Sensitivity of W -boson measurements to low-mass right-handed neutrinos

A low-mass right-handed neutrino could interact with electroweak bosons via mixing, a mediator particle, or loop corrections. Using an effective field theory, we determine constraints on these interactions from <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>W</a:mi> </a:math> -boson measurements at hadron colliders. Due to the difference in the initial states at the Tevatron and the LHC, <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>W</c:mi> </c:math> -boson decays to a right-handed neutrino would artificially increase the mass measured at the Tevatron while only affecting the difference between <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msup> <e:mi>W</e:mi> <e:mo>+</e:mo> </e:msup> </e:math> and <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:msup> <g:mi>W</g:mi> <g:mo>−</g:mo> </g:msup> </g:math> mass measurements at the LHC. Measurements from CDF and the LHC are used to infer the corresponding parameter values, which are found to be inconsistent between the two. The LHC experiments can improve sensitivity to these interactions by measuring the cosine of the helicity angle using <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mi>W</i:mi> </i:math> bosons produced with transverse momentum above <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mo>≈</k:mo> <k:mn>50</k:mn> <k:mtext> </k:mtext> <k:mtext> </k:mtext> <k:mi>GeV</k:mi> </k:math> .