Higgs boson decay to two photons and dispersion relations
Higgs boson decay to two photons and dispersion relations
复制标题
希格斯玻色子衰变成两个光子和色散关系
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
A. Vainshtein
中科院分区：
文献类型：
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作者：
K. Melnikov;A. Vainshtein
讨论了利用色散关系计算Higgs玻色子通过W环衰变到双光子的振幅。参数化这种衰减的形状因子F_W（s）的虚部在四维中是明确的。当用它计算未减色散积分时，得到了形状因子F_W（s）的有限结果。然而，用这种方法得到的F_W（s）与基于维数正则化的图解计算结果相差一个常数项。对于F_W（s），通过写一个减去一次的色散关系，很容易就能弥补缺失的常数，但为什么要做减法，这一点还不清楚。本文的目的是详细研究这个问题。我们表明，正确的常数可以恢复内的色散的方法在许多方面，但是，要么需要引入紫外线调节器或非物理的自由度;不受管制和unsubtracted计算在酉规范是不够的，尽管这样的计算给出了一个有限的结果。
We discuss the computation of the Higgs boson decay amplitude to two photons through the W-loop using dispersion relations. The imaginary part of the form factor F_W(s) that parametrizes this decay is unambiguous in four dimensions. When it is used to calculate the unsubtracted dispersion integral, the finite result for the form factor F_W(s) is obtained. However, the F_W(s) obtained in this way differs by a constant term from the result of a diagrammatic computation, based on dimensional regularization. It is easy to accommodate the missing constant by writing a once-subtracted dispersion relation for F_W(s) but it is unclear why the subtraction needs to be done. The goal of this paper is to investigate this question in detail. We show that the correct constant can be recovered within a dispersive approach in a number of ways that, however, either require an introduction of an ultraviolet regulator or unphysical degrees of freedom; unregulated and unsubtracted computations in the unitary gauge are insufficient, in spite of the fact that such computations give a finite result.