Measurement of the neutral weak form factors of the proton

Journal Article · Mon Feb 01 00:00:00 EST 1999 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.82.1096· OSTI ID:328559

Aniol, K A; Epstein, M B; Margaziotis, D J ^[1]; Deur, A ^[2]; Gasparian, A ^[3]; Spradlin, M; Wilson, R ^[4]; Garibaldi, F ^[5]; Chen, J; Chudakov, E; de Jager, C W; Deur, A; Gomez, J; Hansen, O; Kuss, M; LeRose, J; Michaels, R; Price, J S; Rutt, P M; Saha, A ; Wojtsekhowski, B ^[6]; Madey, R; Petratos, G G; Prout, D; Suleiman, R ^[7]; Dale, D ^[8]; Glamazdin, A; Gorbenko, V; Pomatsalyuk, R ^[9]; Kim, D H; Kim, M S ^[10]; Ewell, L ^[11]; Fissum, K; Gao, J; Liyanage, N ^[12]; Calarco, J; Hersman, F; Holtrop, M; Leuschner, M ^[13]; Punjabi, V ^[14]; Vlahovic, B ^[15]; Jutier, C; McCormick, K; Todor, L; Ulmer, P E ^[16]; Cates, G D; Humensky, B; Kumar, K S; Mastromarino, P; Miller, G W; Spradlin, M ^[17]; Fleck, A ^[18]; Gilman, R; McIntyre, J; others, and

---

1. California State University Los Angeles, Los Angeles, California 90032 (United States)
2. LPC, Universite Blaise Pascal/IN2P3, F-63177 Aubiere (France)
3. Hampton University, Hampton, Virginia 23668 (United States)
4. Harvard University, Cambridge, Massachusetts 02138 (United States)
5. Istituto Nazionale di Fisica Nucleare, Sezione Sanita, 00161 Roma (Italy)
6. Thomas Jefferson National Accelerator Laboratory, Newport News, Virginia 23606 (United States)
7. Kent State University, Kent, Ohio 44242 (United States)
8. University of Kentucky, Lexington, Kentucky 40506 (United States)
9. Kharkov Institute of Physics and Technology, Kharkov 310108 (Ukraine)
10. Kyungpook National University, Taegu 702-701 (Korea)
11. University of Maryland, College Park, Maryland 20742 (United States)
12. Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
13. University of New Hampshire, Durham, New Hampshire 03824 (United States)
14. Norfolk State University, Norfolk, Virginia 23504 (United States)
15. North Carolina Central University, Durham, North Carolina 27707 (United States)
16. Old Dominion University, Norfolk, Virginia 23508 (United States)
17. Princeton University, Princeton, New Jersey 08544 (United States)
18. University of Regina, Regina, SK S4S 0A2 (Canada)

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point [{l_angle}{theta}{sub lab }{r_angle}=12.3{degree} and {l_angle}Q{sup 2}{r_angle}=0.48 (GeV /c){sup 2} ] is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G{sup s}{sub E} . The result, A={minus}14.5{plus_minus}2.2 ppm , is consistent with the electroweak standard model and no additional contributions from strange quarks. In particular, the measurement implies G{sup s}{sub E}+0.39G{sup s}{sub M}=0.023 {plus_minus}0.034(stat){plus_minus}0.022( syst){plus_minus}0.026({delta}G{sup n}{sub E}) , where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 328559
• Journal Information: Physical Review Letters, Vol. 82, Issue 6; Other Information: PBD: Feb 1999
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
PROTONS
ELECTROMAGNETIC FORM FACTORS
P INVARIANCE
STANDARD MODEL
QUARKS
STRANGE PARTICLES
ELECTRON-PROTON INTERACTIONS
QUANTUM CHROMODYNAMICS