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  1. Book ; Online: Threshold $\pi^-$ Photoproduction on the Neutron

    Briscoe, W. J. / Kudryavtsev, A. E. / Strakovsky, I. I. / Tarasov, V. E. / Workman, R. L.

    2020  

    Abstract: Recent data from the PIONS$@$MAX-lab Collaboration, measuring the total cross section of the pion incoherent photoproduction $\gamma d\to\pi^-pp$ near threshold, have been used to extract the E$_{0+}$ multipole and total cross section of the reaction $\ ... ...

    Abstract Recent data from the PIONS$@$MAX-lab Collaboration, measuring the total cross section of the pion incoherent photoproduction $\gamma d\to\pi^-pp$ near threshold, have been used to extract the E$_{0+}$ multipole and total cross section of the reaction $\gamma n\!\to\!\pi^-p$, also near threshold. These are the first measurements of the reaction $\gamma d\to\pi^-pp$ in the threshold region. The value of E$_{0+}$ is extracted through a fit to the deuteron data in a photoproduction model accounting for final-state interactions. The model takes an $S$-wave approximation for the elementary reaction $\gamma n\!\to\!\pi^-p$ with E$_{0+}\! = $ const in the threshold region. The obtained value E$_{0+} = -31.86\pm 0.8$ (in $10^{-3}/m_{\pi^+}$ units) is in agreement with other existing results. Model predictions for the total cross section $\sigma(\gamma n\!\to\!\pi^-p)$ are also given.

    Comment: 7 pages, 4 figures, 2 tables
    Keywords Nuclear Theory ; High Energy Physics - Experiment ; High Energy Physics - Phenomenology ; Nuclear Experiment
    Subject code 612
    Publishing date 2020-04-03
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Book ; Conference proceedings: Proceedings of the 9h International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon

    Briscoe, W. J / Haberzettl, H

    The George Washington University, Wasgington, D.C., U.S.A., 26 - 31 July 2001

    (Pi-N newsletter ; 16.2001)

    2002  

    Title variant Proceedings of the MENU 2001 Symposium
    Institution MENU
    Center for Nuclear Studies
    Event/congress International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon (MENU) (9, 2001.07.26-31, Washington)
    Author's details MENU2001. Eds.: H. Haberzettl; W. J. Briscoe
    Series title Pi-N newsletter ; 16.2001
    Language English
    Size X, 442 S
    Publisher Center for Nuclear Studies
    Publishing place Washington, DC
    Document type Book ; Conference proceedings
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  3. Article ; Online: First Measurement Using Elliptically Polarized Photons of the Double-Polarization Observable E for γp→pπ^{0} and γp→nπ^{+}.

    Afzal, F / Spieker, K / Hurck, P / Abt, S / Achenbach, P / Adlarson, P / Ahmed, Z / Akondi, C S / Annand, J R M / Arends, H J / Bashkanov, M / Beck, R / Biroth, M / Borisov, N / Braghieri, A / Briscoe, W J / Cividini, F / Collicott, C / Costanza, S /
    Denig, A / Dieterle, M / Downie, E J / Drexler, P / Fegan, S / Gardner, S / Ghosal, D / Glazier, D I / Gorodnov, I / Gradl, W / Gurevich, D / Heijkenskjöld, L / Hornidge, D / Huber, G M / Kashevarov, V L / Kay, S J D / Korolija, M / Krusche, B / Lazarev, A / Livingston, K / Lutterer, S / MacGregor, I J D / Macrae, R G / Manley, D M / Martel, P P / Miskimen, R / Mocanu, M / Mornacchi, E / Mullen, C / Neganov, A / Neiser, A / Oberle, M / Ostrick, M / Otte, P B / Paudyal, D / Pedroni, P / Powell, A / Reicherz, G / Rostomyan, T / Sfienti, C / Sokhoyan, V / Steffen, O / Strakovsky, I I / Strub, T / Supek, I / Thiel, A / Thiel, M / Thomas, A / Usov, Yu A / Wagner, S / Walford, N K / Watts, D P / Werthmüller, D / Wettig, J / Witthauer, L / Wolfes, M / Zachariou, N

    Physical review letters

    2024  Volume 132, Issue 12, Page(s) 121902

    Abstract: We report the measurement of the helicity asymmetry E for the pπ^{0} and nπ^{+} final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. ... ...

    Abstract We report the measurement of the helicity asymmetry E for the pπ^{0} and nπ^{+} final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g., G) and circularly polarized photons (e.g., E) and a longitudinally polarized target. The new data cover a photon energy range 270-1400 MeV for the pπ^{0} final state (230-842 MeV for the nπ^{+} final state) and the full range of pion polar angles, θ, providing the most precise measurement of the observable E. A moment analysis gives a clear observation of the pη cusp in the pπ^{0} final state.
    Language English
    Publishing date 2024-04-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.132.121902
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Progress on Neutron-Target Multipoles above 1 GeV

    Rossi P. / Paris M. / Mirazite M. / Kudryavtsev A.E. / Dutta D. / Briscoe W.J. / Gao H. / Chen W. / Strakovsky I.I. / Stepanyan S. / Tarasov V.E. / Workman R.L.

    EPJ Web of Conferences, Vol 37, p

    2012  Volume 08005

    Abstract: We report a new extraction of nucleon resonance couplings using π− photo-production cross sections on the neutron. The world database for the process γn → π−p above 1 GeV has quadrupled with the addition of new differential cross sections from the CEBAF ... ...

    Abstract We report a new extraction of nucleon resonance couplings using π− photo-production cross sections on the neutron. The world database for the process γn → π−p above 1 GeV has quadrupled with the addition of new differential cross sections from the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab in Hall B. Differential cross sections from CLAS have been improved with a new final-state interaction determination using a diagrammatic technique taking into account the SAID phenomenological NN and πN final-state interaction amplitudes. Resonance couplings have been extracted and compared to previous determinations. With the addition of these new cross sections, significant changes are seen in the high-energy behavior of the SAID cross sections and amplitudes.
    Keywords Physics ; QC1-999 ; Science ; Q ; DOAJ:Physics (General) ; DOAJ:Physics and Astronomy
    Language English
    Publishing date 2012-12-01T00:00:00Z
    Publisher EDP Sciences
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Measurement of Compton Scattering at MAMI for the Extraction of the Electric and Magnetic Polarizabilities of the Proton.

    Mornacchi, E / Martel, P P / Abt, S / Achenbach, P / Adlarson, P / Afzal, F / Ahmed, Z / Annand, J R M / Arends, H J / Bashkanov, M / Beck, R / Biroth, M / Borisov, N / Braghieri, A / Briscoe, W J / Cividini, F / Collicott, C / Costanza, S / Denig, A /
    Dolzhikov, A S / Downie, E J / Drexler, P / Fegan, S / Gardner, S / Ghosal, D / Glazier, D I / Gorodnov, I / Gradl, W / Günther, M / Gurevich, D / Heijkenskjöld, L / Hornidge, D / Huber, G M / Käser, A / Kashevarov, V L / Kay, S J D / Korolija, M / Krusche, B / Lazarev, A / Livingston, K / Lutterer, S / MacGregor, I J D / Manley, D M / Miskimen, R / Mocanu, M / Mullen, C / Neganov, A / Neiser, A / Ostrick, M / Paudyal, D / Pedroni, P / Powell, A / Rostomyan, T / Sokhoyan, V / Spieker, K / Steffen, O / Strakovsky, I / Strub, T / Thiel, M / Thomas, A / Usov, Yu A / Wagner, S / Watts, D P / Werthmüller, D / Wettig, J / Wolfes, M / Zachariou, N

    Physical review letters

    2022  Volume 128, Issue 13, Page(s) 132503

    Abstract: A precise measurement of the differential cross sections dσ/dΩ and the linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost 4π detector at the ... ...

    Abstract A precise measurement of the differential cross sections dσ/dΩ and the linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost 4π detector at the Mainz Microtron. The incident photons were produced by the recently upgraded Glasgow-Mainz photon tagging facility and impinged on a cryogenic liquid hydrogen target, with the scattered photons detected in the Crystal Ball/TAPS setup. Using the highest statistics Compton scattering data ever measured on the proton along with two effective field theories (both covariant baryon and heavy-baryon) and one fixed-t dispersion relation model, constraining the fits with the Baldin sum rule, we have obtained the proton electric and magnetic polarizabilities with unprecedented precision: α_{E1}=10.99±0.16±0.47±0.17±0.34, β_{M1}=3.14±0.21±0.24±0.20±0.35; in units of 10^{-4}  fm^{3} where the errors are statistical, systematic, spin polarizability dependent, and model dependent.
    Language English
    Publishing date 2022-04-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.128.132503
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Book ; Online: AI-assisted Optimization of the ECCE Tracking System at the Electron Ion Collider

    Fanelli, C. / Papandreou, Z. / Suresh, K. / Adkins, J. K. / Akiba, Y. / Albataineh, A. / Amaryan, M. / Arsene, I. C. / Gayoso, C. Ayerbe / Bae, J. / Bai, X. / Baker, M. D. / Bashkanov, M. / Bellwied, R. / Benmokhtar, F. / Berdnikov, V. / Bernauer, J. C. / Bock, F. / Boeglin, W. /
    Borysova, M. / Brash, E. / Brindza, P. / Briscoe, W. J. / Brooks, M. / Bueltmann, S. / Bukhari, M. H. S. / Bylinkin, A. / Capobianco, R. / Chang, W. -C. / Cheon, Y. / Chen, K. / Chen, K. -F. / Cheng, K. -Y. / Chiu, M. / Chujo, T. / Citron, Z. / Cline, E. / Cohen, E. / Cormier, T. / Morales, Y. Corrales / Cotton, C. / Crafts, J. / Crawford, C. / Creekmore, S. / Cuevas, C. / Cunningham, J. / David, G. / Dean, C. T. / Demarteau, M. / Diehl, S.

    2022  

    Abstract: The Electron-Ion Collider (EIC) is a cutting-edge accelerator facility that will study the nature of the "glue" that binds the building blocks of the visible matter in the universe. The proposed experiment will be realized at Brookhaven National ... ...

    Abstract The Electron-Ion Collider (EIC) is a cutting-edge accelerator facility that will study the nature of the "glue" that binds the building blocks of the visible matter in the universe. The proposed experiment will be realized at Brookhaven National Laboratory in approximately 10 years from now, with detector design and R&D currently ongoing. Notably, EIC is one of the first large-scale facilities to leverage Artificial Intelligence (AI) already starting from the design and R&D phases. The EIC Comprehensive Chromodynamics Experiment (ECCE) is a consortium that proposed a detector design based on a 1.5T solenoid. The EIC detector proposal review concluded that the ECCE design will serve as the reference design for an EIC detector. Herein we describe a comprehensive optimization of the ECCE tracker using AI. The work required a complex parametrization of the simulated detector system. Our approach dealt with an optimization problem in a multidimensional design space driven by multiple objectives that encode the detector performance, while satisfying several mechanical constraints. We describe our strategy and show results obtained for the ECCE tracking system. The AI-assisted design is agnostic to the simulation framework and can be extended to other sub-detectors or to a system of sub-detectors to further optimize the performance of the EIC detector.

    Comment: 16 pages, 18 figures, 2 appendices, 3 tables
    Keywords Physics - Instrumentation and Detectors ; Computer Science - Machine Learning ; High Energy Physics - Experiment ; Nuclear Experiment ; Physics - Computational Physics
    Subject code 670 ; 006
    Publishing date 2022-05-18
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: First Measurement of Hard Exclusive π^{-}Δ^{++} Electroproduction Beam-Spin Asymmetries off the Proton.

    Diehl, S / Trotta, N / Joo, K / Achenbach, P / Akbar, Z / Armstrong, W R / Atac, H / Avakian, H / Baashen, L / Baltzell, N A / Barion, L / Bashkanov, M / Battaglieri, M / Bedlinskiy, I / Benmokhtar, F / Bianconi, A / Biselli, A S / Bossù, F / Brinkmann, K-T /
    Briscoe, W J / Bulumulla, D / Burkert, V / Capobianco, R / Carman, D S / Carvajal, J C / Celentano, A / Charles, G / Chatagnon, P / Chesnokov, V / Ciullo, G / Cole, P L / Contalbrigo, M / Costantini, G / Crede, V / D'Angelo, A / Dashyan, N / De Vita, R / Deur, A / Djalali, C / Dupre, R / Ehrhart, M / El Alaoui, A / El Fassi, L / Elouadrhiri, L / Fegan, S / Filippi, A / Gavalian, G / Glazier, D I / Golubenko, A A / Gosta, G / Gothe, R W / Gotra, Y / Griffioen, K / Hafidi, K / Hakobyan, H / Hattawy, M / Hayward, T B / Heddle, D / Hobart, A / Holtrop, M / Illari, I / Ireland, D G / Isupov, E L / Jo, H S / Johnston, R / Keller, D / Khachatryan, M / Khanal, A / Kim, A / Kim, W / Klimenko, V / Kripko, A / Kubarovsky, V / Kuhn, S E / Lagerquist, V / Lanza, L / Leali, M / Lee, S / Lenisa, P / Li, X / MacGregor, I J D / Marchand, D / Mascagna, V / Matousek, G / McKinnon, B / McLauchlin, C / Meziani, Z E / Migliorati, S / Milner, R G / Mineeva, T / Mirazita, M / Mokeev, V / Moran, P / Munoz Camacho, C / Naidoo, P / Neupane, K / Niccolai, S / Niculescu, G / Osipenko, M / Pandey, P / Paolone, M / Pappalardo, L L / Paremuzyan, R / Paul, S J / Phelps, W / Pilleux, N / Pokhrel, M / Poudel, J / Price, J W / Prok, Y / Radic, A / Raue, B A / Reed, T / Richards, J / Ripani, M / Ritman, J / Rossi, P / Sabatié, F / Salgado, C / Schadmand, S / Schmidt, A / Sharabian, Y G / Shrestha, U / Sokhan, D / Sparveris, N / Spreafico, M / Stepanyan, S / Strakovsky, I / Strauch, S / Turisini, M / Tyson, R / Ungaro, M / Vallarino, S / Venturelli, L / Voskanyan, H / Voutier, E / Watts, D P / Wei, X / Williams, R / Wishart, R / Wood, M H / Yurov, M / Zachariou, N / Zhao, Z W / Zurek, M

    Physical review letters

    2023  Volume 131, Issue 2, Page(s) 21901

    Abstract: The polarized cross-section ratio σ_{LT^{'}}/σ_{0} from hard exclusive π^{-}Δ^{++} electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2  GeV/10.6  GeV incident electron beam and ... ...

    Abstract The polarized cross-section ratio σ_{LT^{'}}/σ_{0} from hard exclusive π^{-}Δ^{++} electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2  GeV/10.6  GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5  GeV^{2} up to 7  GeV^{2}. The reaction provides a novel access to the d-quark content of the nucleon and to p→Δ^{++} transition generalized parton distributions. A comparison to existing results for hard exclusive π^{+}n and π^{0}p electroproduction is provided, which shows a clear impact of the excitation mechanism, encoded in transition generalized parton distributions, on the asymmetry.
    Language English
    Publishing date 2023-07-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.131.021901
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Measurement of the helicity dependence for single π0 photoproduction from the deuteron

    Cividini, Federico / Dieterle, Michael / Abt, S. / Achenbach, Patrik / Adlarson, P. / Afzal, F. / Ahmed, Zafar / Annand, John R.M. / Arends, Hans Jürgen / Bashkanov, Mikhail / Beck, Reinhard / M. Biroth / Borisov, N. / Braghieri, A. / Briscoe, W.J. / Collicott, Cristina / Costanza, Susanna / Denig, A. / Dolzhikov, A.S. /
    Downie, E.J. / Drexler, P. / Fegan, Suzanne / Fix, A. / Gardner, S. / Ghosal, D. / Glazier, D.I. / Gorodnov, I. / Gradl, W. / Günther, M. / Gurevich, D. / Heijkenskjöld, L. / Hornidge, D. / Huber, G.M. / Käser, A. / Kashevarov, V.L. / Kay, S.J.D. / Korolija, M. / Krusche, B. / Lazarev, A. / Livingston, K. / Lutterer, S. / MacGregor, I.J.D. / Manley, D.M. / Martel, P.P. / Miskimen, R. / Mocanu, M. / Mornacchi, E. / Mullen, C. / Neganov, A. / Neiser, A. / Ostrick, M. / Paudyal, D. / Pedroni, P. / Powell, A. / Rostomyan, T. / Sokhoyan, V. / Spieker, K. / Steffen, O. / Strakovsky, I. / Strub, T. / Thiel, A. / Thiel, M. / Thomas, A. / Usov, Yu.A. / Wagner, S. / Watts, D.P. / Werthmüller, D. / Wettig, J. / Witthauer, L. / Wolfes, M. / Zachariou, N.

    2022  

    Abstract: The helicity-dependent single π0 photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π0 production off the proton and the neutron have been measured, for the first ... ...

    Abstract The helicity-dependent single π0 photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π0 production off the proton and the neutron have been measured, for the first time, from the threshold region up to the photon energy 1.4 GeV. The experiment was performed at the tagged photon facility of the MAMI accelerator and used a circularly polarised photon beam and longitudinally polarised deuteron target. The reaction products were detected using the large acceptance Crystal Ball/TAPS calorimeter, which covered 97% of the full solid angle. Comparing the cross section from the deuteron with the sum of free nucleon cross sections provides a quantitative estimate of the effects of the nuclear medium on pion production. In contrast, comparison of the E helicity asymmetry data from quasi-free protons off deuterium with data from a free proton target indicates that nuclear effects do not significantly affect this observable. As a consequence, it is deduced that the helicity asymmetry E on a free neutron can be reliably extracted from measurements on a deuteron in quasi-free kinematics.

    58

    6
    Keywords DDC::500 Naturwissenschaften und Mathematik::530 Physik
    Subject code 530
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Measurement of Compton Scattering at MAMI for the Extraction of the Electric and Magnetic Polarizabilities of the Proton

    Mornacchi, E. / Martel, P. P. / Abt, S. / Achenbach, Patrick / Adlarson, P. / Afzal, Farah Noreen / Ahmed, Zafar / Annand, John R.M. / Arends, Hans-Juergen / Bashkanov, Mikhail / Beck, Reinhard / Biroth, M. / Borisov, N. / Braghieri, A. / Briscoe, W. J. / Cividini, Federico / Collicott, C. / Costanza, S. / Denig, A. /
    Dolzhikov, A.S. / Downie, E.J. / Drexler, P. / Fegan, S. / Gardner, S. / Ghosal, D. / Glazier, D.I. / Gorodnov, I. / Gradl, W. / Günther, M. / Gurevich, D. / Heijkenskjöld, L. / Hornidge, D. / Huber, G.M. / Käser, A. / Kashevarov, V.L. / Kay, S.J.D. / Korolija, M. / Krusche, B. / Alexander, Lazarev / Livingston, K. / Lutterer, S. / MacGregor, I.J.D. / Manley, D.M. / Miskimen, R. / Mocanu, Ana M. / Mullen, Claudius C. / Neganov, A. / Neiser, A. / Ostrick, M. / Paudyal, D. / Pedroni, P. / Powell, A. / Rostomyan, T. / Sokhoyan, V. / K. Spieker / Wirth, Steffen / Strakovsky, I. / Strub, T. / Thiel, M. / Thomas, A. / Usov, Yu.A. / Wagner, S. / Watts, D.P. / Werthmüller, D. / Wettig, J. / Wolfes, M. / Zachariou, N.

    2022  

    Abstract: A precise measurement of the differential cross sections dσ/dΩ and the linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost 4π detector at the ... ...

    Abstract A precise measurement of the differential cross sections dσ/dΩ and the linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost 4π detector at the Mainz Microtron. The incident photons were produced by the recently upgraded Glasgow-Mainz photon tagging facility and impinged on a cryogenic liquid hydrogen target, with the scattered photons detected in the Crystal Ball/TAPS setup. Using the highest statistics Compton scattering data ever measured on the proton along with two effective field theories (both covariant baryon and heavy-baryon) and one fixed-t dispersion relation model, constraining the fits with the Baldin sum rule, we have obtained the proton electric and magnetic polarizabilities with unprecedented precision: α_{E1}=10.99±0.16±0.47±0.17±0.34, β_{M1}=3.14±0.21±0.24±0.20±0.35; in units of 10^{-4} fm^{3} where the errors are statistical, systematic, spin polarizability dependent, and model dependent.

    128

    13
    Keywords Electromagnetic transitions ; Nuclear reactions ; Nuclear structure & decays ; Photonuclear reactions ; DDC::500 Naturwissenschaften und Mathematik
    Subject code 530
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Signatures of the d^{*}(2380) Hexaquark in d(γ,pn[over →]).

    Bashkanov, M / Watts, D P / Kay, S J D / Abt, S / Achenbach, P / Adlarson, P / Afzal, F / Ahmed, Z / Akondi, C S / Annand, J R M / Arends, H J / Beck, R / Biroth, M / Borisov, N / Braghieri, A / Briscoe, W J / Cividini, F / Collicott, C / Costanza, S /
    Denig, A / Downie, E J / Drexler, P / Fegan, S / Fix, A / Gardner, S / Ghosal, D / Glazier, D I / Gorodnov, I / Gradl, W / Günther, M / Gurevich, D / Heijkenskjöld, L / Hornidge, D / Huber, G M / Käser, A / Kashevarov, V L / Korolija, M / Krusche, B / Lazarev, A / Livingston, K / Lutterer, S / MacGregor, I J D / Manley, D M / Martel, P P / Miskimen, R / Mornacchi, E / Mullen, C / Neganov, A / Neiser, A / Ostrick, M / Otte, P B / Paudyal, D / Pedroni, P / Powell, A / Prakhov, S N / Ron, G / Sarty, A / Sfienti, C / Sokhoyan, V / Spieker, K / Steffen, O / Strakovsky, I I / Strub, T / Supek, I / Thiel, A / Thiel, M / Thomas, A / Usov, Yu A / Wagner, S / Walford, N K / Werthmüller, D / Wettig, J / Wolfes, M / Zachariou, N / Zana, L A

    Physical review letters

    2020  Volume 124, Issue 13, Page(s) 132001

    Abstract: We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first ... ...

    Abstract We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E_{γ}∼570  MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom. A Legendre polynomial decomposition suggests this behavior could be related to the excitation of the d^{*}(2380) hexaquark.
    Language English
    Publishing date 2020-04-17
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.124.132001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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