Nuclear dependence of azimuthal asymmetry in semi-inclusive deep inelastic scattering

Within the framework of a generalized factorization, semi-inclusive deeply inelastic scattering (SIDIS) cross sections can be expressed as a series of products of collinear hard parts and transverse-momentum-dependent (TMD) parton distributions and correlations. The azimuthal asymmetry $of unpolarized SIDIS in the small transverse momentum region will depend on both twist-2 and 3 TMD quark distributions in target nucleons or nuclei. Nuclear broadening of these twist-2 and 3 quark distributions due to final-state multiple scattering in nuclei is investigated and the nuclear dependence of the azimuthal asymmetry$$ is studied. It is shown that the azimuthal asymmetry is suppressed by multiple parton scattering and the transverse momentum dependence of the suppression depends on the relative shape of the twist-2 and 3 quark distributions in the nucleon. A Gaussian ansatz for TMD twist-2 and 3 quark distributions in nucleon is used to demonstrate the nuclear dependence of the azimuthal asymmetry and to estimate the smearing effect due to fragmentation.Comment: 9 pages in RevTex with 2 figure

Synthesis, Structural Characterization and Catalytic Activity of A Cu(II) Coordination Polymer Constructed from 1,4-Phenylenediacetic Acid and 2,2’-Bipyridine

In order to study the catalytic activity of Cu(II) coordination polymer material, a novel 1D chained Cu(II) coordination polymer material, [CuL(bipy)(H2O)5]n (A1) (H2L = 1,4-phenylenediacetic acid, bipy = 2,2’-bipyridine), has been prepared by the reaction of 1,4-phenylenediacetic acid, 2,2’-bipyridine, Cu(CH3COO)2·H2O and NaOH. The composition of A1 was determined by elemental analysis, IR spectra and single crystal X-ray diffraction. The results of characterization show that each Cu(II) atom adopts six-coordination and forms a distorted octahedral configuration. The catalytic activity and reusability of A1 catalyst for A3 coupling reaction of benzaldehyde, piperidine, and phenylacetylene have been investigated. And the results show that the Cu(II) complex catalyst has good catalytic activity with a maximum yield of 54.3% and stability. Copyright © 2017 BCREC GROUP. All rights reservedReceived: 21st October 2016; Revised: 17th November 2016; Accepted: 22nd November 2016How to Cite: Li-Hua, W., Lei, L., Xin, W. (2017). Synthesis, Structural Characterization and Catalytic Activity of A Cu(II) Coordination Polymer Constructed from 1,4-Phenylenediacetic Acid and 2,2’-Bipyridine. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1): 113-118 (doi:10.9767/bcrec.12.1.735.113-118)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.735.113-118

Twist-4 contributions to the azimuthal asymmetry in SIDIS

We calculate the differential cross section for the unpolarized semi-inclusive deeply inelastic scattering (SIDIS) process $e^-+N \to e^-+q+X$ in leading order (LO) of perturbative QCD and up to twist-4 in power corrections and study in particular the azimuthal asymmetry . The final results are expressed in terms of transverse momentum dependent (TMD) parton matrix elements of the target nucleon up to twist-4. %Under the maximal two-gluon correlation approximation, these TMD parton matrix elements in a nucleus %can be expressed terms of a Gaussian convolution of that in a nucleon with the width given by the jet transport %parameter inside cold nuclei. We also apply it to $e^-+A \to e^-+q+X$ and illustrate numerically the nuclear dependence of the azimuthal asymmetry by using a Gaussian ansatz for the TMD parton matrix elements.Comment: 9 pages, afigur

Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L.) seedlings: passive or active uptake?

<p>Abstract</p> <p>Background</p> <p>Polycyclic aromatic hydrocarbons (PAHs) are of particular concern due to their hydrophobic, recalcitrant, persistent, potentially carcinogenic, mutagenic and toxic properties, and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore, they may threaten human and animal health. However, the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain, since it is beneficial in governing crop contamination by PAHs, remedying soils or waters polluted by PAHs with plants, and modeling potential uptake for risk assessment.</p> <p>Results</p> <p>The possibility that plant roots may take up phenanthrene (PHE), a representative of PAHs, via active process was investigated using intact wheat (<it>Triticum acstivnm L</it>.) seedlings in a series of hydroponic experiments. The time course for PHE uptake into wheat roots grown in Hoagland solution containing 5.62 μM PHE for 36 h could be separated into two periods: a fast uptake process during the initial 2 h and a slow uptake component thereafter. Concentration-dependent PHE uptake was characterized by a smooth, saturable curve with an apparent <it>K</it>_mof 23.7 μM and a <it>V</it>_maxof 208 nmol g^-1fresh weight h^-1, suggesting a carrier-mediated uptake system. Competition between PHE and naphthalene for their uptake by the roots further supported the carrier-mediated uptake system. Low temperature and 2,4-dinitrophenol (DNP) could inhibit PHE uptake equally, indicating that metabolism plays a role in PHE uptake. The inhibitions by low temperature and DNP were strengthened with increasing concentration of PHE in external solution within PHE water solubility (7.3 μM). The contribution of active uptake to total absorption was almost 40% within PHE water solubility. PHE uptake by wheat roots caused an increase in external solution pH, implying that wheat roots take up PHE via a PHE/nH⁺symport system.</p> <p>Conclusion</p> <p>It is concluded that an active, carrier-mediated and energy-consuming influx process is involved in the uptake of PHE by plant roots.</p

Disentangling covariant Wigner functions for chiral fermions

We develop a general formalism for the quantum kinetics of chiral fermions in a background electromagnetic field based on a semiclassical expansion of covariant Wigner functions in the Planck constant $\hbar$. We demonstrate to any order of $\hbar$ that only the time-component of the Wigner function is independent while other components are explicit derivative. We further demonstrate to any order of $\hbar$ that a system of quantum kinetic equations for multiple-components of Wigner functions can be reduced to one chiral kinetic equation involving only the single-component distribution function. These are remarkable properties of the quantum kinetics of chiral fermions and will significantly simplify the description and simulation of chiral effects in heavy ion collisions and Dirac/Weyl semimetals. We present the unintegrated chiral kinetic equations in four-momenta up to $O(\hbar ^2)$ and the integrated ones in three-momenta up to $O(\hbar)$. We find that some singular terms emerge in the integration over the time component of the four-momentum, which result in a new source term contributing to the chiral anomaly, in contrast to the well-known scenario of the Berry phase term. Finally we rewrite our results in any Lorentz frame with a reference four-velocity and show how the non-trivial transformation of the distribution function in different frames emerges in a natural way.Comment: RevTex 4, 14 pages, no figure. Section II and III have been re-organized and expended to three sections (II-IV) to include more details of calculations. Section V has been expanded to include more discussions. A new section (VI) is added about Wigner functions in a general Lorentz frame. Some references are adde