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Döring, M.

Publications and source records attributed to Döring, M..

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Effects of final state interactions on Landau singularities

In certain kinematic and particle mass configurations, triangle singularities may lead to line-shapes which mimic the effects of resonances. This well-known effect is scrutinized here in the presence of final-state rescattering. The goal is achieved first by utilizing general arguments provided by Landau equations, and second by applying a modern scattering formalism with explicit two- and three-body unitarity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Strong interaction physics at the luminosity frontier with 22 GeV electrons at Jefferson Lab

Here, the purpose of this document is to outline the developing scientific case for pursuing an energy upgrade to 22 GeV of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Facility (TJNAF, or JLab). This document was developed with input from a series of workshops held in the period between March 2022 and April 2023 that were organized by the JLab user community and staff with guidance from JLab management (see Sec. 10). The scientific case for the 22 GeV energy upgrade leverages existing or already planned Hall equipment and world-wide uniqueness of CEBAF high-luminosity operations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

The present and future of QCD

This White Paper presents an overview of the current status and future perspective of QCD research, based on the community inputs and scientific conclusions from the 2022 Hot and Cold QCD Town Meeting. We present the This White Paper presents an overview of the current status and future perspective of QCD research, based on the community inputs and scientific conclusions from the 2022 Hot and Cold QCD Town Meeting. We present the progress made in the last decade toward a deep understanding of both the fundamental structure of the sub-atomic matter of nucleon and nucleus in cold QCD, and the hot QCD matter in heavy ion collisions. We identify key questions of QCD research and plausible paths to obtaining answers to those questions in the near future, hence defining priorities of our research over the coming decades.progress made in the last decade toward a deep understanding of both the fundamental structure of the sub-atomic matter of nucleon and nucleus in cold QCD, and the hot QCD matter in heavy ion collisions. We identify key questions of QCD research and plausible paths to obtaining answers to those questions in the near future, hence defining priorities of our research over the coming decades.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Inclusion of $K\Lambda $ electroproduction data in a coupled channel analysis

Exclusive electroproduction reactions provide an access to the structure of excited baryons. To extract electroproduction multipoles encoding this information, the Julich-Bonn-Washington (JBW) analysis framework is extended to the analysis of differential cross sections in KΛ electroproduction. Here this update enlarges the scope of previous coupled-channel analyses of pions and eta mesons, with photoproduction reactions as boundary condition in all analyzed electroproduction reactions. Polarization observables are predicted and compared to recent CLAS data. The comparison shows the relevance of these data to pin down baryon properties.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

New insights into the pole parameters of the Λ(1380), the Λ(1405) and the Σ(1385)

A coupled-channel S- and P-wave next-to-leading order chiral-unitary approach for strangeness S = –1 meson-baryon scattering is extended to include the new data from the KLOE and AMADEUS experiments as well as the Λπ mass distribution of the Σ(1385). The positions of the poles on the second Riemann sheet corresponding to the Σ(1385) pole and the Λ(1380) and Λ(1405) poles as well as the couplings of these states to various channels are calculated. We find that the resonance positions and branching ratios are on average determined with about 20% higher precision when including the KLOE and AMADEUS data. Additionally, for the first time, the correlations between the parameters of the poles are investigated and shown to be relevant. We also find that the Σ(1385) has negligible influence on the properties of the Λ states given the available data. Still, we identify isospin-1 cusp structures in the present solution in light of new measurements of π ± Λ line-shapes by the Belle collaboration.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Light baryon resonances from a coupled-channel study including $$\mathbf {K\Sigma }$$ photoproduction

The Jülich-Bonn dynamical coupled-channel approach is extended to include KΣ photoproduction off the proton. Differential cross section and (double) polarization data for K + Σ 0 and K 0 Σ + are analysed simultaneously with the pion- and photon-induced production of πN, ηN, KΛ, and KΣ final states, totaling almost 72,000 data points for center-of-mass energies W<2.4 GeV. Based on the fit results the spectrum of N * and Δ resonances is extracted in terms of pole positions and residues. We discuss the impact of the γp→KΣ channels in detail and investigate the influence of recent polarization data for ηp photoproduction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Coupled-channels analysis of pion and η electroproduction within the Jülich-Bonn-Washington model

Pion and η electroproduction data are jointly analyzed for the first time, up to a center-of-mass energy of 1.6 GeV. The framework is a dynamical coupled-channels model, based on the recent Jülich-Bonn-Washington analysis of pion electroproduction data for the same energy range. Comparisons are made to a number of single-channel η electroproduction fits. By comparing multipoles of comparable fit quality, we find some of these amplitudes are well determined over the near-threshold region, while others will require fits over an extended energy range.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

The $$\pi f_0(500)$$ decay of the $$a_1(1260)$$

Abstract We evaluate the $$a_1(1260) \rightarrow \pi \sigma (f_0(500))$$ a 1 ( 1260 ) → π σ ( f 0 ( 500 ) ) decay width from the perspective that the $$a_1(1260)$$ a 1 ( 1260 ) resonance is dynamically generated from the pseudoscalar–vector interaction and the $$\sigma $$ σ arises from the pseudoscalar–pseudoscalar interaction. A triangle mechanism with $$a_1(1260) \rightarrow \rho \pi $$ a 1 ( 1260 ) → ρ π followed by $$\rho \rightarrow \pi \pi $$ ρ → π π and a fusion of two pions within the loop to produce the $$\sigma $$ σ provides the mechanism for this decay under these assumptions for the nature of the two resonances. We obtain widths of the order of 13–22 MeV. Present experimental results differ substantially from each other, suggesting that extra efforts should be devoted to the precise extraction of this important partial decay width, which should provide valuable information on the nature of the axial vector and scalar meson resonances and help clarify the role of the $$\pi \sigma $$ π σ channel in recent lattice QCD calculations of the $$a_1$$ a 1 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Jülich-Bonn-Washington model for pion electroproduction multipoles

Pion electroproduction off the proton is analyzed in a new framework based on a general parametrization of transition amplitudes, including constraints from gauge invariance and threshold behavior. Data with energies 1.13 GeV < W < 1.6 GeV and Q 2 below 6 Ge V 2 are included. The model is an extension of the latest Jülich-Bonn solution incorporating constraints from pion-induced and photoproduction data. Here, performing large-scale fits (≈10 5 data) we find a set of solutions with $χ^2_{\text{dof}}$ = 1.69–1.81 which allows us to assess the systematic uncertainty of the approach.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Strong QCD from Hadron Structure Experiments

The topical workshop Strong QCD from Hadron Structure Experiments took place at Jefferson Lab from November 6–9, 2019. Impressive progress in relating hadron structure observables to the strong QCD mechanisms has been achieved from the ab initio QCD description of hadron structure in a diverse array of methods in order to expose emergent phenomena via quasi-particle formation. The wealth of experimental data and the advances in hadron structure theory make it possible to gain insight into strong interaction dynamics in the regime of large quark–gluon coupling (the strong QCD regime), which will address the most challenging problems of the Standard Model on the nature of the dominant part of hadron mass, quark–gluon confinement, and the emergence of the ground and excited state hadrons, as well as atomic nuclei, from QCD. This workshop aimed to develop plans and to facilitate the future synergistic efforts between experimentalists, phenomenologists, and theorists working on studies of hadron spectroscopy and structure with the goal to connect the properties of hadrons and atomic nuclei available from data to the strong QCD dynamics underlying their emergence from QCD. These results pave the way for a future breakthrough extension in the studies of QCD with an Electron–Ion Collider in the U.S.

Brodsky, S. J.↗
DOE OSTI2020

Dalitz plots and lineshape of a 1 ( 1260 ) from a relativistic three-body unitary approach

We formulate the final-state interaction of the a 1 ( 1260 ) resonance decay in a manifestly three-body unitary parametrization and fit it to the a 1 ( 1260 ) line shape measured by the ALEPH experiment. Dalitz plots calculated from this fit are presented. The work demonstrates the feasibility to numerically solve a previously derived amplitude and its generalization to isobars with spin and coupled channels. The model can also be applied to other meson decays and modified for the finite-volume problem as it arises in lattice QCD due to its manifest unitarity.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗