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A post-genomic challenge: learning to read patterns of protein synthesis 总被引:22,自引:0,他引:22
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Abazov VM Abbott B Abdesselam A Abolins M Abramov V Acharya BS Adams DL Adams M Ahmed SN Alexeev GD Alton A Alves GA Arnoud Y Avila C Babintsev VV Babukhadia L Bacon TC Baden A Baffioni S Baldin B Balm PW Banerjee S Barberis E Baringer P Barreto J Bartlett JF Bassler U Bauer D Bean A Beaudette F Begel M Belyaev A Beri SB Bernardi G Bertram I Besson A Beuselinck R Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Blazey G Blekman F Blessing S Boehnlein A Bojko NI Bolton TA Borcherding F Bos K 《Nature》2004,429(6992):638-642
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 (M(t)) and W boson (M(W)) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of M(t) 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 M(t) 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. 相似文献
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