Astral Alchemy: Researchers Synthesize Mysterious Exotic Baryon

A particle accelerator experiment involving scientists from Osaka University created an unusual and extremely unstable particle and calculated its mass. This might help us learn more about the interior workings of ultra-dense neutron stars.

The majority of particles are composed of mixtures of just six different kinds of fundamental particles known as quarks, according to the Standard Model of particle physics. However, there are still a lot of unanswered questions, one of which is the unusual but transient Lambda resonance (1405). Understanding its makeup could help researchers learn more about the incredibly dense matter found in neutron stars. It was originally thought to be a particular mix of the three quarks up, down, and odd.

Now, researchers from Osaka University were a member of a group that was successful in creating (1405) for the first time by fusing a K-meson and a proton and figuring out its complicated mass (mass and width). A odd quark and an up antiquark are both components of the negatively charged particle known as the K-meson.

There are two up quarks and one down quark in the much more common proton that forms up the matter that we are accustomed to. The study demonstrated that instead of being a three-quark excited state, (1405) is best understood as a transiently bound state of the proton and the K-meson.

The team explains the experiment they conducted at the J-PARC accelerator in a paper that was recently published in Physics Letters B. The objective was a deuterium target, which contained one proton and one neutron in each K-meson. A K-meson expelled the neutron in an effective reaction, merging with the proton to create the intended result (1405). According to Kentaro Inoue, one of the study's authors, "the creation of a bound state of a K- meson and a proton was only feasible because the neutron carried away some of the energy."

The fact that quark (1405) has a very low total mass despite having an odd quark that is almost 40 times heavier than an up quark has baffled scientists. By watching how the decay products behaved during the trial, the study team was able to determine the complex mass of (1405) with accuracy.

According to Shingo Kawasaki, another study author, "we anticipate that success in this sort of research can lead to a more precise depiction of ultra-high-density matter that resides in the center of a neutron star." This study suggests that (1405) is an unusual state with a total of five quarks—four quarks and one antiquark—and deviates from the normal categorization, which categorizes particles as either having three quarks or one quark and one antiquark.

This study may help us understand how the Universe first began to develop soon after the Big Bang and what happens to matter when it is subjected to pressures and concentrations that are significantly higher than those we observe in everyday situations.