Seminar FO

One of the primary goals of nuclear physics is to understand the force 
between nucleons, which is a necessary step for understanding the 
structure of nuclei and their interaction. The large body of knowledge 
of the nuclear force that has been acquired was derived from studies 
made on either nucleons or nuclei. Although antinuclei up to 
antihelium-4 have been discovered and their masses measured, little is 
known directly about the nuclear force between antinucleons. We study 
antiproton pair correlations in data collected by the STAR experiment at 
the Relativistic Heavy Ion Collider (RHIC), where gold ions collide with 
a centre-of-mass energy of 200 GeV per nucleon pair. Antiprotons are 
abundantly produced in such collisions, making it feasible to study 
details of the antiproton–antiproton interaction. By applying a 
technique similar to Hanbury Brown and Twiss interferometry, we show 
that the nuclear force between two antiprotons is attractive. In 
addition, we report two key parameters that characterize the 
corresponding strong interaction: the scattering length and the 
effective interaction range. The measured parameters are consistent with 
the corresponding values for proton–proton interactions.
 

Voditelji seminara FO
Damir Paji´c i Ivica Smoli´