Radiative Decay Width of Neutral non-Strange Baryons from PWA

Strakovsky, I. I.; Briscoe, W. J.; Kudryavtsev, A. E.; Kulikov, V.; Martemyanov, M.; Tarasov, V. E.

doi:10.1051/epjconf/20159601030

Cited by 2 publications

(4 citation statements)

References 27 publications

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“…An accurate evaluation of the electromagnetic couplings in meson photo-production remains unknown due to the lack of experiment data on the neutron targets. Moreover, the existing data on neutron target are mainly differential cross sections, only 15% are from polarization observable measurements [16]. Our measurement of the E asymmetry for γn → pπ − is the first for this polarization observable on the neutron target.…”

Section: Chapter 4 E Asymmetry For γN → Pπ −mentioning

confidence: 90%

“…The determination for the four complex amplitudes F 1 , F 2 , F 3 , F 4 need eight independent measurements. For the single and double meson photo-production, there are 64 polarization observables [24]: 16) where I is the reaction rate, Λ is the degree of polarization for the target, ρ f = (1+ σ• P )/2 is the density matrix of the recoil nucleon, δ is the degree of circular polarization of the photon beam, δ l is the degree of linear polarization for the photon beam. There are 9 single polarization observables: P is the polarization observable related to the target nucleon polarization (P x , P y , P z give three observables for target asymmetries), P is the polarization observable relate to the recoil nucleon polarization (P The three groups are using different phenomenological models to parametrize the multipoles.…”

Section: )mentioning

confidence: 99%

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Polarization observables for single and double charged pion photo-production with polarized HD target

Peng

2015

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A complete picture of hadron spectroscopy is important for the understanding of the degrees of freedom inside the hadron in the medium energy region. This study will bridge the gap between the hadron/pion picture in the low-energy region and the quark/gluon picture in the high-energy region. However, while only the low-energy resonances have been well identified, the high-energy excited states are broad and overlapping, so can only be disentangled with Partial Wave Analysis (PWA). The present PWA still has ambiguities due to the lack of experimental data, especially data using a polarized neutron target. The G14 experiment in Hall B of Jefferson Lab was designed and conducted to measure polarization observables from both polarized proton and neutron targets. The reaction channels studied in this dissertation are the single pion (γn → pπ −) and double pion (γp → pπ + π − , and γn → nπ + π −) photo-production. The E asymmetry in the single pion channel shows good agreement at lower energy with the prediction from two PWA groups: SAID from George Washington University and Bonn-Gatchina from University of Bonn. At higher energy, there is a big discrepancy between the experimental result and PWA prediction. This result is significant since the "missing resonances" are in this higher energy region. The polarization observables(I , P z , P z) in the two-pion channel with polarized neutron target are the first results that have been measured, and these three observables(I , P z , P z) in the two-pion channel with polarized proton target are compared with a previous CLAS experiment (G9a). The results are essential for the study of high-energy excited states since this channel has a bigger cross section than the single pion channel in the high-energy region. i First of all, I would like to thank my adviser, Blaine Norum, for his guidance in my PhD study, and for providing me with great freedom to pursue my ideas. I really appreciate his help to get me in his group in my fourth year, and to introduce me to the G14 experiment and the HDice group at Jefferson Lab. During the time I was doing the experiment and the data analysis at Jefferson Lab, he drove to the Lab almost every week to have a meeting with me, this helped me to keep a good pace with my project. During the last year, when I moved back to UVa, Blaine and I were working together on the explanation of an unexpected peak in the missing momentum plot. Even though the peak turned out to be caused by the gaps of the CLAS detectors, his way to pursue an explanation for the peak and his attitude to be careful for a new discovery have taught me a very good lesson of how to do research. I would like to thank Donal Day and Kent Paschke for serving on my thesis committee, and for their precious comments on my thesis. I also would like to thank Nilanga Liyanage and Krishni Wijesooriya for giving me a chance to work with them on nuclear physics and medical physics. None of this work would have been possible without the help from the people in G14 collaboration and the HDice g...

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Section: Chapter 4 E Asymmetry For γN → Pπ −mentioning

confidence: 90%

Section: )mentioning

confidence: 99%

Polarization observables for single and double charged pion photo-production with polarized HD target

Peng

2015

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“…From the above four equations, we can relate the initial photon field multipoles (ELand ML-) and the multipoles for meson photo-production (E l± and M l± ) to the resonance states (N * ), the results for several low order multipole amplitudes are shown in photon M-pole Initial state Final state Multipoles 16) where I is the reaction rate, Λ is the degree of polarization for the target, ρ f = (1+ σ· P )/2 is the density matrix of the recoil nucleon, δ is the degree of circular polarization of the photon beam, δ l is the degree of linear polarization for the photon beam. There are 9 single polarization observables: P is the polarization observable related to the target nucleon polarization (P x , P y , P z give three observables for target asymmetries), P is the polarization observable relate to the recoil nucleon polarization (P x , P y , P z give three observables for recoil asymmetries), I , I s , I c are photon beam asymmetries.…”

Section: Partial Wave Analysismentioning

confidence: 99%

“…Moreover, the existing data on neutron target are mainly differential cross sections, only 15% are from polarization observable measurements [16]. Our measurement of the E asymmetry for γn → pπ − is the first for this polarization observable on the neutron target.…”

mentioning

confidence: 90%

Polarization observables for single and double charged pion photo-production with polarized HD target

Peng

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Radiative Decay Width of Neutral non-Strange Baryons from PWA

Cited by 2 publications

References 27 publications

Polarization observables for single and double charged pion photo-production with polarized HD target

Polarization observables for single and double charged pion photo-production with polarized HD target

Polarization observables for single and double charged pion photo-production with polarized HD target

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