Research Highlight

Study may unveil secrets of neutron stars

doi:10.1038/nindia.2020.43 Published online 13 March 2020

X-ray image of a young neutron star moving away from the site of its original supernova.

© ROSAT Project, NASA

Nuclear physicists have gained new insights into particle interactions that take place in the cores of neutron stars1. The results of their latest analyses may offer a new way to search and probe whether fundamental symmetries are violated in the universe. 

They analysed results from particle detectors at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in the United States, which is used to accelerate beams of gold ions and make them collide with one another, recreating conditions that prevailed in the early universe.

At temperatures 250,000 times as hot as the centre of the Sun, the RHIC produces plasma of quarks and gluons, the smallest components of matter that make up ordinary protons and neutrons.     

The scientists, including researchers from the Variable Energy Cyclotron Centre in Kolkata, Panjab University in Chandigarh and the Indian Institute of Science Education in Research in Berhampur, India, used the STAR detector, a house-size massive detector that can track thousands of particles produced by each collision at the RHIC.

They measured the binding energy that holds the components of strange matter that consists of atoms whose nuclei are made of particles called strange quarks.  

The strange matter’s atomic nucleus is known as a ‘hypertriton’. The measurements reveal that the binding energy holding together the components of the hypertriton is greater than the one obtained by previous experiments.

The new value, the researchers say, could be useful for understanding the properties of neutron stars, where strange quarks may be common. Comparing masses of a hypertriton and its antimatter counterpart, the antihypertriton, the scientists didn’t track any deviation from the symmetry.

The RHIC collisions offer a way to peer into the particle interactions within the distant cosmic objects such as neutron stars and other phenomena of the universe without leaving Earth.


References

1. Adam, J. et al. Measurement of the mass difference and the binding energy of the hypertriton and antihypertriton. Nat. Phys.(2020) Doi: 10.1038/s41567-020-0799-7