对质心能量为13 TeV的ATLAS多轻子搜索进行再分析得到的双荷希格斯玻色子排除限修正
Revised exclusion limits on doubly charged Higgs bosons from a reanalysis of the ATLAS multi-lepton search at $\sqrt{s} = 13$,TeV
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中文总结 AI 辅助
本研究通过再分析ATLAS多轻子搜索数据，修正双荷希格斯玻色子的排除限，将左右对称II型 seesaw模型与Zee-Babu模型的预期下限分别下调至~950 GeV和~770 GeV。
中文摘要 AI 辅助
ATLAS利用Run 2完整数据集对双产生双荷希格斯玻色子的多轻子末态进行搜索[Eur. Phys. J. C 83 (2023) 605]，该搜索在本质上无本底的四轻子道驱动下，给出了迄今为止双荷标量粒子质量的最强排除限。我们发现，该分析辅助流所隐含的四轻子信号效率，超出了由该搜索的等分支比假设、轻子τ衰变分支比及ATLAS轻子重建效率导出的严格与质量无关的上限。我们证明，若不引入远高于实际值的假率， hadronic τ或喷注误认无法解释该超出量。我们独立重现信号并利用修正后的信号产额、ATLAS本底预测及不确定度，以及pyhf中实现的相同CL_s程序重新计算排除限。所得预期限系统地高于ATLAS的预期限，幅度约为2倍或更高。这在左右对称II型 seesaw模型中将预期 lower mass bound从1065 GeV移至~950 GeV，在Zee-Babu模型中从880 GeV移至~770 GeV。
英文摘要
The ATLAS search for pair-produced doubly charged Higgs bosons in multi-lepton final states using the full Run 2 dataset [Eur. Phys. J. C 83 (2023) 605] reports the strongest limits to date on the mass of doubly charged scalars, driven by an essentially background-free four-lepton channel. We show that the four-lepton signal efficiency implied by the auxiliary cutflow of that analysis exceeds a strict, mass-independent upper bound derived from the equal-branching-ratio assumption of the search, the leptonic $τ$ branching fractions, and the ATLAS lepton reconstruction efficiencies. We show that this excess cannot be explained by hadronic $τ$ or jet misidentification without invoking fake rates far above realistic values. We regenerate the signal independently and recompute the exclusion limit, using the corrected signal yields, the ATLAS background predictions and uncertainties, and the same $CL_s$ procedure implemented in pyhf. The resulting expected limit lies systematically above the ATLAS expected limit, by roughly a factor of two or more. This shifts the expected lower mass bound from $1065$ GeV to $\sim950$ GeV in the left-right symmetric type-II seesaw model, and from $880$ GeV to $\sim770$ GeV in the Zee--Babu model.
