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We investigate properties of the Delta(1232) and nucleon spectral functions at finite temperature and baryon density within a hadronic model. The medium modifications of the Delta consist of a renormalization of its pion-nucleon cloud and…

Nuclear Theory · Physics 2007-05-23 H. van Hees , R. Rapp

The elastic $\pi N$ scattering is investigated for the $I=3/2$ channel dominated by the $\Delta(1232)$ resonance at finite baryon density, employing the effective Lagrangian approach at the tree-level Born approximation. The quark-meson…

Nuclear Theory · Physics 2023-06-01 Hyeon-dong Han

Analysis is performed of calculations of the elastic scattering differential cross sections of pions on the $^{28}$Si, $^{40}$Ca, $^{58}$Ni and $^{208}$Pb nuclei at energies from 130 to 290 MeV basing on the microscopic optical potential…

Nuclear Theory · Physics 2012-10-04 E. V. Zemlyanaya , V. K. Lukyanov , K. V. Lukyanov , E. I. Zhabitskaya , M. V. Zhabitsky

A covariant model of elastic pion-nucleon scattering based on the Bethe-Salpeter equation is presented. The kernel consists of s- and u-channel nucleon and delta poles, along with rho and sigma exchange in the t-channel. A good fit is…

Nuclear Theory · Physics 2011-04-15 A. D. Lahiff , I. R. Afnan

The electromagnetic pion production reactions are investigated within the dynamical coupled-channels model developed in {\bf Physics Reports, 439, 193 (2007)}. The meson-baryon channels included in this study are $\gamma N$, $\pi N$, $\eta…

Nuclear Theory · Physics 2008-11-26 B. Julia-Diaz , T. -S. H. Lee , A. Matsuyama , T. Sato , L. C. Smith

We study the mass of a nucleon in a nucleus using a model recently introduced for a nucleon current with a pion cloud component. The method of QCD sum rules is used to determine the mass shifts for nucleons to first order in nuclear density…

Nuclear Theory · Physics 2007-05-23 Andrew J. Harey , Leonard S. Kisslinger

In this work the elastic scattering of two nucleons is calculated in chiral effective field theory at next-to-leading order taking into account the coupled N$\Delta$-, $\Delta$N- and $\Delta\Delta$-channels. To solve the coupled channel…

Nuclear Theory · Physics 2020-08-28 Susanne Strohmeier , Norbert Kaiser

A covariant model of elastic pion-nucleon scattering based on the Bethe-Salpeter equation is presented. We obtain a good description of the S- and P-wave phase shifts up to 360 MeV laboratory energy. We also compare results from the…

Nuclear Theory · Physics 2007-05-23 A. D. Lahiff , I. R. Afnan

The ETH model of the pion-nucleon ($\pi N$) interaction contains $t$-channel $\sigma$- and $\rho$-exchange graphs, as well as the $s$- and $u$-channel contributions with the well-established $s$ and $p$ baryon states with masses below $2$…

High Energy Physics - Phenomenology · Physics 2014-05-09 Evangelos Matsinos , Günther Rasche

We construct a relativistic and unitary approach to 'high' energy pion- and photon-nucleon reactions taking the $\pi N, \pi \Delta$, $\rho N$, $\omega N$, $\eta N, K \Lambda, K \Sigma$ final states into account. Our scheme dynamically…

Nuclear Theory · Physics 2010-12-16 M. F. M. Lutz , Gy. Wolf , B. Friman

Our extraction of the pion-nucleon coupling constant from \pi p elastic scattering data is outlined. A partial wave analysis (T_{\pi} < 2100 MeV) is performed simultaneously with a fixed-t dispersion relation analysis (T_{\pi} < 800 MeV).…

Nuclear Theory · Physics 2009-10-31 M. M. Pavan , R. A. Arndt , I. I. Strakovsky , R. L. Workman

Measurements of elastic scattering of 21.5 MeV pi+ and pi- by Si, Ca, Ni and Zr were made using a single arm magnetic spectrometer. Absolute calibration was made by parallel measurements of Coulomb scattering of muons. Parameters of a…

Modifications of Delta(1232) and nucleon spectral functions at finite temperature and baryon density are evaluated in terms of resonant scattering off thermal pions, as well as a renormalization of the vacuum Delta-width including vertex…

Nuclear Theory · Physics 2007-05-23 Hendrik van Hees , Ralf Rapp

We extend the analysis of elastic pion-nucleon scattering up to $O(p^4)$ level using extended-on-mass-shell subtraction scheme within the framework of covariant baryon chiral perturbation theory. Numerical fits to partial wave phase shift…

High Energy Physics - Phenomenology · Physics 2013-04-23 Yun-Hua Chen , De-Liang Yao , H. Q. Zheng

We analyse the SM97 partial wave amplitudes for nucleon--nucleon (NN) scattering to 2.5 GeV, in which resonance and meson production effects are evident for energies above pion production threshold. Our analyses are based upon boson…

Nuclear Theory · Physics 2008-11-26 H. V. von Geramb , K. A. Amos , H. Labes , M. Sander

We develop a novel approach to chiral meson-baryon dynamics incorporating unitarity constraints and explicit resonance fields. It is based on the most general structure of any pion-nucleon partial wave amplitude neglecting the unphysical…

Nuclear Theory · Physics 2009-10-31 Ulf-G. Meißner , J. A. Oller

Calculations of the elastic $I=\frac{3}{2}$ nucleon-pion scattering phase shifts on two lattice QCD ensembles with $m_\pi=200\mathrm{MeV}$ and $280\mathrm{MeV}$ are presented. The ensembles both employ $N_\mathrm{f} = 2+1$ Wilson clover…

High Energy Physics - Lattice · Physics 2019-11-25 Christian Walther Andersen , John Bulava , Ben Hörz , Colin Morningstar

Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model and the scaling model according to nucleon effective mass, effects of elastic and inelastic NN scattering cross sections on pion-/pion+ in the neutron-rich reaction…

Nuclear Theory · Physics 2011-12-07 Gao-Chan Yong

Neutrinos with energy of order 10~MeV, such as from pion decay-at-rest sources, are an invaluable tool for studying low-energy neutrino interactions with nuclei -- previously enabling the first measurement of coherent elastic…

High Energy Physics - Phenomenology · Physics 2022-12-23 Bhaskar Dutta , Wei-Chih Huang , Jayden L. Newstead , Vishvas Pandey

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