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Résumé |
Jefferson Lab has just started to resume operation after a $350 million upgrade to 12 GeV. One of the main science motivations that drives this upgrade is the measurement of 'Generalized Parton Distributions (GPDs)', which will allow for the first time to engage in nuclear tomography to uncover the true three-dimensional structure of the nucleon. Likewise, one of the two science motivations for a proposed electron-ion collider is 'precision imaging of the sea-quarks and gluons to determine the spin, flavor and spatial structure of the nucleon'. In the near term, determination the of GPDs is also one of the main goals of the COMPASS II program. I will explain how these experiments can access the spatial nucleon structure and how that relates to other observables, such as quark orbital angular momentum (OAM), the nucleon anomalous magnetic moment, and transverse single-spin asymmetries.The same final state interaction forces acting on the active quark causing transverse single-spin asymmetries can also modify the longitudinal orbital angular momentum (OAM) of the struck quark as it leaves the target. The resulting change in OAM can be related to the difference between Ji's definition of quark OAM and that of Jaffe-Manohar. |
