Thomas Boettcher

Rethinking assumptions about protons and nuclei with LHCb

Abstract
Parton densities in protons and nuclei are crucial tools for interpreting data from hadron colliders like RHIC and the LHC. Our understanding of parton densities is based on some key assumptions about the production and interaction of quarks and gluons inside of hadrons. In this talk, I'll present LHCb measurements that challenge some of these assumptions by probing the structure of protons and nuclei in extreme kinematic regimes. I'll present a study of Z boson production in association with charm quarks that shows evidence for an intrinsic charm-quark component of the proton wavefunction. I'll also present studies of light-hadron production in proton-lead collisions and discuss their implications for our understanding of nuclear effects in proton-ion collisions.