119182289
Single spin asymmetry in lepton angular distribution of Drell-Yan processes
A bstractWe study the single spin asymmetry in the lepton angular distribution of Drell-Yan processes in the framework of collinear factorization. The asymmetry has been studied in the past and different results have been obtained. In our study we take an approach different than that used in the existing study. We explicitly calculate the transverse-spin dependent part of the differential cross-section with suitable parton states. Because the spin is transverse, one has to take multi-parton states for the purpose. Our result agrees with one of the existing results. A possible reason for the disagreement with others is discussed.
119224580
Gauge invariance and QCD twist-3 factorization for single spin asymmetries
A bstractThe collinear factorization at twist-3 for Drell-Yan processes is studied with the motivation to solve the discrepancy in literature about the single spin asymmetry in the lepton angular distribution, and to show how QCD gauge invariance is realized in the hadronic tensor. The obtained result here agrees with our early result derived with a totally different approach. In addition to the asymmetry we can construct another two observables to identify the spin effect. We show that the gauge invariance of different contributions in the hadronic tensor is made in different ways by summing the effects of gluon exchanges. More interestingly is that we can show that the virtual correction to one structure function of the hadronic tensor, hence to some weighted SSA observables, is completely determined by the quark form factor. This will simplify the calculation of higher order corrections. The corresponding result in semi-inclusive DIS is also given for the comparison with Drell-Yan processes.
53552875
QCD corrections of all structure functions in transverse momentum dependent factorization for Drell-Yan processes
A bstractWe study the one-loop correction in Transverse-Momentum-Dependent(TMD) factorization for Drell-Yan processes at small transverse momentum of the lepton pair. We adopt the so-called subtractive approach, in which one can systematically construct contributions for subtracting long-distance effects represented by diagrams. The perturbative parts are obtained after the subtraction. We find that the perturbative coefficients of all structure functions in TMD factorization at leading twist are the same. The perturbative parts can also be studied with scattering of partons instead of hadrons. In this way, the factorization of many structure functions can only be examined by studying the scattering of multi-parton states, where there are many diagrams. These diagrams have no similarities to those treated in the subtractive approach. As an example, we use existing results of one structure function responsible for Single-Spin-Asymmetry, to show that these diagrams in the scattering of multi-parton states are equivalent to those treated in the subtractive approach after using Ward identity.
119108158
Azimuthal Dependence of DIS with Spin-1 Target
We study DIS with a spin-1 hadron or a nucleus polarized in arbitrary direction. The differential cross-section in this case will have an azimuthal dependence. We derive the dependence by including contributions from twist-2- and twist-3 QCD operators. The twist-3 contribution is computed at tree-level. A spin-1 hadron or nucleus can have nonzero tensor polarization. We find that all structure functions related to the tensor-polarization of the initial hadron can be extracted by study the azimuthal dependence. A nonzero result of the structure functions of a nucleus from experiment will indicate nontrivial inner structure of the nucleus.
118575585
QCD evolutions of twist-3 chirality-odd operators
We study the scale dependence of twist-3 distributions defined with chirality-odd quark-gluon operators. To derive the scale dependence we explicitly calculate these distributions of multi-patron states instead of a hadron. Taking one-loop corrections into account we obtain the leading evolution kernel in the most general case. In some special cases the evolutions are simplified. We observe that the obtained kernel in general does not get simplified in the large-N-c limit in contrast to the case of those twist-3 distributions defined only with chirality-odd quark operators. In the later, the simplification is significant. (C) 2012 Elsevier B.V. All rights reserved.
121030648
Systematic study of reaction functions of weakly bound nuclei
120119782
Calculation of half-lives of cluster decay by using proximity potential with a new universal function
Abstract The half-lives of cluster decays are calculated using proximity potential model with a new universal function, and compared to the experimentally measured values and the theoretical ones of liquid drop model. The results of the present calculations show reasonable agreement with the experimental data as well as the half-life calculations of liquid drop model. In the present work, it is certified that proximity potential model with the new universal function can be used successfully to calculate the half-lives of cluster decays for heavy nuclei.
119585509
Systematic analysis of the effect of a positive Q-value neutron transfer in fusion reactions
118079649
Cross-section measurement and analysis for the Sm-149 (n, alpha) Nd-146 reaction at 6.0 MeV
We have measured the $^{149}\mathrm{Sm}(n,\ensuremath{\alpha})^{146}\mathrm{Nd}$ cross section at 6.0 MeV to be $0.12\ifmmode\pm\else\textpm\fi{}0.018$ mb. This is the first reported result for this cross section in the MeV region and so should be helpful for constraining nuclear data evaluations (which differ by a factor of 40 for this reaction at this energy) and for testing and improving nuclear models. The experiment was performed at the at the 4.5-MV Van de Graaff accelerator of Peking University. Neutrons were produced via the $^{2}\mathrm{H}(d,n)^{3}\mathrm{He}$ reaction using a deuterium gas target, and absolute neutron flux was determined with a small $^{238}\mathrm{U}$ fission chamber. Alpha particles were detected using a two-section gridded ionization chamber in which two large-area $^{149}\mathrm{Sm}{}_{2}{\mathrm{O}}_{3}$ samples were placed back-to-back so that the cross section and forward/backward ratio were measured for nearly the entire 4$\ensuremath{\pi}$ solid angle. The data were compared to statistical-model predictions using the code talys. Good agreement between the measured and theoretical cross sections could be obtained with a small modification of the $\ensuremath{\alpha}$-optical potential parameters from their default values in talys. However, we were not able to reproduce the measured forward/backward ratio. In addition, using the previously reported $^{147}\mathrm{Sm}(n,\ensuremath{\alpha})^{144}\mathrm{Nd}$ cross section at 6.0 MeV together with our new result, good agreement was found between the measured and predicted cross-section ratio for these two isotopes. Finally, none of the existing evaluated data libraries are in agreement with our new data to within the experimental uncertainties.
120110625
Study of the universal function of nuclear proximity potential between α and nuclei from density-dependent nucleon-nucleon interaction
The universal function of proximity potential between α and nuclei is systematically studied from the double-folding model with the density-dependent nucleon-nucleon interaction (CDM3Y6) by analyzing different target nuclei with Z = 48–92. The analytical formula of universal function is obtained at s0 > −1 by fitting all of the calculated values. Using this formula we calculate the half-lives of α decay for heavy nuclei in comparison with the values of the experimental data. It is shown that the half-lives of the α decay calculated from the presently obtained universal function in proximity potential can keep within a factor of 3 with the experimental data.