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Reblogged from Science on the Net

For the first time the prestigious Lise Meitner Prize, which is awarded every two years by the Nuclear Physics Division of the European Physics Society (EPS), has been given to an Italian researcher: Paolo Giubellino, director of research and coordinator of the INFN international ALICE (A Large Ion Collider Experiment) at CERN in Geneva. Actually, the winner is ALICE itself, because Giubellino was just one of the four winners of the prize and they are all involved in ALICE. The other three are Johanna Stachel (Physikalisches Institut der Universität Heidelberg, Germany), Peter Braun-Munzinger (GSI, Germany), and Jürgen Schukraft (CERN, Switzerland). But why ALICE was rewarded? As Giubellino tells us, there are two different reasons for considering ALICE a flagship of global research: its contribution in clarifying the history of the universe and the structure of the matter.

Starting from the latter, ALICE allowed to elucidate the mechanisms of the so-called strong interaction, which is one of the four fundamental forces, the one that ties together the parts that make up the atomic nucleus, i.e., proton-proton, but also quark-quark.

“The point is that the strong interaction between two particles, unlike for example the gravitational force, increases with the distance between them,” Giubellino explains. “Therefore, if one attempts to free a quark by separating it from others, the energy of the interaction becomes so large that eventually it is enough to create a quark-antiquark pair. This feature is called confinement, and it means that we never can observe quarks if they are isolated but only when they are bound inside hadrons. However, the fact that force grows with distance indicates an alternative way to pursue the study of free quarks: if one can take many works and squeeze them together in a small volume, they will be very close to one another and therefore experience very little interaction point. They will be free, albeit in a small volume. How do we obtain this? Using the Large Hadron Collider.

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