Related papers: Annihilation range and final-state interaction in …
We use a distorted wave approximation approach which includes $^3P_0$ and $^3S_1$ quark-antiquark annihilation mechanisms to reproduce the data set from LEAR on $\bar p p\to \pi^+\pi^-$ in the range from 360 to 1550 MeV/c. Improvements of…
We present a geometric interpretation of the so-called annihilation range in reactions of the type $\bar pp \to$ {\em two light mesons} based upon Lorentz effects in the highly relativistic final states ($\gamma=E_{\mathrm{cm}}/2mc^2\simeq…
Quark model intrinsic wave functions of highly energetic pions in the reaction \bar pp->\pi^-\pi^+ are subjected to a relativistic treatment. The annihilation is described in a constituent quark model with A2 and R2 flavor-flux topology and…
We present a new fit to the LEAR data on antiproton-proton -> pi^- pi^+ differential cross sections and analyzing powers motivated by relativistic considerations. Within a quark model describing this annihilation we argue, since the pions…
Results for d$\sigma$/d$\Omega$ and $A_N$ in the reaction $\bar{p}p \rightarrow \pi^- \pi^+$ are predicted by a simple quark model. They are compared to recent experimental data from LEAR, as well as to previous predictions from…
The s-channel annihilation of proton and antiproton into a neutral pion and a real or virtual photon followed by lepton pair emission is studied. Such mechanism is expected to play a role at moderate values of the total energy $\sqrt{s}$,…
We consider the $\pi^+\pi^-\pi_0\gamma$ final state in electron-positron annihilation at cms energies not far from the threshold. Both initial and final state radiations of the hard photon is considered but without interference between…
We propose to describe the process $ p ~ \bar{p} \rightarrow \pi^+ ~ \pi^-$ in a perturbative, QCD motivated framework in which a hard $ud \, \bar{u} \bar{d} \rightarrow d \, \bar{d} $ annihilation factorizes from soft transition…
We analyze the origin of the structures observed in the reactions $e^+e^-\to 3(\pi^+\pi^-)$, $2(\pi^+\pi^-\pi^0)$, $\omega\pi^+\pi^-\pi^0$, and $e^+e^-\to 2(\pi^+\pi^-)\pi^0$ around the antiproton-proton ($\bar pp$) threshold. We calculate…
The $\Delta$-excitation in $\overline{p}d$ annihilation at rest was studied. The annihilation amplitude from the statistical model and the $\pi N$ amplitude from the resonance model were adopted in our calculations. We analyze the invariant…
A new analysis of S-wave production amplitudes for the reaction $\pi^- p_{\uparrow} \rightarrow \pi^+ \pi^- n$ on a transversely polarized target is performed. It is based on the results obtained by the CERN-Cracow -Munich collaboration in…
We study antiproton-proton annihilation at rest into $\pi\phi$ and $\gamma\phi$. Rescattering by $\overline{K^*}K+K^*\overline{K}$ and $\rho^{+}\rho^{-}$ for $\overline{p}p\rightarrow\pi\phi$ states is sizable, of order $(0.90\, {\rm…
In the first Born approximation we study the reactions $K\phi\to\pi K$, $\rho K$, $\pi K^*$, and $\rho K^*$ with quark-antiquark annihilation and creation. Transition amplitudes are derived with the development in spherical harmonics of the…
Antiproton-nucleus optical potentials fitted to $\bar p$-atom level shifts and widths are used to calculate the recently reported very low energy ($p_{L}<100$ MeV/c) $\bar p$ cross sections for annihilation on light nuclei. The apparent…
Partial wave amplitudes have been extracted from accurate data on pbar + p -> pi + pi by a method which incorporates the theoretical constraints of analyticity and crossing symmetry. The resulting solution gives a good fit to the…
Charge-exchange rescattering $\pi^+\pi^-\to \pi^0\pi^0$ leads to a cusp effect in the $\pi^0\pi^0$ invariant mass spectrum of processes with $\pi^0\pi^0$ in the final state which can be used to measure $\pi\pi$ $S$-wave scattering lengths.…
We report measurements of the observed cross sections for $e^+e^-\to\omega \pi^+\pi^-$, $\omega K^+K^-$, $\omega p\bar p$, $K^+K^-\rho^0\pi^0$, $K^+K^-\rho^+\pi^-+c.c.$, $K^{*0}K^-\pi^+\pi^0+c.c.$, $K^{*+}K^-\pi^+\pi^-+c.c.$,…
We present a review of BaBar results on e+e- annihilations into exclusive hadronic final states using the initial state radiation technique. Cross sections over the sqrt{s} range from threshold to 4.5 GeV, with very small point-to-point…
A method of measuring e+e- annihilation cross sections at low energy sqrt{s}< 5 GeV, using initial-state radiation, is described. Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass energy, obtained via ISR, are…
In order to establish links between p-wave pion production in nucleon-nucleon collisions and low energy three-nucleon scattering, an extensive programme of experiments on pion production is currently underway at COSY-ANKE. The final proton…