Search for contact interactions in opposite-sign dimuon events in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper searches for contact interactions in high-mass opposite-sign dimuon events at 7 TeV, setting new lower limits on the compositeness energy scale, and finds results consistent with the standard model.

Contribution

It provides the first limits on contact interactions at 7 TeV using dimuon events, improving constraints on quark-muon compositeness models.

Findings

Lower limit on Lambda is 9.5 TeV for destructive interference.

Lower limit on Lambda is 13.1 TeV for constructive interference.

Results are consistent with the standard model expectations.

Abstract

Results are reported from a search for the effects of contact interactions using events with a high-mass, oppositely charged muon pair. The events are collected in proton-proton collisions at sqrt(s) = 7 TeV using the Compact Muon Solenoid detector at the Large Hadron Collider. The data sample corresponds to an integrated luminosity of 5.3 inverse femtobarns. The observed dimuon mass spectrum is consistent with that expected from the standard model. The data are interpreted in the context of a quark- and muon-compositeness model with a left-handed isoscalar current and an energy scale parameter Lambda. The 95% confidence level lower limit on Lambda is 9.5 TeV under the assumption of destructive interference between the standard model and contact-interaction amplitudes. For constructive interference, the limit is 13.1 TeV. These limits are comparable to the most stringent ones reported to date.