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丈量宇宙最强力
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作者 斯坦利·j.布罗德斯基 亚历山大·德尔 +2 位作者 克雷格·D.罗伯茨 李新鹏(翻译) 崔著钫(审校) 《环球科学》 2024年第11期24-31,共8页
宇宙中最强之力,也恰巧被称作强力。我们从来没有亲眼见证过它强大的力量,因为这种力仅作用在亚原子尺度。在这一尺度下,强力会将质子和中子中的夸克束缚在一起,然后将这些核子结合成原子核。宇宙中迄今为止已知的四种基本力是引力、电... 宇宙中最强之力,也恰巧被称作强力。我们从来没有亲眼见证过它强大的力量,因为这种力仅作用在亚原子尺度。在这一尺度下,强力会将质子和中子中的夸克束缚在一起,然后将这些核子结合成原子核。宇宙中迄今为止已知的四种基本力是引力、电磁力、弱力和强力,其中强力是最强的——它是引力的100万亿万亿万亿(1038)倍。但与此同时,它也是我们现在所知最少的基本力。 展开更多
关键词 亚原子 引力 夸克 电磁力 弱力 原子核 强力 宇宙
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Reanalysis of the top-quark pair hadroproduction and a precise determination of the top-quark pole mass at the LHC
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作者 Sheng-Quan Wang Xing-Gang Wu +1 位作者 jian-Ming Shen stanley j.brodsky 《Chinese Physics C》 SCIE CAS CSCD 2021年第11期25-33,共9页
In this study,we calculate the tt pQCD production cross-section at the NNLO and determine the top-quark pole mass from recent measurements at the LHC at the center-of-mass energy √S=13 TeV to a high precision by appl... In this study,we calculate the tt pQCD production cross-section at the NNLO and determine the top-quark pole mass from recent measurements at the LHC at the center-of-mass energy √S=13 TeV to a high precision by applying the principle of maximum conformality(PMC).The PMC provides a systematic method that rigorously eliminates QCD renormalization scale ambiguities by summing the nonconformalβcontributions into the QCD coupling constant.The PMC predictions satisfy the requirements of renormalization group invariance,including renormalization scheme independence,and the PMC scales accurately reflect the virtuality of the underlying production subprocesses.By using the PMC,an improved prediction for the tt production cross-section is obtained without scale ambiguities,which in turn provides a precise value for the top-quark pole mass.Moreover,the prediction of PMC calculations that the magnitudes of higher-order PMC predictions are well within the error bars predicted from the known lower-order has been demonstrated for the top-quark pair production.The resulting determination of the top-quark pole mass,m^(pole)_(t)=172.5±1.4 GeV,from the LHC measurement at √S=13 TeV agrees with the current world average cited by the Particle Data Group(PDG).The PMC prediction provides an important high-precision test of the consistency of pQCD and the SM at √S=13 TeV with previous LHC measurements at lower CM energies. 展开更多
关键词 top-quark pole mass production cross-section principle of maximum conformality
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