We propose a theory which exploits the charge-exchange reactions (3He,3Hπ+) and (p,nπ+) as effective sources of virtual pions. We consider processes in which the creation of virtual pions is followed by conventional coupled-channel pion scattering to discrete nuclear states. This picture allows us to incorporate successful theories of pion scattering and utilize virtual pions as probes of the n...

Results of the computer simulation of dilepton production from the expanding pion gas created in ultrarelativistic Pb+Pb 160 GeV/n collisions are presented. Finite size of the expanding pion gas influences invariant mass spectrum of dileptons. Sensitivity of the shape of dilepton mass spectrum to the initial stage of the pion gas is discussed. Second order asymmetry in azimuthal distribution of...

The polarizabilities of the pion have been predicted in several different theoretical frameworks. The status of these is reviewed.

It is proposed to search for free quarks near their production thresholds. If the current-quark masses for u, d quarks are smaller than the pion mass, uū and dd̄ pairs produced below the pion pair threshold, would not have sufficient energy to hadronize and could be observable. In the case of large u,d quark masses and also for the heavy quarks, production near threshold may show hadronization p...

measurement of bose-einstein correlations in the production of like-signed pion pairs has been made with the amy detector at tristan. an event sample of 10120 hadronic events with ranging between 50 to 61 gev was used. these measurements indicate a strength of the enhancement of ? = 0.61m.07, with a typical correlation size of ro = 1.16±.08 fm. this value of ? is consistent with measurements at...

The special features of forward pion photoproduction at high energies are discussed. It is established that the cross section for single pion production can generally be expected to have a forward dip barring a conspiracy between Regge trajectories. Photoproduction of the A,(l+) meson followed by its decay is suggested as an important source of high energy forward pions. Submitted to Phys. Rev....

In high energy heavy ion collisions the pion multiplicity is large, and one might expect that pions are radiated semi-classically. The axial symmetry of the collision and approximately zero isotopic spin of the colliding nuclei result then in peculiar isotopic spin – azimuth correlations of the produced pions. These correlations are easy to test – and should be tested Alexander von Humboldt For...

The dispersion relations which allow to express the two-pion light-cone distribution amplitudes (DA’s) in a wide range of two-pion invariant masses (including the resonance region) in terms of ππ scattering phase shifts and of a few low-energy subtraction constants are derived. The corresponding subtraction constants can be determined in the low energy region–where the effective chiral theory i...