 |
Particle physicists study the basic blocks of matter and the forces between them by colliding particles of matter together at very high energies. The collisions create the fundamental constituents that no longer exist in ordinary matter, but which were common in the energetic early Universe. |
By concentrating a large amount of energy into the smallest possible volume, equal numbers
of particles of matter and antimatter are created from pure energy according to the
equation E = mc2. The energy concentrations created correspond to the
conditions prevailing in the early Universe, less than a tenth of a thousandth of a
millionth of a second (10-10 s) after the Big Bang. In this way, particle
physics probes the conditions of the very early Universe minute fractions of a second
after it began.
The highest energy concentrations achieved at CERN so far have been with nuclei of lead
atoms, accelerated in the Super Proton Synchrotron. In these collisions, the energy
concentration may be sufficient for the nucleons (protons and neutrons) within the nuclei
to "merge" for an instant, so that the quarks and gluons normally locked within
the nucleons form a "quark-gluon plasma". This state of matter should have
existed in the very early Universe, before it had cooled sufficiently for the quarks and
gluons to condense out to form the protons and neutrons of familiar matter. In experiments
like these, particle physics probes forms of matter unseen since the very early Universe.
© Copyright CERN - Last modified on 1998-02-18 - Tradotto da Sofia Sabatti