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Full-Text Articles in Physics

Challenges With Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato, B. Wang Dec 2018

Challenges With Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato, B. Wang

Physics Faculty Publications

We survey the current phenomenological status of semi-inclusive deeply inelastic scattering at moderate hard scales and in the limit of very large transverse momentum. As the transverse momentum becomes comparable to or larger than the overall hard scale, the differential cross sections should be calculable with fixed order perturbative QCD (pQCD) methods, while small transverse momentum (transverse-momentum-dependent factorization) approximations should eventually break down. We find large disagreement between HERMES and COMPASS data and fixed order calculations done with modern parton densities, even in regions of kinematics where such calculations should be expected to be very accurate. Possible interpretations are suggested.


Simulation Of Black Hole Inner Accretion Disk-Corona And Optimization Of The Hard X-Ray Polarimeter, X-Calibur, Banafsheh Beheshtipour Aug 2018

Simulation Of Black Hole Inner Accretion Disk-Corona And Optimization Of The Hard X-Ray Polarimeter, X-Calibur, Banafsheh Beheshtipour

Arts & Sciences Electronic Theses and Dissertations

Mass accreting stellar mass and supermassive black holes are strong sources of X-rays. The X- ray observations enable studies of the process of black hole accretion and give us information about the spacetime background. In the framework of my thesis work, I have continued the development of a general-relativistic ray-tracing code enabling the simulation of the Comptonization of photons in the hot accretion disk corona. I use the code to investigate the impact of various approximation schemes for modeling the Comptonization finding that a fully relativistic treatment is needed for accurate predictions in the soft and hard X- ray regimes …


One-Loop Evolution Of Parton Pseudo-Distribution Functions On The Lattice, Anatoly Radyushkin Jul 2018

One-Loop Evolution Of Parton Pseudo-Distribution Functions On The Lattice, Anatoly Radyushkin

Physics Faculty Publications

We incorporate recent calculations of one-loop corrections for the reduced Ioffe-time pseudo-distribution m(v, z(3)(2) thorn to extend the leading-logarithm analysis of lattice data obtained by Orginos et al. We observe that the one-loop corrections contain a large term reflecting the fact that effective distances involved in the most important diagrams are much smaller than the nominal distance z(3). The large correction in this case may be absorbed into the evolution term, and the perturbative expansion used for extraction of parton densities at the μ ≈ 2 GeV scale is under control. The extracted parton distribution is rather close to global …


Numerical Study Of The Relativistic Three-Body Quantization Condition In The Isotropic Approximation, Raúl A. Briceño, Maxwell T. Hansen, Stephen R. Sharpe Jan 2018

Numerical Study Of The Relativistic Three-Body Quantization Condition In The Isotropic Approximation, Raúl A. Briceño, Maxwell T. Hansen, Stephen R. Sharpe

Physics Faculty Publications

We present numerical results showing how our recently proposed relativistic three-particle quantization condition can be used in practice. Using the isotropic (generalized s-wave) approximation, and keeping only the leading terms in the effective range expansion, we show how the quantization condition can be solved numerically in a straightforward manner. In addition, we show how the integral equations that relate the intermediate three-particle infinite-volume scattering quantity, Kdf,3, to the physical scattering amplitude can be solved at and below threshold. We test our methods by reproducing known analytic results for the 1/L expansion of the threshold state, the volume …