by Panos Charitos. Published: 13 October 2012

In the recent Quark Matter 2012 conference, the ALICE collaboration announced the production of the highest human-made temperature in the universe. The highest temperature of approximately 5.5 trillion Kelvin was produced at the Large Hadron Collider at CERN by smashing heavy ions after accelerating them to 99% of the speed of light. Although more data processing is needed to convert the measured energy to an exact temperature it is believed that this would be more than 5 trillion Kelvins. Paolo Giubellino said: «It’s a very delicate measurement. Give us a few weeks and it’ll be out”. That's about 38% hotter than the old record, set by the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, New York, by smashing gold ions together.

LHC collided lead ions at extraordinarily high speeds in order to produce quark-gluon plasma (QGP), a state of matter which existed immediately following the Big Bang. In these conditions, quarks and gluons – the basic building blocks of matter- were not confined inside composite particles like neutrons and protons but were free in this exciting form of matter called QGP. The universe was so hot for any nuclei to exist but was rather dominated by this exotic form of matter which we can’t see today in our daily observations since the universe further cooled down. With more data still being analysed and further data-taking scheduled for next February ALICE is closer than ever to unravel the properties of the primordial state of the universe.

ALICE sets new record for the hottest spot in the Universe

ALICE experiment is designed to study this new state of matter (QGP) as it expands and cools aiming to provide new understandings on how ordinary matter (i.e. protons, neutrons, nucleons) was formed and the role that strong interaction played in this process. Under the extreme conditions reproduced at LHC, protons and neutrons “melt” freeing quarks and gluons and allow us to study their interactions.

“The field of heavy-ion physics is crucial for probing the properties of matter in the primordial universe, one of the key questions of fundamental physics that LHC and its experiments are designed to address. It illustrates how in addition to the investigation of the recently discovered Higgs-like boson, physicists at the LHC are studying many other important phenomena in both proton–proton and lead–lead collisions,” said CERN Director-General Rolf Heuer. The ALICE team will continue to study the conditions under which quark-gluon plasma comes to exist in hopes of better understanding its properties.

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