CERN Discovers Two New unseen particles – La Vanguardia

Madrid. (EP) .- The LHCb experiment responsible Large Hadron Collider (LHC) at CERN announced Wednesday the Discovery Two new particles of the baryon family, made up of quarks

These particles, known as Xi_b’- and Xi_b * -., were predicted by the quark model, but had not been seen before. As the LHC accelerates protons, new particles are baryons made of three quarks and united by the strong force (one of the four fundamental interactions in nature). However, the types of quarks are different.

The new particles containing both Xib beauty quark (b), a stranger (s) and one down (d), while the proton is composed of two up quarks (u) and down (d). Because the b quark mass, these particles are six times more massive than a proton.

However, experts suggest that the particles are more than the sum of its parts, and that its mass depends also on how they are configured. Each quark has a property called spin. In Xi_b’-, the spins of the two lightest quarks pointing in opposite directions, while in Xi_b * – are aligned

This difference makes it a little heavier to Xi_b * particle. -. “Nature has been generous and given us two particles for the price of one,” said one of the leaders of the experiment, Matthew Charles.

The scientist explained that the Xi_b’- has a mass close to the sum of its decay products and, if a little lighter, would not have seen anything. “This is an exciting result. Thanks to the excellent hadron identification capability of LHCb, unique among the LHC experiments, we were able to identify a clear signal on the merits,” he noted researcher Steven Blusk.

In addition to the masses of these particles, whose findings have been published in Physical Review Letters , the research team studied their rates of production and their decay widths (a measure of stability) among other details.

They fit predictions

The results are consistent with the predictions of quantum chromodynamics (QCD), part of the Standard Model of Physics Particle theory describing elementary particles and their interactions.

Check QCD with high accuracy is key to improving the understanding of the dynamics of quarks, models that are very difficult to calculate. “If we want to find new physics beyond the Standard Model, we first need an accurate picture,” said coordinator Patrick Koppenburg LHCb physics.

In his view, “these high-precision studies help us differentiate effects between the Standard Model and any new or unexpected thing in the future. “

The measurements were performed with data taken at the LHC during 2011-2012. Currently it is being prepared after his first break, to operate at higher energies and more intense beams. Is scheduled to start operating again in Spring 2015.

The LHCb collaboration consists of 670 scientists and 250 technicians and engineers from 65 institutions representing 16 countries, including Spain. In this experiment, the University of Santiago de Compostela (USC), the University of Barcelona (UB), the Universitat Ramon Llull (URL) involved, and recently joined the Institute of Corpuscular Physics (IFIC, CSIC-UV).