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arXiv 1506.06804hep-ex
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用CMS探测器观测标准模型类希格斯玻色子双光子共振

Observation and Measurement of a Standard Model Higgs Boson-like Diphoton Resonance with the CMS Detector

Mingming Yang

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摘要：

本论文关注的是一种新粒子的观测及其性质的测量，从在欧洲核子研究中心大型强子对撞机（LHC）的CMS实验中通过衰变为两个光子来寻找希格斯玻色子，到2011年和2012年CMS探测器收集的完整LHC“运行I”数据，包括在$\sqrt{s}$ $=$ $7~\mathrm{TeV}$与$L$ $=$ $5.1~\mathrm{fb^{-1}}$以及在$\sqrt{s}$ $=$ $8~\mathrm{TeV}$与$L$ $=$ $19.7~\mathrm{fb^{-1}}$处的质子-质子碰撞事件，以及最终校准。特别是，观察到超过背景预期的事件，在质量为124.7 GeV时具有5.7标准差的局部显著性，这构成了通过双光子衰变通道观察到新粒子。进一步的测量提供了这个新粒子的精确质量为$124.72_{-0.36}^{+0.35}$ GeV = 124.72 $_{-0.32}^{+0.31}$（stat）$_{-0.16}^{+0.16}$（syst）GeV。它的总产生截面乘以相对于标准模型希格斯玻色子的双光子衰变分支比被确定为$1.12_{-0.23}^{+0.26}$ = 1.12 $_{-0.21}^{+0.21}$（stat）$_{-0.09}^{+0.15}$（syst），与希格斯玻色子的预期一致。进一步提取它相对于希格斯玻色子的性质，包括希格斯玻色子产生过程的产生截面时间衰变分支比，玻色子和费米子的耦合，以及光子和胶子的有效耦合，都与标准模型希格斯玻色子的预期相一致。

英文摘要：

This thesis concerns the observation of a new particle and the measurements of its properties, from the search of the Higgs boson through its decay into two photons at the CMS experiment at CERN's Large Hadron Collider (LHC), on the full LHC "Run I" data collected by the CMS detector during 2011 and 2012, consisting of proton-proton collision events at $\sqrt{s}$ $=$ $7~\mathrm{TeV}$ with $L$ $=$ $5.1~\mathrm{fb^{-1}}$ and at $\sqrt{s}$ $=$ $8~\mathrm{TeV}$ with $L$ $=$ $19.7~\mathrm{fb^{-1}}$, with the final calibration. In particular, an excess of events above the background expectation is observed, with a local significance of 5.7 standard deviations at a mass of 124.7 GeV, which constitutes the observation of a new particle through the two photon decay channel. A further measurement provides the precise mass of this new particle as $124.72_{-0.36}^{+0.35}$ GeV = 124.72$_{-0.32}^{+0.31}$(stat)$_{-0.16}^{+0.16}$(syst) GeV. Its total production cross section times two photon decay branching ratio relative to that of the Standard Model Higgs boson is determined as $1.12_{-0.23}^{+0.26}$ = 1.12$_{-0.21}^{+0.21}$(stat)$_{-0.09}^{+0.15}$(syst), compatible with the Higgs boson expectation. Further extractions of its properties relative to the Higgs boson, including the production cross section times decay branching ratios for separate Higgs production processes, couplings to bosons and to fermions, and effective couplings to the photon and to the gluon, are all compatible with the expectations for the Standard Model Higgs boson.

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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