标题： 朝向宇宙常数问题的有效粒子-弦解决方法 显示英文标题

标题： Towards an Effective Particle-String Resolution of the Cosmological Constant Problem

摘要： 从有效场论的角度重新审视宇宙学常数问题。 虽然引力与粒子物理之间的联系尚未在量子领域中得到实验验证，但其受到标准模型量子场论在短距离处的成功以及广义相对论在大距离处的成功所严重限制。 乍看之下，将粒子物理与引力结合不可避免地导致一个低于弱尺度的有效场论，该理论会受到宇宙学常数的大辐射修正的影响。 因此，这个参数必须非常精细地调整，以符合实验范围。 使用熟悉的量子场论，详细描述了这种类似困境及其解决方法。 通过类比抽象出的漏洞是，在小于$10^{-2}$电子伏特的尺度上，引力子可能存在“复合性”，这会截断来自标准模型物理的宇宙学常数的大贡献。 从实验上看，这会在即将到来的亚厘米尺度引力测试中表现为牛顿定律的显著失效。 目前，弦理论是这种复合性的唯一已知例子。 提出引力部分由张力非常低的弦组成，这些弦与围绕每个点状标准模型粒子的弦论“晕”相互作用。 显示英文摘要

摘要： The Cosmological Constant Problem is re-examined from an effective field theory perspective. While the connection between gravity and particle physics has not been experimentally probed in the quantum regime, it is severely constrained by the successes of Standard Model quantum field theory at short distances, and classical General Relativity at large distances. At first sight, it appears that combining particle physics and gravity inevitably leads to an effective field theory below the weak scale which suffers from large radiative corrections to the cosmological constant. Consequently, this parameter must be very finely tuned to lie within the experimental bounds. An analog of just this type of predicament, and its resolution, are described in some detail using only familiar quantum field theory. The loop-hole abstracted from the analogy is the possibility of graviton ``compositeness'' at a scale less than $10^{-2}$ eV, which cuts off the large contributions to the cosmological constant from standard model physics. Experimentally, this would show up as a dramatic breakdown of Newton's Law in upcoming sub-centimeter tests of gravity. Currently, strings are the only known example of such compositeness. It is proposed that the gravitational sector comprises strings of very low tension, which couple to a stringy ``halo'' surrounding each point-like standard model particle.