Publications
Publication Information
| Title | Roper resonance: Toward a solution to the fifty year puzzle |
| Authors | Volker Burkert, Craig Roberts |
| JLAB number | JLAB-PHY-18-2 |
| LANL number | arXiv:1710.02549 |
| Other number | DOE/OR/23177-4244 |
| Document Type(s) | (Journal Article) |
| Associated with EIC: | No |
| Supported by Jefferson Lab LDRD Funding: | No |
| Funding Source: | Nuclear Physics (NP) |
|
Journal Compiled for Reviews of Modern Physics Volume 91 Issue 01 Page(s) 011003 Refereed | |
| Publication Abstract: | Discovered in 1963, the Roper resonance appears to be an exact copy of the proton except that its mass is 50% greater and it is unstable. These features of the Roper have been very difficult to explain so that for half a century this lightest excited state of the proton has defied understanding. The last decade has presented a new challenge, viz. precise information on the proton-to-Roper electroproduction transition form factors. Reaching to momentum transfer Q2?4.5??GeV2, the data probe a domain within which hard valence-quark degrees of freedom could be expected to determine form factor behavior. An explanation of the Roper should combine an understanding of all these things. This is a prodigious task, but a ten-year international collaborative effort, involving experimentalists and theorists, has presented a candidate solution to the puzzle. Namely, the observed Roper is at the heart of the protons first radial excitation, consisting of a dressed-quark core augmented by a meson cloud that reduces the core mass by approximately 20% and materially alters its electroproduction form factors on Q2<2m2N, where mN is the protons mass. This Colloquium describes the experimental developments which enabled electroproduction data to be procured within a domain that is the purview of strong quantum chromodynamics, thereby providing challenges and opportunities for modern theory, and surveys the developments in reaction models and QCD theory that have enabled this picture of the Roper resonance to be drawn. |
| Experiment Numbers: | other |
| Group: | Hall B |
| Document: | |
| DOI: | https://doi.org/10.1103/RevModPhys.91.011003 |
| Accepted Manuscript: | BurkertRobertsW_R3.pdf |
| Supporting Documents: | |
| Supporting Datasets: | |