The chances of detecting "lumps" in nuclear nuclei
What do atomic nuclei really look like? Are the protons and neutrons in them distributed chaotically? Or perhaps they merge into alpha clusters, which are clumps made of two protons and two neutrons? For a few light nuclei, experimental confirmation of the individuality or familial nature of nucleons will now be easier, thanks to predictions made by physicists from Krakow and Kielce.
Any reasonably conscientious high school student knows exactly what an atomic nucleus looks like: it’s a conglomeration of randomly distributed protonsow and neutronointo (i.e. nucleonow). However, physicists themselves do not have such unambiguous ideas. As early as 1931, just 20 years after the discovery of the atomic nucleus, the first suggestions were made that protons and neutrons in atomic nuclei combine into helium nuclei, and thus into groups of dwoch protonsow and dwoch neutronow, often referred to as alpha clusters. Atomic nuclei, however, are objects so extremely small and difficult to study that, although almost a century has passed since the first predictions, it has still not been possible to unambiguously confirm the presence of a cluster in themointo alpha.
Merging objectow w groups favor lowering energy in physical systems. This powerful, universal mechanism occurs in nature in roof different size scales: quarks merge into mesons or baryons, atoms into molecules, stars into galaxies, and galaxies into groups of galaxies. In the case of atomic nuclei, computer simulations suggest that eq. in the nucleus of beryllium 9Be there are two alpha clusters and one neutron (the whole complex would look like a dumbbell). There should be three alpha clusters in the nucleus of carbon 12C (so the shape of the nucleus would be trojiangular), four in oxygen 16O (here the nucleus would resemble a pyramid), ten in calcium 40Ca and fourteen in nickel 56Ni.
In 2014, scientists at the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Krakow, Poland, in a jointoIn the case of atomic nuclei, computer simulations suggest that, for example, physicists from the Universidad de Granada, have presented waysob trace detectionoin the primordial structure of atomic nuclei in the velocity distribution of particles diverging from the collision point of ultrarelativistic light atomic nuclei with a shield made of heavy nuclei, such as leadoIn 208Pb or gold 197Au. oEarly predictions were centered around theowayoIn the detection of clusteroin alpha in carbon 12C nuclei.
– In our latest publication, written together with physicists from the Institute of Physics at Jan Kochanowski University in Kielce, we provide more detailedos predictions about the possibility of observing a traceoin the clusterow alpha in atomic nuclei. In doing so, we show how these clusters could be detected in more nuclei, not only of carbon 12C, but also of beryllium 7Be and 9Be and oxygen 16O – mowi prof. dr hab. Wojciech Broniowski (IFJ PAN, UJK).
Detection method clusterow alpha in atomic nuclei, described in the publication wyrochewed by editorointo journals „Physical Review C”, is based on an interesting relationship. Heavy atomic nuclei, even if they were composed of clusters ofoin alpha, are so large that, to a good approximation, they can be treated as fairly homogeneous spheres. When a light atomic nucleus strikes such a nucleus at ultrarelativistic velocity (which is very close to the speed of light), the energy of the collision is so great that protons and neutrons decay for fractions of a second into quarks and gluons that cluster together. It is formed inotime perhaps the most exotic fluid: quark-gluon plasma.
– In our work, we note that if the light atomic nucleus is not homogeneous, the quark-gluon plasma cloud formed by the collision is deformed. Its shape will at least to some extent correspond to that of a light nucleus. Thus, the plasma will spill in all directions, but in the rotions in different directions at slightly different speeds,” explains Dr. hab. Maciej Rybczynski, prof. UJK.
The quark-gluon plasma cools so fast that direct observation of it is not currently possible. After just a few femtoseconds (millionths of a billionth of a second), quarks and gluons reassemble into particles in a process called hadronization.
– In the directions in whichorych quark-gluon plasma flowed a little faster, we can expect slightly higher velocities of particles formed during hadronization. Thus, if we register with sufficient precision the momentum of particles diverging from the point of collision, we are potentially able to from small roThe plant will extract information about the shape of the nucleus, whichore hit the shield. In addition, the information will be about the nuclear in its basic state, explains Milena Piotrowska, a doctoral student at UJK.
Research physicistow with the IFJ PAN and UJK, coofunded by a grant from theoat the National Science Center, provide concrete theoretical predictions. The next step now belongs to physicistsoin experimental facilities working at high-energy gas pedals such as the Super Proton Synchrotron (SPS) or Large Hadron Collider (LHC) at Europe’s CERN or the Relativistic Heavy-Ion Collider (RHIC) at the US Brookhaven National Laboratory. Since experiments confirming the lumped structure of atomic nuclei do not require expansion of currently operating apparatus, they will be able to be carried out in the coming years.