Related papers: Enhanced pion production in DCC dynamics
A two-mode boson model, widely used for the physics of fast rotating nuclei and Bose-Einstein condensates, is studied in the context of entanglement control. We derive an analytical expression for the entanglement between the fields in this…
We suggest two methods for the detection of the formation of disoriented chiral condensates in heavy ion collisions. We show that the variance in the number of charged pions (in a suitable range of momentum space) provides a signature for…
The time evolution from coherent states to squeezed states of high density excitons is studied theoretically based on the boson formalism and within the Random Phase Approximation. Both the mutual interaction between excitons and the…
We investigate threshold pion photoproduction in the framework of heavy baryon chiral perturbation theory. We give the expansion of the electric dipole amplitude $E_{0+}$ to three orders in $\mu$, the ratio of the pion to nucleon mass, and…
The posibility of large charge and isospin fluctuations in high-energy heavy ion-collisions is studied within the framework of the nonlinear $\sigma $-model with quark degrees of freedom. The multipion exchange potential between two quarks…
The effects of mode-mode and isospin-isospin correlations on nonequilibrium chiral dynamics are investigated by using the method of the time dependent variational approach with squeezed states as trial states. Our numerical simulations show…
Production of pions in high-energy collisions with nuclei in the kinematics prohibited for free nucleons ("cumulative pions") is studied in the fusing color string model.The model describes the so-called direct mechanism for cumulative…
We analyse the extension of Chiral Perturbation Theory to describe a meson gas out of thermal equilibrium. For that purpose, we let the pion decay constant be a time-dependent function and work within the Schwinger-Keldysh contour…
Using the O(4) linear $\sigma$ model, we address the topic of non-equilibrium relaxation of an inhomogeneous initial configuration due to quantum and thermal fluctuations. The space-time evolution of an inhomogeneous fluctuation of the…
The probability distribution in $R$, the proportion of neutral pions to all pions emitted in heavy ion collisions in certain kinematic regions, has been suggested as a signal of a disoriented chiral condensate (D$\chi$C). Here we note that…
We have calculated the effect of the inclusion of final state interactions on pion production from nuclei with incident pion beams. We find that the effect of absorption, along with geometric considerations, explains much of the enhancement…
A theoretical scheme which relates multiparticle states generated in ultrarelativistic nuclear collisions to a QCD phase transition is considered in the framework of the universality class provided by the 3-D Ising model. Two different…
Pions produced via the $D^{+} \to \pi^{+} \overline{K^{0}}$ decay are in an entangled superposition of energy states because the $\overline{K^{0}}$ is not a mass eigenstate. This presents an opportunity to access kaon mixing parameters via…
Recent BaBaR data on the pion transition form factor, whose Q^2 dependence is much steeper then predicted by asymptotic Quantum Chromodynamics (QCD), have caused a renewed interest in its theoretical description. We present here a formalism…
We study the particle production in the early stage of the ultrarelativistic heavy-ion collisions. To this end the Boltzmann kinetic equations for gluons and pions with elastic rescattering are considered together with a simple model for…
We develop an extension of chiral perturbation theory to the $\Delta$(1232)-resonance energy region and apply it to investigate the pion electroproduction off the nucleon ($e^- N \to e^- N\pi$). We present a complete calculation of this…
We show that the time-dependence of correlation functions in an extended quantum system in d dimensions, which is prepared in the ground state of some hamiltonian and then evolves without dissipation according to some other hamiltonian, may…
We propose a novel mechanism for DCC formation in a first-order chiral phase transition. In this case the effective potential for the chiral order parameter has a local minimum at $\Phi\sim 0$ in which the chiral field can be ``trapped''.…
We extend chiral perturbation theory to study a meson gas out of thermal equilibrium. Assuming that the system is initially in equilibrium below the critical temperature and working within the Schwinger-Keldysh contour technique, we define…
The production of (eta,eta')- mesons during the decay of a CP-odd phase is studied within an evolution operator approach. We derive a quantum kinetic equation starting from the Witten-DiVecchia-Veneziano Lagrangian for pseudoscalar mesons…