Jet color chemistry and anomalous baryon production in AAAA-collisions

We study anomalous high-$p_T$ baryon production in $AA$-collisions due to formation of the two parton collinear $gq$ system in the anti-sextet color state for quark jets and $gg$ system in the decuplet/anti-decuplet color states for gluon jets. Fragmentation of these states, which are absent for $NN$-collisions, after escaping from the quark-gluon plasma leads to baryon production. Our qualitative estimates show that this mechanism can be potentially important at RHIC and LHC energies.Comment: 20 pages, 4 figures, Eur.Phys.J. versio

Nuclear effects in the Drell-Yan process at very high energies

We study Drell-Yan (DY) dilepton production in proton(deuterium)-nucleus and in nucleus-nucleus collisions within the light-cone color dipole formalism. This approach is especially suitable for predicting nuclear effects in the DY cross section for heavy ion collisions, as it provides the impact parameter dependence of nuclear shadowing and transverse momentum broadening, quantities that are not available from the standard parton model. For p(D)+A collisions we calculate nuclear shadowing and investigate nuclear modification of the DY transverse momentum distribution at RHIC and LHC for kinematics corresponding to coherence length much longer than the nuclear size. Calculations are performed separately for transversely and longitudinally polarized DY photons, and predictions are presented for the dilepton angular distribution. Furthermore, we calculate nuclear broadening of the mean transverse momentum squared of DY dileptons as function of the nuclear mass number and energy. We also predict nuclear effects for the cross section of the DY process in heavy ion collisions. We found a substantial nuclear shadowing for valence quarks, stronger than for the sea.Comment: 46 pages, 18 figures, title changed and some discussion added, accepted for publication in PR

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

Point View in Bird and Flower Painting

在中国传统绘画中，点景是极其重要的一种表达方式。石涛所研究的绘画问题中，情感、理性、力量都是不可缺少的，如何恰当地运用这三者，却有可能导致完全不同的创作结果。而点景正是这三者的集合点，不仅要用心灵去感受自然对象的内在精神，不能因为对象的限制而使感受层次也受到限制，把眼睛之受升华为心理之受。在绘画作品中合理地运用点景能使画家的情感与物象更加融合，画家自身的主观感受在画面上得到充分的体现，以一种小的特殊表现符号流露出画家作品里表达的象征倾向和审美概念，对画面的构图及意境有着画龙点睛的作用。本文以花鸟画点景为研究对象，重点介绍了点景的表现与意义；进一步阐述了点景在传统花鸟画构成中的作用，着重论述其在...The “point view” is extremely important as a means of expression in the traditional Chinese painting. Emotion, rationality and power are essential in the Shi Tao studied painting, and how to properly use them may lead to the creation of a completely different result. For the reason that “point view” is a collection of these three points, shouldn’t we only use the soul to feel the inner spirit of n...学位：文学硕士院系专业：艺术教育学院美术系_美术学学号：1862007115166