Published November 1, 2010 | Version v1
Report

N* program at CLAS

Description

The N* program is one of the major goals of CLAS experiments in Jefferson Lab and many outstanding results have been carried out. In this note, I will present some highlight recent measurements of nucleon resonance transition form factors from electro-production as the second resonances. The new pion electro-production data resolve a longstanding puzzle of the nature of the Roper resonance, and confirm the assertion of the symmetric constituent quark model of the Roper as the first radial excitation of the nucleon. The single pion electro-production data for high Q2 confirms the slow fall off of the S11(1535) transition form factor with Q2, and better constrain the branching ratios βNπ:βNη = 0.50:0.45. For the first time, the longitudinal transition amplitude to the S11(1535) was extracted from the ηπ+ data. Also, new results on the transition amplitudes for the D13(1520) resonance are presented showing a rapid transition from helicity 3/2 dominance seen at the real photon point to helicity 1/2 dominance at higher Q2.

Availability note (English)

Available from Nuclear Physics B - Proceedings Supplements; Volumes 207-208, pages 216-219 (Oct-Nov 2010)

Additional details

Publishing Information

Imprint Pagination
4 p.
Report number
JLAB-PHY--10-1139

Conference

Title
QCD 10 (25th Anniversary)
Acronym
15. International QCD Conference
Dates
28 Jun - 3 Jul 2010
Place
Montpellier (France)

Optional Information

Contract/Grant/Project number
AC05-06OR23177
Notes
doi http://dx.doi.org/10.1016/j.nuclphysbps.2010.10.056
Funding organization
USDOE Office of Science (United States)
Secondary number(s)
DOE/OR--23177-1493