This is why it came as surprise to the ASACUSA scientists that, when they used liquid helium, which has a much higher density than gaseous helium, in their new research study, they saw a decline in the width of the antiproton spectral lines.
Additionally, when they reduced the temperature of the liquid helium to worths listed below the temperature at which the liquid becomes a superfluid, i.e. streams with no resistance, they discovered an abrupt additional constricting of the spectral lines.
Masaki Hori, ASACUSA co-spokesperson. Credit: CERN
” This habits was unanticipated,” says Anna Sótér, who was the principal PhD trainee working on the experiment and is now an assistant teacher at ETHZ. “The optical action of the hybrid helium atom in superfluid helium is starkly different to that of the exact same hybrid atom in high-density gaseous helium, in addition to that of many typical atoms in superfluids or liquids.”
The scientists believe that the surprising behavior observed is linked to the radius of the electronic orbital, i.e. the range at which the hybrid helium atoms electron lies. In contrast to that of lots of typical atoms, the radius of the hybrid atoms electronic orbital changes really little bit when laser light is shone on the atom and therefore does not affect the spectral lines even when the atom is immersed in superfluid helium. Additional research studies are required to validate this hypothesis.
The scientists think that the unexpected habits observed is linked to the radius of the electronic orbital, i.e. the range at which the hybrid helium atoms electron is situated. In contrast to that of many regular atoms, the radius of the hybrid atoms electronic orbital modifications very bit when laser light is shone on the atom and thus does not affect the spectral lines even when the atom is immersed in superfluid helium. Scientists might develop other hybrid helium atoms, such as pionic helium atoms, in superfluid helium using various antimatter and unique particles, to study their reaction to laser light in detail and measure the particle masses. The considerable constricting of the lines in superfluid helium recommends that hybrid helium atoms could be utilized to study this form of matter and potentially other condensed-matter stages.
” Our research study suggests that hybrid matter– antimatter helium atoms could be used beyond particle physics, in particular in condensed-matter physics and possibly even in astrophysics experiments,” says ASACUSA co-spokesperson Masaki Hori. “We have perhaps made the initial step in using antiprotons to study condensed matter.”
ASACUSA Experiment. Credit: CERN
The ASACUSA partnership is well used to making hybrid matter– antimatter helium atoms to figure out the antiprotons mass and compare it with that of the proton. These hybrid atoms contain an antiproton and an electron around the helium nucleus (instead of 2 electrons around a helium nucleus) and are made by blending antiprotons produced at CERNs antimatter factory with a helium gas that has a low atomic density and is kept at low temperature.
Low gas densities and temperatures have actually played a crucial role in these antimatter research studies, which include determining the action of the hybrid atoms to laser light in order to determine their light spectrum. High gas densities and temperatures result in spectral lines, triggered by shifts of the antiproton or electron between energy levels, that are too broad, or even obscured, to permit the mass of the antiproton relative to that of the electron to be determined.
Scientists may produce other hybrid helium atoms, such as pionic helium atoms, in superfluid helium using various antimatter and unique particles, to study their action to laser light in detail and measure the particle masses. The considerable constricting of the lines in superfluid helium suggests that hybrid helium atoms might be used to study this form of matter and potentially other condensed-matter stages.
Recommendation: “High-resolution laser resonances of antiprotonic helium in superfluid 4He” by Anna Sótér, Hossein Aghai-Khozani, Dániel Barna, Andreas Dax, Luca Venturelli and Masaki Hori, 16 March 2022, Nature.DOI: 10.1038/ s41586-022-04440-7.
The result may open doors to a number of lines of research study in particle physics and beyond.
A hybrid matter — antimatter helium atom containing an antiproton, the protons antimatter equivalent, in location of an electron has an unforeseen reaction to laser light when immersed in superfluid helium, reports the ASACUSA partnership at CERN. The outcome, explained in a paper published on March 16, 2022, in the journal Nature, might open doors to several lines of research study.