Antoniadis I, Babalic E M, Ghilencea D M
CERN Theory Division, 1211 Geneva 23, Switzerland.
Theoretical Physics Department, National Institute of Physics and Nuclear Engineering (IFIN-HH), MG-6, 077125 Bucharest, Romania ; Department of Mathematics and Natural Sciences, University of Craiova, 13 A. I., Cuza street, 200585 Craiova, Romania.
Eur Phys J C Part Fields. 2014;74(9):3050. doi: 10.1140/epjc/s10052-014-3050-9. Epub 2014 Sep 25.
In MSSM models with various boundary conditions for the soft breaking terms ([Formula: see text]) and for a Higgs mass of 126 GeV, there is a (minimal) electroweak fine-tuning [Formula: see text] to [Formula: see text] for the constrained MSSM and [Formula: see text] for non-universal gaugino masses. These values, often regarded as unacceptably large, may indicate a problem of supersymmetry (SUSY) breaking, rather than of SUSY itself. A minimal modification of these models is to lower the SUSY breaking scale in the hidden sector ([Formula: see text]) to few TeV, which we show to restore naturalness to more acceptable levels [Formula: see text] for the most conservative case of low [Formula: see text] and ultraviolet boundary conditions as in the constrained MSSM. This is done without introducing additional fields in the visible sector, unlike other models that attempt to reduce [Formula: see text]. In the present case [Formula: see text] is reduced due to additional (effective) quartic Higgs couplings proportional to the ratio [Formula: see text] of the visible to the hidden sector SUSY breaking scales. These couplings are generated by the auxiliary component of the goldstino superfield. The model is discussed in the limit its sgoldstino component is integrated out so this superfield is realized non-linearly (hence the name of the model) while the other MSSM superfields are in their linear realization. By increasing the hidden sector scale [Formula: see text] one obtains a continuous transition for fine-tuning values, from this model to the usual (gravity mediated) MSSM-like models.
在具有软破缺项（[公式：见正文]）的各种边界条件以及希格斯质量为126 GeV的最小超对称标准模型（MSSM）中，对于约束MSSM，存在（最小）电弱微调，范围从[公式：见正文]到[公式：见正文]；对于非通用规范微子质量，微调范围是[公式：见正文]。这些值通常被认为大得不可接受，这可能表明是超对称（SUSY）破缺的问题，而非超对称本身的问题。对这些模型进行的最小修改是将隐藏区的超对称破缺尺度（[公式：见正文]）降低到几太电子伏特（TeV），我们证明，对于低[公式：见正文]和紫外边界条件的最保守情况（如在约束MSSM中），这样做能将自然性恢复到更可接受的水平（[公式：见正文]）。与其他试图降低[公式：见正文]的模型不同，此做法无需在可见区引入额外场。在当前情况下，[公式：见正文]因与可见区和隐藏区超对称破缺尺度之比[公式：见正文]成正比的额外（有效）四次希格斯耦合而降低。这些耦合由金斯顿超场的辅助分量产生。在将其超伴子分量积分掉的极限情况下讨论该模型，所以这个超场以非线性方式实现（因此该模型得名），而其他MSSM超场以线性方式实现。通过提高隐藏区尺度[公式：见正文]，可以得到微调值从该模型到通常的（引力介导的）类MSSM模型的连续过渡。
