Scientists from Osaka University participated in a particle accelerator experiment that created an exotic and highly unstable particle and determined its mass. This could contribute to a better understanding of the inner workings of extremely dense neutron stars.
The Standard Model of particle physics explains that most particles are made up of combinations of six types of fundamental entities called quarks. However, many mysteries still remain, one of which is an exotic but temporary lambda resonance Λ(1405). It was previously thought to be a special combination of three quarks (up, down, and strange), and learning about its composition could help reveal information about the extremely dense matter in neutron stars.
Researchers from Osaka University were now part of a team that succeeded in synthesizing Λ(1405) for the first time by combining K. – Determination of the mass (mass and width) of the meson and proton and complex. K – A meson is a negatively charged particle containing a strange quark and an antiquark.
The much more familiar proton that makes up the stuff we’re used to has two up quarks and one down quark. The researchers showed that Λ(1405) is best viewed as a temporally bound state of K. – meson and proton, unlike the three-quark excited state.
In a recently published study Physics Letters B, the group describes an experiment they performed at the J-PARC accelerator. K fired at a deuterium target – mesons, each containing a proton and a neutron. During the successful reaction of K – The meson ejects a neutron and then combines with a proton to form the desired Λ(1405). “The formation of the K-bound state – The meson and proton were only possible because the neutron took some of the energy,” says study author Kentaro Inoue.
One feature that puzzled scientists about Λ(1405) was that although it contained a strange quark that was almost 40 times heavier than the top quark, its total mass was very small. During the experiment, the research team was able to successfully measure the complex mass Λ(1405) by observing the behavior of the decay products.
“We hope that progress in this type of research will lead to a more precise description of the ultra-high-density matter found in the core of a neutron star,” says Shingo Kawasaki, another author of the study. This study proposes that Λ(1405) is an unusual case, consisting of four quarks and an antiquark, with a total of 5 quarks, and does not fit the conventional classification of particles containing three quarks or one quark and one antiquark.
This research could provide a better understanding of the early formation of the universe shortly after the Big Bang and what happens when matter is subjected to pressures and densities far beyond what we normally see.
Source: Port Altele
