The strange quark polarisation puzzle - unfinished quest

by Marcin Stolarski (LIP)

Thursday 30 May 2013, 11:30 → 12:30 UTC

LIP _ Lisbon

In the simplest Quark Parton Model the proton spin is built out of spin of three valence quarks. The measurements done 25 years ago in the EMC experiment at CERN have shown that quarks carry only small fraction of the proton spin. This discovery was called the "spin crisis".

The other conclusion of this measurement is the fact that the strange quark polarisation in the nucleon is expected to be large and negative. However, using different method, the results obtained more recently in two other experiments do not support a significant negative polarisation of the strange quarks... Further investigations has so far given contradictory results...

In this seminar I will discuss the younger brother of the spin crisis:
 "The strange quark polarisation puzzle".
 

Slides sem.pdf