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arXiv 1006.0249hep-ph
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WZ顶夸克包在重子生成中的可能作用

Possible Role of the WZ-Top-Quark Bags in Baryogenesis

Victor V. Flambaum, Edward Shuryak

摘要:

SM中最重的成员--规范玻色子$W,Z$、顶夸克和反夸克--可以形成希格斯真空的集体袋状激发,只要它们的数量足够大,无论是在零温度还是有限温度下。由于希格斯真空期望值(VEV)在它们内部被显著修改,因此它们被称为“袋”。在这项工作中,我们认为,创造这样的对象可以解释某些数值研究的宇宙学重子。作为一个例子的混合模型,结合通货膨胀预热冷电弱过渡,我们确定了“点的不间断相”的数值研究发现这种情况下与$W-Z$袋。我们认为,重子数违反应主要发生在这些对象内部,并表明,在数值模拟中计算的速率可以使用有限大小的纯规范sphaleron解决方案,以前开发的QCD背景下由卡特,奥斯特洛夫斯基和Shuryak(COS)的分析解释。此外,我们指出,在这些袋顶夸克/反夸克的显着存在(这是不包括在这些数值研究)。虽然基本的sphaleron指数保持不变的顶部的存在,我们发现,顶部有助于稳定他们更长的时间。转变速率的另一个增强来自于拓扑转变中顶部的“再循环”。包含费米子(顶部)提高sphaleron率高达2个数量级。最后,我们讨论了解释重子不对称性所需的CP破坏的大小,并论证了正确大小的袋子中的顶-反顶粒子数的差异可能来自于顶部衰变和顶部传播到袋子中的CP不对称性,这是由于Farrar-Shaubnikov效应造成的。

英文摘要:

The heaviest members of the SM -- the gauge bosons $W,Z$ and the top quarks and antiquarks -- may form collective bag-like excitations of the Higgs vacuum provided their number is large enough, both at zero and finite temperatures. Since Higgs vacuum expectation value (VEV) is significantly modified inside them, they are called "bags". In this work we argue that creation of such objects can explain certain numerical studies of cosmological baryogenesis. Using as an example a hybrid model, combining inflationary preheating with cold electroweak transition, we identify "spots of unbroken phase" found in numerical studies of this scenario with such $W-Z$ bags. We argue that the baryon number violation should happen predominantly inside these objects, and show that the rates calculated in numerical simulations can be analytically explained using finite-size pure gauge sphaleron solutions, developed previously in the QCD context by Carter, Ostrovsky and Shuryak (COS). Furthermore, we point out significant presence of the top quarks/antiquarks in these bag (which were not included in those numerical studies). Although the basic sphaleron exponent remains unchanged by the top's presence, we find that tops help to stabilize them for a longer time. Another enhancement of the transition rate comes from the "recycling" of the tops in the topological transition. Inclusion of the fermions (tops) enhances the sphaleron rate by up to 2 orders of magnitude. We finally discuss the magnitude of the CP violation needed to explain the observed baryonic asymmetry of the Universe, and give arguments that the difference in the top-antitop population in the bag of the right magnitude can arise both from CP asymmetries in the top decays and in top propagation into the bags, due to Farrar-Shaposhnikov effect.

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