Search

Chiral anomaly of gamma transition into three pions are studied in a framework of nonlocal chiral quark model. In the local limit the result is in agreement with chiral perturbative theory and reproducesWess-Zumino-Witten anomaly. Transition form factor of gamma into three pions in nonlocal quark model has a correction which vanishes in local limit.

We complete our derivation of upper limits on the CP violating ηππ and η‘ππ couplings from an analysis of their two-loop contribution to the neutron electric dipole moment (nEDM). As a result we obtain numerical upper limits for the ηππ and η‘ππ branchings and couplings which are important for planned experiments at JLab. We also derive upper limits on the CP violating θ̅parameter of QCD θ̅< 2.8 × 10−10

The light-by-light contribution from the axial-vector (AV) mesons exchanges to the muon anomalous magnetic moment is estimated in the framework of the nonlocal chiral quark model. The preliminary answer for contributions from a1 and f1 mesons to (g-2)_mu is 0.34 x 10^(-11) and does not support the Melnikov-Vainshtein estimate 2.2 x 10^(-11)., Comment: 5 pages, talk at e+e- Collisions From Phi to Psi 2019

Soon, new experiments at FNAL and J-PARC will measure the muon anomalous magnetic moments with better accuracy than before. From theoretical side, the uncertainty of the standard model prediction is dominated by the hadronic contributions. Current status of the experimental data and theoretical calculations are briefly discussed., 9 pages. Contribution to QUARKS-2016, 19th International Seminar on High Energy Physics, Pushkin, Russia, 29 May - 4 June, 2016

The data for the upper limit on the electric dipole moment of the neutron (nEDM) can be explained by using different mechanisms beyond the Standard Model (SM). The nEDM can be generated by a CP-violating transition of η and η′ mesons into pion pairs. We derive the upper limits for the rates of the CP-violating decays η(η′) → 2π are by orders of magnitude more stringent than those from existing experiments so far.