论文标题
从CMB温度上绑定了非颗粒的宇宙不透明度
A bound on the cosmic opacity of unparticles from the CMB temperature
论文作者
论文摘要
Unmarticle Cosmology对宇宙学的黑暗部门提供了非常规的前景，越来越具有挑战性的$λ\ mbox {cdm} $通过$ h_0 $ - 张力。该模型来自有限温度损坏的辐射的辐射对称性，该模型通过非辐射校正描述，其能量密度未知符号。这种对称性破裂具有符号歧义，其中有关IR固定点的校正是正常或速度。虽然第一个在最近的一项研究中排除了，但后者具有延迟温度$ t_c \ simeq 4 \，t_ {cmb} $与$ω_ {\ cal u} \ simeq 1 $（$ω_ {$ω_ {\ cal u} \ cal U} \ simeq 10^4Ω_}宇宙微波背景（CMB）的温度。因此，$ t_ {cmb} $暴露于巨大的热浴中，受到宇宙的天文年龄$ t_ {u，0} $的约束。在与CMB的任何热量交换中，相对温度偏移$ΔT/T $在此仅限于$ t_ {u，0} $的不确定性。这将与CMB光子相互作用的有效横截面与$σ_{γ\ Mathcal {u}}} \ Lessim 10^{ - 40} \ \ mbox {M}^2 = 10^{ - 3} { - 3} \ \ mbox {nb} $。假设在宽带质量和非颗粒的能量光谱之间进行标准横截面，则更严格的绑定$σ_{γ\ Mathcal {u}}} \ Lessim 10^{ - 3} \，\ Mbox {pb} $ derives cobe-firas per cobe-firas在光谱上扭曲的cobe-firas约束。第一个是Photon-Neutrino $σ_{γν} $和Photon-Photon横截面$σ_{γγ} $的中间，第二个与$σ_{γν} $相当。这些约束将延迟时间的宇宙学（如果存在）放在标准模型的边缘。
Unparticle cosmology gives an unconventional outlook on the dark sector of cosmology, increasingly challenging $Λ\mbox{CDM}$ by $H_0$-tension. This model derives from a finite temperature broken conformal symmetry of radiation, described by a non-radiative correction with unknown sign in energy density. This symmetry breaking has a sign ambiguity, in which corrections about the IR fixed point are normal or tachyonic. While the first has been ruled out in a recent study, the latter possesses a late-time temperature $T_c\simeq 4\,T_{CMB}$ associated with $Ω_{\cal U}\simeq 1$ ($Ω_{\cal U} \simeq 10^4 Ω_{CMB}$), where $T_{CMB}$ denotes the temperature of the Cosmic Microwave Background (CMB). Thus exposed to the enormous heat bath of unparticles, $T_{CMB}$ is constrained by the astronomical age of the Universe $T_{u,0}$. The relative temperature shift $ΔT/T$ in any heat exchange to the CMB is hereby limited to the uncertainty of a few percent in $T_{u,0}$. This bounds the effective cross-section of unparticles interactions with CMB photons to $σ_{γ\mathcal{U}} \lesssim 10^{-40}\ \mbox{m}^2=10^{-3}\ \mbox{nb}$. Assuming a standard cross-section across the broadband mass and energy spectrum of unparticles, a more stringent bound $σ_{γ\mathcal{U}} \lesssim 10^{-3}\,\mbox{pb}$ derives from COBE-FIRAS constraints on spectral distortions. The first is midway of photon-neutrino $σ_{γν}$ and photon-photon cross sections $σ_{γγ}$, the second is on par with $σ_{γν}$. These constraints put late-time unparticle cosmology, if present, at the edge of the standard model.
