Superpartner mass measurement technique using 1D orthogonal decompositions of the Cambridge transverse mass variable...

We propose a new model-independent technique for mass measurements in missing energy events at hadron colliders. We illustrate our method with the most challenging case of a single-step decay chain. We consider inclusive same-sign chargino pair production in supersymmetry, followed by leptonic decays to sneutrinos χ+ χ+ → ℓ+ ℓ'+ ν(ℓ)ν(ℓ') and invisible decays ν(ℓ) → ν(ℓ) χ(1)(0). We introduce two one-dimensional decompositions of the Cambridge MT2 variable: M(T2∥) and M(T2⊥), on the direction of the upstream transverse momentum P→T and the direction orthogonal to it, respectively. We show that the sneutrino mass Mc can be measured directly by minimizing the number of events N(Mc) in which MT2 exceeds a certain threshold, conveniently measured from the end point M(T2⊥)(max) (Mc).