In this note, we clarify a point concerning the power divergence in lattice calculations of ∆I = 1/2 K → ππ decay amplitudes. There have been worries that this divergence might show up in the Minkowski amplitudes at MK = Mπ with all the mesons at rest. Here we demonstrate, via an explicit calculation in leading-order Chiral Perturbation Theory, that the power divergence is absent at the above k...

With t-channel ρ, f 2 (1270) exchange and the ππ → ρρ → ππ box diagram contribution, we reproduce the ππ isotensor S-wave and D-wave scattering phase shifts and inelasticities up to 2.2 GeV quite well in a K-matrix formalism. The t-channel ρ exchange provides repulsive negative phase shifts while the t-channel f 2 (1270) gives an attractive force to increase the phase shifts for ππ scattering a...

There have been a number of recent experimental investigations of the nonadiabatic relaxation dynamics of aniline following excitation to the first three singlet excited states, 1(1)ππ*, 1(1)π3s/πσ* and 2(1)ππ*. Motivated by differences between the interpretations of experimental observations, we have employed CASSCF and XMCQDPT2 calculations to explore the potential energy landscape and relaxa...

The cis → trans photo-isomerisation of azobenzene, after excitation to the nπ* and ππ* states, is revisited theoretically using non-adiabatic dynamics simulations in order reproduce rationalize experimentally measured quantum yields.

We report the study of ee → Υ(1S)ππ, Υ(2S)ππ, Υ(3S)ππ, and Υ(1S)KK, near the peak of the Υ(5S) resonance. The results are based on a data sample of 21.7 fb collected with the Belle detector at the KEKB ee collider. Attributing the signals to the Υ(5S) resonance, the partial widths Γ(Υ(5S) → Υ(1S)ππ) = 0.59± 0.04(stat)± 0.09(syst) MeV and Γ(Υ(5S) → Υ(2S)ππ) = 0.85 ± 0.07(stat) ± 0.16(syst) MeV a...

Data on Ke4 decays allow one to extract experimental information on the elastic ππ scattering amplitude near threshold, and to confront the outcome of the analysis with predictions made in the framework of QCD. These predictions concern an isospin symmetric world, while experiments are carried out in the real world, where isospin breaking effects – generated by electromagnetic interactions and ...

Within the finite-temperature Greens-function formalism we study the equation of state of a hot interacting pion gas at zero chemical potential. Employing realistic ππ meson-exchange interactions we selfconsistently calculate the in-medium single-pion selfenergy and the ππ scattering amplitude in the quasiparticle approximation. These quantities are then used to evaluate the thermodynamic poten...

The production and decay of vector mesons (ρ,ω) in pA and AA reactions is studied with particular emphasis on their in-medium spectral functions. It is explored within transport calculations if hadronic in-medium decays like ππ or πγ might provide complementary information to their dilepton (ee) decays. Whereas the ππ signal from the ρ-meson is found to be strongly distorted by pion rescatterin...

The cusp effect in K → 3π and data on Ke4 decays allow one to extract experimental information on the elastic ππ scattering amplitude near threshold, and to confront the outcome of the analyses with predictions made in the framework of QCD. In my talk I pointed out that these predictions concern an isospin symmetric world, while experiments are carried out in the real world, where isospin break...

Di erences in the behaviour of matter and antimatter have been observed in K and B meson decays, but not yet in any baryon decay. Such di erences are associatedwith the non-invariance of fundamental interactions under the combined chargeconjugation and parity transformations, known as CP violation. Here, using data from the LHCb experiment at the LargeHadron Collider, we search for CP-violating...