Thesis

Study of the Strange Quark Polarisation Puzzle in the COMPASS experiment at CERN

• Call:

  IDPASC Portugal - PHD Programme 2015

• Academic Year:

  2015 / 2016

• Domain:

  Experimental Particle Physics

• Supervisor:

  Paula Bordalo

• Co-Supervisor:

  Marcin Stolarski

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  COMPASS is a high-energy physics experiment at CERN. Its purpose is the study of hadron structure, namely a better understanding of the spin structure of the nucleon. In that view, data already collected by COMPASS in previous years of deep inelastic scattering of a muon beam off a polarized target offer a very interesting framework to the deep understanding of nucleon structure, addressing subjects like the gluon polarisation in the nucleon and the polarized parton distribution functions. In particular, the strange quark polarisation puzzle is an interesting open topic. The extraction of strange asymmetries, s↑↑(x) and s↑↓(x), coming from the two experimental spin configurations, parallel and antiparallel, allows the measurement of the spin dependent strange parton distribution, Δs(x). This procedure is based on very reliable kaon identification, from the RICH detector, and should use the more advanced tools like artificial Neural Networks or other techniques as genetic algorithms.