scholarly journals Role of Spin in NN → NNπ

2016 ◽  
Vol 40 ◽  
pp. 1660061
Author(s):  
Vadim Baru

The recent measurements of the reactions [Formula: see text] and [Formula: see text] by the ANKE collaboration at COSY are analyzed with the focus on the p-wave pion production amplitudes. These amplitudes are known to provide an important connection between [Formula: see text] and other low-energy few-nucleon reactions. The results of the recent partial wave analysis of the ANKE data are discussed and compared with the theoretical predictions.

2019 ◽  
Vol 199 ◽  
pp. 02001
Author(s):  
I. Ciepał ◽  
W. Przygoda ◽  
A. V. Sarantsev

Pion beams are perfect tools to probe resonance excitations at a fixed energy, thus properties of baryonic resonances and their coupling channels can be studied. The HADES Collaboration performed a systematic scan around the second resonance region at four different pion beam momenta 0.656, 0.69, 0.748 and 0.8 GeV/c in π− p reaction. The role of the N(1520) resonance in conjunction with the intermediate ρ-meson production has been studied in the framework of a partial wave analysis. Preliminary results on exclusive channels with one pion (π− p) and two pions (nπ+π− and pπ−π0) in the final state are presented.


2019 ◽  
Vol 199 ◽  
pp. 01024
Author(s):  
I. Ciepał ◽  
W. Przygoda ◽  
A. V. Sarantsev

Pion beams are perfect tools to probe resonance excitations at a fixed energy, thus properties of baryonic resonances and their coupling channels can be studied. The HADES Collaboration performed a systematic scan around the second resonance region at four different pion beam momenta 0.656, 0.69, 0.748 and 0.8 GeV/c in π− p reaction. The role of the N(1520) resonance in conjunction with the intermediate ρ-meson production has been studied in the framework of a partial wave analysis. Preliminary results on exclusive channels with one pion (π− p) and two pions (nπ+π− and pπ−π0) in the final state are presented.


2019 ◽  
Vol 199 ◽  
pp. 02003 ◽  
Author(s):  
Fabian Krinner

The Compass spectrometer at CERN has collected a large data set for diffractive three-pion production of 46 × 106 exclusive events. Based on previous conventional Partial-Wave Analyses (PWA), we performed a “freed-isobar PWA” on the same data, removing model assumptions on the dynamic isobar amplitudes for dominating waves. In this analysis, we encountered continuous mathematical ambiguities, which we were able to identify and resolve. This analysis gives an unprecedented insight in the interplay of 2π and 3π dynamics in the process. As an example we show results for a spin-exotic wave $J_{{X^ - }}^{PC} = {1^{ - + }}$ wave.


1980 ◽  
Vol 336 (3) ◽  
pp. 331-346 ◽  
Author(s):  
R. Koch ◽  
E. Pietarinen

2003 ◽  
Vol 18 (03) ◽  
pp. 355-366
Author(s):  
A. Donnachie

The role of analyticity in partial wave analysis is emphasized and the concept of two-component duality is introduced and illustrated with examples from π N scattering. An intrinsic n-fold ambiguity in partial wave analysis is discussed in terms of Barrelet zeros and techniques for removing the ambiguities are outlined. The problems of resonance backgrounds are touched upon.


2020 ◽  
Vol 241 ◽  
pp. 03001
Author(s):  
I. Ciepał

Pion beams are important tools to study features of baryonic resonances and their decay channels because resonances are produced in s-channel at fixed mass equal to √s. In 2014 the HADES collaboration has performed systematic measurements in the second resonance region scanning around the mass of the N*(1520). Pion beams at four momenta (0.654, 0.686, 0.738 and 0.787 GeV/c) impinging on polyethylene and carbon targets have been used. With the use of the multichannel Partial Wave Analysis (PWA) the role of the N*(1520) resonance in conjunction with the intermediate ρ-meson production has been studied. Preliminary results at 0.654 GeV/c on exclusive production of two pions (ηπ+π- and pπ-π0) in the final state are presented.


2007 ◽  
Author(s):  
R. A. Arndt ◽  
W. J. Briscoe ◽  
I. I. Strakovsky ◽  
R. L. Workman

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