المؤلفون: Ruth, D, Zielinski, R, Gu, C, Allada (Cummings), M, Badman, T, Huang, M, Liu, J, Zhu, P, Allada, K, Zhang, J, Camsonne, A, Chen, J-P, Slifer, K, Aniol, K, Annand, J, Arrington, J, Averett, T, Baghdasaryan, H, Bellini, V, Boeglin, W, Brock, J, Carlin, C, Chen, C, Cisbani, E, Crabb, D, Daniel, A, Day, D, Duve, R, Fassi, L El, Friedman, M, Fuchey, E, Gao, H, Gilman, R, Glamazdin, S, Gueye, P, Hafez, M, Han, Y, Hansen, O, Shabestari, M Hashemi, Hen, O, Higinbotham, D, Horn, T, Iqbal, S, Jensen, E, Kang, H, Keith, CD, Kelleher, A, Keller, D, Khanal, H, Korover, I, Kumbartzki, G, Li, W, Lichtenstadt, J, Lindgren, R, Long, E, Malace, S, Markowitz, P, Maxwell, J, Meekins, DM, Meziani, ZE, McLean, C, Michaels, R, Mihovilovič, M, Muangma, N, Camacho, C Munoz, Musson, J, Myers, K, Oh, Y, Carmignotto, M Pannunzio, Perdrisat, C, Phillips, S, Piasetzky, E, Pierce, J, Punjabi, V, Qiang, Y, Reimer, PE, Roblin, Y, Ron, G, Rondon, O, Russo, G, Saenboonruang, K, Sawatzky, B, Shahinyan, A, Shneor, R, Širca, S, Sjoegren, J, Solvignon-Slifer, P, Sparveris, N, Sulkosky, V, Wesselmann, F, Yan, W, Yang, H, Yao, H, Ye, Z, Yurov, M, Zhang, Y, Zhao, YX, Zheng, X

المصدر: Nature Physics. 18(12)

مصطلحات موضوعية: Mathematical Sciences, Physical Sciences, Fluids & Plasmas

الوصف: The strong interaction is not well understood at low energies or for interactions with low momentum transfer. Chiral perturbation theory gives testable predictions for the nucleonic generalized polarizabilities, which are fundamental quantities describing the nucleon’s response to an external field. We report a measurement of the proton’s generalized spin polarizabilities extracted with a polarized electron beam and a polarized solid ammonia target in the region where chiral perturbation theory is expected to be valid. The investigated structure function g2 characterizes the internal spin structure of the proton. From its moments, we extract the longitudinal–transverse spin polarizability δLT and twist-3 matrix element and polarizability d2¯. Our results provide discriminating power between existing chiral perturbation theory calculations and will help provide a better understanding of this strong quantum chromodynamics regime.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/5b9859fzTest

المؤلفون: Ruth, D., Zielinski, R., Gu, C., Allada, M., Badman, T., Huang, M., Liu, J., Zhu, P., Allada, K., Zhang, J., Camsonne, A., Chen, J. P., Slifer, K., Aniol, K., Annand, J., Arrington, J., Averett, T., Baghdasaryan, H., Bellini, V., Boeglin, W., Brock, J., Carlin, C., Chen, C., Cisbani, E., Crabb, D., Daniel, A., Day, D., Duve, R., Fassi, L. El, Friedman, M., Fuchey, E., Gao, H., Gilman, R., Glamazdin, S., Gueye, P., Hafez, M., Han, Y., Hansen, O., Shabestari, M. Hashemi, Hen, O., Higinbotham, D., Horn, T., Iqbal, S., Jensen, E., Kang, H., Keith, C. D., Kelleher, A., Keller, D., Khanal, H., Korover, I., Kumbartzki, G., Li, W., Lichtenstadt, J., Lindgren, R., Long, E., Malace, S., Markowitz, P., Maxwell, J., Meekins, D. M., Meziani, Z. E., McLean, C., Michaels, R., Mihovilovic, M., Muangma, N., Camacho, C. Munoz, Musson, J., Myers, K., Oh, Y., Carmignotto, M. Pannunzio, Perdrisat, C., Phillips, S., Piasetzky, E., Pierce, J., Punjabi, V., Qiang, Y., Reimer, P. E., Roblin, Y., Ron, G., Rondon, O., Russo, G., Saenboonruang, K., Sawatzky, B., Shahinyan, A., Shneor, R., Sjoegren, J., Solvignon-Slifer, P., Sparveris, N., Sulkosky, V., Wesselmann, F., Yan, W., Yang, H., Yao, H., Ye, Z., Yurov, M., Zhang, Y., Zhao, Y. X., Zheng, X.

مصطلحات موضوعية: Nuclear Experiment, High Energy Physics - Experiment

الوصف: The strong interaction is not well understood at low energy, or for interactions with low momentum transfer $Q^2$, but one of the clearest insights we have comes from Chiral Perturbation Theory ($\chi$PT). This effective treatment gives testable predictions for the nucleonic generalized polarizabilities -- fundamental quantities describing the nucleon's response to an external field. We have measured the proton's generalized spin polarizabilities in the region where $\chi$PT is expected to be valid. Our results include the first ever data for the transverse-longitudinal spin polarizability $\delta_{LT}$, and also extend the coverage of the polarizability $\bar{d_2}$ to very low $Q^2$ for the first time. These results were extracted from moments of the structure function $g_2$, a quantity which characterizes the internal spin structure of the proton. Our experiment ran at Jefferson Lab using a polarized electron beam and a polarized solid ammonia (NH$_3$) target. The $\delta_{LT}$ polarizability has remained a challenging quantity for $\chi$PT to reproduce, despite its reduced sensitivity to higher resonance contributions; recent competing calculations still disagree with each other and also diverge from the measured neutron data at very low $Q^2$. Our proton results provide discriminating power between existing calculations, and will help provide a better understanding of this strong QCD regime.

الوصول الحر: http://arxiv.org/abs/2204.10224Test

المؤلفون: Sulkosky, V., Peng, C., Chen, J. -P., Deur, A., Abrahamyan, S., Aniol, K. A., Armstrong, D. S., Averett, T., Bailey, S. L., Beck, A., Bertin, P., Butaru, F., Boeglin, W., Camsonne, A., Cates, G. D., Chang, C. C., Choi, Seonho, Chudakov, E., Coman, L., Cornejo, J. C, Craver, B., Cusanno, F., De Leo, R., de Jager, C. W., Denton, J. D., Dhamija, S., Feuerbach, R., Finn, J. M., Frullani, S., Fuoti, K., Gao, H., Garibaldi, F., Gayou, O., Gilman, R., Glamazdin, A., Glashausser, C., Gomez, J., Hansen, J. -O., Hayes, D., Hersman, B., Higinbotham, D. W., Holmstrom, T., Humensky, T. B., Hyde, C. E., Ibrahim, H., Iodice, M., Jiang, X., Kaufman, L. J., Kelleher, A., Keister, K. E., Kim, W., Kolarkar, A., Kolb, N., Korsch, W., Kramer, K., Kumbartzki, G., Lagamba, L., Laine, V., Laveissiere, G., Lerose, J. J., Lhuillier, D., Lindgren, R., Liyanage, N., Lu, H. -J., Ma, B., Margaziotis, D. J., Markowitz, P., McCormick, K., Meziane, M., Meziani, Z. -E., Michaels, R., Moffit, B., Monaghan, P., Nanda, S., Niedziela, J., Niskin, M., Pandolfi, R., Paschke, K. D., Potokar, M., Puckett, A., Punjabi, V. A., Qiang, Y., Ransome, R., Reitz, B., Roche, R., Saha, A., Shabetai, A., Sirca, S., Singh, J. T., Slifer, K., Snyder, R., Solvignon, P., Stringer, R., Subedi, R., Tobias, W. A., Ton, N., Ulmer, P. E., Urciuoli, G. M., Vacheret, A., Voutier, E., Wang, K., Wan, L., Wojtsekhowski, B., Woo, S., Yao, H., Yuan, J., Zhan, X., Zheng, X., Zhu, L.

المصدر: Nature Physics, Vol. 17 687-692 (2021)

مصطلحات موضوعية: Nuclear Experiment

الوصف: Understanding the nucleon spin structure in the regime where the strong interaction becomes truly strong poses a challenge to both experiment and theory. At energy scales below the nucleon mass of about 1 GeV, the intense interaction among the quarks and gluons inside the nucleon makes them highly correlated. Their coherent behaviour causes the emergence of effective degrees of freedom, requiring the application of non-perturbative techniques, such as chiral effective field theory. Here, we present measurements of the neutron's generalized spin-polarizabilities that quantify the neutron's spin precession under electromagnetic fields at very low energy-momentum transfer squared down to 0.035 GeV$^2$. In this regime, chiral effective field theory calculations are expected to be applicable. Our data, however, show a strong discrepancy with these predictions, presenting a challenge to the current description of the neutron's spin properties.
Comment: V1: initial version submitted to Nature Physics. V2: Published version. 16 pages, 7 figures. Additional material: 4 data tables (18 pages) V3: Typo corrected in author list. Paper content unchanged

الوصول الحر: http://arxiv.org/abs/2103.03333Test

المؤلفون: Wijesooriya, K, Afanasev, A, Amarian, M, Aniol, K, Becher, S, Benslama, K, Bimbot, L, Bosted, P, Brash, E, Calarco, J, Chai, Z, Chang, C C, Chang, T, Chen, J P, Choi, S, Chudakov, E, Churchwell, S, Crovelli, D, Dieterich, S, Dumalski, S, Dutta, D, Epstein, M, Fissum, K, Fox, B, Frullani, S, Gao, H, Gao, J, Garibaldi, F, Gayou, O, Gilman, R, Glamazdin, S, Glashausser, C, Gomez, J, Gorbenko, V, Hansen, O, Holt, R J, Hovdebo, J, Huber, G M, De Jager, C W, Jiang, X, Jones, C, Jones, M K, Kelly, J, Kinney, E, Kooijman, E, Kumbartzki, G, Kuss, M, LeRose, J, Liang, M, Lindgren, R, Liyanage, N, Malov, S, Margaziotis, D J, Markowitz, P, McCormick, K, Meekins, D, Meziani, Z E, Michaels, R, Mitchell, J, Morand, L, Perdrisat, C F, Pomatsalyuk, R, Punjabi, V, Ransome, R D, Roche, R, Rvachev, M, Saha, A, Sarty, A, Schulte, E C, Simon, Daniel, Strauch, S, Suleiman, R, Todor, L, Ulmer, P E, Urciuoli, G M, Wojtsekhowski, B, Xiong, F, Xu, W

الوصف: We present measurements of the recoil proton polarization for the d(γ⃗,p⃗)n reaction at θc.m. = 90° for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization py vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(γ,p)ncross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.

وصف الملف: application/pdf

العلاقة: Physical Review Letters, 0031-9007, 2001, 86:14, s. 2975-2979

الإتاحة: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-94197Test

المؤلفون: Sulkosky, V., Singh, J. T., Peng, C., Chen, J. -P., Deur, A., Abrahamyan, S., Aniol, K. A., Armstrong, D. S., Averett, T., Bailey, S. L., Beck, A., Bertin, P., Butaru, F., Boeglin, W., Camsonne, A., Cates, G. D., Chang, C. C., Choi, Seonho, Chudakov, E., Coman, L., Cornejo, J. C, Craver, B., Cusanno, F., De Leo, R., de Jager, C. W., Denton, J. D., Dhamija, S., Feuerbach, R., Finn, J. M., Frullani, S., Fuoti, K., Gao, H., Garibaldi, F., Gayou, O., Gilman, R., Glamazdin, A., Glashausser, C., Gomez, J., Hansen, J. -O., Hayes, D., Hersman, B., Higinbotham, D. W., Holmstrom, T., Humensky, T. B., Hyde, C. E., Ibrahim, H., Iodice, M., Jiang, X., Kaufman, L. J., Kelleher, A., Keister, K. E., Kim, W., Kolarkar, A., Kolb, N., Korsch, W., Kramer, K., Kumbartzki, G., Lagamba, L., Laine, V., Laveissiere, G., Lerose, J. J., Lhuillier, D., Lindgren, R., Liyanage, N., Lu, H. -J., Ma, B., Margaziotis, D. J., Markowitz, P., McCormick, K., Meziane, M., Meziani, Z. -E., Michaels, R., Moffit, B., Monaghan, P., Nanda, S., Niedziela, J., Niskin, M., Pandolfi, R., Paschke, K. D., Potokar, M., Puckett, A., Punjabi, V. A., Qiang, Y., Ransome, R., Reitz, B., Roche, R., Saha, A., Shabetai, A., Sirca, S., Slifer, K., Snyder, R., Solvignon, P., Stringer, R., Subedi, R., Tobias, W. A., Ton, N., Ulmer, P. E., Urciuoli, G. M., Vacheret, A., Voutier, E., Wang, K., Wan, L., Wojtsekhowski, B., Woo, S., Yao, H., Yuan, J., Zhan, X., Zheng, X., Zhu, L.

المصدر: Phys.Lett.B 805 135428 (2020)

مصطلحات موضوعية: Nuclear Experiment, High Energy Physics - Experiment

الوصف: The spin-structure functions $g_1$ and $g_2$, and the spin-dependent partial cross-section $\sigma_\mathrm{TT}$ have been extracted from the polarized cross-sections differences, $\Delta \sigma_{\parallel}\hspace{-0.06cm}\left(\nu,Q^{2}\right)$ and $\Delta \sigma_{\perp}\hspace{-0.06cm}\left(\nu,Q^{2}\right)$ measured for the $\vec{^\textrm{3}\textrm{He}}(\vec{\textrm{e}},\textrm{e}')\textrm{X}$ reaction, in the E97-110 experiment at Jefferson Lab. Polarized electrons with energies from 1.147 to 4.404 GeV were scattered at angles of 6$^{\circ}$ and 9$^{\circ}$ from a longitudinally or transversely polarized $^{3}$He target. The data cover the kinematic regions of the quasi-elastic, resonance production and beyond. From the extracted spin-structure functions, the first moments $\overline{\Gamma_1}\hspace{-0.06cm}\left(Q^{2}\right)$, $\Gamma_2\hspace{-0.06cm}\left(Q^{2}\right)$ and $I_{\mathrm{TT}}\hspace{-0.06cm}\left(Q^{2}\right)$ are evaluated with high precision for the neutron in the $Q^2$ range from 0.035 to 0.24~GeV$^{2}$. The comparison of the data and the chiral effective field theory predictions reveals the importance of proper treatment of the $\Delta$ degree of freedom for spin observables.
Comment: 7 pages, 5 figures, 3 tables. Version published in Phys. Lett. B

الوصول الحر: http://arxiv.org/abs/1908.05709Test

المؤلفون: Guèye, P, Kabir, AA, Giuliani, P, Glister, J, Lee, BW, Gilman, R, Higinbotham, DW, Piasetzky, E, Ron, G, Sarty, AJ, Strauch, S, Adeyemi, A, Allada, K, Armstrong, W, Arrington, J, Arenaövel, H, Beck, A, Benmokhtar, F, Berman, BL, Boeglin, W, Brash, E, Camsonne, A, Calarco, J, Chen, JP, Choi, S, Chudakov, E, Coman, L, Craver, B, Cusanno, F, Dumas, J, Dutta, C, Feuerbach, R, Freyberger, A, Frullani, S, Garibaldi, F, Hansen, J-O, Holmstrom, T, Hyde, CE, Ibrahim, H, Ilieva, Y, Jiang, X, Jones, MK, Katramatou, AT, Kelleher, A, Khrosinkova, E, Kuchina, E, Kumbartzki, G, LeRose, JJ, Lindgren, R, Markowitz, P, Beck, S May-Tal, McCullough, E, Meekins, D, Meziane, M, Meziani, Z-E, Michaels, R, Moffit, B, Norum, BE, Petratos, GG, Oh, Y, Olson, M, Paolone, M, Paschke, K, Perdrisat, CF, Potokar, M, Pomatsalyuk, R, Pomerantz, I, Puckett, A, Punjabi, V, Qian, X, Qiang, Y, Ransome, RD, Reyhan, M, Roche, J, Rousseau, Y, Sawatzky, B, Schulte, E, Schwamb, M, Shabestari, M, Shahinyan, A, Shneor, R, Širca, S, Slifer, K, Solvignon, P, Song, J, Sparks, R, Subedi, R, Urciuoli, GM, Wang, K, Wojtsekhowski, B, Yan, X, Yao, H, Zhan, X, Zhu, X

المصدر: The European Physical Journal A. 56(9)

مصطلحات موضوعية: Affordable and Clean Energy, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics

الوصف: In the original PDF online version of this article, the references 22–26 were missing.These are the missing references.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/996843fdTest

المؤلفون: Guèye, P, Kabir, AA, Giuliani, P, Glister, J, Lee, BW, Gilman, R, Higinbotham, DW, Piasetzky, E, Ron, G, Sarty, AJ, Strauch, S, Adeyemi, A, Allada, K, Armstrong, W, Arrington, J, Arenaövel, H, Beck, A, Benmokhtar, F, Berman, BL, Boeglin, W, Brash, E, Camsonne, A, Calarco, J, Chen, JP, Choi, S, Chudakov, E, Coman, L, Craver, B, Cusanno, F, Dumas, J, Dutta, C, Feuerbach, R, Freyberger, A, Frullani, S, Garibaldi, F, Hansen, J-O, Holmstrom, T, Hyde, CE, Ibrahim, H, Ilieva, Y, Jiang, X, Jones, MK, Katramatou, AT, Kelleher, A, Khrosinkova, E, Kuchina, E, Kumbartzki, G, LeRose, JJ, Lindgren, R, Markowitz, P, Beck, S May-Tal, McCullough, E, Meekins, D, Meziane, M, Meziani, Z-E, Michaels, R, Moffit, B, Norum, BE, Petratos, GG, Oh, Y, Olson, M, Paolone, M, Paschke, K, Perdrisat, CF, Potokar, M, Pomatsalyuk, R, Pomerantz, I, Puckett, A, Punjabi, V, Qian, X, Qiang, Y, Ransome, RD, Reyhan, M, Roche, J, Rousseau, Y, Sawatzky, B, Schulte, E, Schwamb, M, Shabestari, M, Shahinyan, A, Shneor, R, Širca, S, Slifer, K, Solvignon, P, Song, J, Sparks, R, Subedi, R, Urciuoli, GM, Wang, K, Wojtsekhowski, B, Yan, X, Yao, H, Zhan, X, Zhu, X

المصدر: The European Physical Journal A. 56(5)

مصطلحات موضوعية: nucl-ex, nucl-th, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics

الوصف: Measurements of elastic electron scattering data within the past decade have highlighted two-photon exchange contributions as a necessary ingredient in theoretical calculations to precisely evaluate hydrogen elastic scattering cross sections. This correction can modify the cross section at the few percent level. In contrast, dispersive effects can cause significantly larger changes from the Born approximation. The purpose of this experiment is to extract the carbon-12 elastic cross section around the first diffraction minimum, where the Born term contributions to the cross section are small to maximize the sensitivity to dispersive effects. The analysis uses the LEDEX data from the high resolution Jefferson Lab Hall A spectrometers to extract the cross sections near the first diffraction minimum of 12C at beam energies of 362 MeV and 685 MeV. The results are in very good agreement with previous world data, although with less precision. The average deviation from a static nuclear charge distribution expected from linear and quadratic fits indicate a 30.6% contribution of dispersive effects to the cross section at 1 GeV. The magnitude of the dispersive effects near the first diffraction minimum of 12C has been confirmed to be large with a strong energy dependence and could account for a large fraction of the magnitude for the observed quenching of the longitudinal nuclear response. These effects could also be important for nuclei radii extracted from parity-violating asymmetries measured near a diffraction minimum.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/3qx4d61vTest

المؤلفون: Gueye, P., Glister, A. A. Kabir J., Lee, B. W., Gilman, R., Higinbotham, D. W., Piasetzky, E., Ron, G., Sarty, A. J., Strauch, S., Adeyemi, A., Allada, K., Armstrong, W., Arrington, J., Arenhovel, H., Beck, A., Benmokhtar, F., Berman, B. L., Boeglin, W., Brash, E., Camsonne, A., Calarco, J., Chen, J. P., Choi, S., Chudakov, E., Coman, L., Craver, B., Cusanno, F., Dumas, J., Dutta, C., Feuerbach, R., Freyberger, A., Frullani, S., Garibaldi, F., Hansen, J. -O., Holmstrom, T., Hyde, C. E., Ibrahim, H., Ilieva, Y., Jiang, X., Jones, M. K., Katramatou, A. T., Kelleher, A., Khrosinkova, E., Kuchina, E., Kumbartzki, G., LeRose, J. J., Lindgren, R., Markowitz, P., Beck, S. May-Tal, McCullough, E., Meekins, D., Meziane, M., Meziani, Z. -E., Michaels, R., Moffit, B., Norum, B. E., Petratos, G. G., Oh, Y., Olson, M., Paolone, M., Paschke, K., Perdrisat, C. F., Potokar, M., Pomatsalyuk, R., Pomerantz, I., Puckett, A., Punjabi, V., Qian, X., Qiang, Y., Ransome, R. D., Reyhan, M., Roche, J., Rousseau, Y., Sawatzky, B., Schulte, E., Schwamb, M., Shabestari, M., Shahinyan, A., Shneor, R., Sirca, S., Slifer, K., Solvignon, P., Song, J., Sparks, R., Subedi, R., Urciuoli, G. M., Wang, K., Wojtsekhowski, B., Yan, X., Yao, H., Zhan, X., Zhu, X.

المصدر: Eur. Phys. J. A 56 (2020) 126

مصطلحات موضوعية: Nuclear Experiment, Nuclear Theory

الوصف: Measurements of elastic electron scattering data within the past decade have highlighted two-photon exchange contributions as a necessary ingredient in theoretical calculations to precisely evaluate hydrogen elastic scattering cross sections. This correction can modify the cross section at the few percent level. In contrast, dispersive effects can cause significantly larger changes from the Born approximation. The purpose of this experiment is to extract the carbon-12 elastic cross section around the first diffraction minimum, where the Born term contributions to the cross section are small to maximize the sensitivity to dispersive effects. The analysis uses the LEDEX data from the high resolution Jefferson Lab Hall A spectrometers to extract the cross sections near the first diffraction minimum of 12C at beam energies of 362 MeV and 685 MeV. The results are in very good agreement with previous world data, although with less precision. The average deviation from a static nuclear charge distribution expected from linear and quadratic fits indicate a 30.6% contribution of dispersive effects to the cross section at 1 GeV. The magnitude of the dispersive effects near the first diffraction minimum of 12C has been confirmed to be large with a strong energy dependence and could account for a large fraction of the magnitude for the observed quenching of the longitudinal nuclear response. These effects could also be important for nuclei radii extracted from parity-violating asymmetries measured near a diffraction minimum.
Comment: 14 pages, 10 figures

الوصول الحر: http://arxiv.org/abs/1805.12441Test

المؤلفون: Gilman, R., Downie, E. J., Ron, G., Strauch, S., Afanasev, A., Akmal, A., Arrington, J., Atac, H., Ayerbe-Gayoso, C., Benmokhtar, F., Benmouna, N., Bernauer, J., Blomberg, A., Briscoe, W. J., Cioffi, D., Cline, E., Cohen, D., Cohen, E. O., Collicott, C., Deiters, K., Diefenbach, J., Dongwi, B., Ghosal, D., Golossanov, A., Gothe, R., Higinbotham, D., Hornidge, D., Ilieva, Y., Kalantarians, N., Kohl, M., Krusche, B., Kumbartzki, G., Lavrukhin, I., Li, L., Lichtenstadt, J., Lin, W., Liyanage, A., Lorenzon, W., Mesick, K. E., Meziani, Z. -E., Mohanmurthy, P., Moran, P., Nazeer, J., Piasetzsky, E., Ransome, R., Raymond, R., Reggiani, D., Reimer, P. E., Richter, A., Rostomyan, T., Roy, P., Sarty, A., Shamai, Y., Sparveris, N., Steinberg, N., Strakovsky, I., Sulkosky, V., Tadepalli, A. S., Taragin, M.

مصطلحات موضوعية: Physics - Instrumentation and Detectors, Nuclear Experiment

الوصف: The difference in proton radii measured with $\mu p$ atoms and with $ep$ atoms and scattering remains an unexplained puzzle. The PSI MUSE proposal is to measure $\mu p$ and $e p$ scattering in the same experiment at the same time. The experiment will determine cross sections, two-photon effects, form factors, and radii independently for the two reactions, and will allow $\mu p$ and $ep$ results to be compared with reduced systematic uncertainties. These data should provide the best test of lepton universality in a scattering experiment to date, about an order of magnitude improvement over previous tests. Measuring scattering with both particle polarities will allow a test of two-photon exchange at the sub-percent level, about a factor of four improvement on uncertainties and over an order of magnitude more data points than previous low momentum transfer determinations, and similar to the current generation of higher momentum transfer electron experiments. The experiment has the potential to demonstrate whether the $\mu p$ and $ep$ interactions are consistent or different, and whether any difference results from novel physics or two-photon exchange. The uncertainties are such that if the discrepancy is real it should be confirmed with $\approx$5$\sigma$ significance, similar to that already established between the regular and muonic hydrogen Lamb shift.

الوصول الحر: http://arxiv.org/abs/1709.09753Test

المؤلفون: Puckett, AJR, Brash, EJ, Jones, MK, Luo, W, Meziane, M, Pentchev, L, Perdrisat, CF, Punjabi, V, Wesselmann, FR, Afanasev, A, Ahmidouch, A, Albayrak, I, Aniol, KA, Arrington, J, Asaturyan, A, Baghdasaryan, H, Benmokhtar, F, Bertozzi, W, Bimbot, L, Bosted, P, Boeglin, W, Butuceanu, C, Carter, P, Chernenko, S, Christy, ME, Cornejo, JC, Covrig, S, Danagoulian, S, Daniel, A, Davidenko, A, Day, D, Dhamija, S, Dutta, D, Ent, R, Frullani, S, Fenker, H, Frlez, E, Garibaldi, F, Gaskell, D, Gilad, S, Gilman, R, Goncharenko, Y, Hafidi, K, Hamilton, D, Higinbotham, DW, Hinton, W, Horn, T, Hu, B, Huang, J, Huber, GM, Jensen, E, Keppel, C, Khandaker, M, King, P, Kirillov, D, Kohl, M, Kravtsov, V, Kumbartzki, G, Li, Y, Mamyan, V, Margaziotis, DJ, Marsh, A, Matulenko, Y, Maxwell, J, Mbianda, G, Meekins, D, Melnik, Y, Miller, J, Mkrtchyan, A, Mkrtchyan, H, Moffit, B, Moreno, O, Mulholland, J, Narayan, A, Nedev, S, Nuruzzaman, Piasetzky, E, Pierce, W, Piskunov, NM, Prok, Y, Ransome, RD, Razin, DS, Reimer, P, Reinhold, J, Rondon, O, Shabestari, M, Shahinyan, A, Shestermanov, K, Širca, S, Sitnik, I, Smykov, L, Smith, G, Solovyev, L, Solvignon, P, Subedi, R, Tomasi-Gustafsson, E, Vasiliev, A, Veilleux, M, Wojtsekhowski, BB, Wood, S

مصطلحات موضوعية: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Proton form factors, Magnetic spectrometer, Electromagnetic calorimeter, Proton polarimeter, Polarization transfer method, Spin transport, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Other Physical Sciences, Nuclear & Particles Physics, Nuclear and plasma physics

الوصف: The GEp-III and GEp-2γ experiments, carried out in Jefferson Lab's Hall C from 2007–2008, consisted of measurements of polarization transfer in elastic electron–proton scattering at momentum transfers of Q2=2.5,5.2,6.8, and 8.54 GeV 2. These measurements were carried out to improve knowledge of the proton electromagnetic form factor ratio R=μpGEp∕GMp at large values of Q2 and to search for effects beyond the Born approximation in polarization transfer observables at Q2=2.5GeV2. The final results of both experiments were reported in a recent archival publication. A full reanalysis of the data from both experiments was carried out in order to reduce the systematic and, for the GEp-2γ experiment, statistical uncertainties. This technical note provides additional details of the final analysis omitted from the main publication, including the final evaluation of the systematic uncertainties.

الوصول الحر: https://escholarship.org/uc/item/6wg3v5gvTest