Image description: Artistic visualization of unstable particle interactions. Image source: Astronoo AI.
Each particle contains enormous energy, governed by subtle and complex mechanisms, studied within the fascinating realm of particle physics.
Quarks and leptons are the elementary particles that make up all the ordinary matter we know, while bosons are the mediators of the fundamental forces of nature. These quantum constituents are described by the Standard Model of elementary particles.
Protons and neutrons are composite particles, made up of a complex assembly of quarks held together by gluons.
The pentaquark is a composite particle with a more complex structure than a proton. Pentaquarks are exotic subatomic particles composed of five quarks.
A pentaquark consists of four quarks ($q$) and one antiquark ($\bar{q}$), symbolically written as $(qqqq\bar{q})$. This structure allows for a great diversity of combinations, making their study particularly complex.
Unlike the proton, pentaquarks are extremely unstable and decay rapidly into other particles, such as mesons or baryons.
It is impossible to isolate a single quark because the strong interaction, which binds them, becomes increasingly intense as quarks move farther apart. This phenomenon is known as "quark confinement".
In contrast, when quarks are very close to each other, the strong interaction weakens, giving rise to a property called "asymptotic freedom".
Pentaquarks are detected indirectly in high-energy physics experiments (such as at the LHCb at CERN) through the products of their decay.
Pentaquarks were experimentally detected in 2015. This discovery confirmed the existence of exotic forms of matter that had been theoretically predicted since the 1960s.
Describing a pentaquark as a subtle combination of a baryon and a meson is a partial and plausible description, but other configurations, such as the compact state, are also considered.