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Full-Text Articles in Quantum Physics
First Measurement Of Hard Exclusive 𝛑⁻Δ⁺⁺ Electroproduction Beam-Spin Asymmetries Off The Proton, S. Diehl, N. Trotta, K. Joo, P. Achenbach, Z. Akbar, W. R. Armstrong, H. Atac, H. Avakian, L. Baashen, N. A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, F. Bossù, K.-T. Brinkman, M. Zurek, Et Al., Clas Collaboration
First Measurement Of Hard Exclusive 𝛑⁻Δ⁺⁺ Electroproduction Beam-Spin Asymmetries Off The Proton, S. Diehl, N. Trotta, K. Joo, P. Achenbach, Z. Akbar, W. R. Armstrong, H. Atac, H. Avakian, L. Baashen, N. A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, F. Bossù, K.-T. Brinkman, M. Zurek, Et Al., Clas Collaboration
Physics Faculty Publications
The polarized cross-section ratio σLT′/σ0 from hard exclusive π−Δ++ electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2 GeV/10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5 GeV2 up to 7 GeV2. The reaction provides a novel access to the d-quark content of the nucleon and to p→Δ++ transition generalized parton …
Multidimensional, High Precision Measurements Of Beam Single Spin Asymmetries In Semi-Inclusive 𝜋⁺ Electroproduction Off Protons In The Valence Region, S. Diehl, A. Kim, G. Angelini, K. Joo, S. Adhikari, M. J. Amaryan, M. Arratia, H. Atac, H. Avakian, C. Ayerbe Gayoso, N. A. Baltzell, L. Barion, S. Bastami, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, F. Bossù, Et Al.
Multidimensional, High Precision Measurements Of Beam Single Spin Asymmetries In Semi-Inclusive 𝜋⁺ Electroproduction Off Protons In The Valence Region, S. Diehl, A. Kim, G. Angelini, K. Joo, S. Adhikari, M. J. Amaryan, M. Arratia, H. Atac, H. Avakian, C. Ayerbe Gayoso, N. A. Baltzell, L. Barion, S. Bastami, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, F. Bossù, Et Al.
Physics Faculty Publications
High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here a high precision multidimensional study of single π+ SIDIS data over a large kinematic range in Bjorken x, fractional energy, and transverse momentum of the hadron as well as photon virtualities Q2 ranging from 1–7 GeV2. In particular, the structure function ratio FsinϕLU/FUU has been determined, where FsinϕLU is a twist-3 …
B-Meson Ioffe-Time Distribution Amplitude At Short Distances, Shuai Zhao, Anatoly V. Radyushkin
B-Meson Ioffe-Time Distribution Amplitude At Short Distances, Shuai Zhao, Anatoly V. Radyushkin
Physics Faculty Publications
We propose the approach for a lattice investigation of light cone distribution amplitudes (LCDA) of heavy-light mesons, such as the B meson, using the formalism of parton pseudodistributions. A basic ingredient of the approach is the study of short-distance behavior of the B-meson Ioffe-time distribution amplitude (ITDA), which is a generalization of the B-meson LCDA in coordinate space. We construct a reduced ITDA for the B meson, and derive the matching relation between the reduced ITDA and the LCDA. The reduced ITDA is ultraviolet finite, which guarantees that the continuum limit exists on the lattice.
Transverse Polarization Of Σ+ (1189) In Photoproduction On A Hydrogen Target In Clas, Clas Collaboration, C. S. Nepali, M. Amaryan, K. P. Adhikari, H. Baghdasaryan, S. Bültmann, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, B. Torayev, L. B. Weinstein
Transverse Polarization Of Σ+ (1189) In Photoproduction On A Hydrogen Target In Clas, Clas Collaboration, C. S. Nepali, M. Amaryan, K. P. Adhikari, H. Baghdasaryan, S. Bültmann, 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 Σ+(1189) hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson Laboratory are presented. The Σ+(1189) was reconstructed in the exclusive reaction γ+p→K0S+Σ+(1189) via the Σ+→pπ0 decay mode. The K0S was reconstructed in the invariant mass of two oppositely charged pions with the π0 identified in the missing mass of the detected pπ+π− final state. Experimental data were collected in the photon energy range Eγ=1.0 –3.5 GeV (√s range 1.66–2.73 GeV). We observe a large negative polarization …
Search For The Photoexcitation Of Exotic Mesons In The Π+Π+Π- System, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, S. Bektasoglu, S. Bültmann, 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 Π+Π+Π- System, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, S. Bektasoglu, S. Bültmann, 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 π+π+π− system photoproduced by the charge exchange reaction γp→π+π+π−(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 83 000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the …
Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, Clas Collaboration, K. P. Adhikari, S. L. Careccia, T. A. Forest, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, C. S. Nepali, M. R. Niroula, H. Seraydaryan
Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, Clas Collaboration, K. P. Adhikari, S. L. Careccia, T. A. Forest, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, C. S. Nepali, M. R. Niroula, H. Seraydaryan
Physics Faculty Publications
We present results on the electroexcitation of the low mass resonances Δ(1232)P33 , N(1440)P11 , N(1520)D13 , and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for π electroproduction off the proton. The data were analyzed using two conceptually different approaches—fixed-t dispersion relations and a unitary isobar model—allowing us to …
An Estimate Of The Branching Fraction Of Tau -> Pi Eta 'Nu(Tau), Shmuel Nussinov, A. Soffer
An Estimate Of The Branching Fraction Of Tau -> Pi Eta 'Nu(Tau), Shmuel Nussinov, A. Soffer
Mathematics, Physics, and Computer Science Faculty Articles and Research
We calculate the expected branching fraction of the second-class-current decay tau -> pi eta 'nu(tau), motivated by a recent experimental upper-limit determination of this quantity. The largest contribution to the branching fraction is due to the intermediate a(0)(980) scalar meson, assuming it is a (u) over bard state. Smaller contributions arise from a(0)(1450), rho(770), and rho(1450). Our calculated values are substantially below the experimental upper limit, and are smaller still if the a(0)(980) is a four-quark state, as often suggested. Thus, a precise measurement or tight upper limit has the potential to determine the nature of the a(0)(980), as well …
Cross Sections And Beam Asymmetries For E ⃗ P → Enπ+ In The Nucleon Resonance Region For 1.7 ⩽ Q2 ⩽ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration
Cross Sections And Beam Asymmetries For E ⃗ P → Enπ+ In The Nucleon Resonance Region For 1.7 ⩽ Q2 ⩽ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration
Physics Faculty Publications
The exclusive electroproduction process e ⃗ p → e'nπ+ was measured in the range of the photon virtuality Q2 =1.7-4.5 GeV2, and the invariant mass range for the n π+ system of W=1.15-1.7 GeV using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive π+ production from protons with nearly full coverage in the azimuthal and polar angles of the nπ+ center-of-mass system. The nπ+ channel has particular sensitivity to the isospin 1/2 excited nucleon states, and together with the pπ0 final state will serve …
Measurement Of Ep→Epπᵒ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang
Measurement Of Ep→Epπᵒ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang
Physics Faculty Publications
The beam spin asymmetry (BSA) in the exclusive reaction →ep→epπ0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The xB,Q2,t , and ϕ dependences of the π0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sinϕ function and their amplitudes are extracted. Overall, they are of the order of 0.04–0.11 and roughly independent of t . This is the signature of a nonzero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as …
Η 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
Η 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 γp→ηp 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 = 1.75 GeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S11 resonance with mass ∼1.8 GeV couples to the ηN channel.
The Ep → E'P Η Reaction At And Above The S₁₁ (1535) Baryon Resonance, R. Thompson, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, Et Al., The Clas Collaboration
The Ep → E'P Η Reaction At And Above The S₁₁ (1535) Baryon Resonance, R. Thompson, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, Et Al., The Clas Collaboration
Physics Faculty Publications
New cross sections for the reaction ep → ep η are reported for total center of mass energy W = 1.5-1.86 GeV and invariant momentum transfer Q2 = 0.25-1.5 (GeV/c)2. This large kinematic range allows extraction of important new information about response functions, photocouplings, and etaN coupling strengths of baryon resonances. Newly observed structure at W ~ 1.65 GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S11(1535) resonance.
Electroproduction Of The Λ(1520) Hyperon, M. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, S. E. Kuhn, R. A. Niyazov, L. B. Weinstein, Et Al., The Clas Collaboration
Electroproduction Of The Λ(1520) Hyperon, M. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, S. E. Kuhn, R. A. Niyazov, L. B. Weinstein, Et Al., The Clas Collaboration
Physics Faculty Publications
The reaction e→pe′K+Λ(1520) with Λ(1520)→p′K− was studied at electron beam energies of 4.05, 4.25, and 4.46 GeV, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cos θK+, φK+, Q2, and W dependencies of Λ(1520) electroproduction are presented for the kinematic region 0.9 < Q2 < 2.4 GeV2 and 1.95 < W < 2.65 GeV. Also, the Q2 dependence of the Λ(1520) decay angular distribution is presented for the first time. The cosθK+ angular distributions suggest t-channel diagrams dominate the production process. Fits to the Λ(1520) t-channel helicity frame decay angular distributions indicate the m …