A search for large extra spatial dimensions via virtual-graviton exchange in the diphoton channel has been carried out with the CMS detector at the LHC. No excess of events above the standard model expectations is found using a data sample collected in proton-proton collisions at sqrt(s) = 7 TeV and corresponding to an integrated luminosity of 36 inverse picobarns. New lower limits on the effective Planck scale in the range of 1.6-2.3 TeV at the 95% confidence level are set, providing the most restrictive bounds to date on models with more than two large extra dimensions.

A search for signatures of extra dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at √s = 7 TeV corresponding to an integrated luminosity of 2.2 fb−1. In the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3-3.8 TeV at the 95% confidence level. These limits are the most restrictive bounds on virtual-graviton exchange to date. The most restrictive lower limits to date are also set on the mass of the first graviton excitation in the Randall-Sundrum model in the range of 0.86-1.84 TeV, for values of the associated coupling parameter between 0.01 and 0.10.

A search for large extra dimensions in the diphoton final state using the interpretation of the ADD model is presented. The analysis is performed using 35.9fbinv of data from proton-proton collisions during Run II of the Large Hadron Collider that was recorded by the Compact Muon Solenoid detector in the year 2016. The center of mass energy of the proton-proton system was 13TeV. Events from both data and the Standard Model diphoton background monte-carlo simulation are selected by a cut-based photon identification that has been tuned for photons with high transverse momentum. The simulated Standard Model diphoton events are corrected to NNLO precision by a k-factor calculated by MCFM. The contribution from events with one or two jets misidentified as photons is derived by a data-driven method. The observed data are consistent with the Standard Model. Limits on the ultraviolet cutoff parameter of the ADD model of large extra dimensions MS are calculated as a function of the number of extra dimensions n in the GRW, HLZ, and Hewett conventions for the dependence of the total cross section on MS. In the GRW convention, we observe a 95\% lower limit on MS of 7.6TeV.

Results are presented from a search for particle dark matter (DM), extra dimensions, and unparticles using events containing a jet and an imbalance in transverse momentum. The data were collected by the CMS detector in proton-proton collisions at the LHC and correspond to an integrated luminosity of 19.7 fb$^{-1}$ at a centre-of-mass energy of 8 TeV. The number of observed events is found to be consistent with the standard model prediction. Limits are placed on the DM-nucleon scattering cross section as a function of the DM particle mass for spin-dependent and spin-independent interactions. Limits are also placed on the scale parameter $M_\mathrm{D}$ in the ADD model of large extra dimensions, and on the unparticle model parameter $\Lambda_\mathrm{U}$. The constraints on ADD models and unparticles are the most stringent limits in this channel and those on the DM-nucleon scattering cross section are an improvement over previous collider results.