properties of a specific particle – and the determination of their theoretical significance,” CERN said in the statement. “This discovery will contribute to understanding how the three constituent quarks are bound inside a baryon and also for probing the correlation between quarks, which plays a key role in describing multi-quark states, such as tetraquarks and pentaquarks.”
Tetraquarks and pentaquarks, as is evident from their names, are exotic particles containing four and five quarks, respectively. The existence of these particles was also confirmed by researchers associated with the LHCb experiment at CERN last year.
The discovery of new particles allows physicists to understand how quarks interact with each other, and to look for chinks in the armor of the Standard Model, which, despite its phenomenal success, is still woefully incomplete. Once the LHC restarts later this year, it may even lead to the discovery of particles predicted by supersymmetry, which posits the existence of more massive “super partners” for every known particle.