14 DAY TRIAL // The Large Hadron Collider switched from using protons for its collisions to heavier lead ions recently, so that the events would produce more data than ever before. Some three weeks into the studies, this has already resulted in new insights of how the Universe looked like at the Big Bang.
The goal of the LHC is to determine if the theorized Higgs boson exist, and if supersymmetry indeed permeates the Universe. Three detectors are also looking for previously-unseen elementary particles.
The way the research is conducted is heavy ions are accelerated through 27-kilometer-long tunnels in opposite directions, and then slammed into each other at cross points, where the detectors are placed.
Using heavy lead ions, the accelerators can produce energetic collisions, which produce a shower of particles every time the ions slam into each other. By analyzing what happens in the first fractions of a second after the impacts, researchers can gain insight into the early Universe.
Their interest is understanding how the Cosmos looked like thousands of a second after the Big Bang took place. Theories hold that exotic states of matter were produced, and physicists want to recreate them inside the observation chambers.
This is precisely what investigators with the ALICE detector on the LHC did. Just days after ion collisions began, they published two research papers on the resulting explosions. The studies were conducted quickly, as ALICE is specialized in researching heavy ions.
A few days ago, two other teams, operating the ATLAS and CMS particle detectors, also published early results of their studies. The ATLAS paper appeared in the November 25 issue of the scientific journal Physical Review Letters.
The CMS investigation will be detailed on December 2, at a seminar that will take place at the European Organization for Nuclear Research (CERN), which operates the LHC.
“It is impressive how fast the experiments have arrived at these results, which deal with very complex physics,” explains official Sergio Bertolucci, who is the research director at the Organization.
“The experiments are competing with each other to publish first, but then working together to assemble the full picture and cross check their results. It’s a beautiful example of how competition and collaboration is a key feature of this field of research,” he goes on to say.
The newly-obtained data show that quark gluon plasma was obtained in the LHC detectors, and that the material's traits are the same as the ones discovered by experts operating the RHIC collider at the Brookhaven National Laboratory (BNL), in the US.
But the main result of the new studies is that certain theories seeking to explain how the Universe formed when it first developed are wrong, AlphaGalileo reports.
“With nuclear collisions, the LHC has become a fantastic 'Big Bang' machine. In some respects, the quark-gluon matter looks familiar, still the ideal liquid seen at RHIC, but we’re also starting to see glimpses of something new,” says ALICE spokesman Jürgen Schukraft.
The LHC detectors are tremendously precise,and this allows them to see things that other instruments of this type are blind to. One such example is a phenomenon called jet quenching.
These jets are formed by elementary particles called quarks and gluons, that are produced following ion collisions, and which “fly” away from the impact points at high speeds.
As they move through the hot dense medium, they interact wildly, producing readings that have never been recorded before. The LHC is literally breaking new ground in particle physics.
As a concept, jet quenching refers to the process of particle jets having their energy levels gradually degraded by the medium in which they travel. By studying quenching, experts can also derive more data about the quark-gluon plasma (QGP).
“ATLAS is the first experiment to report direct observation of jet quenching. The excellent capabilities of ATLAS to determine jet energies enabled us to observe a striking imbalance in energies of pairs of jets, where one jet is almost completely absorbed by the medium,” says Fabiola Gianotti.
“It’s a very exciting result of which the Collaboration is proud, obtained in a very short time thanks in particular to the dedication and enthusiasm of young scientists,” adds the official, who is a spokesperson for ATLAS.