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We present STAR measurements of the azimuthal anisotropy parameter $v_2$ and the binary-collision scaled centrality ratio $R_{CP}$ for kaons and lambdas ($\Lambda+\bar{\Lambda}$) at mid-rapidity in Au+Au collisions at $\sqrt{s_{_{NN}}}=200$…

Nuclear Experiment · Physics 2012-08-27 STAR Collaboration

It is demonstrated within the dibaryon-induced model for $NN$ interaction that $pp$ scattering in $P$ waves is governed mainly by the production of the intermediate dibaryon resonances. Two dibaryon resonances with a mass of about 2200 MeV…

Nuclear Theory · Physics 2021-01-04 O. A. Rubtsova , V. I. Kukulin , M. N. Platonova

The $\pi^-p \to e^+e^- n$ and $\pi^+n \to e^+e^- p$ reaction cross sections are calculated below and in the vicinity of the vector meson ($\rho^0$, $\omega$) production threshold. These processes are largely responsible for the emission of…

Nuclear Theory · Physics 2014-11-18 Madeleine Soyeur , Matthias F. M. Lutz , Bengt Friman

We calculate the spin-polarizabilities of the nucleon by means of dispersion relation, where the pion photoproduction amplitude predicted by chiral soliton model is utilized. We consider the $N\pi$ and $\Delta\pi$ channels in the…

Nuclear Theory · Physics 2009-10-31 Y. Tanushi , S. Saito , M. Uehara

With an effective Lagrangian approach, we give a full analysis on the $NN \to NN\pi\pi$ and $\bar{N}N\to \bar{N}N\pi\pi$ reactions by exploring the roles of various resonances with mass up to 1.72 GeV. We find large contributions from…

Nuclear Theory · Physics 2011-03-02 Xu Cao , Bing-Song Zou , Hu-Shan Xu

We present here the results of calculations of photoelectrons' angular anisotropy and spin-polarization parameters for a number of semi-filled shell atoms. We consider ionization of outer or in some cases next to the outer electrons in a…

Atomic Physics · Physics 2007-05-23 M. Ya. Amusia , L. V. Chernysheva

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…

Nuclear Theory · Physics 2025-11-18 Li-Yuan Zhang , Che Ming Ko , Yu-Gang Ma , Qi-Ye Shou , Kai-Jia Sun , Rui Wang , Song Zhang

In many reactions leading to excitations of the nucleon the Roper resonance $N^*(1440)$ can be sensed only by complex partial-wave analyses. In nucleon-nucleon collisions the isoscalar single-pion production as well as specific two-pion…

High Energy Physics - Experiment · Physics 2025-07-03 Heinz Clement

We present calculations of dielectron anisotropic flow in heavy-ion collisions at HADES beam energies from a hadronic transport approach. The ongoing experimental analysis employs the traditional reaction plane method to evaluate the flow…

Nuclear Theory · Physics 2025-02-03 Renan Hirayama , Hannah Elfner

The $\pi^-/\pi^+$ ratio is examined as a function of isospin asymmetry and beam energy for central collisions induced by neutron-rich nuclei within an isospin-dependent hadronic transport model. The $\pi^-/\pi^+$ ratio is found to increase…

Nuclear Theory · Physics 2009-11-07 Bao-An Li

A resonance model for two-pion production in the pion-nucleon reaction is developed that includes information obtained in the analysis of pion-nucleon scattering in a meson-exchange model. The baryonic resonances Delta(1232), N*(1440),…

Nuclear Theory · Physics 2007-05-23 S. Schneider , S. Krewald , Ulf-G. Meißner

In order to illustrate the capabilities of COMPASS using a hadronic beam, I review some of the azimuthal asymmetries in hadronic collisions, that allow for the extraction of transversity, Sivers and Boer-Mulders functions, necessary to…

High Energy Physics - Phenomenology · Physics 2007-08-03 Marco Radici , Francesco Conti , Alessandro Bacchetta , Andrea Bianconi

The dependence of the differential cross section and polarization observables in the $\bar N+N\to \pi +e^++e^-$ reaction on the polarizations of the proton target and antiproton beam (the produced electron may be unpolarized or…

Nuclear Theory · Physics 2015-06-05 G. I. Gakh , E. Tomasi-Gustafsson , A. Dbeyssi , A. G. Gakh

Results are presented of an analysis of proton and charged pion azimuthal distributions measured with respect to the reaction plane in Au + Au collisions at a beam momentum of about 11 AGeV/c. The azimuthal anisotropy is studied as a…

Nuclear Experiment · Physics 2008-11-26 J. Barrette

We have performed a detailed study of dilepton production from pp collisions including the subthreshold $\rho$ production via baryonic resonances (N(1520), N(1700)) in addition to the conventional dilepton sources as $\pi^0, \eta, \omega$…

Nuclear Theory · Physics 2009-10-31 E. L. Bratkovskaya , W. Cassing , M. Effenberger , U. Mosel

Differential production cross sections of K$^-$ and K$^+$ mesons have been measured as function of the polar emission angle in Ni+Ni collisions at a beam energy of 1.93 AGeV. In near-central collisions, the spectral shapes and the widths of…

The spin effect of electrons/positrons ($e^-$/$e^+$) and polarization effect of $\gamma$ photons are investigated in the interaction of two counter-propagating linearly polarized 10-PW-class laser pulses with a thin foil target. The…

Dielectron production in reactions $\pi^- p \rightarrow n e^+e^-$ and $\pi^- p \rightarrow n e^+e^- \gamma$ at energies less than 1 GeV is studied assuming electron-positron pair production to occur in the virtual time-like photon splitting…

High Energy Physics - Phenomenology · Physics 2019-07-25 A. P. Jerusalimov , G. I. Lykasov

Employing the recently developed neXus model, we compare the yields of different hadrons in ultra-relativistic collisions: electron-positron annihilation at 91 GeV, proton-proton scattering at 17 GeV and nucleus-nucleus collisions at 17 GeV…

High Energy Physics - Phenomenology · Physics 2007-05-23 H. Drescher , J. Aichelin , K. Werner

The electromagnetic transitions of $^9$Be with linearly polarized $\gamma$-rays are calculated by using the $\alpha$~+~$\alpha$~+~$n$ three-body model and the complex-scaled solutions of the Lippmann-Schwinger equation; the azimuthal angle…

Nuclear Theory · Physics 2019-01-02 Yuma Kikuchi , Kazuyuki Ogata , Takehito Hayakawa , Satoshi Chiba