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The total cross section for the $pp \to pp \pi^0$ reaction at energies close to threshold is calculated within the frame of a chiral perturbation theory, taking into account tree and one loop diagrams up to chiral order D=2. Two-pion loop…

Nuclear Theory · Physics 2007-05-23 E. Gedalin , A. Moalem , L. Razdolskaya

We analyze $J/\psi-$ production in nucleon-nucleon collisions near threshold in the framework of a general model independent formalism, which can be applied to any reaction $N+N\to N+N+V^0$, where $V^0=\omega$, $\phi$, or $J/\psi$. Such…

Nuclear Theory · Physics 2008-11-26 Michail P. Rekalo , Egle Tomasi-Gustafsson

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…

Nuclear Theory · Physics 2014-11-20 Jun Xu , Che Ming Ko , Yongseok Oh

The cross section for production of Phi mesons in proton-nucleus reactions is calculated as a function of the target mass. The decay width of the Phi meson is affected by the change of the masses of the Phi, K+ and K- mesons in the medium.…

Nuclear Theory · Physics 2009-11-10 H. W. Barz , M. Zetenyi

The isoscalar single-pion production exhibits a broad bump in the energy dependence of the total cross section, which does not correspond to the usual opening of the $N^*(1440)$ production channel with subsequent pion decay. In…

Nuclear Experiment · Physics 2022-07-14 H. Clement , T. Skorodko , E. Doroshkevich

We show theoretical results for $(\gamma, \pi^0 \pi^0)$ production on nucleons and nuclei in the kinematical region where the scalar isoscalar $\pi \pi$ amplitude is influenced by the $\sigma$ pole. The final state interaction of the pions…

Nuclear Theory · Physics 2011-02-09 L. Roca , E. Oset , M. J. Vicente Vacas

Differential cross sections of the reactions $pp \to d\pi^+$ and $pp \to pn\pi^+$ have been measured at $T_p = 400$ MeV by detecting the charged ejectiles in the angular range $4^0 \leq \Theta_{Lab} \leq 21^\circ$. The deduced total cross…

The total cross section for the near threshold eta production in proton-proton collisions has been investigated with the assumption that the production mechanism is due to the emission of a meson x (pi, eta, sigma) from one of the nucleons…

Nuclear Theory · Physics 2009-10-30 M. Batinic , A. Svarc , T. -S. H. Lee

Scaling features of particles produced in pi-p and pi-A collisions over a high-pT range at high energies are studied. The general concept of z-scaling is applied for the analysis of pi-p and pi-A experimental data on the inclusive cross…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. P. Skoro , M. V. Tokarev , Yu. A. Panebratsev , I. Zborovsky

The cross section for prompt neutral and charged three pion production in pp interactions was measured at excess energies in the range 160 - 217 MeV. That comprises the first measurement of the pp->pp pi0pi0pi0 reaction and the comparison…

Vector meson ($V = \omega, \phi$) production in near-threshold elementary nucleon-nucleon collisions $pp\to ppV$, $pn\to pnV$ and $pn\to dV$ is studied within an effective meson-nucleon theory. It is shown that a set of effective parameters…

Nuclear Theory · Physics 2008-11-26 L. P. Kaptari , B. Kampfer

High-energy hadronic reactions with proton-to-neutron transitions (and vice versa) with small momentum transfer allow to study the properties of nearly on-shell pions, which cannot be accessed otherwise. We overview the recent results for…

High Energy Physics - Phenomenology · Physics 2015-11-02 B. Z. Kopeliovich , I. K. Potashnikova , Ivan Schmidt

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

In this review we present the recent advances for calculations of the reactions $NN\to NN\pi$ using chiral effective field theory. Discussed are the next-to-next-to leading order loop contributions with nucleon and Delta-isobar for near…

Nuclear Theory · Physics 2015-06-17 Vadim Baru , Christoph Hanhart , Fred Myhrer

Heavy meson production in nucleon-nucleon collisions is discussed within a meson exchange model of hadronic interactions, paying special attention to the basic dynamics that determine the behavior of the cross sections near the threshold…

Nuclear Theory · Physics 2007-05-23 K. Nakayama

The total cross section of the $pp\to pp\pi^0$ reaction near threshold is calculated in pionless effective field theory with a di-baryon and external pions. The amplitudes for a leading one-body and subleading contact neutral pion…

Nuclear Theory · Physics 2008-11-26 Shung-ichi Ando

It is demonstrated that many aspects of nuclear collisions, as for instance the evolution of $\pi^{+}/\pi^{-}$ and $K/\pi$ ratios with $x_F$ and $\sqrt{s}$, are influenced by isospin effects already present in elementary nucleon--nucleon…

High Energy Physics - Experiment · Physics 2011-09-13 Ondrej Chvala

We present a method to compute off-shell effects for processes involving resonant particles at hadron colliders with the possibility to include realistic cuts on the decay products. The method is based on an effective theory approach to…

High Energy Physics - Phenomenology · Physics 2010-01-28 Pietro Falgari , Paul Mellor , Adrian Signer

We calculate the cross sections for the $p(p,n\pi^{+})p$ and $p(p,p\pi^{0})p$ reactions for proton beam energies near threshold in a covariant one-boson-exchange model, which incorporates the exchange of $\pi$, $\rho$, $\sigma$ and $\omega$…

Nuclear Theory · Physics 2009-10-30 R. Shyam , U. Mosel

The model for charge symmetry breaking in the reaction np --> dpi^0 applied earlier around the Delta region is used to calculate the integrated forward-backward asymmetry of the cross section close to threshold. The mixing of the pi and eta…

Nuclear Theory · Physics 2009-10-31 J. A. Niskanen