Diphoton signals in theories with large extra dimensions to NLO QCD at hadron colliders

Abstract

We present a full next-to-leading order (NLO) QCD corrections to diphoton production at the hadron colliders in both standard model and ADD model. The invariant mass and rapidity distributions of the diphotons are obtained using a semi-analytical two cut-off phase space slicing method which allows for a successful numerical implementation of various kinematical cuts used in the experiments. The fragmentation photons are systematically removed using smooth-cone-isolation cuts on the photons. The NLO QCD corrections not only stabilise the perturbative predictions but also enhance the production cross section significantly.

Search for high-mass diphoton resonances inppcollisions ats=8 TeVwith the ATLAS detector

“…These results for the K-factor were provided by the authors of Refs. [38,39], using updated calculations at ffiffi ffi s p ¼ 8 TeV. Given these theory predictions for σ × BRðG Ã → γγÞ, the upper limits on σ ×BRðG Ã →γγÞ from Table IV do not take into account any theory uncertainties in the prediction of σ × BRðG Ã → γγÞ for the RS signal.…”

The two-loop QCD correction to massive spin-2 resonance $$ \rightarrow q \bar{q} g $$ → q q ¯ g

“…At hadron colliders, QCD corrections to these processes are necessary to make precise quantitative predictions and to have control over the theoretical uncertainties. To next-to-leading-order (NLO) accuracy, these processes have been studied in the context of ADD [5][6][7][8][9][10] and RS [11][12][13][14][15]. The effect of parton shower (PS) has also been considered [16][17][18].…”

Quark and gluon spin-2 form factors to two-loops in QCD

“…Renormalisation and factorisation scale dependences of a cross section to a particular order in perturbation theory give an estimate of the uncalculated higher order corrections. Presently next-to-leading order (NLO) QCD calculations have been done for di-lepton [10][11][12], di-photon [13,14] and di-electroweak gauge boson [15][16][17] productions via virtual KK modes in addition to the SM contributions. These virtual contributions have been incorporated in the AMC@NLO frame work and results to NLO+PS accuracy are now available for most of the di-final state processes [18,19].…”