The reversal of aromaticity and antiaromaticity upon excitation to the lowest ππ* state impacts on photophysics photoreactivity various annulenes. This unifying principle can guide rationalization a plethora excited-state reactions has strong predictive power in design new photochemical transformations. For more details, see Review by H. Ottosson et al. (DOI: 10.1002/chem.202203748)

A joint analysis of the ππ and ππ S-wave amplitudes including results of three experiments has been performed. Using our theoretical model of the ππ production in which not only the pion exchange but also the a1 meson exchange were taken into account we have obtained a unique solution (called ”down-flat”) for the scalar-isoscalar phase shifts. Thus a long-standing problem of ambiguities in the ...

It is well known that one can use B → ππ decays to probe the CP-violating phase α. In this paper we show that these same decays can be used to search for new physics. This is done by comparing two weak phases which are equal in the standard model: the phase of the t-quark contribution to the b → d penguin amplitude, and the phase of B d–B 0 d mixing. In order to make such a comparison, we requi...

We perform a detailed Regge analysis of NN , πN , KN , ππ and πK scattering. From it, we find expressions that represent the ππ scattering amplitudes with an accuracy of a few percent, for exchange of isospin zero, and ∼ 15% for exchange of isospin 1, and this for energies s > 1.4GeV and for momentum transfers |t| < ∼ 0.4GeV. These Regge formulas are perfectly compatible with the low energy (s ...

Electromagnetic corrections to the low-energy π+π− → π0π0 scattering amplitude at next-to-leading order in the chiral expansion are reviewed. Their effects on the corresponding scattering lengths are estimated and compared to the two-loop strong interaction contributions. Key-Words: Chiral perturbation theory, Pion, Electromagnetic corrections. Contribution to the Eighth International Symposium...

The leading twist parametrization of dipion mass distribution in hard exclusive reactions is proposed. Its parameters are related to quark distributions (usual and skewed) in the pion and to distributions amplitudes of mesons (π, ρ, etc.). We show that measurements of the shape of dipion mass distribution in hard exclusie reactions can give important information about partonic structure of the ...

The present theoretical status of the parameter for direct CP violation ε/ε in the Standard Model is reviewed and compared with most recent experimental measurements of the same quantity. After collecting the basic expressions for ε/ε, the situation of hadronic matrix element calculations is summarised. The matrix elements constitute the dominant source of uncertainty for theoretical determinat...