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arXiv 1208.0837hep-ph
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SUSY模型中似然的微调代价

The fine-tuning cost of the likelihood in SUSY models

D. M. Ghilencea, G. G. Ross

摘要:

在超对称模型中,电弱标度(EW标度)相对于其参数gamma_i={m_0,m_{1/2},mu_0,A_0,B_0,.}和拟合实验数据的最大似然L通常被视为两个不同的问题。我们表明,如果一个方面的EW最低条件的限制,固定的EW规模,这种普遍持有的观点是不正确的,可能性包含所有的信息微调。在这种情况下,我们表明,校正后的似然率等于通常的似然率L和传统的微调措施的EW规模的三角洲的比率L/三角洲。对于集合{gamma_i}上的积分似然获得了类似的结果,其可以被写为比率L/Delta的表面积分,其中gamma_i空间中的表面由EW最小约束确定。因此,大的似然实际上需要大的比率L/Delta,或者等价地,小的chi^2_{new}=chi^2_{old}+2*ln(Delta)。这显示了由超对称性强制执行的EW尺度稳定性的似然(chi^2_{new})的微调成本,这在数据拟合中被忽略。一个很好的chi^2_{new}/d.o.f.因此,\approx 1要求SUSY模型具有微调量Delta<<exp(d.o.f./ 2),它提供了一个可接受的微调模型无关的标准。如果不满足这一标准,那么就可以排除没有进一步的卡方面积/d.o.f.的超对称模型。分析.拟合数据的数值方法可以很容易地适应这种影响。

英文摘要:

In SUSY models, the fine tuning of the electroweak (EW) scale with respect to their parameters gamma_i={m_0, m_{1/2}, mu_0, A_0, B_0,...} and the maximal likelihood L to fit the experimental data are usually regarded as two different problems. We show that, if one regards the EW minimum conditions as constraints that fix the EW scale, this commonly held view is not correct and that the likelihood contains all the information about fine-tuning. In this case we show that the corrected likelihood is equal to the ratio L/Delta of the usual likelihood L and the traditional fine tuning measure Delta of the EW scale. A similar result is obtained for the integrated likelihood over the set {gamma_i}, that can be written as a surface integral of the ratio L/Delta, with the surface in gamma_i space determined by the EW minimum constraints. As a result, a large likelihood actually demands a large ratio L/Delta or equivalently, a small chi^2_{new}=chi^2_{old}+2*ln(Delta). This shows the fine-tuning cost to the likelihood (chi^2_{new}) of the EW scale stability enforced by SUSY, that is ignored in data fits. A good chi^2_{new}/d.o.f.\approx 1 thus demands SUSY models have a fine tuning amount Delta<<exp(d.o.f./2), which provides a model-independent criterion for acceptable fine-tuning. If this criterion is not met, one can thus rule out SUSY models without a further chi^2/d.o.f. analysis. Numerical methods to fit the data can easily be adapted to account for this effect.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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