Quantum Physics Commons^™

Neutron Valence Structure From Nuclear Deep Inelastic Scattering, E. P. Segarra, A. Schmidt, T. Kutz, D. W. Higinbotham, E. Piasetzky, M. Strikman, L. B. Weinstein, O. Hen

Physics Faculty Publications

Mechanisms of spin-flavor SU(6) symmetry breaking in quantum chromodynamics (QCD) are studied via an extraction of the free neutron structure function from a global analysis of deep inelastic scattering (DIS) data on the proton and on nuclei from A = 2 (deuterium) to 208 (lead). Modification of the structure function of nucleons bound in atomic nuclei (known as the EMC effect) are consistently accounted for within the framework of a universal modification of nucleons in short-range correlated (SRC) pairs. Our extracted neutron-to-proton structure function ratio Fⁿ₂/F^p₂ becomes constant for x_B ≥ 0.6, equaling 0.47 …

Measurement Of The Structure Function Of The Nearly Free Neutron Using Spectator Tagging In Inelastic ²H(E,E'Pˢ) X Scattering With Clas, S. Tkachenko, S. E. Kuhn, J. Zhang, K. P. Adhikari, M. J. Amaryan, A. Klein, S. Koirala, M. Mayer, L. Zana, Clas Collaboration

Physics Faculty Publications

Background: Much less is known about neutron structure than that of the proton due to the absence of free neutron targets. Neutron information is usually extracted from data on nuclear targets such as deuterium, requiring corrections for nuclear binding and nucleon off-shell effects. These corrections are model dependent and have significant uncertainties, especially for large values of the Bjorken scaling variable x . As a consequence, the same data can lead to different conclusions, for example, about the behavior of the d quark distribution in the proton at large x .

Purpose: The Barely Off-shell Nucleon Structure experiment at Jefferson …

Experimental Results In Dis, Sidis And Des From Jefferson Lab, Sebastian E. Kuhn

Physics Faculty Publications

Jefferson Lab’s electron accelerator in its present incarnation, with a maximum beam energy slightly above 6 GeV, has already enabled a large number of experiments expanding our knowledge of nucleon and nuclear structure (especially in Deep Inelastic Scattering—DIS—at moderately high x, and in the resonance region). Several pioneering experiments have yielded first results on Deeply Virtual Compton Scattering (DVCS) and other Deep Exclusive Processes (DES), and the exploration of the rich landscape of transverse momentum‐dependent (TMD) structure functions using Semi‐Inclusive electron scattering (SIDIS) has begun. With the upgrade of CEBAF to 12 GeV now underway, a significantly larger kinematic …

Global Analysis Of Data On The Proton Structure Function G₁ And The Extraction Of Its Moments, M. Osipenko, S. Simula, W. Melnitchouk, P. Bosted, V. Burkert, E. Christy, K. Griffioen, C. Keppel, S. Kuhn, G. Ricco

Physics Faculty Publications

Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g₁ in the range 0.17 < Q² < 30 (GeV/c)². We compute for the first time low-order moments of g, and study their evolution from small to large values of Q². The analysis includes the latest data on both the unpolarized inclusive cross sections and the ratio R = σ _L/σ_T from Jefferson Lab, as well as a new model for the transverse asymmetry A₂ in the resonance region. The contributions of …

Higher Twist Analysis Of The Proton G₁ Structure Function, M. Osipenko, W. Melnitchouk, S. Simula, P. Bosted, V. Burkert, M. E. Christy, K. Griffioen, C. Keppel, S. E. Kuhn

Physics Faculty Publications

We perform a global analysis of all available spin-dependent proton structure function data, covering a large range of Q², 1 ⩽ Q² ⩽ 30 GeV², and calculate the lowest moment of the g₁ structure function as a function of Q². From the Q² dependence of the lowest moment we extract matrix elements of twist-4 operators, and determine the color electric and magnetic polarizabilities of the proton to be X_E= 0.026 ± 0.015(stat) ± ^0.021_0.024 (sys) and X_B= -0.013 ∓ 0.007(stat) ∓ ^0.010 _0.012(sys), respectively.