Scalar unparticle signals at the LHC

Abstract

If the scale invariance exists in nature, the so-called unparticle physics may become part of reality. The only way to refute or confirm this idea is through the experiments one of which is the Large Hadron Collider (LHC). One of the peculiar properties of the unparticle stuff is that it gives striking multi-photon signals which has been studied through only the unparticle self-interactions. By considering not only the self-interactions of unparticles but also all the other possible contributions, which are dominant, a detailed study of the processes, within a scalar unparticle scenario, $pp\to 4\gamma$, $pp\to 2\gamma 2g$, $pp\to 2\gamma 2\ell$, $pp\to 4e$, $pp\to 4\mu$ and $pp\to 2e2\mu$ at $\sqrt{s}=14$ TeV at the LHC is carried out. We use basic selection cuts and analyze various distributions to discriminate the signals over the Standard Model backgrounds and discuss what seems to be the most likely channel among the above ones for an indirect manifestation of unparticle effects. We follow a new approach to tackle the issue with the three-point correlation function for the scalar unparticle self-interactions. We also obtain the exclusion region in the unparticle parameter space from the available two-photon data of the LHC.