Single transverse-spin asymmetry in Drell-Yan lepton angular distribution

We calculate a single transverse-spin asymmetry for the Drell-Yan lepton-pair's angular distribution in perturbative QCD. At leading order in the strong coupling constant, the asymmetry is expressed in terms of a twist-3 quark-gluon correlation function T_F^{(V)}(x_1,x_2). In our calculation, the same result was obtained in both light-cone and covariant gauge in QCD, while keeping explicit electromagnetic current conservation for the virtual photon that decays into the lepton pair. We also present a numerical estimate of the asymmetry and compare the result to an existing other prediction.Comment: 15 pages, Revtex, 5 Postscript figures, uses aps.sty, epsfig.st

Single Spin Asymmetry in Lepton Angular Distribution of Drell-Yan Processes

We study the single spin asymmetry in the lepton angular distribution of Drell-Yan processes in the frame work 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.Comment: Typos corrected. Conclusions unchange

Technology, creativity and the media in engineering China’s future

Political, economic and intellectual elites in China have for some time been in the grip of ‘futurology’ as they reflect on thirty years’ of extraordinary economic development and ask ‘what next’? China has a dream, in fact it has many visions of what it may become, reflecting robust debate and competition to define the nation’s future course of reform and development (Callahan, 2013). On assuming the top party and state positions in October 2012 Xi Jinping quickly unveiled the China Dream (Zhonguomeng) as the maxim for his leadership. Although specification of what the dream will entail is yet to be fully explicated, one thing is certain: low-cost production and outsourcing more advanced economies’ dirty jobs is neither the subject of China’s dream nor is it any longer considered the means to delivering it. The ‘world’s factory’ model that facilitated China’s remarkable economic growth has come under pressure from all sides, as the party acknowledges its unsustainability and people deal with the consequences. Party elites and policymakers have taken significant steps toward a different and more sustainable model to secure long term growth and it is hoped that low-end manufacturing will give way to a service based economy and consumer culture facilitated by urbanization, migration and developing greater creative capacity. These plans are underpinned by the ambition to become an ‘innovative nation’ (chuangxinxing de guojia), to develop soft power resources to go with economic might, and to raise the ‘quality’ (suzhi) of the people. As the three books covered in this review essay demonstrate, technology, culture and the media are closely implicated, and closely controlled, in the Chinese state’s quest for development

A Systematic Framework to Derive N-glycan Biosynthesis Process and the Automated Construction of Glycosylation Networks

published_or_final_versio

Nodeless superconductivity in Ca3Ir4Sn13: evidence from quasiparticle heat transport

We report resistivity $\rho$ and thermal conductivity $\kappa$ measurements on Ca$_3$Ir$_4$Sn$_{13}$ single crystals, in which superconductivity with $T_c \approx 7$ K was claimed to coexist with ferromagnetic spin-fluctuations. Among three crystals, only one crystal shows a small hump in resistivity near 20 K, which was previously attributed to the ferromagnetic spin-fluctuations. Other two crystals show the $\rho \sim T^2$ Fermi-liquid behavior at low temperature. For both single crystals with and without the resistivity anomaly, the residual linear term $\kappa_0/T$ is negligible in zero magnetic field. In low fields, $\kappa_0(H)/T$ shows a slow field dependence. These results demonstrate that the superconducting gap of Ca$_3$Ir$_4$Sn$_{13}$ is nodeless, thus rule out nodal gap caused by ferromagnetic spin-fluctuations.Comment: 5 pages, 4 figure

Incommensurate itinerant antiferromagnetic excitations and spin resonance in the FeTe0.6_{0.6}Se0.4_{0.4} superconductor

We report on inelastic neutron scattering measurements that find incommensurate itinerant like magnetic excitations in the normal state of superconducting FeTe$_{0.6}$Se$_{0.4}$ (\Tc=14K) at wave-vector $\mathbf{Q}_{inc}=(1/2\pm\epsilon,1/2\mp\epsilon)$ with $\epsilon$=0.09(1). In the superconducting state only the lower energy part of the spectrum shows significant changes by the formation of a gap and a magnetic resonance that follows the dispersion of the normal state excitations. We use a four band model to describe the Fermi surface topology of iron-based superconductors with the extended $s(\pm)$ symmetry and find that it qualitatively captures the salient features of these data.Comment: 7 pages and 5 figure

The structures of Hausdorff metric in non-Archimedean spaces

For non-Archimedean spaces $X$ and $Y,$ let $\mathcal{M}_{\flat } (X), \mathfrak{M}(V \rightarrow W)$ and $\mathfrak{D}_{\flat }(X, Y)$ be the ballean of $X$ (the family of the balls in $X$), the space of mappings from $X$ to $Y,$ and the space of mappings from the ballen of $X$ to $Y,$ respectively. By studying explicitly the Hausdorff metric structures related to these spaces, we construct several families of new metric structures (e.g., $\widehat{\rho } _{u}, \widehat{\beta }_{X, Y}^{\lambda }, \widehat{\beta }_{X, Y}^{\ast \lambda }$) on the corresponding spaces, and study their convergence, structural relation, law of variation in the variable $\lambda,$ including some normed algebra structure. To some extent, the class $\widehat{\beta }_{X, Y}^{\lambda }$ is a counterpart of the usual Levy-Prohorov metric in the probability measure spaces, but it behaves very differently, and is interesting in itself. Moreover, when $X$ is compact and $Y = K$ is a complete non-Archimedean field, we construct and study a Dudly type metric of the space of $K-$valued measures on $X.$Comment: 43 pages; this is the final version. Thanks to the anonymous referee's helpful comments, the original Theorem 2.10 is removed, Proposition 2.10 is stated now in a stronger form, the abstact is rewritten, the Monna-Springer is used in Section 5, and Theorem 5.2 is written in a more general for