Novel Phenomenology of Parton Distributions from the Drell-Yan Process

The Drell-Yan massive lepton-pair production in hadronic collisions provides a unique tool complementary to the Deep-Inelastic Scattering for probing the partonic substructures in hadrons. We review key concepts, approximations, and progress for QCD factorization of the Drell-Yan process in terms of collinear or transverse momentum dependent (TMD) parton distribution functions. We present experimental results from recent fixed-target Drell-Yan as well as $W$ and $Z$ boson production at colliders, focussing on the topics of flavor structure of the nucleon sea as well as the extraction of novel Sivers and Boer-Mulders functions via single transverse spin asymmetries and azimuthal lepton angular distribution of the Drell-Yan process. Prospects for future Drell-Yan experiments are also presented.Comment: 50 pages and 23 figures, and references added and minor typos correcte

Study on Seismic Dynamic Response of Shallow-Buried Subway Station Structure and Ancillary Facilities

Strong earthquakes can cause damages to structural members and also yield non-negligible damages to nonstructural facilities, the latter being closely related to earthquake-induced inertial forces. At present, the acceleration response regularity of shallow-buried subway station structure is not very clear. Using the finite-element software ABAQUS, a dynamic soil-structure interaction model for a two-story subway station structure is established. The distribution of the peak acceleration response of the structure is obtained, and the damage assessment of non-structural facilities is carried out based on the structural acceleration response. The results demonstrate that, in general, the peak acceleration responses of the subway station structure increase from lower to upper story levels, while the peak acceleration responses at the same height are practically equal. Moreover, the peak accelerations of a shallow-buried subway station structure are generally less than or close to the peak ground acceleration. Furthermore, the nonstructural facilities are slightly damaged when subjected to a peak bedrock input acceleration of 0.1 g, and moderately damaged under a peak bedrock input acceleration in the range 0.2 – 0.6 g. Based on the acceleration response characteristics, it is proposed that the peak surface acceleration can be used as an index to evaluate the damage of non-structural facilities in shallow-buried subway station structure, which is simple, practical and basically meets the precision requirements