The mystery of what dwells within dead stars could be solved at last, thanks to supercomputer simulations that show neutron stars are comprised of "cold quark matter."
Earlier this month, almost 700 physicists from all over the world met in Houston, Texas, to attend the 30th edition of the Quark Matter conference, the largest conference in the field of heavy-ion physics. At this meeting, the ALICE collaboration presented its first results based on data collected with the upgraded detector in 2022, the first year of Run 3 of the LHC. Before the start of Run 3, ALICE underwent a major upgrade of its experimental apparatus to allow the recording of 50-100 times more Pb-Pb collisions and up to 500 times more proton-proton collisions than in previous runs. In addition, upgrades of the tracking detectors improved the pointing resolution by a factor 3-6. All in all, many new high-precision results will become available in the coming years. One of the new results presented at the Quark Matter conference was the measurement of the production of two different states of charmonia in proton-proton collisions. Charmonia are particles that consist of a charm and a