Seminar

Title: Pion structure from Sum Rules

Speaker: Dr. Alexandr Pimikov (Bogoliubov Laboratory of Theoretical Physics, JINR & IMP, CAS)

Time: 10:00AM, Dec.25th (Friday)

Place: Theoretical Physics Division，319

Abstract:

The quark structure of the pion is considered using two theoreticalapproaches based on different types of Sum Rules within QCD: QCD Sum Rules with nonlocal condensates and Light Cone Sum Rules .This scheme is used to address the pion distribution amplitude (DA) andthe pion-photon transition form factor. Our main objectives are twofold:(i) To compare our theoretical predictions with the existing data of CELLO, CLEO, BaBar, and Belle, paying particular attention to the low-mid momentum region, where the BESIII Collaboration is going to publish data on this observable. For the time being, we use only the simulated BESIII data. Our analysis includes all perturbative (i.e., radiative) corrections and nonperturbative terms of higher twist which are currently known. A key element of the investigation is the detailed estimation of the uncertainties related to these contributions. (ii) The second objective is related to the shape of the pion DA. Recent works (including ours) have found that the existing data set severe constraints on the profile of the pion DA. In particular, the kinematic endpoint regions seem to play an important role. Our work attempts to contribute to a better understanding of this important issue.