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  • University of Tuzla

    University of Tuzla (est. 1976) is public university located in Tuzla. It's the most important and major educational and scientific institution in northeast Bosnia.

STRONG 2020 Workshop

 

STRONG 2020 (14-16 September - University of York) is included in the activities of the working package WP25 (Light-and heavy-quark hadron spectroscopy) of the project STRONG-2020. It has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 824093.

POSTER: SE  PWA for pion photoproduction with vfixed-t analyticity

The major topics of the workshop will cover:

1) Precision calculations in non-perturbative QCD: Effective Field Theories, analyticity, dispersion relations and Lattice QCD

2) Spectroscopy & Exotic states

3) Hadron Decays & Production

4) Form factors, LECs, fundamental parameters of QCD and light nuclei
spectroscopy

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Single-energy partial-wave analysis for pion photoproduction with fixed-t analyticity

Received 15 July 2021

Accepted 20 August 2021

DOI:https://doi.org/10.1103/PhysRevC.104.034605

©2021 American Physical Society

Abstract

Experimental data for pion photoproduction including differential cross sections and various polarization observables from four reaction channels, $\gamma p \rightarrow \pi^0 p$, $\gamma p \rightarrow \pi^+ n$, $\gamma n \rightarrow \pi^− p$, and $\gamma n \rightarrow \pi^0  n$, from threshold up to W= 2.2 GeV were used in order to perform a single-energy partial-wave analysis with minimal model dependence by imposing constraints from unitarity and fixed-t analyticity in an iterative procedure. Reaction models were only used as a starting point in the very first iteration. We demonstrate that with this procedure partial-wave amplitudes can be obtained which show only a minimal dependence on the initial model assumptions. The analysis was obtained in full isospin, and the Watson theorem is enforced for energies below W= 1.3 GeV but is even fulfilled up to W≈ 1.6 GeV in many partial waves. Electromagnetic multipoles $E_{ℓ\pm}$ and $M _{ℓ\pm}$ are presented and discussed for S, P, D, and F waves.

 


 

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Single-energy partial wave analysis for π0 photoproduction on the proton with fixed-t analyticity imposed

  • Received 16 August 2019

DOI:https://doi.org/10.1103/PhysRevC.100.055203

©2019 American Physical Society

 

Abstract 

High-precision data of the $\gamma p \rightarrow \pi^0p$ reaction from its threshold up to W=1.9GeV have been used in order to perform a single-energy partial-wave analysis with minimal model dependence. Continuity in energy was achieved by imposing constraints from fixed-t analyticity in an iterative procedure. Reaction models were only used as starting point in the very first iteration. We demonstrate that, with this procedure, partial-wave amplitudes can be obtained which show only a minimal dependence on the initial model assumptions.


 

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SFB-S3 Collaboration meeting - Mainz 2019 Program


SFB-S3 Collaboration meeting
Partial Wave Analysis with Analytical Constraints
Mainz, 18-21 February 2019

Talks can be downloaded from our GitHub Page

Monday, 18 February, 10:00-12:00, A2 meeting room, Neubau, 1OG, 01-122

Jugoslav Stahov/Hedim Osmanovic: Preliminary results on single-energy PWA for $\gamma,\pi$
Rifat Omerovic:  Data binning for PWA of pion photoproduction

Monday, 18 February, 14:00-17:00, A2 meeting room, Neubau, 1OG
Discussions

Tuesday, 19 February, 10:00-12:00, KPH Seminar Room, Foyer

Michael Ostrick: Opening
Andrey Sarantsev: Eta Photoproduction in the Bonn-Gatchina model
Deborah Rönchen: Eta Photoproduction in the Jülich-Bonn model

Tuesday, 19 February, 14:00-17:00, KPH, Seminar Room


R.Beck, F.Afzal : New experimental results from ELSA and MAMI
Lothar Tiator: Eta Photoproduction in the MAID model
Alfred Svarc: Phase Ambiguities in Eta Photoproduction
Discussions

Tuesday, 19 February, 17:30 dinner in "Plaka"

Wednesday, 20 February, 10:00-12:00, A2 meeting room, Neubau, 1OG, 01-122

Kirill Nikonov: Dispersion Relations for Eta Photoproduction
Misha Gorchtein: Behaviour of Regge background under DR
Victor Kashevarov: Results on DR for high energies and proton and neutron

Wednesday, 20 February, 14:00-17:00, A2 meeting room, Neubau, 1OG
Discussions

Thursday, 21 February, 10:00-12:00, A2 meeting room, Neubau, 1OG, 01-122
Discussions
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Eta and etaprime photoproduction on the nucleon with the isobar model EtaMAID2018

L. Tiator, M. Gorchtein, V. L. Kashevarov, K. Nikonov, M. Ostrick, M. Hadžimehmedović, R. Omerović, H. Osmanović, J. Stahov, A. Švarc
The European Physical Journal A

Received 13 July 2018,  Accepted 20 October 2018.  First Online 06 December 2018
DOI https://doi.org/10.1140/epja/i2018-12643-x 
Publisher Name Springer Berlin Heidelberg
Print ISSN 1434-6001 Online ISSN 1434-601X

The isobar model EtaMAID has been updated with new and high precision data for 𝜂 and 𝜂′ photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The background is described in a recently developed Regge cut model, and for the resonance part the whole list of nucleon resonances has been investigated with 21 𝑁∗ states contributing to 𝜂 photoproduction and 12 𝑁∗ states contributing to 𝜂′ photoproduction. A new approach is discussed to avoid double counting in the overlap region of Regge and resonances. A comparison is done among four newly updated partial waves analyses for observables and partial waves. Finally, the possibility of a narrow resonance near 𝑊=1900 MeV is discussed, that would be able to explain unexpected energy and angular dependence of observables in 𝑝(𝛾,𝜂′)𝑝 near 𝜂′ threshold.
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Role of angle-dependent phase rotations of reaction amplitudes in η photoproduction on protons


A. Švarc, H. Osmanović, M. Hadžimehmedović, R. Omerović, J. Stahov, M. Gorchteyn, V. Kashevarov, K. Nikonov, M. Ostrick, and L. Tiator
Phys. Rev. C 98, 045206 – Published 19 October 2018

Received 20 July 2018
DOI: https://doi.org/10.1103/PhysRevC.98.045206 

It was recently proved that the invariance of observables with respect to angle-dependent phase rotations of reaction amplitudes mixes multipoles, changing also their relative strength [A. Švarc et al., Phys. Rev. C 97, 054611 (2018)]. Modern partial wave analyses (PWAs) in η photoproduction on protons in the center-of-mass energy range 1.5≤W≤2.0 GeV, either energy-dependent (ED) or single-energy (SE) ones, do not take this effect into consideration. It is commonly accepted that all PWAs give very similar results for the E0+ multipole, but notable differences in this and all other partial waves still remain. In this paper we demonstrate that once these phase rotations are properly taken into account, all ED and SE partial wave analysis in η photoproduction become almost identical for the dominant E0+ multipole, and the agreement among all other multipoles becomes much better. We also show that measured observables are almost equally well reproduced in all PWAs, and the remaining differences among multipoles can be attributed solely to the difference in predictions for unmeasured observables. So, new measurements are needed.

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About PWA TUZLA

We are theoretical physicists at Faculty of Natural Sciences and Mathematics - University of Tuzla. Our group is a part of the Mainz - Tuzla - Zagreb Partial Wave Analysis collaboration.

As a part of the MTZ PWA, our results are "above the line" in PDG library.

Related sites

Physics Department >>
University of Tuzla >>
PMF Tuzla >>
Mainz-Tuzla-Zagreb PWA >>
PDG - Particle Data Group >>
MAID Mainz >>
GWU/SAID Washington >>
Bonn-Gatchina PWA >>
JPac Center Indiana Uni. >>
CLAS Phy. Database >>
JPac Center Indiana Uni. >>
ETA MAID 2018 >>
Jülich-Bonn-Washington Collaboration >>

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