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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¦
First Exclusive Measurement Of Deeply Virtual Compton Scattering Off 4He: Toward The 3d Tomography Of Nuclei, M. Hattawy, N. A. Baltzell, R. DuprĆ©, K. Hafidi, S. Stepanyan, S. BĆ¼ltmann, R. De Vita, A. El Alaoui, L. El Fassi, H. Egiyan, B. Torayev, D. Adikaram, M. J. Amaryan, G. Charles, M. Khachatryan, A. Klein, S. E. Kuhn, M. Mayer, Y. Prok, L. B. Weinstein, Z. W. Zhao
First Exclusive Measurement Of Deeply Virtual Compton Scattering Off 4He: Toward The 3d Tomography Of Nuclei, M. Hattawy, N. A. Baltzell, R. DuprĆ©, K. Hafidi, S. Stepanyan, S. BĆ¼ltmann, R. De Vita, A. El Alaoui, L. El Fassi, H. Egiyan, B. Torayev, D. Adikaram, M. J. Amaryan, G. Charles, M. Khachatryan, A. Klein, S. E. Kuhn, M. Mayer, Y. Prok, L. B. Weinstein, Z. W. Zhao
Physics Faculty Publications
We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized 4He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling 4 ā¦
Rosenbluth Separation Of The Ī 0 Electroproduction Cross Section Off The Neutron, M. Mazouz, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Canan, C. E. Hyde, S. Koirala, M. N. H. Rashad
Rosenbluth Separation Of The Ī 0 Electroproduction Cross Section Off The Neutron, M. Mazouz, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Canan, C. E. Hyde, S. Koirala, M. N. H. Rashad
Physics Faculty Publications
We report the first longitudinal-transverse separation of the deeply virtual exclusive Ļ0 electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dĻL/dt, dĻT/dt, dĻLT/dt, and dĻTT/dt are extracted as a function of the momentum transfer to the recoil system at Q2 = 1.75 GeV2 and xB = 0.36. The ed -> edĻ0 cross sections are found compatible with the small values expected from theoretical models. The en -> enĻ0 cross sections show a dominance from the response to transversely polarized ā¦
Target And Beam-Target Spin Asymmetries In Exclusive Pion Electroproduction For Q2 > 1 Gev2 . I. Ep ā EĻ+N, P. E. Posted, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, R. A. Badui, J. Ball, N. A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinsky, S. BĆ¼ltmann, S. E. Kuhn, B. Torayev, L. B. Weinstein, J. Zhang
Target And Beam-Target Spin Asymmetries In Exclusive Pion Electroproduction For Q2 > 1 Gev2 . I. Ep ā EĻ+N, P. E. Posted, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, R. A. Badui, J. Ball, N. A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinsky, S. BĆ¼ltmann, S. E. Kuhn, B. Torayev, L. B. Weinstein, J. Zhang
Physics Faculty Publications
Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive Ļ+ electroproduction reaction Ī³āpānĻ+. 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 range covered is 1.1 < W < 3 GeV and 1 < Q2 < 6 GeV2. Results were obtained for about 6000 bins in W, Q2, cos(Īøā), and Ļā. Except at forward angles, very large target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previous ā¦
Issues And Opportunities In Exotic Hadrons, R.A. BriceƱo, T. D. Cohen, S. Coito, J. J. Dudek, E. Eichten, R. E. Mitchell
Issues And Opportunities In Exotic Hadrons, R.A. BriceƱo, T. D. Cohen, S. Coito, J. J. Dudek, E. Eichten, R. E. Mitchell
Physics Faculty Publications
The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons. Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks, pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and ā¦
Separated Response Functions In Exclusive, Forward Ī Ā± Electroproduction On Deuterium, G. M. Huber, H. P. Blok, A. Klein, L. M. Qin, K. Vansyoc, Jefferson Lab, FĻ Collaboration
Separated Response Functions In Exclusive, Forward Ī Ā± Electroproduction On Deuterium, G. M. Huber, H. P. Blok, A. Klein, L. M. Qin, K. Vansyoc, Jefferson Lab, FĻ Collaboration
Physics Faculty Publications
Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q2, 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 Ļ- and Ļ+ 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 ā¦
Exclusive Ī įµ Electroproduction At W > 2 Gev With Clas, I. Bedlinskiy, K. P. Adhikari, L. El Fassi, A. Klein, S. E. Kuhn, Clas Collaboration
Exclusive Ī įµ Electroproduction At W > 2 Gev With Clas, I. Bedlinskiy, K. P. Adhikari, L. El Fassi, A. Klein, S. E. Kuhn, Clas Collaboration
Physics Faculty Publications
Exclusive neutral-pion electroproduction (ep ā e'p'Ļ0 was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections d4Ļ/dtdQ2dxBdĪ¦Ļ and structure functions ĻT+ ĻµĻL, ĻTT, and ĻLT as functions of t were obtained over a wide range of Q2 and xB. The data are compared with Regge and handbag theoretical calculations. Analyses in both frameworks find that a large dominance of transverse processes is necessary to explain the experimental results. For the Regge analysis it is found ā¦
Transverse Polarization Of Ī£+ (1189) In Photoproduction On A Hydrogen Target In Clas, Clas Collaboration, C. S. Nepali, M. Amaryan, K. P. Adhikari, H. Baghdasaryan, S. BĆ¼ltmann, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, B. Torayev, L. B. Weinstein
Transverse Polarization Of Ī£+ (1189) In Photoproduction On A Hydrogen Target In Clas, Clas Collaboration, C. S. Nepali, M. Amaryan, K. P. Adhikari, H. Baghdasaryan, S. BĆ¼ltmann, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, B. Torayev, L. B. Weinstein
Physics Faculty Publications
Experimental results on the Ī£+(1189) hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson Laboratory are presented. The Ī£+(1189) was reconstructed in the exclusive reaction Ī³+pāK0S+Ī£+(1189) via the Ī£+āpĻ0 decay mode. The K0S was reconstructed in the invariant mass of two oppositely charged pions with the Ļ0 identified in the missing mass of the detected pĻ+Ļā final state. Experimental data were collected in the photon energy range EĪ³=1.0 ā3.5 GeV (ās range 1.66ā2.73 GeV). We observe a large negative polarization ā¦
Search For The Photoexcitation Of Exotic Mesons In The Ī +Ī +Ī - System, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, S. Bektasoglu, S. BĆ¼ltmann, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, L. M. Qin, S. Tkachenko, L. B. Weinstein, J. Zhang
Search For The Photoexcitation Of Exotic Mesons In The Ī +Ī +Ī - System, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, S. Bektasoglu, S. BĆ¼ltmann, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, L. M. Qin, S. Tkachenko, L. B. Weinstein, J. Zhang
Physics Faculty Publications
A search for exotic mesons in the Ļ+Ļ+Ļā system photoproduced by the charge exchange reaction Ī³pāĻ+Ļ+Ļā(n) was carried out by the CLAS Collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A partial wave analysis was performed on a sample of 83ā000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the ā¦
Beam Spin Asymmetries In Deeply Virtual Compton Scattering (Dvcs) With Clas At 4.8 Gev, G. Gavalian, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, N. Guler, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, R. A. Niyazov, L. M. Qin, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Yun, J. Zhang, Clas Collaboration
Beam Spin Asymmetries In Deeply Virtual Compton Scattering (Dvcs) With Clas At 4.8 Gev, G. Gavalian, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, N. Guler, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, R. A. Niyazov, L. M. Qin, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Yun, J. Zhang, Clas Collaboration
Physics Faculty Publications
We report measurements of the beam spin asymmetry in deeply virtual Compton scattering (DVCS) at an electron beam energy of 4.8 GeV using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The DVCS beam spin asymmetry has been measured in a wide range of kinematics, 1.02<2.8 (GeV/c)2, 0.12<xB<0.48, and 0.1<āt<0.8 (GeV/c)2, using the reaction āepāeā²pX. The number of H(e,eā²Ī³p) and H(e,eā²Ļ0p) events are separated in each (Q2,xB,t) bin by a fit to the line shape of the H(e,eā²p)X M2x distribution. The validity of the method was studied in detail ā¦
Ī Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, S. Stepanyan, J. Yun, Et Al., Clas Collaboration
Ī Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, S. Stepanyan, J. Yun, Et Al., Clas Collaboration
Physics Faculty Publications
Differential cross sections for Ī³pāĪ·p have been measured with tagged real photons for incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information for protons scattered in the production process. The data provide the first extensive angular distribution measurements for the process above W = 1.75āāGeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S11 resonance with mass ā¼1.8āāGeV couples to the Ī·N channel.