在大型強子對撞機的緊湊渺子線圈偵測器，使用13兆電子伏特的質子-質子對撞尋找會衰變到一對希格斯玻色子且最終狀態為四個底夸克的重共振態;Search for heavy resonances decaying to a pair of Higgs bosons in four b quark final state in pp collisions at √s = 13 TeV using the CMS detector at the LHC

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/75280

Title:	在大型強子對撞機的緊湊渺子線圈偵測器，使用13兆電子伏特的質子-質子對撞尋找會衰變到一對希格斯玻色子且最終狀態為四個底夸克的重共振態;Search for heavy resonances decaying to a pair of Higgs bosons in four b quark final state in pp collisions at √s = 13 TeV using the CMS detector at the LHC
Authors:	李功喬;III, Gregorio de Leon
Contributors:	物理學系
Keywords:	重共振態;卡魯拉-凱勒重力子;輻射子;希格斯玻色子;底夸克;雙底夸克標記子;Heavy resonances;Bulk Graviton;Radion;Higgs boson;b quarks;double-b tagger
Date:	2017-11-10
Issue Date:	2018-01-16 10:43:48 (UTC+8)
Publisher:	國立中央大學
Abstract:	在這篇論文的分析裡, 我們尋找重共振態(卡魯拉-凱勒重力子或輻射子)衰變到一對標準模型的希格斯粒子的現象。兩個希格斯玻色子進一步衰變為一對底夸克-反底夸克作為最終狀態。這篇分析用的數據是來自質心能量為13兆電子伏特的質子對撞，這是對應到2015年用緊湊渺子線圈偵測器在大型強子對撞機第二階段運行時所搜集的2.7逆飛靶的積分亮度。因為這些共振態粒子的質量大於１兆電子伏特，所以這些希格斯玻色子具有高動量，而希格斯粒子衰變成的兩個底夸克會被重建成一個強子噴流。另外, 我們使用一個新的標記演算法"雙底夸克標記子"來辨認在希格斯噴流裡的兩個底夸克, 我們也使用"字母表" 方法來估計背景事件的數目。預測出來的背景事件數目顯示出了它跟搜集到的數據有很好的一致性，並且在所蒐搜集到的數據裡沒有觀察到顯著的多餘事件。因此這個結果可以用95%信心水準的上限來詮釋。在質量範圍在1兆電子伏特到4.5兆電子伏特之間，重力子跟輻射子存在的可能性都還沒有辦法排除。對於所假設的額外彎曲維度模型的這些參數並在所給定的質量範圍內，還需要更多的統計數據才能排除它們的可能性。;The search for heavy resonances (i.e. Kaluza-Klein Bulk Graviton and Radion) decaying to a pair of standard model Higgs bosons is presented. Both Higgs bosons decay further to b quark-antiquark pairs as the final state. The data used for this analysis were from the proton-proton collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 2.7 fb−1 and were collected by the CMS detector during the Run-II of the LHC in 2015. These resonance particles have masses that are ≥ 1 TeV, thus the Higgs bosons are highly Lorentz-boosted and each H → b ̄b can be reconstructed as one hadronic jet. A new tagging algorithm called “double-b tagger” is used to identify the b ̄b pairs inside the Higgs jet. The “Alphabet” method is used to estimate the background. The predicted background shows good agreement with the data and no significant data excess was observed. The results are then interpreted in terms of 95% CLs upper limit on the production cross section of the resonances. No exclusion was made on both Bulk Graviton and Radion mass between 1000 to 4500 GeV. A larger data sample is needed to exclude from the given mass range for the assumed WED model parameter.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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