Structure of the nucleon’s low-lying excitations
- Univ. Estadual Paulista, Sao Paulo (Brazil)
- Univ. Cruzeiro do Sul, Sao Paulo (Brazil)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Forschungszentrum Julich and JARA, Julich (Germany)
- Univ. Autonoma de Barcelona, Bellaterra (Barcelona) (Spain)
- Univ. of Science and Technology of China, Anhui (People's Republic of China)
Here, 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, JP = 1/2±) 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±) doublets will prove valuable in testing links between emergent mass generation and observable phenomena and, plausibly, thereby revealing dynamical features of confinement.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP); USDOE
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1480433
- Alternate ID(s):
- OSTI ID: 1421305
- Journal Information:
- Physical Review D, Vol. 97, Issue 3; ISSN 2470-0010
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Spectrum of Light- and Heavy-Baryons
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journal | April 2019 |
Bound state properties from the functional renormalization group
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journal | March 2019 |
Bound state properties from the Functional Renormalisation Group | text | January 2018 |
Hyperons in thermal QCD: A lattice view | text | January 2018 |
Masses of ground-state mesons and baryons, including those with heavy quarks | text | January 2019 |
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