Recent status of leptohadron hypothesis

TGD predicts the existence of color octet excitations of ordinary leptons forming 'leptohadrons' as their color singlet bound states. There is some evidence on the existence of leptohadrons: the production of anomalous $e^+e^-$ pairs in heavy ion collisions, Karmen anomaly, the anomalously high decay rate of ortopositronium (Op) and anomalous production of low energy $e^+e^-$ pairs in hadronic collisions. PCAC makes it possible to predict the couplings of leptopion to leptons. The new contribution to Op decay rate is of correct order of magnitude and the anomaly allows to determine the precise value of the parameter $f_{\pi_L}$. Sigma model realization of PCAC makes it possible to construct a model for the production of leptohadrons in the electromagnetic fields of the colliding nuclei. $\pi_L$ develops vacuum expectation value proportional to the 'instanton density' $E\cdot B$ and it is possible to relate leptohadron production rates to the Fourier transform of $E\cdot B$. Anomalous $e^+e^-$ pairs must originate from $\sigma_L \pi_L$ pairs via $\sigma_L\rightarrow e^+e^-$ decay. The peculiar production characteristics of leptomesons are reproduced, the order of magnitude for the production cross section is correct and various decay rates are within experimental bounds. A resonance in photon photon scattering at cm energy equal to leptopion mass is predicted and leptobaryon pair production in heavy ion collisions is in principle possible. Leptopion contribution to the $\nu-e$ and $\bar{\nu}-e$ scattering should dominate at low energies.