A precision measurement of the mass of the top quark

By Delphi collaboration. Nature, 2004

217 citations recorded by the source corpus.

The standard model of particle physics contains parameters—such as particle masses—whose origins are still unknown and which cannot be predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark (Mt) and W boson (MW) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of Mt can therefore indicate where to look for the Higgs, and indeed whether the hypothesis of a standard model Higgs is consistent with experimental data. As top quarks are produced in pairs and decay in only about 10-24 s into various final states, reconstructing their masses from their decay products is very challenging. Here we report a technique that extracts more information from each top-quark event and yields a greatly improved precision (of ± 5.3 GeV/c2) when compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the only other measurements available, the new world average for Mt becomes 178.0 ± 4.3 GeV/c2. As a result, the most likely Higgs mass increases from the experimentally excluded value of 96 to 117 GeV/c2, which is beyond current experimental sensitivity. The upper limit on the Higgs mass at the 95% confidence level is raised from 219 to 251 GeV/c2.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/8aac5259e162c98aaebeb5359c9d5d01d3bc8e51

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Citations in the corpus

A review of the mass measurement techniques proposed for the Large Hadron Collider (2010, methodology): “For example, currently they are being used for top quark mass measurements [170, 171] and Higgs boson searches [172] at the Tevatron.”
Playing tag with ANN: boosted top identification with pattern recognition (2015, methodology): “d kinematic constraints built into them can also be used to study jet substructure, with the Template Overlap Method (TOM) [23–26] being the most notable example. More recently, Matrix Element Method [27,28] inspired techniques such as Shower Deconstruction have emerged [29,30], where a boosted jet ”
Looking Inside Jets (2019, methodology): “s respectively. From these probabilities one can build an ideal classier11 ˜(pN) = P(pNjS) P(pNjB) : (5.31) This fundamental observation is also the foundation of the so-called matrix-element method [159,160], used in various applications in particle phenomenology with xedorder matrix elements [161,”