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Full-Text Articles in Physics
Measurement Of Spin-Density Matrix Elements In P(770) Production With A Linearly Polarized Photon Beam At Eš¾ = 8.2-8.8 Gev, S. Adhikari, F. Afzal, C. S. Akondi, M. Albrecht, M. Amaryan, V. Arroyave, A. Asaturyan, A. Austregesilo, Z. Baldwin, F. Barbosa, J. Barlow, E. Barriga, R. Barsotti, T. D. Beattie, V. V. Berdnikov, T. Black, W. Boeglin, W. J. Briscoe, T. Britton, B. Zihlmann, Et Al., Gluex Collaboration
Measurement Of Spin-Density Matrix Elements In P(770) Production With A Linearly Polarized Photon Beam At Eš¾ = 8.2-8.8 Gev, S. Adhikari, F. Afzal, C. S. Akondi, M. Albrecht, M. Amaryan, V. Arroyave, A. Asaturyan, A. Austregesilo, Z. Baldwin, F. Barbosa, J. Barlow, E. Barriga, R. Barsotti, T. D. Beattie, V. V. Berdnikov, T. Black, W. Boeglin, W. J. Briscoe, T. Britton, B. Zihlmann, Et Al., Gluex Collaboration
Physics Faculty Publications
The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized 8.5 GeV photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and neutral particles. We present measurements of spin-density matrix elements for the photoproduction of the vector meson Ļ(770). The statistical precision achieved exceeds that of previous experiments for polarized photoproduction in this energy range by orders of magnitude. We confirm a high degree of s-channel helicity conservation at small squared four-momentum transfer t and are able to extract the t dependence of natural- and unnatural-parity exchange contributions to ā¦
Polarized Structure Function Ī£Lt' From šā°P Electroproduction Data In The Resonance Region At 0.2 GevĀ² < QĀ² < 1.0 GevĀ², E. L. Isupov, V. D. Burkert, A. A. Golubenko, K. Joo, N. S. Markov, V. I. Mokeev, L. C. Smith, N. Zachariou, W. R. Armstrong, H. Atac, Et Al
Polarized Structure Function Ī£Lt' From šā°P Electroproduction Data In The Resonance Region At 0.2 GevĀ² < QĀ² < 1.0 GevĀ², E. L. Isupov, V. D. Burkert, A. A. Golubenko, K. Joo, N. S. Markov, V. I. Mokeev, L. C. Smith, N. Zachariou, W. R. Armstrong, H. Atac, Et Al
Physics Faculty Publications
The first results on the ĻLTā² structure function in exclusive Ļ0p electroproduction at invariant masses of the final state of 1.5GeV < W < 1.8 GeV and in the range of photon virtualities 0.4 GeV2 < Q2 < 1.0 GeV2 were obtained from data on beam spin asymmetries and differential cross sections measured with the CLAS detector at Jefferson Lab. The Legendre moments determined from the ĻLTā² structure function have demonstrated sensitivity to the contributions from the nucleon resonances in the second and third resonance regions. These new data on the beam spin asymmetries in Ļ0p electroproduction extend the opportunities for the extraction of the nucleon resonance electro-excitation amplitudes in ā¦
Measurement Of The QĀ² Dependence Of The Deuteron Spin Structure Function G1 And Its Moments At Low QĀ² With Clas, Clas Collaboration, K. P. Adhikari, L. El Fassi, S E. Kuhn, M. J. Amaryan, S. BĆ¼ltmann, G. Charles, Gail Dodge, N. Guler, C. E. Hyde, A. Klein, D. Payette, J. Poudel, Y. Prok, L. B. Weinstein, J. Zhang, Z. W. Zhao
Measurement Of The QĀ² Dependence Of The Deuteron Spin Structure Function G1 And Its Moments At Low QĀ² With Clas, Clas Collaboration, K. P. Adhikari, L. El Fassi, S E. Kuhn, M. J. Amaryan, S. BĆ¼ltmann, G. Charles, Gail Dodge, N. Guler, C. E. Hyde, A. Klein, D. Payette, J. Poudel, Y. Prok, L. B. Weinstein, J. Zhang, Z. W. Zhao
Physics Faculty Publications
We measured the g1 spin structure function of the deuteron at low Q2, where QCD can be approximated with chiral perturbation theory (ĻPT). The data cover the resonance region, up to an invariant mass of W ā 1.9āāGeV. The generalized Gerasimov-Drell-Hearn sum, the moment Īd1 and the spin polarizability Ī³d0 are precisely determined down to a minimum Q2 of 0.02āāGeV2 for the first time, about 2.5 times lower than that of previous data. We compare them to several ĻPT calculations and models. These results are the first in a ā¦
Measurement Of The Helicity Asymmetry E In Ī©āĪ +Ī ĖĪ įµ Photoproduction, Z. Akbar, P. Roy, S. Park, V. Crede, A. V. Anisovich, I. Denisenko, E. Klempt, V. A. Nikonov, A. V. Sarantsev, K. P. Adhikari, M. J. Amaryan, G. Charles, A. Klein, Y. Prok, J. Zhang, Z. W. Zhao
Measurement Of The Helicity Asymmetry E In Ī©āĪ +Ī ĖĪ įµ Photoproduction, Z. Akbar, P. Roy, S. Park, V. Crede, A. V. Anisovich, I. Denisenko, E. Klempt, V. A. Nikonov, A. V. Sarantsev, K. P. Adhikari, M. J. Amaryan, G. Charles, A. Klein, Y. Prok, J. Zhang, Z. W. Zhao
Physics Faculty Publications
The double-polarization observable E was studied for the reaction Ī³pāpĻ using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ĻāĻ+Ļ-Ļ0, using a circularly polarized tagged-photon beam with energies ranging from the Ļ threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720)3/2+ nucleon ā¦
Determination Of The Proton Spin Structure Functions For 0.05 < Q2 <5gev2 Using Clas, R. G. Fersch, N. Guler, P. Bosted, A. Deur, K. Griffioen, C. Keith, S E. Kuhn, R. Minehart, Y. Prok, K. P. Adhikari, S. BĆ¼ltmann, S. Careccia, Gail Dodge, V. G. Lagerquist, L. B. Weinstein
Determination Of The Proton Spin Structure Functions For 0.05 < Q2 <5gev2 Using Clas, R. G. Fersch, N. Guler, P. Bosted, A. Deur, K. Griffioen, C. Keith, S E. Kuhn, R. Minehart, Y. Prok, K. P. Adhikari, S. BĆ¼ltmann, S. Careccia, Gail Dodge, V. G. Lagerquist, L. B. Weinstein
Physics Faculty Publications
We present the results of our final analysis of the full data set of gp1 Q2, the spin structure function of the proton, collected using CLAS at Jefferson Laboratory in 2000-2001. Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.7 GeV were scattered from proton targets 15NH3 dynamically polarized along the beam direction) and detected with CLAS. From the measured double spin asymmetries, we extracted virtual photon asymmetries Ap1 and Ap2 and spin structure functions g p1 and gp2 over a wide kinematic range (0.05 GeV ā¦
Target And Beam-Target Spin Asymmetries In Exclusive Pion Electroproduction For QĀ² > 1 GevĀ² . Ii. Epā EĻĀŗp, Clas Collaboration, K. P. Adhikari, D. Adikaram, M. J. Amaryan, S. BĆ¼ltmann, N. Guler, S E. Kuhn, A. Klein, S. Koirala, B. Torayev, J. Zhang, Z. W. Zhao
Target And Beam-Target Spin Asymmetries In Exclusive Pion Electroproduction For QĀ² > 1 GevĀ² . Ii. Epā EĻĀŗp, Clas Collaboration, K. P. Adhikari, D. Adikaram, M. J. Amaryan, S. BĆ¼ltmann, N. Guler, S E. Kuhn, A. Klein, S. Koirala, B. Torayev, J. Zhang, Z. W. Zhao
Physics Faculty Publications
Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive Ļ0 electroproduction reaction Ī³āpāpĻ0, expanding an analysis of the Ī³āpānĻ+ reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1 < W < 3 GeV and 1 < Q2< 6 GeV2 . Results were obtained for about 5700 bins in W, Q2, cos(Īøā) , and Ļā. The beam-target asymmetries were found to generally be greater than zero, with ā¦
Measurement Of Target And Double-Spin Asymmetries For The Ep ā EĻ+(N) Reaction In The Nucleon Resonance Region At Low QĀ², Clas Collaboration, K. P. Adhikari, S E. Kuhn, D. Adikaram, M. J. Amaryan, S. BĆ¼ltmann, Gail Dodge, N. Guler, L. B. Weinstein
Measurement Of Target And Double-Spin Asymmetries For The Ep ā EĻ+(N) Reaction In The Nucleon Resonance Region At Low QĀ², Clas Collaboration, K. P. Adhikari, S E. Kuhn, D. Adikaram, M. J. Amaryan, S. BĆ¼ltmann, Gail Dodge, N. Guler, L. B. Weinstein
Physics Faculty Publications
We report measurements of target- and double-spin asymmetries for the exclusive channel āeāp ā eĻ+(n) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35(GeV/c)2. The Q2 access was made possible by a custom-built Cherenkov detector ā¦