Recoil polarization for Δ excitation in pion electroproduction -: art. no. 102002

被引：63

作者：

Kelly, JJ ^{[1
]}

Roché, RE

Chai, Z

Jones, MK

Gayou, O

Sarty, AJ

Frullani, S

Aniol, K

Beise, EJ

Benmokhtar, F

Bertozzi, W

Boeglin, WU

Botto, T

Brash, EJ

Breuer, H

Brown, E

Burtin, E

Calarco, JR

Cavata, C

Chang, CC

Chant, NS

Chen, JP

Coman, M

Crovelli, D

De Leo, R

Dieterich, S

Escoffier, S

Fissum, KG

Garde, V

Garibaldi, F

Georgakopoulus, S

Gilad, S

Gilman, R

Glashausser, C

Hansen, JO

Higinbotham, DW

Hotta, A

Huber, GM

Ibrahim, H

Iodice, M

de Jager, CW

Jiang, X

Klimenko, A

Kozlov, A

Kumbartzki, G

Kuss, M

Lagamba, L

Laveissière, G

LeRose, JJ

Lindgren, RA

机构：

[1] Univ Maryland, Dept Phys, College Pk, MD 20742 USA

[2] Florida State Univ, Tallahassee, FL 32306 USA

[3] MIT, Cambridge, MA 02139 USA

[4] Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA

[5] St Marys Univ, Halifax, NS B3H 3C3, Canada

[6] Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy

[7] Ist Super Sanita, Phys Lab, I-00161 Rome, Italy

[8] Calif State Univ Los Angeles, Los Angeles, CA 90032 USA

[9] Rutgers State Univ, Piscataway, NJ 08854 USA

[10] Florida Int Univ, Miami, FL 33199 USA

[11] Univ Athens, Athens, Greece

[12] Univ Regina, Regina, SK S4S 0A2, Canada

[13] Univ Georgia, Athens, GA 30602 USA

[14] CEA Saclay, F-91191 Gif Sur Yvette, France

[15] Univ New Hampshire, Durham, NH 03824 USA

[16] Lund Univ, SE-22100 Lund, Sweden

[17] Univ Blaise Pascal Clermont Ferrand, F-177 Aubiere, France

[18] CNRS, IN2P3, LPC 63, F-177 Aubiere, France

[19] Univ Massachusetts, Amherst, MA 01003 USA

[20] Old Dominion Univ, Norfolk, VA 23529 USA

[21] Univ Virginia, Charlottesville, VA 22901 USA

[22] Renaissance Technol Corp, Moscow 117333, Russia

[23] Eastern Kentucky Univ, Richmond, KY 40475 USA

[24] Coll William & Mary, Williamsburg, VA 23187 USA

[25] Univ Ljubljana, Jozef Stefan Inst, SI-1001 Ljubljana, Slovenia

[26] Norfolk State Univ, Norfolk, VA 23504 USA

[27] Univ Illinois, Urbana, IL 61801 USA

来源：

PHYSICAL REVIEW LETTERS | 2005年 / 95卷 / 10期

关键词：

D O I：

10.1103/PhysRevLett.95.102001

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q(2)=1.0 (GeV/c)(2), obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re (S1+/M1+)= -(6.84 +/- 0.15)% and Re (E1+/M1+)= -(2.91 +/- 0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and l(pi)<= 1 truncation.

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