Document Type



We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of the 2.7-5.4 fb-1 of pp- collisions collected during Run II of the Fermilab Tevatron collider. Combining measurements that simultaneously determine the fractions of the W bosons with longitudinal (f0) and right-handed (f+) helicities, we find f0= 0.722 ± 0.081[±0.062(stat) ± 0.052(syst)] and f+ = -0.033 ± 0.046[±0.034(stat) ± 0.031(syst)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f0 = 0.682 ± 0.057[±0.035(stat) ± 0.046(syst)] for fixed f+ and f+ = -0.015 ± 0.035[±0.018(stat) ± 0.030(syst)] for fixed f0. The results are consistent with standard model expectations.



Publication Date



D0 Collaboration

Original Citation

Combination of CDF adn D0 measurements of the W boson helicity in top quark decays. T. Aaltonen et al. [CDF and D0 Collaborations] Phys. Rev. D 85 071106 (2012).

Legacy Department

Department of Physics


We thank the staffs at Fermilab and collaborating institutions, and acknowledge support from the DOE and NSF (USA); CEA and CNRS/IN2P3 (France); FASI, Rosatom and RFBR (Russia); CNPq, FAPERJ, FAPESP, and FUNDUNESP (Brazil); DAE and DST (India); INFN (Italy); Ministry of Education, Culture, Sports, Science, and Technology (Japan); Colciencias (Colombia); CONACyT (Mexico); World Class University Program, National Research Foundation, NRF (Korea); CONICET and UBACyT (Argentina); Australian Research Council (Australia); FOM (The Netherlands); STFC and the Royal Society (United Kingdom); MSMT and GACR (Czech Republic); CRC Program and NSERC (Canada); Academy of Finland (Finland); BMBF and DFG (Germany); SFI (Ireland); Slovak R&D Agency (Slovakia); Programa Consolider-Ingenio 2010 (Spain); Swedish Research Council (Sweden); Swiss National Science Foundation (Switzerland); NSC (Republic of China); CAS and CNSF (China); and the A. P. Sloan Foundation (USA).






American Physical Society



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