Q2 dependence of quadrupole strength in the γ*p→Δ+(1232)→pπ0 transition -: art. no. 122001

被引：218

作者：

Joo, K ^{[1
]}

Smith, LC

Burkert, VD

Minehart, R

Aznauryan, IG

Elouadrhiri, L

Stepanyan, S

Adams, GS

Amaryan, MJ

Anciant, E

Anghinolfi, M

Armstrong, DS

Asavapibhop, B

Audit, G

Auger, T

Avakian, H

Barrow, S

Bagdasaryan, H

Battaglieri, M

Beard, K

Bektasoglu, M

Bertozzi, W

Bianchi, N

Biselli, AS

Boiarinov, S

Bonner, BE

Brooks, WK

Calarco, JR

Capitani, GP

Carman, DS

Carnahan, B

Cole, PL

Coleman, A

Cords, D

Corvisiero, P

Crabb, D

Crannell, H

Cummings, J

De Sanctis, E

De Vita, R

Degtyarenko, PV

Demirchyan, RA

Denizli, H

Dennis, LC

Deppman, A

Dharmawardane, KV

Dhuga, KS

Djalali, C

Dodge, GE

Doughty, D

机构：

[1] Univ Virginia, Dept Phys, Charlottesville, VA 22903 USA

[2] Christopher Newport Univ, Newport News, VA 23606 USA

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

[4] Yerevan Phys Inst, Yerevan 375036, Armenia

[5] Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA

[6] Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA

[7] Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA

[8] Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA

[9] Duke Univ, Durham, NC 27706 USA

[10] Univ Edinburgh, Dept Phys & Astrophys, Edinburgh EH9 3JZ, Midlothian, Scotland

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

[12] Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA

[13] Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA

[14] George Washington Univ, Dept Phys, Washington, DC 20052 USA

[15] Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy

[16] Ist Nazl Fis Nucl, Sez Genova, I-16146 Genoa, Italy

[17] Ist Nazl Fis Nucl, Dipartimento Fis, I-16146 Genoa, Italy

[18] Inst Theoret & Expt Phys, Moscow 117259, Russia

[19] Inst Phys Nucl, IN2P3, F-91406 Orsay, France

[20] James Madison Univ, Dept Phys, Harrisonburg, VA 22807 USA

[21] Kyungpook Natl Univ, Dept Phys, Taegu 702701, South Korea

[22] MIT Bates Linear Accelerator, Middleton, MA 01949 USA

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

[24] Ohio Univ, Dept Phys, Athens, OH 45701 USA

[25] Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA

[26] Rensselaer Polytech Inst, Dept Phys, Troy, NY 12181 USA

[27] Rice Univ, Bonner Lab, Houston, TX 77251 USA

[28] CEA Saclay, DAPNIA, SPhN, F-91191 Gif Sur Yvette, France

[29] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

[30] Univ Connecticut, Dept Pharm, Storrs, CT 06269 USA

[31] Univ Massachusetts, Dept Phys, Amherst, MA 01003 USA

[32] Univ New Hampshire, Dept Phys, Durham, NH 03824 USA

[33] Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA

[34] Univ Richmond, Dept Phys, Richmond, VA 23173 USA

[35] Univ S Carolina, Dept Phys, Columbia, SC 29208 USA

[36] Univ Texas, Dept Phys, El Paso, TX 79968 USA

[37] Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA

来源：

PHYSICAL REVIEW LETTERS | 2002年 / 88卷 / 12期

关键词：

D O I：

10.1103/PhysRevLett.88.122001

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual tensor forces between quarks or distortions from the pion cloud. Sensitivity to quark versus pion degrees of freedom occurs through the Q(2) dependence of the magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in the gamma* p --> Delta(+) --> ppi(0) transition. We report new experimental values for the ratios E1+/M1+ and S1+/M1+ over the range Q(2) = 0.4-1.8 GeV2, extracted from precision p(e,e'p)pi(0) data using a truncated multipole expansion. Results are best described by recent unitary models in which the pion cloud plays a dominant role.

引用

页码：122001 / 122001

页数：5

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