We analyze cosmic microwave background (CMB) data taking into account the effects of a momentum dependent effective sound speed (MESS) . This approach allows to study the effects of primordial entropy perturbations in a model independent way, and its implementation requires a minimal modification of existing CMB fitting numerical codes developed for single scalar field models. We adopt a phenomenological approach, and study the effects of a local variation of the MESS around the scale where other analysis have shown some deviation from an approximately scale invariant curvature perturbation spectrum. We obtain a substantial improvement of the fit with respect to a model without MESS, showing that primordial entropy perturbations can be an explanation of these deviations.

我们考虑到动量相关有效声速（MESS）的影响来分析宇宙微波背景（CMB）数据。这种方法允许以独立于模型的方式研究原始熵扰动的影响，并且其实现方式需要对为单标量场模型开发的现有CMB拟合数字代码进行最小的修改。我们采用一种现象学的方法，研究了MESS在尺度附近的局部变化的影响，其他分析也表明了与近似尺度不变曲率摄动谱的某些偏离。我们获得了相对于没有MESS的模型的拟合的实质性改进，表明原始熵扰动可以解释这些偏差。