A Search for Long-Lived Neutral Particles Decaying to Dijets with the CMS detector at the Large Hadron Collider

A search is performed for long-lived massive neutral particles decaying to quark-antiquark pairs. The experimental signature is a distinctive topology of a pair of hadronic jets originating at a secondary vertex. Events were collected by the CMS detector at the LHC during pp collisions at s = 8 TeV, and selected from data samples corresponding to 18.5/fb-1 of integrated luminosity. No significant excess is observed above Standard Model expectations and an upper limit is set with 95% confidence level on the production cross section of a heavy scalar particle, H0, in the mass range 200 to 1000 GeV, decaying into a pair of long-lived neutral X0 particles in the mass range 50 to 350 GeV, where each of the X0 particles decay to quark-antiquark pairs. For X0 mean proper lifetimes of 0.1 to 200 cm, the upper limits are typically 0.5--200 fb.