Publications (101)
A dispersion theoretical approach to the threshold amplitudes of pion photoproduction
O. Hanstein, D. Drechsel, L. Tiator
We give predictions for the partial wave amplitudes of pion photoproduction near threshold by means of dispersion relations at fixed t. The free parameters of this approach are det…
Baryon Resonance Analysis from MAID
L. Tiator, D. Drechsel, S. S. Kamalov +1
The unitary isobar model MAID2007 has been used to analyze the recent data of pion electroproduction. The model contains all four-star resonances in the region below W=2 GeV and bo…
A dispersive approach to pion photo- and electroproduction
D. Drechsel, B. Pasquini, L. Tiator
The relativistic amplitudes of pion photo- and electroproduction are calculated by dispersion relations at constant t. Several sum rules and low-energy theorems for the threshold a…
Accurate Test of Chiral Dynamics in the \boldmath Reaction
D. Hornidge, P. Aguar Bartolome, J. R. M. Annand +64
A precision measurement of the differential cross sections and the linearly polarized photon asymmetry $Σ\equiv (dÏ_\perp - dÏ_\parallel) \slash (dÏ_\perp + dÏ_\para…
The GDH Sum Rule and Related Integrals
D. Drechsel, S. S. Kamalov, L. Tiator
The spin structure of the nucleon resonance region is analyzed on the basis of our phenomenological model MAID. Predictions are given for the Gerasimov-Drell-Hearn sum rule as well…
Measurements of Double-Polarized Compton Scattering Asymmetries and Extraction of the Proton Spin Polarizabilities
P. P. Martel, R. Miskimen, P. Aguar-Bartolome +76
The spin polarizabilities of the nucleon describe how the spin of the nucleon responds to an incident polarized photon. The most model-independent way to measure the nucleon spin p…
Two-body Mechanisms in Pion Photoproduction on the Trinucleon
S. S. Kamalov, L. Tiator, C. Bennhold
A breakdown of the Impulse Approximation is studied in pion photoproduction on He at high momentum transfers. The usual DWIA formalism with Faddeev wave functions which works w…
A reggeized model for eta and eta-prime photoproduction
Wen-Tai Chiang, Shin Nan Yang, L. Tiator +2
A reggeized model for ηand η' photoproduction on the nucleon is presented. In this model, t-channel vector meson exchanges are described in terms of Regge trajectories to comply…
Cross Section for measured at Mainz/A2
W. J. Briscoe, M. Hadzimehmedovi, A. E. Kudryavtsev +89
The differential cross section evaluated for 27 energy bins span the photon-energy range 290-813 MeV (W = 1.195-1.553 GeV) and the pion c.m. polar production angle…
Amplitude- and truncated partial-wave analyses combined: A novel, almost theory-independent single-channel method for extracting photoproduction multipoles directly from measured data
A. Å varc, Y. Wunderlich, L. Tiator
Amplitude- and truncated partial-wave analyses are combined into a single procedure and a novel, almost theory-independent single-channel method for extracting multipoles directly…
Eta and Etaprime Photoproduction on the Nucleon with the Isobar Model EtaMAID2018
L. Tiator, M. Gorchtein, V. L. Kashevarov +7
The isobar model EtaMAID has been updated with new and high precision data for eta and etaprime photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The backgro…
Regge phenomenology in and photoproduction
V. L. Kashevarov, M. Ostrick, L. Tiator
The and reactions at photon beam energies above 4 GeV are investigated within Regge models. The models include -channel exchanges of vector (…
Measurement of the transverse target and beam-target asymmetries in meson photoproduction at MAMI
C. S. Akondi, J. R. M. Annand, H. J. Arends +67
We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the reaction up to a center-of-mass energ…
Measurement of the recoil polarization in the p (\vec e, e' \vec p) pi^0 reaction at the Î(1232) resonance
Th. Pospischil, P. Bartsch, D. Baumann +39
The recoil proton polarization has been measured in the p (\vec e,e'\vec p) pi^0 reaction in parallel kinematics around W = 1232 MeV, Q^2 = 0.121 (GeV/c)^2 and epsilon = 0.718 usin…
The complete experiment for photoproduction of pseudoscalar mesons in a truncated partial wave analysis
Y. Wunderlich, R. Beck, L. Tiator
The complete experiment problem in the truncated partial wave analysis of pseudoscalar meson photoproduction with suppressed t-channel exchanges is investigated. The focus is set t…
Excitation of S11 resonances in pion scattering and pion photoproduction on the proton
Guan-Yeu Chen, S. S. Kamalov, Shin Nan Yang +2
A self-consistent analysis of pion scattering and pion photoproduction within a coupled channels dynamical model is presented. In the case of pion photoproduction, we obtain backgr…
The position and the residues of the delta resonance pole in pion photoproduction
O. Hanstein, D. Drechsel, L. Tiator
We have analyzed the and multipole amplitudes of pion photoproduction in the framework of fixed- dispersion relations. Applying the speed plot…
Nucleon-to-Delta transition form factors in chiral effective field theory using the complex-mass scheme
M. Hilt, T. Bauer, S. Scherer +1
We calculate the form factors of the electromagnetic nucleon-to--resonance transition to third chiral order in manifestly Lorentz-invariant chiral effective field theory. For t…
Elastic Pion Scattering on the Deuteron in a Multiple Scattering Model
S. S. Kamalov, L. Tiator, C. Bennhold
Pion elastic scattering on deuterium is studied in the KMT multiple scattering approach developed in momentum space. Using a Paris wave function and the same methods and approximat…
Pion photo- and electroproduction with chiral MAID
M. Hilt, B. C. Lehnhart, S. Scherer +1
We present a calculation of pion photo- and electroproduction in manifestly Lorentz-invariant baryon chiral perturbation theory up to and including order . We fix the low-ener…
Electromagnetic transition form factors of the Roper resonance in effective field theory
T. Bauer, S. Scherer, L. Tiator
We analyze the form factors of the electromagnetic nucleon-to-Roper-resonance transition in the framework of low-energy effective field theory. A systematic power-counting procedur…
Quasifree Eta Photoproduction from Nuclei
F. X Lee, L. E. Wright, C. Bennhold +1
Quasifree photoproduction from nuclei is studied in the Distorted Wave Impulse Approximation (DWIA). The elementary eta production operator contains Born terms, vector meson a…
Pion Photo- and Electroproduction and the Chiral MAID Interface
M. Hilt, B. C. Lehnhart, S. Scherer +1
We discuss the extended on-mass-shell scheme for manifestly Lorentz-invariant baryon chiral perturbation theory. We present a calculation of pion photo- and electroproduction up to…
Multipole analysis of pion photoproduction based on fixed t dispersion relations and unitarity
O. Hanstein, D. Drechsel, L. Tiator
We have analysed pion photoproduction imposing constraints from fixed t dispersion relations and unitarity. Coupled integral equations for the S and P wave multipoles were derived…
Photoproduction of eta-mesons on the deuteron above S11(1535) in the presence of a narrow P11(1670) resonance
A. Fix, L. Tiator, M. V. Polyakov
Incoherent photoproduction of eta-mesons on the deuteron is considered. The main attention is paid to the region above the S11(1535) resonance where rather narrow resonance like st…
Single-energy partial wave analysis for pion photoproduction with fixed-t analyticity
H. OsmanoviÄ, M. HadžimehmedoviÄ, R. OmeroviÄ +5
Experimental data for pion photoproduction including differential cross sections and various polarization observables from four reaction channels, , …
Nucleon resonances in ÏN scattering up to energies \sqrt(s) < 2.0 GeV
Guan Yeu Chen, S. S. Kamalov, Shin Nan Yang +2
A meson-exchange model for pion-nucleon scattering was previously constructed using a three-dimensional reduction scheme of the Bethe-Salpeter equation for a model Lagrangian invol…
Dispersion Theory and the Low Energy Constants for Neutral Pion Photoproduction
B. Pasquini, D. Drechsel, L. Tiator
The relativistic amplitudes of pion photoproduction are evaluated by dispersion relations at t=const. The imaginary parts of the amplitudes are taken from the MAID model covering t…
A connection between angular dependent phase ambiguities and the uniqueness of the partial wave decomposition
A. Å varc, Y. Wunderlich, H. OsmanoviÄ +8
Unconstrained partial-wave amplitudes obtained at discrete energies from fits to complete sets of experimental data may not vary smoothly with energy, and are in principle non-uniq…
Generalized sum rules of the nucleon in the constituent quark model
M. Gorchtein, D. Drechsel, M. M. Giannini +2
We study the generalized sum rules and polarizabilities of the nucleon in the framework of the hypercentral constituent quark model. We include in the calculation all the well know…
Study of and photoproduction at MAMI
V. L. Kashevarov, P. Ott, S. Prakhov +87
The reactions and have been measured from their thresholds up to the center-of-mass energy GeV with the tagged-photon facilities at the Mainz Mi…
Analysis of eta production using a generalized Lee model
J. Denschlag, L. Tiator, D. Drechsel
We have investigated the processes N(, )N and N(, )N close to eta threshold using a simple, nonrelativistic Lee model which has the advantage of being analytically…
Pion interaction with the trinucleon up to the eta production threshold
S. S. Kamalov, L. Tiator, C. Bennhold
Pion elastic, charge exchange scattering and induced eta production on the trinucleon systems are investigated in a coupled-channels approach in momentum space with Fadeev wave fun…
Empirical transverse charge densities in the nucleon-to-P11(1440) transition
L. Tiator, M. Vanderhaeghen
Using recent experimental data, we analyze the electromagnetic transition from the nucleon to the P11(1440) resonance. From the resulting empirical transition form factors, we map…
Study of the gp-->etap reaction with the Crystal Ball detector at the Mainz Microtron(MAMI-C)
E. F. McNicoll, S. Prakhov, I. I. Strakovsky +81
The gp-->etap reaction has been measured with the Crystal Ball and TAPS multiphoton spectrometers in the energy range from the production threshold of 707 MeV to 1.4 GeV (1.49 =< W…
Towards an understanding of discrete ambiguities in truncated partial wave analyses
Y. Wunderlich, A. Å varc, R. L. Workman +2
It is well known that the observables in a single-channel scattering problem remain invariant once the amplitude is multiplied by an overall energy- and angle-dependent phase. This…
A unitary isobar model for pion photo- and electroproduction on the proton up to 1 GeV
D. Drechsel, O. Hanstein, S. S. Kamalov +1
A new operator for pion photo- and electroproduction has been developed for nuclear applications at photon equivalent energies up to 1 GeV. The model contains Born terms, vector me…
Baryon transition form factors at the pole
L. Tiator, M. Döring, R. L. Workman +5
Electromagnetic resonance properties are uniquely defined at the pole and do not depend on the separation of the resonance from background or the decay channel. Photon-nucleon bran…
Vector form factor of the pion in chiral effective field theory
D. Djukanovic, J. Gegelia, A. Keller +2
The vector form factor of the pion is calculated in the framework of chiral effective field theory with vector mesons included as dynamical degrees of freedom. To construct an effe…
Overview of Dynamic Models for gamma N -> Delta
D. Drechsel, L. Tiator
We present an overview of dynamic and related models for pion electroproduction on the nucleon due to Delta(1232) excitation. The electromagnetic multipoles and their ratios obtain…
Measurement of pi^0 photoproduction on the proton at MAMI C
P. Adlarson, F. Afzal, C. S. Akondi +88
Differential cross sections for the gamma p -> pi^0 p reaction have been measured with the A2 tagged-photon facilities at the Mainz Microtron, MAMI C, up to the center-of-mass ener…
Measurement of the decay at MAMI
P. Adlarson, F. Afzal, C. S. Akondi +75
An experimental study of the decay has been conducted with the best up-to-date statistical accuracy, by measuring mesons produced in the $γp \to ΅
Electromagnetic Excitation of Nucleon Resonances
L. Tiator, D. Drechsel, S. S. Kamalov +1
Recent progress on the extraction of electromagnetic properties of nucleon resonance excitation through pion photo- and electroproduction is reviewed. Cross section data measured a…
Single-Energy Partial Wave Analysis for Photoproduction on Proton with Fixed- Analyticity Imposed
H. OsmanoviÄ, M. HadžimehmedoviÄ, R. OmeroviÄ +7
High precision data of the reaction from its threshold up to ~GeV have been used in order to perform a single-energy partial wave analysis with minimal model…
Amplitude reconstruction from complete electroproduction experiments and truncated partial-wave expansions
L. Tiator, R. L. Workman, Y. Wunderlich +1
We compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the electroproduction of pseudoscalar mesons. We giv…
Measurement of the LT-asymmetry in Ï^0 electroproduction at the energy of the Î(1232) resonance
D. Elsner, A. Süle, P. Barneo +29
The reaction p(e,e'p)pi^0 has been studied at Q^2=0.2 (GeV/c)^2 in the region of W=1232 MeV. From measurements left and right of q, cross section asymmetries Ï_LT have been obtain…
PWA tools in Hadronic Spectroscopy
S. Ceci, M. Döring, E. Epple +21
The mini-proceedings of the Workshop on PWA tools in Hadronic Spectroscopy held in Mainz from February 18th to 20th, 2013.
Generalized polarizabilities and electroexcitation of the nucleon
D. Drechsel, S. S. Kamalov, G. Krein +2
Generalized nucleon polarizabilities for virtual photons can be defined in terms of electroproduction cross sections as function of the 4-momentum transfer . In particular, th…
Analysis of angular distributions in gamma N \to pi0 eta N
A. Fix, M. Ostrick, L. Tiator
Angular distributions in the final state of pi0-eta photoproduction on nucleons are considered. As a formal base the familiar isobar model is used in which the (pi0 eta N) state is…
Unitary Isobar Model - MAID2007
D. Drechsel, S. S. Kamalov, L. Tiator
The unitary isobar model MAID2007 has been developed to analyze the world data of pion photo- and electroproduction. The model contains both a common background and several resonan…
New Insights into the Coupling of and Mesons to the Nucleon
M. Kirchbach, L. Tiator, S. Neumeier +1
We show that the contact couplings of neutral pseudoscalar and axial mesons to the nucleon are proportional to , the fraction of nucleon spin carried by the strange quark sea,…
Recent developments in the dynamical and unitary isobar models for pion electromagnetic production
Shin Nan Yang, Guan Yeu Chen, S. S. Kamalov +2
gamma N->Delta transition form factors and threshold pi^0 photo- and electroproduction are studied with the new version of MAID and a dynamical model. By re-analyzing the recent Jl…
On the Coupling of the Meson to the Nucleon
M. Kirchbach, L. Tiator
The pseudoscalar and pseudovector coupling constants are calculated from an effective vertex associated with the triangle diagram. The predicted values are in a…
The NN Coupling in Eta Photoproduction
L. Tiator, C. Bennhold, S. S. Kamalov
Low-energy eta photoproduction on the nucleon is studied in an effective Lagrangian approach that contains Born terms, vector meson and nucleon resonance contributions. The resonan…
Note on the definitions of branching ratios of overlapping resonances
V. Burkert, V. Crede, E. Klempt +8
Branching ratios for the decay of hadrons with large width or near thresholds depend on their definition. We test different definitions and show that rather different branching rat…
Pion photo- and electroproduction and the chiral MAID interface
M. Hilt, B. C. Lehnhart, S. Scherer +1
We discuss the extended on-mass-shell scheme for manifestly Lorentz-invariant baryon chiral perturbation theory. We present a calculation of pion photo- and electroproduction up to…
Pion electroproduction on the nucleon and the generalized GDH sum rule
L. Tiator, D. Drechsel, S. S. Kamalov
Results of the recently developed unitary isobar model (MAID) are presented for the spin asymmetries, structure functions and relevant sum rules in the resonance region. The model…
Singularity structure of the pi N scattering amplitude in a meson-exchange model up to energies W < 2.0 GeV
L. Tiator, S. S. Kamalov, S. Ceci +4
Within the previously developed Dubna-Mainz-Taipei meson-exchange model, the singularity structure of the pi N scattering amplitudes has been investigated. For all partial waves up…
Electroproduction of nucleon resonances
L. Tiator, D. Drechsel, S. Kamalov +3
The unitary isobar model MAID has been extended and used for a partial wave analysis of pion photo- and electroproduction in the resonance region W < 2 GeV. Older data from the wor…
First measurement of target and beam-target asymmetries in the reaction
J. R. M. Annand, H. J. Arends, R. Beck +64
The first data on target and beam-target asymmetries for the reaction at photon energies from 1050 up to 1450 MeV are presented. The measurements were performed usi…
The Impact of New Polarization Data from Bonn, Mainz and Jefferson Laboratory on Multipoles
A. V. Anisovich R. Beck, M. Döring, M. Gottschall +14
New data on pion-photoproduction off the proton have been included in the partial wave analyses Bonn-Gatchina and SAID and in the dynamical coupled-channel approach Jülich-Bonn. A…
Dispersion Theoretical Analysis of Pion Photoproduction at Threshold and in the Delta Region
L. Tiator
A new partial wave analysis of pion photoproduction has been obtained in the framework of fixed-t dispersion relations valid form threshold up to 500 MeV. It is based on new Mainz…
Photoproduction of and Mesons on Proton
V. L. Kashevarov, L. Tiator, M. Ostrick
New high-precision total and differential cross sections for and photoproduction on the proton obtained by the A2 Collaboration at the Mainz Microtron are presented. The…
P11 Resonances with Dubna-Mainz-Taipei Dynamical Model for pi-N Scattering and Pion Electromagnetic Production
Shin Nan Yang, S. S. Kamalov, L. Tiator
We present the results on P11 resonances obtained with Dubna-Mainz-Taipei (DMT) dynamical model for pion-nucleon scattering and pion electromagnetic production. The extracted value…
Measurement of the beam-helicity asymmetry in the p(e_pol,e'p)pi_0 reaction at the energy of the Delta(1232) resonance
P. Bartsch, D. Baumann, J. Bermuth +32
In a p(e_pol,e'p)pi_0 out-of-plane coincidence experiment at the 3-spectrometer setup of the Mainz Microtron MAMI, the beam-helicity asymmetry has been precisely measured around th…
Hypernuclear Physics with Photons
C. Bennhold, T. Mart, F. X. Lee +7
We review the opportunities and challenges in the field of hypernuclear physics with electromagnetic probes. An overview is presented regarding our current understanding of the ele…
The Generalized Gerasimov-Drell-Hearn Integral and the Spin Structure of the Nucleon
D. Drechsel, S. S. Kamalov, G. Krein +1
The spin structure functions g1 and g2 have been calculated in the resonance region and for small and intermediate momentum transfer. The calculation is based on a gauge-invariant…
The Fubini-Furlan-Rossetti Sum Rule Revisited
B. Pasquini, D. Drechsel, L. Tiator
The Fubini-Furlan-Rossetti sum rule for pion photoproduction on the nucleon is evaluated by dispersion relations at constant t, and the corrections to the sum rule due to the finit…
Recoil polarization and beam-recoil double polarization measurement of ηelectroproduction on the proton in the region of the S_{11}(1535) resonance
H. Merkel, P. Achenbach, C. A. Ayerbe Gayoso +20
The beam-recoil double polarization P_{x'}^h and P_{z'}^h and the recoil polarization P_{y'} were measured for the first time for the p(\vec{e},e'\vec{p})ηreaction at a four-momen…
Nucleon Resonance Excitation with Virtual Photons
L. Tiator, S. Kamalov
The unitary isobar model MAID is used for a partial wave analysis of pion photoproduction and electroproduction data on the nucleon. In particular we have taken emphasis on the reg…
Electromagnetic Production of the Hypertriton
T. Mart, L. Tiator, D. Drechsel +1
Kaon photoproduction on He3, gamma + He3 --> K+ + Hypertriton, is studied in the framework of the impulse approximation. Realistic He3 wave functions obtained as solutions of Fadde…
Pion Electroproduction on the Nucleon and the Generalized GDH Sum Rule
L. Tiator, D. Drechsel, S. S. Kamalov
We present predictions for the spin structure functions of the proton and the neutron in the framework of a unitary isobar model for one-pion photo- and electroproduction. Our resu…
Multipole analysis for pion photoproduction with MAID and a dynamical models
S. S. Kamalov, D. Drechsel, L. Tiator +1
Results of new analysis of pion photoproduction data obtained with Dynamical and MAID models are presented
Dispersion relation analysis of neutral pion photo- and electroproduction at threshold using the MAID and SAID solutions
S. S. Kamalov, L. Tiator, D. Drechsel +4
Neutral pion photo- and electroproduction at threshold is analyzed in the framework of dispersion relations. For this purpose, we evaluate the real threshold amplitudes in terms of…
Photoproduction of -mesons off the deuteron
I. Jaegle, T. Mertens, A. Fix +62
Quasi-free photoproduction of mesons off nucleons bound in the deuteron has been measured with the combined Crystal Barrel - TAPS detector. The experiment was done at a tagge…
Baryon photo-decay amplitudes at the pole
R. L. Workman, L. Tiator, A. Sarantsev
We derive relations for baryon photo-decay amplitudes both for the Breit-Wigner and the pole positions. With an updated SAID partial wave analysis, technically similar to the earli…
and photoproduction with EtaMAID including Regge phenomenology
V. L. Kashevarov, L. Tiator, M. Ostrick
We present a new version of the EtaMAID model for and photoproduction on nucleons. The model includes 23 nucleon resonances parameterized with Breit-Wigner shapes. The b…
Photoproduction of the Hypertriton
T. Mart, D. Kusno, C. Bennhold +2
In the framework of the impulse approximation we study the photoproduction of the hypertriton H by using realistic He wave functions obtained as solutions of Faddeev equ…
Application of the single-channel, single-energy AA/PWA method to photoproduction
A. Å varc, Y. Wunderlich, L. Tiator
The new single-channel, single-energy partial wave analysis method based on a simultaneous use of amplitude and partial wave analysis called AA/PWA, developed and tested on ph…
and Excitations and the Quark Model
E. Klempt, V. Burkert, U. Thoma +2
The spectrum of and excitations is reviewed taking into account (nearly) all hyperon resonances which were seen in early analyses or in one of the recent partial-wave ana…
gamma* N -> Delta transition form factors: a new analysis of the JLab data on p(e,e'p)pi0 at Q^2=2.8 and 4.0 (GeV/c)^2
S. S. Kamalov, S. N. Yang, D. Drechsel +2
Recent JLab data of the differential cross section for the reaction p(e,e'p)pi0 in the invariant mass region of 1.1 < W < 1.4 GeV at four-momentum transfer squared Q^2= 2.8 and 4.0…
Invariant Amplitudes for Pion Electroproduction
B. Pasquini, D. Drechsel, L. Tiator
The invariant amplitudes for pion electroproduction on the nucleon are evaluated by dispersion relations at constant t with MAID as input for the imaginary parts of these amplitude…
The E2/M1 and C2/M1 ratios and form factors in N -> Delta transitions
L. Tiator, D. Drechsel, O. Hanstein +2
A partial wave analysis of pion photoproduction has been obtained in the framework of fixed-t dispersion relations valid from threshold up to 500 MeV. In the resonance region we ha…
Multipole Analysis of a Benchmark Data Set for Pion Photoproduction
R. A. Arndt, I. Aznauryan, R. M. Davidson +8
We have fitted low- and medium-energy benchmark datasets employing methods used in the MAID/SAID and dynamical model analyses. Independent fits from the Mainz, RPI, Yerevan, and Kh…
Recent progress in pion photo- and electroproduction analysis
L. Tiator, D. Drechsel, S. Kamalov +1
Pion photo- and electroproduction has been studied at threshold and in the resonance region below W=2GeV. At threshold pi^0 production can be very well explained within a dynamical…
Fixed-t analyticity as a constraint in single energy partial wave analyses of meson photoproduction reactions
H. OsmanoviÄ, M. HadžimehmedoviÄ, R. OmeroviÄ +6
Partial wave amplitudes of meson photoproduction reactions are an important source of information in baryon spectroscopy. We investigate a new approach in single-energy partial wav…
MAID-2015: update with new data and new resonances
V. L. Kashevarov, L. Tiator, M. Ostrick
Recent data for and photoproduction on protons obtained by the A2 Collaboration at MAMI are presented. The total cross section for photoproduction demonstrates…
Coherent and Photoproduction on the Deuteron
S. S. Kamalov, L. Tiator, C. Bennhold
Coherent pion photoproduction, , is calculated in a coupled channels approach in momentum space using an elementary production operator that includes Born terms, vecto…
Photo- and Electroproduction of Eta Mesons
G. Knöchlein, D. Drechsel, L. Tiator
Eta photo- and electroproduction off the nucleon is investigated in an effective lagrangian approach that contains Born terms and both vector meson and nucleon resonance contributi…
From Experimental Data to Pole Parameters in a Direct Way (Angle Dependent Continuum Ambiguity and Laurent + Pietarinen Expansion)
A. Å varc, Y. Wunderlich, H. OsmanoviÄ +8
Unconstrained partial-wave amplitudes obtained at discrete energies from fits to complete sets of eight independent observables which are required to uniquely reconstruct reaction…
An isobar model for eta photo- and electroproduction on the nucleon
Wen-Tai Chiang, Shin Nan Yang, L. Tiator +1
An isobar model containing Born terms, vector meson exchange and nucleon resonances is used to analyze recent eta photoproduction data for cross section and beam asymmetry, as well…
Threshold pi^0 photo- and electro-production in a meson-exchange model
S. N. Yang, Guan-Yeu Chen, S. S. Kamalov +2
We show that, within a meson-exchange dynamical model describing well most of the existing pion electromagnetic production data up to the second resonance region, one is also able…
The physical meaning of scattering matrix singularities in coupled-channel formalisms
S. Capstick, A. Svarc, L. Tiator +8
The physical meaning of bare and dressed scattering matrix singularities has been investigated. Special attention has been attributed to the role of well known invariance of scatte…
Eta photoproduction
L. Tiator, G. Knoechlein, C. Bennhold
We present a combined analysis of the new eta photoproduction data for total and differential cross sections, target asymmetry and photon asymmetry. Using basic assumptions, this a…
Analysis of resonance multipoles from polarization observables in eta photoproduction
L. Tiator, D. Drechsel, G. Knoechlein +1
A combined analysis of new eta photoproduction data for total and differential cross sections, target asymmetry and photon asymmetry is presented. Using a few reasonable assumption…
Amplitude reconstruction from complete experiments and truncated partial-wave expansions
R. L. Workman, L. Tiator, Y. Wunderlich +2
We compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial wave analysis, applied to the photoproduction of pseudo-scalar mesons. The app…
Medium Effects in Coherent Pion Photo- and Electroproduction on 4He and 12C
D. Drechsel, L. Tiator, S. S. Kamalov +1
Coherent pi0 photo- and electroproduction on 4He and 12C nuclei is investigated in the framework of a distorted wave impulse approximation in momentum space. The elementary process…
A Rosetta Stone Relating Conventions In Photo-Meson Partial Wave Analyses
A. M. Sandorfi, B. Dey, A. Sarantsev +2
A new generation of complete experiments in pseudoscalar meson photo-production is being pursued at several laboratories. While new data are emerging, there is some confusion regar…
Complex-mass scheme and resonances in EFT
T. Bauer, D. Djukanovic, J. Gegelia +2
The complex-mass scheme (CMS) provides a consistent framework for dealing with unstable particles in quantum field theory and has been successfully applied to various loop calculat…
Pi0 photo- and electroproduction at threshold within a dynamical model
S. S. Kamalov, G. -Y. Chen, S. N. Yang +2
We show that, within a meson-exchange dynamical model describing most of the existing pion electromagnetic production data up to the second resonance region, one is also able to ob…