The UB participates in second period of operation of the Large Hadron Collider

A beam of protons enters the LHCb detector on the left, creating a B0s particle, which decays into two muons (purple tracks crossing the whole detector). Image: CERN
A beam of protons enters the LHCb detector on the left, creating a B0s particle, which decays into two muons (purple tracks crossing the whole detector). Image: CERN
Research
(25/02/2015)

After a two-year shutdown, the Large Hadron Collider (LHC), located at the headquarters of the European Organization for Nuclear Research (CERN), in Geneva (Switzerland), is scheduled to restart early in 2015. The collision energy at restart will be 13 teraelectron volts (TeV), a significant increase over the initial LHC run, 8 TeV in 2012.

A beam of protons enters the LHCb detector on the left, creating a B0s particle, which decays into two muons (purple tracks crossing the whole detector). Image: CERN
A beam of protons enters the LHCb detector on the left, creating a B0s particle, which decays into two muons (purple tracks crossing the whole detector). Image: CERN
Research
25/02/2015

After a two-year shutdown, the Large Hadron Collider (LHC), located at the headquarters of the European Organization for Nuclear Research (CERN), in Geneva (Switzerland), is scheduled to restart early in 2015. The collision energy at restart will be 13 teraelectron volts (TeV), a significant increase over the initial LHC run, 8 TeV in 2012.

During this second period of operation, the Group on Experimental Particle Physics of the Institute of Cosmos Sciences of the UB (ICCUB) continues participating in the experiment LHCb, specialised in the analysis of b quarks.

According to Lluís Garrido, director of ICCUB, “the LHCb will be able to collect data of higher energy proton-proton collisions. This will increase by 4 times the detected number of particles containing b quarks”. He adds: “On this new period, the LHC will allow us to get more insight into the asymmetry between matter and antimatter”.

ICCUB researchers have contributed to the LHCb upgrade with the design, production and test of improvements focused on the calorimeter, tracking devices and the analysis of radioactive processes.

The LHCb detector worked successfully during its first period of operation, between 2008 and 2013. One of the milestones achieved by the experiment during this period was to observe the decay of B meson into a pair of muons (B0S → μμ) with a production rate compatible with the predictions made by the Standard Model of particle physics. The search for the B0s→μμ decay was considered as one of the most stringent tests of the Standard Model. “This provides a fine-grained filter for the new physics models. All models of physics beyond the Standard Model will have to test their compatibility with this important result”, points out Garrido.

Moreover, the experiment discovered two new particles in the baryon family: the Xi_b'- and Xi_b*-, which were predicted to exist by the quark model but had never been seen before. These particles are made from three quarks: one beauty (b), one strange (s), and one down (d) quark. For example, protons are composed by two u quarks and one d quark. Thanks to the heavyweight b quarks, they are more than six times as massive as the proton.

 

Tenth anniversary of the Particle Physics Workshop

Upper secondary students interested in particle physics can participate in the Particle Physics Workshop, organised within the international science dissemination project Hands on Particle Physics. Every year, around 10,000 students from more than 40 countries around the world participate in the initiative. The activities that take place at the UB are organised by the Group on Experimental Particle Physics of the ICCUB. On the tenth edition, 160 students participate in the workshop, which takes place on 2 and 9 March.