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Title: Precision Measurement of the p ( e , e ' p ) π 0 Reaction at Threshold

Abstract

New results are reported from a measurement of $$\pi^0$$ electroproduction near threshold using the p(e, e´p) π⁰ reaction. The experiment was designed to determine precisely the energy dependence of $s-$ and $p-$wave electromagnetic multipoles as a stringent test of the predictions of Chiral Perturbation Theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time, complete coverage of the $$\phi^*_{\pi}$$ and $$\theta^*_{\pi}$$ angles in the $$p \pi^0$$ center-of-mass was obtained for invariant energies above threshold from 0.5 MeV up to 15 MeV. The 4-momentum transfer $Q^2$ coverage ranges from 0.05 to 0.155 (GeV/c)$^2$ in fine steps. A simple phenomenological analysis of our data shows strong disagreement with $p-$wave predictions from ChPT for $Q^2>0.07$ (GeV/c)$^2$, while the $s-$wave predictions are in reasonable agreement.

Authors:
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Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Univ. of Virginia, Charlottesville, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Contributing Org.:
Jefferson Hall A Collaboration
OSTI Identifier:
1179440
Alternate Identifier(s):
OSTI ID: 1179742; OSTI ID: 1417863
Report Number(s):
JLAB/PHY-15-2013; DOE/OR-23177-3313
Journal ID: ISSN 0031-9007; PRLTAO; FG02-97ER41025; NSF MRI Award No. 021635; JLAB-E04-007; TRN: US1600762
Grant/Contract Number:  
FG02-97ER41025; AC05-06OR23177; 021635; SC0014325
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 114; Journal Issue: 19; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Chirapatpimol, K., Shabestari, M. H., Lindgren, R. A., Smith, L. C., Annand, J. R. M., Higinbotham, D. W., Moffit, B., Nelyubin, V., Norum, B. E., Allada, K., Aniol, K., Ardashev, K., Armstrong, D. S., Arndt, R. A., Benmokhtar, F., Bernstein, A. M., Bertozzi, W., Briscoe, W. J., Bimbot, L., Camsonne, A., Chen, J. -P., Choi, S., Chudakov, E., Cisbani, E., Cusanno, F., Dalton, M. M., Dutta, C., Egiyan, K., Fernàndez-Ramìrez, C., Feuerbach, R., Fissum, K. G., Frullani, S., Garibaldi, F., Gayou, O., Gilman, R., Gilad, S., Goity, J., Gomez, J., Hahn, B., Hamilton, D., Hansen, J. -O., Huang, J., Igarashi, R., Ireland, D., de Jager, C. W., Jin, X., Jiang, X., Jinasundera, T., Kellie, J., Keppel, C. E., Kolb, N., LeRose, J., Liyanage, N., Livingston, K., McNulty, D., Mercado, L., Michaels, R., Mihovilovič, M., Qian, S., Qian, X., Mailyan, S., Mamyan, V., Marrone, S., Monaghan, P., Nanda, S., Perdrisat, C. F., Piasetzky, E., Protopopescu, D., Punjabi, V., Qiang, Y., Rachek, I. A., Rakhman, A., Riordan, S., Ron, G., Rosner, G., Saha, A., Sawatzky, B., Shahinyan, A., Širca, S., Sparveris, N., Subedi, R. R., Suleiman, R., Strakovsky, I., Sulkosky, V., Moinelo, J., Voskanyan, H., Wang, K., Wang, Y., Watson, J., Watts, D., Wojtsekhowski, B., Workman, R. L., Yao, H., Zhan, X., and Zhang, Y. Precision Measurement of the p(e,e'p)π0 Reaction at Threshold. United States: N. p., 2015. Web. doi:10.1103/PhysRevLett.114.192503.
Chirapatpimol, K., Shabestari, M. H., Lindgren, R. A., Smith, L. C., Annand, J. R. M., Higinbotham, D. W., Moffit, B., Nelyubin, V., Norum, B. E., Allada, K., Aniol, K., Ardashev, K., Armstrong, D. S., Arndt, R. A., Benmokhtar, F., Bernstein, A. M., Bertozzi, W., Briscoe, W. J., Bimbot, L., Camsonne, A., Chen, J. -P., Choi, S., Chudakov, E., Cisbani, E., Cusanno, F., Dalton, M. M., Dutta, C., Egiyan, K., Fernàndez-Ramìrez, C., Feuerbach, R., Fissum, K. G., Frullani, S., Garibaldi, F., Gayou, O., Gilman, R., Gilad, S., Goity, J., Gomez, J., Hahn, B., Hamilton, D., Hansen, J. -O., Huang, J., Igarashi, R., Ireland, D., de Jager, C. W., Jin, X., Jiang, X., Jinasundera, T., Kellie, J., Keppel, C. E., Kolb, N., LeRose, J., Liyanage, N., Livingston, K., McNulty, D., Mercado, L., Michaels, R., Mihovilovič, M., Qian, S., Qian, X., Mailyan, S., Mamyan, V., Marrone, S., Monaghan, P., Nanda, S., Perdrisat, C. F., Piasetzky, E., Protopopescu, D., Punjabi, V., Qiang, Y., Rachek, I. A., Rakhman, A., Riordan, S., Ron, G., Rosner, G., Saha, A., Sawatzky, B., Shahinyan, A., Širca, S., Sparveris, N., Subedi, R. R., Suleiman, R., Strakovsky, I., Sulkosky, V., Moinelo, J., Voskanyan, H., Wang, K., Wang, Y., Watson, J., Watts, D., Wojtsekhowski, B., Workman, R. L., Yao, H., Zhan, X., & Zhang, Y. Precision Measurement of the p(e,e'p)π0 Reaction at Threshold. United States. doi:10.1103/PhysRevLett.114.192503.
Chirapatpimol, K., Shabestari, M. H., Lindgren, R. A., Smith, L. C., Annand, J. R. M., Higinbotham, D. W., Moffit, B., Nelyubin, V., Norum, B. E., Allada, K., Aniol, K., Ardashev, K., Armstrong, D. S., Arndt, R. A., Benmokhtar, F., Bernstein, A. M., Bertozzi, W., Briscoe, W. J., Bimbot, L., Camsonne, A., Chen, J. -P., Choi, S., Chudakov, E., Cisbani, E., Cusanno, F., Dalton, M. M., Dutta, C., Egiyan, K., Fernàndez-Ramìrez, C., Feuerbach, R., Fissum, K. G., Frullani, S., Garibaldi, F., Gayou, O., Gilman, R., Gilad, S., Goity, J., Gomez, J., Hahn, B., Hamilton, D., Hansen, J. -O., Huang, J., Igarashi, R., Ireland, D., de Jager, C. W., Jin, X., Jiang, X., Jinasundera, T., Kellie, J., Keppel, C. E., Kolb, N., LeRose, J., Liyanage, N., Livingston, K., McNulty, D., Mercado, L., Michaels, R., Mihovilovič, M., Qian, S., Qian, X., Mailyan, S., Mamyan, V., Marrone, S., Monaghan, P., Nanda, S., Perdrisat, C. F., Piasetzky, E., Protopopescu, D., Punjabi, V., Qiang, Y., Rachek, I. A., Rakhman, A., Riordan, S., Ron, G., Rosner, G., Saha, A., Sawatzky, B., Shahinyan, A., Širca, S., Sparveris, N., Subedi, R. R., Suleiman, R., Strakovsky, I., Sulkosky, V., Moinelo, J., Voskanyan, H., Wang, K., Wang, Y., Watson, J., Watts, D., Wojtsekhowski, B., Workman, R. L., Yao, H., Zhan, X., and Zhang, Y. Wed . "Precision Measurement of the p(e,e'p)π0 Reaction at Threshold". United States. doi:10.1103/PhysRevLett.114.192503. https://www.osti.gov/servlets/purl/1179440.
@article{osti_1179440,
title = {Precision Measurement of the p(e,e'p)π0 Reaction at Threshold},
author = {Chirapatpimol, K. and Shabestari, M. H. and Lindgren, R. A. and Smith, L. C. and Annand, J. R. M. and Higinbotham, D. W. and Moffit, B. and Nelyubin, V. and Norum, B. E. and Allada, K. and Aniol, K. and Ardashev, K. and Armstrong, D. S. and Arndt, R. A. and Benmokhtar, F. and Bernstein, A. M. and Bertozzi, W. and Briscoe, W. J. and Bimbot, L. and Camsonne, A. and Chen, J. -P. and Choi, S. and Chudakov, E. and Cisbani, E. and Cusanno, F. and Dalton, M. M. and Dutta, C. and Egiyan, K. and Fernàndez-Ramìrez, C. and Feuerbach, R. and Fissum, K. G. and Frullani, S. and Garibaldi, F. and Gayou, O. and Gilman, R. and Gilad, S. and Goity, J. and Gomez, J. and Hahn, B. and Hamilton, D. and Hansen, J. -O. and Huang, J. and Igarashi, R. and Ireland, D. and de Jager, C. W. and Jin, X. and Jiang, X. and Jinasundera, T. and Kellie, J. and Keppel, C. E. and Kolb, N. and LeRose, J. and Liyanage, N. and Livingston, K. and McNulty, D. and Mercado, L. and Michaels, R. and Mihovilovič, M. and Qian, S. and Qian, X. and Mailyan, S. and Mamyan, V. and Marrone, S. and Monaghan, P. and Nanda, S. and Perdrisat, C. F. and Piasetzky, E. and Protopopescu, D. and Punjabi, V. and Qiang, Y. and Rachek, I. A. and Rakhman, A. and Riordan, S. and Ron, G. and Rosner, G. and Saha, A. and Sawatzky, B. and Shahinyan, A. and Širca, S. and Sparveris, N. and Subedi, R. R. and Suleiman, R. and Strakovsky, I. and Sulkosky, V. and Moinelo, J. and Voskanyan, H. and Wang, K. and Wang, Y. and Watson, J. and Watts, D. and Wojtsekhowski, B. and Workman, R. L. and Yao, H. and Zhan, X. and Zhang, Y.},
abstractNote = {New results are reported from a measurement of $\pi^0$ electroproduction near threshold using the p(e, e´p) π⁰ reaction. The experiment was designed to determine precisely the energy dependence of $s-$ and $p-$wave electromagnetic multipoles as a stringent test of the predictions of Chiral Perturbation Theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time, complete coverage of the $\phi^*_{\pi}$ and $\theta^*_{\pi}$ angles in the $p \pi^0$ center-of-mass was obtained for invariant energies above threshold from 0.5 MeV up to 15 MeV. The 4-momentum transfer $Q^2$ coverage ranges from 0.05 to 0.155 (GeV/c)$^2$ in fine steps. A simple phenomenological analysis of our data shows strong disagreement with $p-$wave predictions from ChPT for $Q^2>0.07$ (GeV/c)$^2$, while the $s-$wave predictions are in reasonable agreement.},
doi = {10.1103/PhysRevLett.114.192503},
journal = {Physical Review Letters},
number = 19,
volume = 114,
place = {United States},
year = {2015},
month = {5}
}

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