# ICHEP2012

4-11 July 2012
Melbourne Convention and Exhibition Centre
Australia/Melbourne timezone
ICHEP2012 - 36th International Conference for High Energy Physics

## Spin correlations and W helicity in top events with CMS

5 Jul 2012, 15:15
15m
Room 216 (Melbourne Convention and Exhibition Centre)

### Room 216

#### Melbourne Convention and Exhibition Centre

Melbourne Australia
Parallel Sessions Track 4 - Top Quark Physics

### Speaker

Dr Suharyo Sumowidagdo (University of California Riverside (US))

### Description

Measurement of the polarisation of W bosons and top anti-top spin correlations in top-quark decays are presented. The analysis makes use of top-pair events in proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV using data collected by the CMS experiment during the year 2011. Final states are selected where one of the two W bosons decays into electron-neutrino or muon-neutrino, and the other into quarks. From these events the W-boson helicity fractions and angular asymmetries are extracted. The spin information is extracted from the the angular distributions of the top quark decay products. The results, in agreement with the expectations from the Standard Model, are presented and used to set limits on anomalous contributions to the Wtb vertex.

### Primary author

Dr Suharyo Sumowidagdo (University of California Riverside (US))

 Slides