Virtual https://lanl-us.webex.com/lanl-us/j.php?MTID=m69e70ee814373df888942a5ee4066d47 Thursday, Dec 1st, 2022 3:45 – 4:45 pm (MT) Speaker: Dr. Oleg Denisov INFN, Italy “From Proton Spin Crisis to Hadron Mass Puzzle” Abstract: Proton spin crisis was initiated by the EMC (CERN, SPS) collaboration measurement in late 80’s which says proton spin carried by quarks far smaller than 100%. Where is the rest coming from? Yes, from gluon contribution and orbital momenta, but details still to be understood. Today, the next biggest science question is: why proton is so heavy and pion is so light? The origin of hadron masses is deeply connected to the parton dynamics just like the spin contributions. We are in a very beginning of the journey to find an answer to this question. AMBER is a newly approved fixed-target facility at the M2 beam line of the SPS at CERN, devoted to various fundamental QCD measurements. A determination of the valence-quark PDF of the pion, through Drell-Yan production, would provide the needed sensitivity to the mechanism(s) responsible for the emergence of mass in QCD. While the nucleon parton distributions are known with good precision already, the pion ones are very poorly known, the last measurements being more than 30 years old and suffering from very large uncertainties. The kaon parton dynamics, on the other hand, was never measured. For a longer-term program an upgrade of the M2 beam line with radio-frequency separation of kaon and antiproton beams of high energy and moderate intensity would allow for further unique opportunity to study the light-meson structure, by exploring both kaon-induced Drell-Yan, J/Psi and direct photon production.