寻找Δ+(1232)电激发中的四极矩强度。

Search for quadrupole strength in the electroexcitation of the delta+(1232).

作者信息

Mertz C, Vellidis C E, Alarcon R, Barkhuff D H, Bernstein A M, Bertozzi W, Burkert V, Chen J, Comfort J R, Dodson G, Dolfini S, Dow K, Farkhondeh M, Finn J M, Gilad S, Gothe R W, Jiang X, Joo K, Kaloskamis N I, Karabarbounis A, Kelly J J, Kowalski S, Kunz C, Lourie R W, McIntyre J I, Milbrath B D, Miskimen R, Mitchell J H, Papanicolas C N, Perdrisat C F, Sarty A J, Shaw J, Soong S B, Tieger D, Tschalaer C, Turchinetz W, Ulmer P E, Van Verst S, Warren G A, Weinstein L B, Williamson S, Woo R J, Young A

机构信息

Department of Physics and Astronomy, Arizona State University, tempe 85287, USA.

出版信息

Phys Rev Lett. 2001 Apr 2;86(14):2963-6. doi: 10.1103/PhysRevLett.86.2963.

DOI:10.1103/PhysRevLett.86.2963

PMID:11290083

Abstract

High-precision 1H(e,e'p)pi(0) measurements at Q2 = 0.126 (GeV/c)2 are reported, which allow the determination of quadrupole amplitudes in the gamma*N-->Delta transition; they simultaneously test the reliability of electroproduction models. The derived quadrupole-to-dipole ( I = 3/2) amplitude ratios, R(SM) = (-6.5+/-0.2(stat+sys)+/-2.5(mod))% and R(EM) = (-2.1+/-0.2(stat+sys)+/-2.0(mod))%, are dominated by model error. Previous R(SM) and R(EM) results should be reconsidered after the model uncertainties associated with the method of their extraction are taken into account.

摘要

报道了在Q2 = 0.126 (GeV/c)2下的高精度1H(e,e'p)π(0)测量，这使得能够确定γ*N→Δ跃迁中的四极振幅；它们同时检验了电产生模型的可靠性。推导出的四极与偶极（I = 3/2）振幅比，R(SM) = (-6.5±0.2(统计+系统)±2.5(模型))%和R(EM) = (-2.1±0.2(统计+系统)±2.0(模型))%，主要受模型误差影响。在考虑与其提取方法相关的模型不确定性后，应重新审视之前的R(SM)和R(EM)结果。