LOW ENERGY DOUBLE-PION PHOTOPRODUCTION IN NUCLEI

2005 ◽  
Vol 20 (02n03) ◽  
pp. 578-580 ◽  
Author(s):  
L. ALVAREZ-RUSO ◽  
P. MÜHLICH ◽  
O. BUSS ◽  
U. MOSEL
Keyword(s):  
Transport Model ◽  
Invariant Mass Spectrum ◽  
Pion Photoproduction ◽  
Low Energy ◽  
Medium Effects ◽  
Final State ◽  
Target Mass ◽  
Double Pion ◽  
Final State Interactions ◽  
Coupled Channel

We have investigated π0π0 and π±π0 photoproduction off complex nuclei. Simulations have been performed by means of a semi-classical BUU transport model including a full coupled-channel treatment of the final state interactions. We show that the target mass dependence of the π0π0 invariant mass spectrum as measured by the TAPS collaboration can be explained without introducing medium effects beyond absorption and quasi-elastic scattering of the final state particles. On the other hand, we find considerable discrepancies with the data in the π±π0 channel, which are not understood.

scholarly journals MESON2006 SUMMARY: THEORY

2007 ◽  
Vol 22 (02n03) ◽  
pp. 495-501
Author(s):  
TED BARNES
Keyword(s):  
B Mesons ◽  
Low Energy ◽  
Medium Effects ◽  
Final State ◽  
Hadron Physics ◽  
The Status ◽  
Recent Developments ◽  
Hadronic Production ◽  
Final State Interactions ◽  
Pion Nucleon

This is a summary of theoretical plenary contributions to the biennial hadron physics conference Meson2006, which was the ninth in this series. The topics covered in the meeting include low energy pion-pion and pion-nucleon interactions, photoproduction and hadronic production of light mesons and baryons, in-medium effects, recent developments in charmed mesons, charmonia and B mesons, the status of exotica, and some related topics such as final state interactions. In this contribution we review and summarize the plenary talks presented by theorists at the meeting, and emphasize some of the main points of their presentations. Where appropriate we will add brief comments on some aspects of QCD spectroscopy. Finally, following tradition, we conclude with a new Feynman story.

DOUBLE PION PHOTOPRODUCTION OFF 7Li

2011 ◽  
Vol 26 (03n04) ◽  
pp. 708-711
Author(s):  
◽  
YASSER MAGHRBI ◽  
BERND KRUSCHE
Keyword(s):  
Invariant Mass ◽  
Pion Photoproduction ◽  
Final State ◽  
Incident Photon ◽  
Mass Distributions ◽  
Double Pion ◽  
Final State Interactions ◽  
Medium Modification

Data for quasi-free photoproduction of π0π0 and π0π+/- pairs from 7 Li have been analyzed in view of the in-medium properties of hadrons. Data have been measured with the CB/TAPS detector setup using the Glasgow photon tagging spectrometer for incident photon energies up to 820 MeV. The double π0 invariant mass distributions show an enhancement with respect to the mixed charged channel at small invariant masses. This enhancement could be consistent with an in-medium modification of the ππ interaction in the I = J = 0 channel, however effects from final state interactions must also be considered.

scholarly journals HADRON ATTENUATION AT HERMES BY (PRE)HADRONIC FSI

2005 ◽  
Vol 20 (02n03) ◽  
pp. 615-617
Author(s):  
K. GALLMEISTER ◽  
W. CASSING ◽  
T. FALTER ◽  
U. MOSEL
Keyword(s):  
Transport Model ◽  
High Energy ◽  
Quantum Mechanical ◽  
Hadronic Final State ◽  
Initial State ◽  
Final State ◽  
Quantum Mechanical Treatment ◽  
Final State Interactions ◽  
Coupled Channel ◽  
Hadron Formation

We investigate hadron formation in high energy electroproduction off complex nuclei in the framework of a BUU transport model. Our approach combines a quantum mechanical treatment of the photon's initial state interactions with a semi-classical coupled channel simulation of the (pre)hadronic final-state interactions (FSI). This allows us to study the hadron attenuation observed at HERMES and to get information on the space-time picture of hadron formation separately for π±, π0, K±, p and [Formula: see text].

scholarly journals Three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD final State interactions (THESEUS) for FAIR-NICA-SPSBES/RHIC energies

2018 ◽  
Vol 182 ◽  
pp. 02056 ◽  
Author(s):  
P. Batyuk ◽  
D. Blaschke ◽  
M. Bleicher ◽  
Yu.B. Ivanov ◽  
Iu. Karpenko ◽  
...  
Keyword(s):  
Equations Of State ◽  
Transport Model ◽  
Event Generator ◽  
Final State ◽  
First Order Phase Transition ◽  
First Results ◽  
Rapidity Distributions ◽  
Final State Interactions ◽  
Model Equations ◽  
Fluid Hydrodynamics

We present a new event generator based on the three-fluid hydrodynamics (3FH) approach, followed by a particlization at the hydrodynamic decoupling surface and a subsequent UrQMD afterburner stage based on the microscopic UrQMD transport model that accounts for hadronic final state interactions. First results for Au+Au collisions are presented. The following topics are addressed: the directed flow, transversemass spectra, as well as rapidity distributions of protons, pions and kaons for two model equations of state, one with a first-order phase transition, the other with a crossover transition. Preliminary results on the femtoscopy are also discussed.We analyze the accuracy of reproduction of the 3FH results by the new event generator and the effect of the subsequent UrQMD afterburner stage.

Low energy expansions for double-pion photoproduction

1994 ◽  
Vol 73 (3) ◽  
pp. 400-403 ◽  
Author(s):  
M. Benmerrouche ◽  
E. Tomusiak
Keyword(s):  
Pion Photoproduction ◽  
Low Energy ◽  
Double Pion

scholarly journals EXTRACTION OF RESONANCE PARAMETERS AND ROLE OF THE FINAL STATE INTERACTIONS

2014 ◽  
Vol 26 ◽  
pp. 1460082 ◽  
Author(s):  
IGOR I. STRAKOVSKY ◽  
WILLIAM J. BRISCOE ◽  
ALEXANDER E. KUDRYAVTSEV ◽  
VLADIMIR E. TARASOV
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Impulse Approximation ◽  
Pion Photoproduction ◽  
Final State ◽  
The World ◽  
Final State Interactions ◽  
Watson’S Theorem ◽  
Photoproduction Data

We present an overview of the SAID group effort to analyze new γn → π-p cross sections vs. the world database to get new multipoles and determine neutron electromagnetic couplings. The differential cross section for the processes γn → π-p was extracted from new measurements at CLAS and MAMI-B accounting for Fermi motion effects in the impulse approximation (IA) as well as NN- and πN-FSI effects beyond the IA. We evaluated results of several pion photoproduction analyses and compared πN PWA results as a constraint for analyses of pion photoproduction data (Watson's theorem).

scholarly journals Double pion photoproduction off nuclei – Are there effects beyond final-state interaction?

2013 ◽  
Vol 722 (1-3) ◽  
pp. 69-75 ◽  
Author(s):  
Y. Maghrbi ◽  
R. Gregor ◽  
S. Lugert ◽  
J. Ahrens ◽  
J.R.M. Annand ◽  
...  
Keyword(s):  
Final State Interaction ◽  
Pion Photoproduction ◽  
State Interaction ◽  
Final State ◽  
Double Pion

Comment on "Low Energy Expansions for Double-Pion Photoproduction"

1995 ◽  
Vol 74 (6) ◽  
pp. 1036-1036 ◽  
Author(s):  
V. Bernard ◽  
N. Kaiser ◽  
Ulf -G. Meißner
Keyword(s):  
Pion Photoproduction ◽  
Low Energy ◽  
Double Pion

Electromagnetic breakup of the deuteron in the Δ resonance region

1984 ◽  
Vol 62 (11) ◽  
pp. 1036-1045 ◽  
Author(s):  
W. Leidemann ◽  
H. Arenhövel
Keyword(s):  
Cross Section ◽  
Degrees Of Freedom ◽  
Impulse Approximation ◽  
Resonance Region ◽  
Final State ◽  
Channel Calculation ◽  
Main Emphasis ◽  
Coupled Channel Calculation ◽  
Final State Interactions ◽  
Coupled Channel

The processes d(γ, p)n and d(e, e′p)n have been studied in the Δ resonance region with explicit Δ degrees of freedom in a coupled channel treatment that includes all final state interactions. In particular, the dependence on the model for the potential and the Δ parametrization has been investigated. The main emphasis has been put on the photodisintegration. The total cross section for this process is considerably reduced by inclusion of the Δ interactions, resulting in better agreement with a recent experiment. The angular distribution up to the resonance region shows a stronger forward and backward peaking than experimental results do, while above the resonance the agreement is better. Whereas the γ asymmetry is affected very little by the coupled channel calculation compared with the impulse approximation, the proton polarization is quite sensitive to the proper treatment of the Δ degrees of freedom.

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