6th IDPASC/LIP PhD Students Workshop

Constraints on the chi_c1 and chi_c2 polarizations

26 Jun 2020, 10:25

12m

PhD student talk Session 5

Speaker

Mariana Araújo

Description

Hadron formation is a rather complex problem in the realm of non-perturbative QCD and remains an open question in HEP, despite the significant progress recently made through detailed phenomenological studies of several quarkonium production measurements made at the LHC. A new piece in the global panorama of quarkonium production data has recently been added by CMS: the first measurement of the polarizations of P-wave quarkonia. This is the first clear observation of significantly polarized quarkonium production, the ${\chi }_{c1}$ and ${\chi }_{c2}$ polarizations being almost maximally different. This remarkable observation provides a clean and non-trivial test of any theoretical attempt to explain the mechanisms behind hadron formation, including the widely used approach of NRQCD, which survives the test with flying colours.

Presentation materials

talk_main.pdf