Search for long-lived neutral particles decaying to dijets

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 jets originating at a secondary vertex. Events were collected by the CMS detector at the LHC during pp collisions at $\sqrt{s}=$ 8 TeV, and selected from data samples corresponding to 18.6 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, $\text{H}^0$, in the mass range 200 to 1000 GeV, decaying into a pair of long-lived neutral $\text{X}^0$ particles in the mass range 50 to 350 GeV, which each decay to quark-antiquark pairs. For $\text{X}^0$ mean proper lifetimes of 0.1 to 200 cm the upper limits are typically 0.3$-$300 fb.