First measurement of the left-right asymmetry in Z boson production

We present the first measurement of the left-right cross-section asymmetry (A(LR)) in Z-boson production observed at the SLAC Linear Collider. In 1992 the SLD detector recorded 10 224 Z events produced by the collision of longitudinally polarized electrons with an unpolarized positron beam at a center-of-mass energy of 91.55 GeV. The average electron beam polarization during the run was (22.4 +/- 0.6)%. We measure A(LR) to be 0.100 +/- 0.044 (stat.) +/- 0.004 (syst.), which determines the effective weak mixing angle to be sin2 theta(W)eff = 0.2378 +/- 0.0056 (stat.) +/- 0.0005 (syst.)

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

Understanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics