物理学咬文嚼字之四十三 左右可有别?

左右是个常见的源自日常生活的科学概念.英文物理文献中同左右之分有关的概念有handedness,helicity,spirality,chirality和parity,且关于左(left,link,gauche,sinister,nigh)、右(right,recht,droit,dexterous)的写法也是多样并存的局面.左右的对称性及其破缺在自然界得到了最广泛的表现.     

星系普查确定中微子总质量新的上限

剑桥大学Ｏ .Ｅｌｇａｒｏｙ等 30名英、澳、美学者应用 2度场星系红移普查 (2ｄＦＧＲＳ)数据将中微子总质量上限确定到不及 10亿分之一的氢原子质量 .这是当前最严格的中微子质量上限 .中微子有无质量一直是个不解之谜 .最近几年里 ,大气中微子实验和太阳中微子实验在这个方向上取得了引人注目的进展 .今年 3月 ,Ｓｕｄｂｕｒｙ中微子天文台 (ＳＮＯ)的观测更进一步提供了有力的证据 ,表明中微子有质量已是不争的事实 .但是 ,实验至今仍旧无法测出它们的绝对质量 .2ｄＦＧＲＳ是当前规模最大的星系普查 ,业已观测了 2 2万个以上的星系红移…     

Study of absorption and re-emission processes in a ternary liquid scintillation system

Liquid scintillators are widely used as the neutrino target in neutrino experiments.The absorption and emission of different components of a ternary liquid scintillator （Linear Alkyl Benzene （LAB） as the solvent,2,5-diphenyloxazole （PPO） as the fluor and p-bis-（o-methylstyryl）-benzene （bis-MSB） as wavelength shifter） are studied.It is shown that the absorption of this liquid scintillator is dominant by LAB and PPO at wavelengths less than 349 nm,and the absorption by bis-MSB becomes prevalent at the wavelength larger than 349 nm.The fluorescence quantum yields,which are the key parameters to model the absorption and re-emission processes in large liquid scintillation detectors,are measured.     

高能天体物理前沿鸟瞰 (上)

 很容易确定天体物理诞生的日子,也很容易确定现代宇宙学诞生的日子.前者由基尔霍夫的太阳光谱观测确定,后者由爱因斯坦发表第一个宇宙解确定。但是,很难确定高能天体物理诞生的日子.也许可以作为高能天体物理诞生标志的是巴德和兹威基于1934年发表的一篇论文,题目为《超新星和宇宙线》.     

Hawking radiation of Weyl neutrinos in a rectilinearly non—uniformly accelerating Kinnersley black hole

The quantum thermal effect of Weyl neutrinos in a rectilinearly non-uniformly accelerating Kinnersley black hole is investigated using the generalized tortoise coordinate transformation.The equations that determine the location,the Hawking temperature of the event horizon and the thermal radiation spectrum of neutrinos are derived.Our results show that the location and the temperature of the event horizon depend not only on the time but also on the angle.     

夸克物质中的色超导性理论简介(英文)

夸克-夸克通过单胶子交换的相互作用在其反对称态上是相互吸引的,在致密夸克物质里,这种吸引相互作用会导致费米面上的双夸克凝聚,这就是所谓的夸克配对或色超导现象。本文介绍了夸克配对或色超导现象的基本知识和一些新进展。色超导是一个对称性自发破坏现象,有非常丰富的破缺方式,我们介绍了色超导对称性及其自发破坏模式的分析方法,介绍了怎样计算色超导体两个最基本的变量:能隙和迈斯纳质量。然后我们介绍了描述色超导现象的有效理论。最后是这些理论的一个应用,即计算色超导体里的中微子发射率以及其它输运性质。本文可以作为研究夸克物质理论的入门参考资料。     

Phenomenology of Friedberg-Lee Texture in Left-Right Symmetric Model

We consider that the Higgs triplet Yukawa coupling takes the Friedberg-Lee texture, and the Higgs doublet Yukawa coupling simply identifies with the diagonal Yutawa coupling of charged lepton in the context of left-right symmetric model. In this scenario, the phenomenology, including effective neutrino masses, mixings, and thermal flavor-dependent leptogenesis and lepton flavor violation decays are studied. We investigate the combined constrain of the parameters in this scenario and test its consistency with present data.     

Effects of the δ meson on the direct Urca processes in neutron stars

In the framework of the relativistic mean field theory, the effects of the δ meson on the direct Urca (DURCA) processes are investigated. In a neutron star, the DURCA processes involving nucleons, Λ and Ξ^- can take place while the process involving the Ξ⁰ can not. With the inclusion of the δ meson, the threshold densities for the DURCA processes become lower. With the δ included, the threshold neutron star mass for the DURCA process among nucleons and electrons becomes smaller while the threshold masses for the processes involving hyperons become larger. When the δ meson is included, the total neutrino emissivity remarkably increases in the density range of 0.32--0.41 fm^-3. The total neutrino luminosity increases with the neutron star mass first and then decreases. The neutrino luminosity gets larger with the inclusion of the δ meson. The cooling of the EXO0748-676 is sensitive to the isovector scalar interaction.