LHC tau-pair production constraints on $a_\tau$ and $d_\tau$

Abstract

We point out that relevant constraints on the anomalous magnetic ( a_\tau <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>a</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:math> ) and electric ( d_\tau <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>d</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:math> ) moment of the tau lepton can be derived from tau-pair production measurements performed at the LHC. Our conclusion is based on the observation that the leading relative deviations from the Standard Model prediction for pp \to \tau^+ \tau^- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mi>p</mml:mi> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>−</mml:mo> </mml:msup> </mml:mrow> </mml:math> due to a_\tau <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>a</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:math> and d_\tau <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>d</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:math> are enhanced at high energies. Less precise measurements at hadron colliders can therefore offer the same or better sensitivity to new physics with respect to high-precision low-energy measurements performed at lepton machines. We derive bounds on a_\tau <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>a</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:math> and d_\tau <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>d</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:math> using the full LHC Run II data set on tau-pair production and compare our findings with the current best limits on the tau anomalous moments.

Topics & Concepts