Virtual Visit to CMS at CERN (2016)

On February 24, 2016, at 15 hours, 55 students and 5 teachers in Escola Secundária Dr. Júlio Martins (Portuguese high school), made a virtual visit to CMS at CERN.

The activity was promoted by the European Project Inspiring Science Education (ISE), and it was made, for the second time, with a total of five portuguese schools: Escola Secundária Dr. Júlio Martins (Chaves); Escola Secundária Paços de Ferreira (Paços de Ferreira); Escola Secundária de Loulé (Faro), Agrupamento de Escolas Dra. Laura Ayres (Quarteira); Escola Secundária Adolfo Portela (Águeda).

The students saw the control room, the cavern of CMS (Compact Muon Solenoid) experiment, installed in LHC (Large Hadron Collider) and asked some questions to the scientists.

The students made a contact with Portuguese scientists, Pedro da Silva, André David Mendes and José Carlos da Silva, with technical support of Angelos Alexopoulos, Noemi Beni e Zoltan Zsillasi. They drove our students through CMS control room, and explained all the graphics in their computers, to the CMS cavern, 100 meters deep, and they explained all the objects observed, how it works and characteristics.

On the web:
- CMS virtual visit https://indico.cern.ch/event/502813/overview
- Miguel Neta website http://www.miguelneta.pt/pt/atividades/93-cms-virtual-visit-2016
- EUFISICA blog http://blog.eufisica.com/2016/02/visita-virtual-ao-cms-no-cern-2016.html

Muon Neutrinos Transform to Electron Neutrinos

Super Kamiokande is the worldʼs largest underground neutrino detector,
and is located 1000 metres underground in Kamioka Mine, Hida, Gifu Precture, Japan.
Credit: Image courtesy of Stony Brook University

Yesterday at the European Physical Society meeting in Stockholm, the international T2K collaboration announced definitive observation of muon neutrino to electron neutrino transformation. In 2011, the collaboration announced the first indication of this process, a new type of neutrino oscillation, then; now with 3.5 times more data this transformation is firmly established. The probability that random statistical fluctuations alone would produce the observed excess of electron neutrinos is less than one in a trillion. Equivalently the new results exclude such possibility at 7.5 sigma level of significance. This T2K observation is the first of its kind in that an explicit appearance of a unique flavor of neutrino at a detection point is unequivocally observed from a different flavor of neutrino at its production point.

More info: sciencedaily and Stony Brook University

Rare particle decay detected at LHC

Protons collide in the CMS detector, producing a Bs particle that 
decays into two muons (red lines) in this event display from 2012 (Image: CMS)

New results to be presented today at the European Physical Society's High Energy Physics conference (EPS-HEP 2013) in Stockholm, Sweden, have put the Standard Model of particle physics to one of its most stringent tests to date. The CMS and LHCbexperiments at CERN’s Large Hadron Collider (LHC) will present measurements of one of the rarest measureable processes in physics: the decay of a Bs (pronounced B-sub-s) particle into two muons.

The new measurements show that only a handful of Bs particles per billion decay into pairs of muons. Because the process is so rare, it is an extremely sensitive probe for new physics beyond the Standard Model. Any divergence from the Standard Model prediction would be a clear sign of something new.

Both experiments will present results to a very high level of statistical significance (over 4 sigma for each experiment). These results are in good agreement with the Standard Model.

Font: CERN

Read more:

"A very rare decay has been seen by CMS" - CMS collaboration 

"Measurement of the B0s→μμ branching fraction and search for B0→μμ decays at the LHCb experiment" - LHCb collaboration

• Physics paper on arXiv (CMS collaboration)
• LHCb-PAPER-2013-046 (LHCb collaboration)

HST2012, CERN - Day 11

Today we had a lecture in "Introduction to Particle Detectors"by Frank Hartmann (CERN and KIT - Karlsruhe Institute of Technology)

Before to build the detector we need to know the interactions (photon, charged particles, hadronic interactions, and neutrinos) and what properties we want to measure (energy, momentum, charge, life time, decay modes). How can we separably measure? Creating a detector with various combinations: a tracker, an electromagnetic calorimeter, a hadronic calometer, and a muon system.

The electrons leaves traces in the tracker and in the electromagnetic calorimeter (and stops). The fotons leaves traces in the electromagnetic calorimeter (and stops). The hadrons leaves traces in the tracker, the electromagnetic calorimeter and in the hadronic calorimeter (and stops). The muons leaves traces in all of them.

The principal function of  tracking detectors is measure the tracks of emerging particles; determine charge and momentum in connection with a magnetic field; tracks are reconstructed from measured space-points.