I watched a video by The Royal Institution on YouTube named "What are Pentaquarks and why are they so rare?" which was uploaded 3 years ago. And it was really good at simplifying quantum chromodynamics and what quarks are!! However, I struggled to understand some of the stuff about the data but I think I get some of it!! :D soooooo ill do my best to summarise it ((as if I can ever be concise lmao))
The main answer to the question posed by the title of the video was a solid we dont know what exactly Pentaquarks are and why they're soooo rare buuut scientists at the LHC are working on it!!
Quarks and leptons are the fundamental particles. Quarks in particular are always linked together by te strong nuclear force to form hadrons - you can't EVER find them singularly due to quark confinement ((energy needed to separate two quarks forms mass forming another quark)). However quarks are usually found in quark triplets or quark antiquark pairs!?!?!?! WHY!?!? It could be due to the quarks property colour charge limiting some possibilities. The colour charge is associated with the strong force ((force keeping quarks together)), similar to how the electric charge is linked to the electric force. It acts as a source for the force to act on. The three types of colour charge are : red, green and blue. All together make white. In hadrons, the colour charges cancel out / make white so overall the object is neutral and doesnt experience the strong force. So the only caviat here for other particles containing quarks is the colour charges need to cancel, so it's not really much of a reason why particles containing quarks other than quark triplets and quark-antiquark pairs are soooo rare.
Scientists have been working on this issue....aaannnddd in 2008 tetra quarks (4 quarks) were discovered!! Aaannnd in 2015....drumroll please!! Pentaquarks (5 quarks) were discovered!!! However, they're not stable so decay quickly so cant be directly observed. Thus scientists look for pentaquarks by finding the particles they decay into - psi mesons and protons. And the lack if knowledge we have on pentaquarks shows we really dont know a lot about the strong nuclear force (what forms them) as we dont even know if they're formed of the fusion of a meson and baryon or the fusion of five singular quarks......but yuh...they exist and it's a start!!










