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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Structure of the nucleon's low-lying excitations

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Chen, Chen [1] ; El-Bennich, Bruno [2] ; Roberts, Craig D. [3] ; Schmidt, Sebastian M. [4, 5] ; Segovia, Jorge [6, 7] ; Wan, Shaolong [8, 9]
Total Authors: 6
[1] Univ Estadual Paulista, Inst Fis Teor, Rua Dr Bento Teobaldo Ferraz 271, BR-01140070 Sao Paulo, SP - Brazil
[2] Univ Cruzeiro Sul, Rua Galvao Bueno 868, BR-01506000 Sao Paulo, SP - Brazil
[3] Argonne Natl Lab, Div Phys, Argonne, IL 60439 - USA
[4] Forschungszentrum Julich, Inst Adv Simulat, D-52425 Julich - Germany
[5] JARA, D-52425 Julich - Germany
[6] Univ Autonoma Barcelona, IFAE, E-08193 Bellaterra, Barcelona - Spain
[7] Univ Autonoma Barcelona, BIST, E-08193 Bellaterra, Barcelona - Spain
[8] Univ Sci & Technol China, Dept Modern Phys, Hefei 230026, Anhui - Peoples R China
[9] Univ Sci & Technol China, Inst Theoret Phys, Hefei 230026, Anhui - Peoples R China
Total Affiliations: 9
Document type: Journal article
Source: Physical Review D; v. 97, n. 3 FEB 15 2018.
Web of Science Citations: 16

A continuum approach to the three valence-quark bound-state problem in quantum field theory is used to perform a comparative study of the four lightest (I = 1/2; J(P) = 1/2(+/-)) thorn baryon isospin doublets in order to elucidate their structural similarities and differences. Such analyses predict the presence of nonpointlike, electromagnetically active quark-quark (diquark) correlations within all baryons; and in these doublets, isoscalar-scalar, isovector-pseudovector, isoscalar-pseudoscalar, and vector diquarks can all play a role. In the two lightest (1/2, 1/2(+)) doublets, however, scalar and pseudovector diquarks are overwhelmingly dominant. The associated rest-frame wave functions are largely S-wave in nature; and the first excited state in this 1/2(+) channel has the appearance of a radial excitation of the ground state. The two lightest (1/2, 1/2(-)) doublets fit a different picture: accurate estimates of their masses are obtained by retaining only pseudovector diquarks; in their rest frames, the amplitudes describing their dressed-quark cores contain roughly equal fractions of even-and odd-parity diquarks; and the associated wave functions are predominantly P-wave in nature, but possess measurable S-wave components. Moreover, the first excited state in each negative-parity channel has little of the appearance of a radial excitation. In quantum field theory, all differences between positive-and negative-parity channels must owe to chiral symmetry breaking, which is overwhelmingly dynamical in the light-quark sector. Consequently, experiments that can validate the contrasts drawn herein between the structure of the four lightest (1/2, 1/2(+/-)) thorn doublets will prove valuable in testing links between emergent mass generation and observable phenomena and, plausibly, thereby revealing dynamical features of confinement. (AU)

FAPESP's process: 15/21550-4 - Continuum strong QCD: baryon masses and partonic structure
Grantee:Chen Chen
Support type: Scholarships in Brazil - Post-Doctorate