Measurement of the Generalized Polarizabilities of the Proton in Virtual Compton Scattering at Q2=0.92 and 1.76   G e V 2

• Published in: Physical review letters 2004-09, Vol.93 (12)
• Main Authors: Todor, L., Degrande, N., Jutier, C., Di Salvo, R., Van Hoorebeke, L., Arundell, K., Audit, G., Baylac, M., Bertin, P. Y., Bertozzi, W., Boeglin, W. U., Breuer, H., Burtin, E., Calarco, J. R., Cardman, L. S., Cavata, C., Chang, C. -C., Cisbani, E., Dale, D. S., De Leo, R., d'Hose, N., Elouadrhiri, L., Epstein, M. B., Fissum, K. G., Fonvieille, H., Fournier, G., Frois, B., Gao, H., Gao, J., Gasparian, A., Gilad, S., Gilman, R., Glamazdin, A., Glashausser, C., Gorbenko, V., Grenier, P., Holmes, R., Holtrop, M., Hyde-Wright, C. E., Iodice, M., Jones, M. K., Kato, S., Katramatou, A. T., Kelly, J. J., Kerhoas, S., Ketikyan, A., Kino, K., Kox, S., Kuss, M., Leone, A., LeRose, J. J., Liyanage, N., Lolos, G. J., Manley, D. M., Marchand, C., Margaziotis, D. J., Markowitz, P., Marroncle, J., Martino, J., McIntyre, J., Mehrabyan, S., Meziani, Z. E., Miller, G. W., Nanda, S. K., Offermann, E. A. J. M., Papandreou, Z., Pasquini, B., Perdrisat, C. F., Perrino, R., Petratos, G. G., Platchkov, S., Pomatsalyuk, R., Punjabi, V. A., Pussieux, T., Ransome, R. D., Ravel, O., Real, J. S., Renard, F., Rowntree, D., Rutledge, G., Rutt, P. M., Saha, A., Smith, T., Smirnov, G., Soldi, K., Sorokin, P., Souder, P. A., Templon, J. A., Tieulent, R., Ulmer, P. E., Van der Meer, R. L. J., Vernin, P., Vlahovic, B., Voutier, E., Wijesooriya, K., Wilson, R., Wojtsekhowski, B. B., Zainea, D. G., Zhao, J., Zhou, Z. -L.
• Format: Article
• Language: English
• Subjects: CLOUDS; COMPTON EFFECT; DIPOLES; GLOBAL POSITIONING SYSTEM; MOMENTUM TRANSFER; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PIONS; PROTONS; STRUCTURE FUNCTIONS
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.93.122001

We report a Virtual Compton Scattering study of the proton at low CM energies. We have determined the structure functions P{sub LL} - P{sub TT}/{epsilon} and P{sub LT}, and the electric and magnetic Generalized Polarizabilities (GPs) {alpha}{sub E}(Q{sup 2}) and {beta}{sub M}(Q{sup 2}) at momentum transfer Q{sup 2} = 0.92 and 1.76 GeV{sup 2}. The electric GP shows a strong fall-off with Q{sup 2}, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a fall-off; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q{sup 2}, compensated at higher Q{sup 2} by a paramagnetic contribution from {pi}N intermediate states.