在大型強子對撞機中進一步探索希格斯玻色子的性質

The properties of Higgs boson in the further LHC search

盧致廷(Lu, Chih Ting)

指導教授 ： 張敬民

國立清華大學/理學院/物理學系/博士(2015年)

https://doi.org/10.6843/NTHU.2015.00238

摘要

在 2012 年 7 月大型強子對撞機發現質量為 125~126 GeV 的新粒子。這個新粒子可能就是在 1960 年代提出來傳聞已久標準模型裡的希格斯玻色子或超越標準模型中的其中一個希格斯玻色子。
基於利用不同時期關於希格斯玻色子耦合係數數據的整體分析，我們提出以下關於希格斯玻色子性質的探索：
首先，我們利用額外 U(1) 延伸的 MSSM 模型（UMSSM）去解釋提高的雙光子率在收集完 2012 年的數據後，我們也預測了 Z 光子率和探討其他在 UMSSM 模型中類似希格斯玻色子的性質。
接著，有更多關於這個新粒子的數據收集在 2012~2013 年期間建議這個新粒子極有可能就是傳聞已久標準模型裡的希格斯粒子。一個理論學家急迫想問的問題便是這個希格斯玻色子是否完全解釋自發對稱破缺？目前的數據仍然允許其他的希格斯玻色子或其他 UV 物理去同時解釋自發對稱破缺。我們利用雙規範玻色子散射實驗去探索這些可能性，並且利用 2HDM 模型當做原型。
最後，關於希格斯玻色子耦合係數最近數據的整體分析顯示規範玻色子與希格斯玻色子的耦合係數非常接近標準模型的預測，但是頂夸克，底夸克與希格斯玻色子的耦合係數仍然無法有如此好的準確度。因此我們建議利用偵測單一頂夸克伴隨希格斯玻色子的實驗去決定頂夸克與希格斯玻色子耦合係數的正負號與大小。

關鍵字

希格斯玻色子 ； 大型強子對撞機 ； 超對稱模型 ； 雙規範玻色子散射 ； 頂夸克與希格斯玻色子的耦合

並列摘要

A new particle with mass of 125~126 GeV was discovered at the Large
Hadron Collider (LHC) in July 2012. This may be the long-sought Higgs
boson of the standard model (SM), which was proposed in the 1960's, or one
of the Higgs beyond the SM.
Based on a global analysis of all the Higgs couplings using all the available
data at different stages, we propose the following projects to explore the
properties of Higgs boson :
First, we use the extra U(1) extended MSSM (UMSSM) to explain the
enhanced diphoton rate after collecting data at the end of 2012. We also
predict the Z photon production rate and study the properties of the other Higgs bosons in the UMSSM.
Second, more evidences of this new particle have been collected at the
LHC during 2012~2013 suggesting the new boson is likely to be the long-sought Higgs boson in the SM. One pressing question theorists continue
to ask is whether this Higgs boson is a lone player responsible for the full
electroweak symmetry breaking. Data at that stage still allows room for
additional Higgs bosons or some other UV physics that may play a partial
role in the electroweak symmetry breaking as well. We use WW scattering to investigate such a possibility, using the two-Higgs-doublet model as a
prototype.
Finally, the global study of all the Higgs couplings using current data
shows that the gauge-Higgs coupling is very close to the SM value, but
the Top- and Bottom-Yukawa couplings cannot be determined as precise
as gauge-Higgs coupling. We suggest probing the Top-Yukawa coupling in
associated Higgs production with a single Top Quark to pin down both the
sign and size of the Top-Yukawa coupling.

並列關鍵字

Higgs boson ； LHC ； UMSSM model ； WW Scattering ； Top-Yukawa Coupling

參考文獻

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