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The asymmetry in the energy spectra between mirror nuclei (the Thomas-Ehrman shifts) around $^{16}$O is investigated from a phenomenological viewpoint. The recent data on proton-rich nuclei indicates that the residual nuclear interaction is reduced for the loosely bound s-orbit by as much as 30%, which originates in the broad radial distribution of the proton single-particle wave function., Comment: to appear in Phys. Lett. B, with 3 eps figures

We show in general that there are 108 structure functions in the proton-deuteron Drell-Yan processes. However, there exist only 22 finite ones after integrating the cross section over the virtual-photon transverse momentum \vec Q_T or after taking the limit Q_T->0. There are 11 new structure functions in comparison with the ones of the proton-proton reactions, and they are related to the tensor structure of the deuteron. Parton-model analyses indicate an important tensor structure function V_T^{UQ_0}, which can be measured by a quadrupole spin asymmetry. The Drell-Yan process has an advantage over lepton reactions in finding tensor polarized antiquark distributions. We hope that our studies will be realized in the next-generation RHIC-Spin project and other ones., Comment: 1+4 pages, LaTeX, espcrc1.sty, amsmath.sty, epsfig.sty, wrapfig.sty, 4 eps figures. Talk at the KEK-Tanashi International Symposium on "Physics of Hadrons and Nuclei", Tokyo, Japan, Dec.14-17, 1998. To be published in Nucl. Phys. A. Complete postscript file is available at http://www2.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html Email: 97sm16@edu.cc.saga-u.ac.jp, kumanos@cc.saga-u.ac.jp

We analyze the polarized Drell-Yan processes with spin-1/2 and spin-1 hadrons in a parton model. Quark and antiquark correlation functions are expressed in terms of possible combinations of Lorentz vectors and pseudovectors with the constrains of Hermiticity, parity conservation, and time-reversal invariance. Then, we find tensor polarized distributions for a spin-1 hadron. The naive parton model predicts that there exist 19 structure functions. However, there are only four or five non-vanishing structure functions, depending on whether the cross section is integrated over the virtual-photon transverse momentum \vec Q_T or the limit Q_T->0 is taken. One of the finite structure functions is related to the tensor polarized distribution b_1, and it does not exist in the proton-proton reactions. The vanishing structure functions should be associated with higher-twist physics. The tensor distributions can be measured by the quadrupole polarization measurements. The Drell-Yan process has an advantage over the lepton reaction in the sense that the antiquark tensor polarization could be extracted rather easily., Comment: 27 pages, REVTeX, amsmath.sty, epsfig.sty, revtex.cls, 2 eps figures. Phys. Rev. D in press. Complete postscript file is available at http://www2.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html Email: 97sm16@edu.cc.saga-u.ac.jp, kumanos@cc.saga-u.ac.jp

We discuss transversity distributions and transverse spin asymmetries. First, $Q^2$ evolution results are shown for transversity and longitudinally polarized distributions. Second, the antiquark flavor asymmetry $\Delta_{_T} \bar u/\Delta_{_T} \bar d$ is discussed in two different descriptions, a meson-cloud model and an exclusion model. Both calculations produce a significant $\Delta_T \bar d$ excess over $\Delta_{_T} \bar u$. Third, we explain general formalism of the polarized proton-deuteron Drell-Yan processes. This study is partly intended to find the asymmetry $\Delta_{_T} \bar u/\Delta_{_T} \bar d$ by the p-d asymmetry. However, the existence of tensor structure in the deuteron produces a number of new structure functions. There exist 108 structure functions and 22 ones even after integrating the cross section over the virtual-photon transverse momentum $\vec Q_T$., Comment: 1+3 pages, LATEX with amsmath.sty, epsfig.sty, wrapfig.sty, and sprocl.sty, 2 eps figures. Talk given at the 13th International Symposium on High Energy Spin Physics. Protvino, Russia, Sept. 8 -- 12, 1998, to be published in proceedings by the World Scientific. Complete postscript file including the figures is also available at http://www2.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html Email: 97sm16@edu.cc.saga-u.ac.jp, 98td25@edu.cc.saga-u.ac.jp, kumanos@cc.saga-u.ac.jp, 96td25@edu.cc.saga-u.ac.jp

We discuss general formalism for the structure functions which can be investigated in the polarized Drell-Yan processes with spin-1/2 and spin-1 hadrons. To be specific, the formalism can be applied to the proton-deuteron Drell-Yan processes. Because of the spin-1 nature, there are new structure functions which cannot be studied in the proton-proton reactions. Imposing Hermiticity, parity conservation, and time-reversal invariance, we find that 108 structure functions exist in the Drell-Yan processes. However, the number reduces to 22 after integrating the cross section over the virtual-photon transverse momentum Q_T or after taking the limit Q_T->0. There are 11 new structure functions in addition to the 11 ones in the Drell-Yan processes of spin-1/2 hadrons. The additional structure functions are associated with the tensor structure of the spin-1 hadron, and they could be measured by quadrupole spin asymmetries. For example, the structure functions exist for "intermediate" polarization although their contributions vanish in the longitudinal and transverse polarization reactions. We show a number of spin asymmetries for extracting the polarized structure functions. The proton-deuteron reaction may be realized in the RHIC-Spin project and other future ones, and it could be a new direction of next generation high-energy spin physics., Comment: 16 pages, REVTeX, amsmath.sty, epsfig.sty, revtex.cls, 6 eps figures. Submitted for publication. Complete postscript file is available at http://www2.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html Email: 97sm16@edu.cc.saga-u.ac.jp, kumanos@cc.saga-u.ac.jp

We discuss the studies on structure functions at the possible future RCNP facility. At this stage, an electron-proton or proton-proton collider with sqrt{s}=5 - 10 GeV is considered. We explain large-x physics, nuclear modification of sea-quark and gluon distributions, and tensor spin structure function as the interesting topics at the facility. The large-x parton distributions are important for finding new physics beyond QCD in anomalous events such as the CDF jet data. The nuclear parton distributions are valuable in detecting a quark-gluon signature in heavy-ion reactions. The tensor structure function b_1 is a new field of high-energy spin physics. Considering these physics possibilities, we believe that the possible RCNP facility is important for the hadron-structure community., Comment: 1+10 pages, LATEX2e with epsfig.sty, wrapfig.sty, and amsmath.sty, 5 eps figures. Talk given at the Workshop on Future Plan at RCNP, Osaka, Japan, March 9-10, 1998, to be published in proceedings. Complete postscript file including the figures is available at http://www.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html Email: 97sm16@edu.cc.saga-u.ac.jp, kumanos@cc.saga-u.ac.jp

We discuss polarized parton distributions and their effects on spin asymmetries at RHIC. In particular, transversity distributions and transverse spin asymmetry are studied. First, we show the $Q^2$ evolution difference between a transversity distribution and a corresponding longitudinally polarized distribution. The difference could be an important test of perturbative QCD in high-energy spin physics. Then, the transverse spin asymmetry $A_{TT}$ is calculated with possible transversity distributions. Next, we study antiquark flavor asymmetry $\Delta_{_T} \bar u/ \Delta_{_T} \bar d$ in the transversity distributions by using a simple model. Its effects on the transverse spin asymmetry are also discussed., Comment: 1+5 pages, LATEX with epsfig.sty, wrapfig.sty, and sprocl.sty, 3 eps figures. Talk given at the 6th International Workshop on Deep Inelastic Scattering and QCD. Brussels, Belgium, April 4-8, 1998, to be published in proceedings by the World Scientific. Complete postscript file including the figures is available at http://www.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html Email: 97sm16@edu.cc.saga-u.ac.jp, 98td25@edu.cc.saga-u.ac.jp, kumanos@cc.saga-u.ac.jp, 96td25@edu.cc.saga-u.ac.jp