Completing the Picture of the Roper Resonance

Author(s)

Segovia, Jorge ^{[1, 2]} ; El-Bennich, Bruno ^{[3, 4]} ; Rojas, Eduardo ^{[5, 4]} ; Cloet, Ian C. ^[6] ; Roberts, Craig D. ^[6] ; Xu, Shu-Sheng ^[7] ; Zong, Hong-Shi ^[7]

Affiliation

^[1] Univ Salamanca, Grp Fis Nucl, E-37008 Salamanca - Spain

^[2] Univ Salamanca, IUFFyM, E-37008 Salamanca - Spain

^[3] Univ Estadual Paulista, Inst Fis Teor, BR-01140070 Sao Paulo, SP - Brazil

^[4] Univ Cruzeiro Sul, Lab Fis Teor & Computac, BR-01506000 Sao Paulo, SP - Brazil

^[5] Univ Antioquia, Inst Fis, Medellin - Colombia

^[6] Argonne Natl Lab, Div Phys, Argonne, IL 60439 - USA

^[7] Nanjing Univ, Dept Phys, Nanjing 210093, Jiangsu - Peoples R China

• Document type: Journal article
• Source: Physical Review Letters; v. 115, n. 17 OCT 21 2015.
• Web of Science Citations: 61

Abstract

We employ a continuum approach to the three valence-quark bound-state problem in relativistic quantum field theory to predict a range of properties of the proton's radial excitation and thereby unify them with those of numerous other hadrons. Our analysis indicates that the nucleon's first radial excitation is the Roper resonance. It consists of a core of three dressed quarks, which expresses its valence-quark content and whose charge radius is 80% larger than the proton analogue. That core is complemented by a meson cloud, which reduces the observed Roper mass by roughly 20%. The meson cloud materially affects long-wavelength characteristics of the Roper electroproduction amplitudes but the quark core is revealed to probes with Q(2) greater than or similar to 3m(N)(2). (AU)

• FAPESP's process: 13/16088-4 - Hadron Physics in the era of the 12 GeV upgrade at Jefferson Lab and new flavor-physics facilities
• Grantee: Bruno Omar El-Bennich
• Support type: Regular Research Grants
• FAPESP's process: 12/03275-8 - Unquenching effects in heavy mesons
• Grantee: Eduardo Rojas Pena
• Support type: Scholarships in Brazil - Post-Doctorate