Jun 10 – 14, 2019
Bonn, Campus Poppelsdorf
Europe/Zurich timezone

Partial Wave Analysis of HADES Data for Two-Pion Production in Pion-Nucleon Reactions

Jun 12, 2019, 5:00 PM
HS 5

HS 5

Partial wave analyses and baryon resonance parameter extraction Parallel Session B


Izabela Ciepał (H. Niewodniczanski Institute of Nuclear Physics PAS)


The High Acceptance DiElectron Spectrometer (HADES) [1], installed at GSI Helmholtzzentrum in Darmstadt, was designed to measure emissivity of dense and hot baryonic matter. The microscopic description of the emissivity requires understanding of baryon-virtual photon couplings which can be studied in NN and $\pi$-N reactions. The elementary collisions, especially those with pion beams, also offer a great opportunity to unambiguously fix the description of baryonic resonances and their coupling to the light vector mesons rho and omega, which plays an essential role in baryon→N $\gamma$* transitions. Therefore, to understand resonances production mechanisms a systematic energy scan and high precision data are needed.
In 2014 a large dataset of $\pi$-p scattering have been obtained at the four pion beam momenta 0.656, 0.69, 0.748 and 0.8 GeV/c [2,3]. Two pion final states, $\pi^{+}\pi^{-}$ and $\pi^{-}\pi^{0}$, have been selected and investigated by the multichannel Partial Wave Analysis (PWA) developed by the Bonn-Gatchina group [4].
In this talk, total and a set of differential cross-section distributions of the two pion final states in a function of invariant masses, polar scattering, helicity and Gottfried-Jackson angles will be presented and compared to the PWA solutions. Moreover, separations of cross sections into dominant contributions like $\Delta$(1232)$\pi$,N(938)$\sigma$, N(938)$\rho$, N(1440)$1/2^{+}$ and N(1520)$3/2^{-}$ will be shown. The special attention will be paid to the role of $\rho$-N coupling.

[1] G. Agakichiev et al. (HADES Collab.), Eur. Phys. J. A 41 (2009) 243.
[2] W. Przygoda, EPJ Web of Conferences 130 (2016) 01021.
[3] I. Ciepał, W. Przygoda, EPJ Web of Conferences 199 (2019) 01024.
[4] A.V. Sarantsev, JPS Conf. Proc. 10 (2016) 010005.

Primary authors

Izabela Ciepał (H. Niewodniczanski Institute of Nuclear Physics PAS) Witold Przygoda (Smoluchowski Institue of Physics, Jagiellonian University, Kraków, Poland) Andrey Sarantsev (HISKP)

Presentation materials