Related papers: Isoscalar off-shell effects in threshold pion prod…
The strong interaction effects of isospin- and spin-dependent nucleon-nucleon correlations observed in many-body calculations are interpreted in terms of a one-pion exchange mechanism. Including such effects in computations of nuclear…
In this study, we have considered the contribution of the higher-twist (HT) effects of the subprocesses to inclusive pion pair production cross section in the high energy proton-antiproton collisions by using various pion distribution…
With an effective Lagrangian approach, we analyze several NN \to NN\pi\pi channels by including various resonances with mass up to 1.72 GeV. For the channels with the pion pair of isospin zero, we confirm the dominance of N*(1440)\to…
We present results for the $p p \to p p \omega$ reaction studied by considering two different scenarios: with and without the inclusion of nucleon resonance excitations. The recently measured angular distribution by the COSY-TOF…
The scalar-isoscalar term in the two-pion exchange $NN$ potential is abnormally large and does not respect the hierarchy of effects predicted by chiral perturbation theory. We argue that this anomaly is associated with non-perturbative…
We apply the nuclear model with explicit mesons to photoproduction of neutral pions off protons at the threshold. In this model the nucleons do not interact with each other via a potential but rather emit and absorb mesons that are treated…
The $N\Delta\to NN$ cross sections, which take into account the $\Delta$-mass dependence of M-matrix and momentum $p_{N\Delta}$, are applied on the calculation of pion production within the framework of the UrQMD model. Our study shows that…
Within the framework of the improved isospin dependent quantum molecular dynamics (ImIQMD) model, the pion emission in heavy-ion collisions in the region 1 A GeV is investigated systematically, in which the pion is considered to be mainly…
In order to quantify isospin effects in the comparison of elementary to nuclear collisions, p-p and n-p interactions have been studied in the NA49 experiment in addition to p-Pb and Pb-Pb reactions. Together with first measurements of…
The near-threshold n p -> d pi0 cross section is calculated in chiral perturbation theory to next-to-leading order in the expansion parameter sqrt{M m_pi}/Lambda_chi. At this order irreducible pion loops contribute to the relevant…
Fits of pion-nucleus potentials to large sets of pionic atom data reveal departures of parameter values from the corresponding free $\pi N$ parameters. These medium effects can be quantitatively reproduced by a chiral-motivated model where…
The first attempt is made to provide a quantitative theoretical interpretation of the WASA-at-COSY experimental data on the basic double-pion production reactions $pn \to d \pi^0\pi^0$ and $pn \to d \pi^+\pi^-$ in the energy region $T_p =1$…
Production of pions in proton-nucleus (p+A) reactions outside of a kinematical boundary of proton-nucleon collisions, the so-called cumulative effect, is studied. The kinematical restrictions on pions emitted in backward direction in the…
Predictions of the existence of well-defined deeply bound pionic atom states for heavy nuclei and the eventual observation of such states by the (d,3He) reaction have revived interest in the pion-nucleus interaction at threshold and in its…
We analyze the production of $\phi$ mesons in $\pi N$ and NN reactions in the near-threshold region, using throughout the conventional ``non-strange'' dynamics based on such processes which are allowed by the non-ideal $\omega-\phi$ mixing.…
We present an exploratory study of two pion photo-- and electroproduction off the nucleon in the threshold region. To calculate the pertinent amplitudes, we make use of heavy baryon chiral perturbation theory. We show that due to finite…
We calculate the isospin symmetry violating effects to the reactions $pp\rightarrow d\pi ^+$ and $np\rightarrow d\pi ^0$ arising from the different hadron masses and from the Coulomb interaction between the positive pion and the deuteron.…
The effect of possible in-medium modifications of nucleon-nucleon ($NN$) cross sections on particle production is investigated in heavy ion collisions ($HIC$) at intermediate energies. In particular, using a fully covariant relativistic…
The scaling of pion multiplicities with system size in proton-nucleus and nucleus-nucleus reactions at 200 A GeV is investigated. A nuclear geometry calculation of incoherent multiple scattering including effects of deceleration of the…
We consider pion electroproduction close to threshold for $Q^2$ in the region 1-10 GeV$^2$ on a nucleon target. The momentum transfer dependence of the S-wave multipoles at threshold, $E_{0+}$ and $L_{0+}$, is calculated in the chiral limit…