相关论文: Coherent Pion Pairs from Heavy-Ion Collisions
The high-density behavior of nuclear symmetry energy is among the most uncertain properties of dense neutron-rich matter. Its accurate determination has significant ramifications in understanding not only the reaction dynamics of heavy-ion…
High-energy nuclear collisions provide a unique environment for synthesizing both nuclei and antinuclei (such as $\bar{d}$ and $\overline{^4\text{He}}$) at temperatures ($k_BT\sim100$ MeV) nearly two orders of magnitude above their binding…
The application of the chiral effective theory to processes with two or more nucleons is discussed. We gain a qualitative understanding of the gross features of nuclear physics and quantitative, testable postdictions and predictions…
High intensity back-scattered laser beams will allow the efficient conversion of a substantial fraction of the incident lepton energy into high energy photons, thus significantly extending the physics capabilities of an electron-electron or…
We present a theoretical analysis of high-order harmonic generation from ion-atom collisions in the presence of linearly polarized intense laser pulses. Photons with frequencies significantly higher than in standard atomic high-harmonic…
Effective three meson couplings, based in flavor U(3) quark-antiquark interactions, are considered to describe two light neutral axial meson Strong decays, $A \sim f_1(1285)$ and $f_{1S} (1420)$, and the charged rho meson decay in the…
We report the first experimental observation of the pionic fusion of two heavy ions. The 12C(12C,24Mg)pi0 and 12C(12C,24Na)pi+ cross sections have been measured to be 208 +/- 38 and 182 +/- 84 picobarns, respectively, at E_cm = 137 MeV.…
The differential cross sections for the process $\gamma \gamma \to \pi^0 \pi^0$ have been measured in the kinematic range 0.6 GeV $< W < 4.1$ GeV, $|\cos \theta^*|<0.8$ in energy and pion scattering angle, respectively, in the…
An extended pion source, which can be temporarily created by a high energy nuclear collision, will also absorb and distort the outgoing pions. We discuss how this effect alters the interferometric pattern of the two-pion momentum…
In the scattering of positive pions by nuclei the double-charge-exchange (DCX) reaction creates the possibility of formation of pionic atom states in the vicinity of the threshold of this reaction. These quasi stationary states can manifest…
The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single pion on the nucleon. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is…
We present first results on the scalar WIMP-pion coupling from 1 t$\times$yr of exposure with the XENON1T experiment. This interaction is generated when the WIMP couples to a virtual pion exchanged between the nucleons in a nucleus. In…
The cross sections for producing K$^-$ mesons in nucleon-hyperon elementary processes are estimated assuming one-pion exchange and using the experimentally known pion-hyperon cross sections. The results are implemented in a transport model…
Triple differential cross sections of pions in heavy ion collisions at 1 GeV/nucl. are studied with the IQMD model. After discussing general properties of $\Delta$ resonance and pion production we focus on azimuthal correlations: At…
We show that the tail of the chiral two-pion exchange nucleon-nucleon potential is proportional to the $\pi N$ scalar form factor and discuss how it can be translated into effective scalar meson interactions. We then construct a kernel for…
Two-meson-exchange nucleon-nucleon potentials are derived where either one or both nucleons contains a pair vertex. Physically, the meson-pair vertices are meant to describe in an effective way (part of) the effects of heavy-meson exchange…
We study coherent pion production in neutrino-nucleus scattering in the energy region relevant to the recent neutrino oscillation experiments. Our approach is based on the combined use of the Sato-Lee model and the Delta-hole model. Our…
Using results from the chiral perturbation theory for the s-wave interaction and the delta-resonance model for the p-wave interaction of pions with nucleons, we have evaluated the spectral functions of pions in asymmetric nuclear matter…
The two-pion production in pp-collisions has been investigated at CELSIUS in exclusive measurements from threshold up to $T_p$ = 1.36 GeV. Total and differential cross sections have been obtained for the channels $pn\pi^+\pi^0$,…
The ABC effect - a puzzling low-mass enhancement in the $\pi\pi$ invariant mass spectrum - is known from inclusive measurements of two-pion production in nuclear collisions, where it always showed up, if the participating nucleons fused to…