Does the future of physics need a new Einstein?
You will certainly remember the thunderbolt that sounded on July 4, 2012, when CERN announced the discovery of the famous Higgs boson. The experimental highlighting of the 25th elementary particle of matter was then celebrated as a feat of research in physics. And there was something! For almost 50 years, the Higgs boson had remained a purely theoretical invention. Designed by a group of physicists in 1964, it solved a problem that appeared in the standard model which describes the infinitely small, the universe of elementary particles of matter. It remained to verify the existence, in reality, of this Higgs boson invented to explain the mass of two other bosons and particles of the family of fermions. On March 14, 2013, after refining its calculations, CERN has confirmed the discovery of a Higgs boson. Even if it is not yet certain that it is really “the” Higgs boson, the mass seems said. The standard model of elementary particles established during the 20th century is confirmed in spectacular fashion.
News that seems excellent for physics
However, for many researchers, the Higgs boson represents a near-catastrophe. Indeed, the confirmation of the standard model leaves wide open the fault which separates this description of the infinitely small from the other great theory of physics, that which describes the infinitely large from general relativity established by Albert Einstein in 1915, almost a century ago. A century of divorce between these two parts of physics.
One world but two incompatible theories to describe it
A particle can be called excited: it then contains a certain amount of energy. But to enter this state, it must first absorb a photon. This phenomenon can be caused on hundreds of millions of particles as free atoms. Austrian researchers have successfully extended this control to a solid object. Because “unlike atomic clouds, the density of a solid is a billion times higher and all the atoms are required to move together along the center of mass of the object “, notes in a press release the University of Vienna which piloted a study published on February 21 in the Science News. So how to operate such a quantum control, that is to say relating to the quantification of the energy levels of a particle, on a larger object.
The object chosen by the researchers was a glass ball a thousand times smaller than a grain of sand comprising a few hundred million atoms. To be immobilized and cooled, this set of particles has been isolated as much as possible from environmental influences. To trap it, the researchers used a laser then used as a clamp, closing its two luminous arms on the object, an invention of the American Arthur Ashkin.
The scientific community is working on the planning of a particle accelerator which aims to collide muons and study their interactions. The muon is a fundamental particle, similar to the electron, but heavier, with more mass. Together with the electron and the tau particle (and their respective neutrinos), the muon belongs to the family of leptons. This is a project similar to the CERN of LHC ( Large hadron collider ) in Geneva , which led in 2012 to the empirical confirmation of the existence of the boson theorized by Peter Higgs in the 1960s, and upon the awarding of the Nobel Prize in Physics to the latter in 2013.
The project, still in its preliminary stages (there are many technological challenges to be faced), is to produce muons in large quantities and collide them as it was done with Luck , which however worked with protons (or hadrons): “The hadrons are not simple particles, they are extremely complex. Inside the protons you will find a whole history of nature: they are made from quarks, from gluons, from many things “. Electrons are also very light particles and at very high energies they emit radiation: “to build an electron machine then you have to build a very large machine”. The muons, on the other hand, being heavier have the advantage of being more stable: “The mu are a great hope, it is now a question of setting experimental scientific program that has as its milestone not the proton because it is too complex, not the electron because it radiates, but the mu “.
They are additional particles that could be around” explained Carlo Rubbia. “It is not man; it is nature that decides how things are. We don’t know if our ideas are entirely correct. Now the problem is to create an experimental system for which the answer is objective that comes from the concrete observation of the experimental results, instead of being a working hypothesis. Both are necessary, but it is clear that physics is an experimental art: the theorist suggests many things, but it is not he who decides, it is nature that decides and nature is in the hands of experimental physicists “. The sterile neutrino is a particle that if discovered could open the doors to the so-called “new physics” beyond the standard model of elementary particles, because current theory does not foresee their existence.