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7 results on '"Tang, L. -G."'

1. Exclusive $��^+$ electroproduction off the proton from low to high -t

Author

Basnet, S., Huber, G. M., Li, W. B., Blok, H. P., Gaskell, D., Horn, T., Aniol, K., Arrington, J., Beise, E. J., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Ent, R., Gibson, E., Holt, R. J., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P., Reinhold, J., Roche, J., Sarty, A., Smith, G. R., Tadevosyan, V., Tang, L. G., Tvaskis, V., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between non-perturbative and perturbative Quantum Chromodyanmics as the square of four momentum transfer to the struck proton, -t, is increased. Method: Cross sections for the $^1$H(e,e'$��^+$)n reaction were measured over the -t range of 0.272 to 2.127 GeV$^2$ with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q$^2$ of 2.4 GeV$^2$ and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The -t dependence of the measured $��^+$ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude based theoretical model, but show poor agreement with a Generalized Parton Distribution (GPD) based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t-slopes between the low and high -t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime., 9 pages, 5 figures Physical Review C, in press

Published
2019
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2. Double Spin Asymmetries of Inclusive Hadron Electroproductions from a Transversely Polarized $^3\rm{He}$ Target

Author

The Jefferson Lab Hall A Collaboration, Zhao, Y. X., Allada, K., Aniol, K., Annand, J. R. M., Averett, T., Benmokhtar, F., Bertozzi, W., Bradshaw, P. C., Bosted, P., Camsonne, A., Canan, M., Cates, G. D., Chen, C., Chen, J. -P., Chen, W., Chirapatpimol, K., Chudakov, E., Cisbani, E., Cornejo, J. C., Cusanno, F., Dalton, M., Deconinck, W., de Jager, C. W., De Leo, R., Deng, X., Deur, A., Ding, H., Dolph, P. A. M., Dutta, C., Dutta, D., Fassi, L. El, Frullani, S., Gao, H., Garibaldi, F., Gaskell, D., Gilad, S., Gilman, R., Glamazdin, O., Golge, S., Guo, L., Hamilton, D., Hansen, O., Higinbotham, D. W., Holmstrom, T., Huang, J., Huang, M., Ibrahim, H. F, Iodice, M., Jiang, X., Jin, G., Jones, M. K., Katich, J., Kelleher, A., Kim, W., Kolarkar, A., Korsch, W., LeRose, J. J., Li, X., Li, Y., Lindgren, R., Liyanage, N., Long, E., Lu, H. -J., Margaziotis, D. J., Markowitz, P., Marrone, S., McNulty, D., Meziani, Z. -E., Michaels, R., Moffit, B., Camacho, C. Muñoz, Nanda, S., Narayan, A., Nelyubin, V., Norum, B., Oh, Y., Osipenko, M., Parno, D., Peng, J. -C., Phillips, S. K., Posik, M., Puckett, A. J. R., Qian, X., Qiang, Y., Rakhman, A., Ransome, R., Riordan, S., Saha, A., Sawatzky, B., Schulte, E., Shahinyan, A., Shabestari, M. H., Širca, S., Stepanyan, S., Subedi, R., Sulkosky, V., Tang, L. -G., Tobias, W. A., Urciuoli, G. M., Vilardi, I., Wang, K., Wojtsekhowski, B., Wang, Y., Yan, X., Yao, H., Ye, Y., Ye, Z., Yuan, L., Zhan, X., Zhang, Y., Zhang, Y. -W., Zhao, B., Zheng, X., Zhu, L., Zhu, X., and Zong, X.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report the measurement of beam-target double-spin asymmetries ($A_\text{LT}$) in the inclusive production of identified hadrons, $\vec{e}~$+$~^3\text{He}^{\uparrow}\rightarrow h+X$, using a longitudinally polarized 5.9 GeV electron beam and a transversely polarized $^3\rm{He}$ target. Hadrons ($\pi^{\pm}$, $K^{\pm}$ and proton) were detected at 16$^{\circ}$ with an average momentum $$=2.35 GeV/c and a transverse momentum ($p_{T}$) coverage from 0.60 to 0.68 GeV/c. Asymmetries from the $^3\text{He}$ target were observed to be non-zero for $\pi^{\pm}$ production when the target was polarized transversely in the horizontal plane. The $\pi^{+}$ and $\pi^{-}$ asymmetries have opposite signs, analogous to the behavior of $A_\text{LT}$ in semi-inclusive deep-inelastic scattering., Comment: Published in PRC (92.015207), nuclear experiment, high-energy experiment

Published
2015
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3. Separated Response Functions in Exclusive, Forward $��^{\pm}$ Electroproduction on Deuterium

Author

Huber, G. M., Blok, H. P., Butuceanu, C., Gaskell, D., Horn, T., Mack, D. J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Beise, E. J., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E. F., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P. E., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tadevosyan, V., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., Zihlmann, B., and Collaboration, The Jefferson Lab Fpi

Subjects
FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, $Q^2$, and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in $��^-$ and $��^+$ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Method: Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at W=1.95 GeV, and $Q^2$=2.45 GeV$^2$ at W=2.22 GeV. There was significant coverage in $��$ and $��$, which allowed separation of $��_{L,T,LT,TT}$. Results: $��_L$ shows a clear signature of the pion pole, with a sharp rise at small -t. In contrast, $��_T$ is much flatter versus t. The longitudinal/transverse ratios evolve with $Q^2$ and t, and at the highest $Q^2$=2.45 GeV$^2$ show a slight enhancement for $��^-$ production compared to $��^+$. The $��^-/��^+$ ratio for transverse photons exhibits only a small $Q^2$-dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The $��_{TT}/��_T$ ratio also drops rapidly with $Q^2$, qualitatively consistent with s-channel helicity conservation. The $��^-/��^+$ ratio for longitudinal photons indicates a small isoscalar contamination at W=1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics., 25 pages, 16 figures, 6 tables

Published
2014
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4. Charged pion form factor between $Q^2$=0.60 and 2.45 GeV$^2$. I. Measurements of the cross section for the ${^1}$H($e,e'��^+$)$n$ reaction

Author

Blok, H. P., Horn, T., Huber, G. M., Beise, E. J., Gaskell, D., Mack, D. J., Tadevosyan, V., Volmer, J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract

Cross sections for the reaction ${^1}$H($e,e'��^+$)$n$ were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the CEBAF high-intensity, continous electron beam in order to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from $Q^2$=0.60 to 2.45 GeV$^2$ at an invariant mass of the virtual photon-nucleon system of $W$=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions $��_L$, $��_T$, $��_{LT}$, and $��_{TT}$. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable $t$ at the different values of $Q^2$ are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction ${^1}$H($e,e'��^+$)$n$., 26 pages, 23 figures

Published
2008
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5. Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2

Author

Fpi2 collaboration, Horn, T., Aniol, K., Arrington, J., Barrett, B., Beise, E. J., Blok, H. P., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Ent, R., Gaskell, D., Gibson, E., Holt, R. J., Huber, G. M., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Smith, G. R., Tadevosyan, V., Tang, L. G., Tvaskis, V., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.

Subjects
High Energy Physics::Lattice, Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F_pi) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F_pi is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative Quantum Chromo-Dynamics prediction., Comment: 4 pages, 3 figures, submitted to Physical Review Letters

Published
2006
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6. Determination of the pion charge form factor for Q^2=0.60-1.60 GeV^2

Author

collaboration, The Fpi-1, Tadevosyan, V., Blok, H. P., Huber, G. M., Abbott, D., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Bochna, C., Brash, E. J., Breuer, H., Chant, N., Dunne, J., Eden, T., Ent, R., Gaskell, D., Gilman, R., Gustafsson, K., Hinton, W., Jackson, H., Jones, M. K., Keppel, C., Kim, P. H., Kim, W., Klein, A., Koltenuk, D., Liang, M., Lolos, G. J., Lung, A., Mack, D. J., McKee, D., Meekins, D., Mitchell, J., Mkrtchyan, H., Mueller, B., Niculescu, G. Niculescu I., Pitz, D., Potterveld, D., Qin, L. M., Reinhold, J., Shin, I. K., Stepanyan, S., Tang, L. G., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Volmer, J., Vulcan, W., Wood, S., Yan, C., Zhao, W. -X., and Zihlmann, B.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The data analysis for the reaction H(e,e' pi^+)n, which was used to determine values for the charged pion form factor Fpi for values of Q^2=0.6-1.6 GeV^2, has been repeated with careful inspection of all steps and special attention to systematic uncertainties. Also the method used to extract Fpi from the measured longitudinal cross section was critically reconsidered. Final values for the separated longitudinal and transverse cross sections and the extracted values of Fpi are presented., Comment: 11 pages, 6 figures

Published
2006
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7. Search for the Production of a New Quark Flavor at the c.m.-System Energies between 33 and 35.8 GeV

Author

Barber, D. P., Becker, U., Chen, M., Cheng, C. P., Chu, Y. S., Clare, R., Duinker, P., Fang, G. Y., Fesefeldt, H., Fong, D., Fukushima, M., Guo, J. C., Benda, H., Hariri, A., Herten, G., Ho, M. C., Hsu, H. K., Hsu, T. T., Kadel, R. W., Krenz, W., Li, J., Li, Q. Z., Lu, M., Bohm, A., Luckey, David, Ma, C. M., Ma, D. A., Massaro, G. G. G., Matsuda, T., Newman, H., Pohl, M., Poschmann, F. P., Revol, J. P., Rohde, M., Branson, J. G., Rykaczewski, H., Sinram, K., Tang, H. W., Tang, L. G., Ting, Samuel C. C., Tung, K. L., Vannucci, F., Wang, X. R., Wei, P. S., White, M., Bron, J., Wu, G. H., Wu, T. W., Xi, J. P., Yang, P. C., Yu, C. C., Yu, X. H., Zhang, N. L., Zhu, R. Y., Mark-J Collaboration, Buikman, D., Burger, J. D., Chang, C. C., and Chen, H. S.

Subjects
Quark, Particle physics, MUON [ELECTROPRODUCTION], High Energy Physics::Lattice, Electron–positron annihilation, Hadron, General Physics and Astronomy, DESY PETRA STOR, Elementary particle, TOTAL CROSS SECTION [RATIO], SPECTRUM [THRUST], Nuclear physics, ELECTROPRODUCTION [HADRON], TOTAL CROSS SECTION [ENERGY DEPENDENCE], ddc:550, TOP [SEARCH FOR], ELECTROPRODUCTION [MUON], THRUST [SPECTRUM], Nuclear Experiment, EXPERIMENTAL RESULTS, ENERGY DEPENDENCE [TOTAL CROSS SECTION], Quantum chromodynamics, Physics, HADRON [ELECTROPRODUCTION], Annihilation, Muon, JET [ELECTROPRODUCTION], High Energy Physics::Phenomenology, Quark model, COLLIDING BEAMS [ELECTRON POSITRON], ELECTRON POSITRON [COLLIDING BEAMS], INCLUSIVE REACTION [ELECTRON POSITRON], RATIO [TOTAL CROSS SECTION], ELECTRON POSITRON [ANNIHILATION], ANNIHILATION [ELECTRON POSITRON], ELECTROPRODUCTION [JET], MARK J, High Energy Physics::Experiment, 35.0: 35.8 GEV-CM [33.0]
Abstract

This paper reports the results of a study of hadron production in e/sup +/e/sup -/ collisions at c.m. energies of 33, 35, and 35.8 GeV. Production of a new quark flavor has been sought. The measured values of the total cross section, the thrust distributions, and the study of inclusive muon production show no evidence for the production of a new charge-2/3e quark near threshold. In addition, during an energy scan in the region 29.9< or =..sqrt..s< or =31.6 GeV, no hadron resonance indicating the existence of a bound state composed of charge-2/3e quarks has been found.

Published
1980
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