Cristina Sánchez Gras, PhD at Nikhef, will defend her thesis Monday 12 December 2022 at 13.45 at the Vrije Universiteit Amsterdam.
“Exceptionally empty charm”
Protons, together with neutrons and electrons, make up all matter. Once thought as fundamental particles, protons are made up of quarks and gluons. These are indeed elementary particles, and are bound within the proton by the strong force. Quarks and gluons, known as partons, carry different fractions of the total proton momentum. The probability of a given parton to have a specific fraction of the total proton momentum is given by parton distribution functions (PDFs). The aforementioned momentum fraction is known as Bjorken-x. These PDFs are based on experimental data, and the content of the proton in terms of PDFs is better documented for high Bjorken-x values than for low ones. At low Bjorken-x values, the gluon PDF is expected to be dominant. However, barely any data is available and the gluon PDF remains largely unconstrained in that region. The LHCb experiment allows to access that region via the central exclusive production of charmonia mesons. This diffractive process involves two protons interacting via the exchange of a pomeron and a photon. The thesis presents valuable experimental results that can be used to determine the gluon PDF more precisely at low Bjorken-x values. In addition, this thesis provides some insight on the nature of the pomeron.
“Exceptionally empty charm – Central exclusive production of charmonia at LHCb” (pdf)
The PhD defense will take place Monday 12 december, at 13.45 in the Aula of the Vrije Universiteit, De Boelelaan 1105, 1081 HV Amsterdam.
The defense will be broadcasted online on the VU YouTube channel.
More information on the website of the VU.
Supervisor: prof. dr. H.G. Raven
Co-supervisors: dr. P. Koppenburg and dr. M. Schubiger
Contact: Cristina Sánchez Gras
