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Physics and Astronomy Faculty Publications

Elementary Particles and Fields and String Theory

Quantum chromodynamics

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Articles 1 - 5 of 5

Full-Text Articles in Physics

Measurement Of Unpolarized And Polarized Cross Sections For Deeply Virtual Compton Scattering On The Proton At Jefferson Laboratory With Clas, N. Hirlinger Saylor, B. Guegan, V. D. Burkert, L. Elouadrhiri, M. Garçon, F. X. Girod, M. Guidal, H. S. Jo, V. Kubarovsky, S. Niccolai, P. Stoler, K. P. Adhikari, S. Adhikari, Z. Akbar, M. J. Amaryan, S. Anefalos Pereira, J. Ball, I. Balossino, N. A. Baltzell, L. Barion, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, S. Boiarinov, W. J. Briscoe, W. K. Brooks, S. Bültmann, F. Cao, S. Carman, Wesley P. Gohn Oct 2018

Measurement Of Unpolarized And Polarized Cross Sections For Deeply Virtual Compton Scattering On The Proton At Jefferson Laboratory With Clas, N. Hirlinger Saylor, B. Guegan, V. D. Burkert, L. Elouadrhiri, M. Garçon, F. X. Girod, M. Guidal, H. S. Jo, V. Kubarovsky, S. Niccolai, P. Stoler, K. P. Adhikari, S. Adhikari, Z. Akbar, M. J. Amaryan, S. Anefalos Pereira, J. Ball, I. Balossino, N. A. Baltzell, L. Barion, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, S. Boiarinov, W. J. Briscoe, W. K. Brooks, S. Bültmann, F. Cao, S. Carman, Wesley P. Gohn

Physics and Astronomy Faculty Publications

This paper reports the measurement of polarized and unpolarized cross sections for the epe p γ reaction, which is composed of deeply virtual Compton scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < xB < 0.58, 1.0 < Q2 < 4.8GeV2, and 0.09 < −t < 2.00GeV2. The results are found to be consistent with previous CLAS data, and these new data are discussed in …


Evolution Equations For Connected And Disconnected Sea Parton Distributions, Keh-Fei Liu Aug 2017

Evolution Equations For Connected And Disconnected Sea Parton Distributions, Keh-Fei Liu

Physics and Astronomy Faculty Publications

It has been revealed from the path-integral formulation of the hadronic tensor that there are connected sea and disconnected sea partons. The former is responsible for the Gottfried sum rule violation primarily and evolves the same way as the valence. Therefore, the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations can be extended to accommodate them separately. We discuss its consequences and implications vis-á-vis lattice calculations.


Glue Spin And Helicity In The Proton From Lattice Qcd, Yi-Bo Yang, Raza Sabbir Sufian, Andrei Alexandru, Terrence Draper, Michael J. Glatzmaier, Keh-Fei Liu, Yong Zhao Mar 2017

Glue Spin And Helicity In The Proton From Lattice Qcd, Yi-Bo Yang, Raza Sabbir Sufian, Andrei Alexandru, Terrence Draper, Michael J. Glatzmaier, Keh-Fei Liu, Yong Zhao

Physics and Astronomy Faculty Publications

We report the first lattice QCD calculation of the glue spin in the nucleon. The lattice calculation is carried out with valence overlap fermions on 2 + 1 flavor domain-wall fermion gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The glue spin SG in the Coulomb gauge in the modified minimal subtraction (MS¯) scheme is obtained with one-loop perturbative matching. We find the results fairly insensitive to lattice spacing and quark masses. We also find that the proton momentum dependence of SG in the range 0 ≤ |p …


Locality And Efficient Evaluation Of Lattice Composite Fields: Overlap-Based Gauge Operators, Andrei Alexandru, Ivan Horváth Jan 2017

Locality And Efficient Evaluation Of Lattice Composite Fields: Overlap-Based Gauge Operators, Andrei Alexandru, Ivan Horváth

Physics and Astronomy Faculty Publications

We propose a novel general approach to locality of lattice composite fields, which in case of QCD involves locality in both quark and gauge degrees of freedom. The method is applied to gauge operators based on the overlap Dirac matrix elements, showing for the first time their local nature on realistic path-integral backgrounds. The framework entails a method for efficient evaluation of such nonultralocal operators, whose computational cost is volume independent at fixed accuracy, and only grows logarithmically as this accuracy approaches zero. This makes computation of useful operators, such as overlap-based topological density, practical. The key notion underlying these …


Measurements Of DN2 And AN1: Probing The Neutron Spin Structure, D. Flay, M. Posik, D. S. Parno, Kalyan C. Allada, W. R. Armstrong, T. Averett, F. Benmokhtar, W. Bertozzi, A. Camsonne, M. Canan, G. D. Cates, C. Chen, J. -P. Chen, S. Choi, E. Chudakov, F. Cusanno, M. M. Dalton, W. Deconinck, C. W. De Jager, X. Deng, A. Deur, Chiranjib Dutta, L. El Fassi, G. B. Franklin, M. Friend, H. Gao, F. Garibaldi, S. Gilad, R. Gilman, O. Glamazdin, Ameya Suresh Kolarkar, Wolfgang Korsch Sep 2016

Measurements Of DN2 And AN1: Probing The Neutron Spin Structure, D. Flay, M. Posik, D. S. Parno, Kalyan C. Allada, W. R. Armstrong, T. Averett, F. Benmokhtar, W. Bertozzi, A. Camsonne, M. Canan, G. D. Cates, C. Chen, J. -P. Chen, S. Choi, E. Chudakov, F. Cusanno, M. M. Dalton, W. Deconinck, C. W. De Jager, X. Deng, A. Deur, Chiranjib Dutta, L. El Fassi, G. B. Franklin, M. Friend, H. Gao, F. Garibaldi, S. Gilad, R. Gilman, O. Glamazdin, Ameya Suresh Kolarkar, Wolfgang Korsch

Physics and Astronomy Faculty Publications

We report on the results of the E06-014 experiment performed at Jefferson Lab in Hall A, where a precision measurement of the twist-3 matrix element d2 of the neutron (dn2) was conducted. The quantity dn2 represents the average color Lorentz force a struck quark experiences in a deep inelastic electron scattering event off a neutron due to its interaction with the hadronizing remnants. This color force was determined from a linear combination of the third moments of the 3He spin structure functions, g1 and g2, after nuclear corrections had …