Updated constraints on the cosmic string tension
Updated constraints on the cosmic string tension
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更新了宇宙弦张力的约束
DOI：
10.1103/physrevd.82.023521
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发表时间：
2010
影响因子：
5
通讯作者：
Battye R
中科院分区：
文献类型：
--
作者：
Battye R
我们重新审视了宇宙微波背景（CMB）和物质功率谱对宇宙弦张力的约束，以及脉冲星定时提供的引力波随机背景的限制。我们讨论了模拟弦演化和辐射的不同方法。特别是，我们表明，未连接的段模型可以使用与每种模拟相关的相关长度、均方根弦速度和小尺度结构的计算值来描述细弦（Nambu）和场论（阿贝尔-希格斯）模拟中预期的 CMB 谱。将计算出的光谱应用于 CMB 和 SDSS 数据，我们发现，如果 Nambu 模拟正确并且在阿贝尔-希格斯情况下，则 ()。与之前的工作相比，功率谱斜率之间的简并性大大降低。包含对大爆炸核合成（BBN）重子密度的约束意味着南部和阿贝尔-希格斯情况的重子密度都在该水平附近。作为我们结果的副产品，我们发现有“中等到强”的贝叶斯证据表明，与标准 6 参数拟合相比，CMB、SDSS 和 BBN 的组合排除了 Harrison-Zel’dovich 谱（优势比）。使用辐射时代环路对引力波背景的贡献作为信号的保守下限，对于 和 环路产生大小的特定值，我们发现 for 和 for 。
We reexamine the constraints on the cosmic string tension from cosmic microwave background (CMB) and matter power spectra, and also from limits on a stochastic background of gravitational waves provided by pulsar timing. We discuss the different approaches to modeling string evolution and radiation. In particular, we show that the unconnected segment model can describe CMB spectra expected from thin string (Nambu) and field theory (Abelian-Higgs) simulations using the computed values for the correlation length, rms string velocity and small-scale structure relevant to each variety of simulation. Applying the computed spectra in a fit to CMB and SDSS data we find that() if the Nambu simulations are correct andin the Abelian-Higgs case. The degeneracy betweenand the power spectrum slopeis substantially reduced from previous work. Inclusion of constraints on the baryon density from big bang nucleosynthesis (BBN) imply thatat around thelevel for both the Nambu and Abelian-Higgs cases. As a by-product of our results, we find there is “moderate-to-strong” Bayesian evidence that the Harrison-Zel’dovich spectrum is excluded (odds ratio of) by the combination of CMB, SDSS, and BBN when compared to the standard 6 parameter fit. Using the contribution to the gravitational wave background from radiation era loops as a conservative lower bound on the signal for specific values ofand loop production size,, we find thatforandfor.
影响因子：
5.6
作者：
A. Albrecht
通讯作者：
A. Albrecht