Near-conformal dynamics in a chirally broken system
Near-conformal dynamics in a chirally broken system
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DOI：
10.1103/physrevd.103.014504
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发表时间：
2020-07
影响因子：
5
通讯作者：
T. Appelquist;R. Brower;K. Cushman;G. Fleming;A. Gasbarro;A. Hasenfratz;Xiao-Yong Jin;E. Neil
中科院分区：
文献类型：
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作者：
T. Appelquist;R. Brower;K. Cushman;G. Fleming;A. Gasbarro;A. Hasenfratz;Xiao-Yong Jin;E. Neil
复合希格斯玻色子模型必须表现出与量子色动力学（QCD）非常不同的动力学，无论它们是将希格斯玻色子描述为类玻色子态还是伪南布-戈德斯通玻色子。大尺度分离和大反常尺寸是唯象模型经常需要的。质量分裂系统非常适合复合希格斯模型，因为它们在紫外线下由共形固定点控制，但在红外线下手性断裂。在这项工作中，我们使用晶格场论计算畴壁费米子调查系统与四轻和六重口味。我们演示了附近的共形不动点如何影响在红外线中表现出手征对称性破缺的四种光味的性质。具体来说，我们描述超尺度的维数的物理量，并确定相应的异常质量尺寸。我们得到y_m=1+\gamma^*= 1.47（5）$，表明N_f=10$位于共形窗内。将低能谱与手性微扰理论的预测进行比较，我们观察到非常好的一致性，这支持了4+6质量分裂系统表现出近共形动力学的期望，具有相对较轻的0 ^{++}$等单线态标量。
Composite Higgs models must exhibit very different dynamics from quantum chromodynamics (QCD) regardless whether they describe the Higgs boson as a dilaton-like state or a pseudo-Nambu-Goldstone boson. Large separation of scales and large anomalous dimensions are frequently desired by phenomenological models. Mass-split systems are well-suited for composite Higgs models because they are governed by a conformal fixed point in the ultraviolet but are chirally broken in the infrared. In this work we use lattice field theory calculations with domain wall fermions to investigate a system with four light and six heavy flavors. We demonstrate how a nearby conformal fixed point affects the properties of the four light flavors that exhibit chiral symmetry breaking in the infrared. Specifically we describe hyperscaling of dimensionful physical quantities and determine the corresponding anomalous mass dimension. We obtain $y_m=1+\gamma^*= 1.47(5)$ suggesting that $N_f=10$ lies inside the conformal window. Comparing the low energy spectrum to predictions of dilaton chiral perturbation theory, we observe excellent agreement which supports the expectation that the 4+6 mass-split system exhibits near-conformal dynamics with a relatively light $0^{++}$ isosinglet scalar.