Probing Heavy Spin-2 Bosons with $\gamma \gamma$ final states from Vector Boson Fusion Processes at the LHC

Abstract

New massive spin-2 particles are predicted in theoretical extensions to the Standard Model (SM) attempting to solve the hierarchy problem. Such theories postulate that gravity is diluted compared to the other fundamental forces because it can propagate in extra spatial dimensions. While such theoretical models are of high experimental interest because they predict massive spin-2 particles ($Y_2$) potentially detectable by collider experiments, searches at the Large Hadron Collider (LHC) have thus far produced no significant evidence for their existence. This work considers a hypothetical physics scenario where low coupling strengths between the $Y_2$ and quarks/gluons is the underlying reason behind the null $Y_2$ search results at the LHC, which have mainly relied on Drell-Yan and gluon-gluon fusion production mechanisms. The focus of this paper is a feasibility study to search for $Y_2$ particles using vector boson fusion (VBF) processes at the LHC. In the context of an effective field theory approach with varying couplings ${\kappa }_V$ between $Y_2$ and the weak bosons of the SM, we consider the $Y_2\to \gamma \gamma$ decay mode to show that the requirement of a diphoton pair combined with two high $p_T$ forward jets with large dijet mass and with large separation in pseudorapidity can significantly reduce the SM backgrounds. Assuming proton-proton collisions at $\sqrt{s}=13$ TeV, we present the total VBF production cross sections, $Y_2$ decay widths, and $Y_2\to \gamma \gamma$ branching ratios as a function of $m(Y_2)$, considering universal and non-universal couplings to the SM particles. The unitarity-violating phase space is described. The proposed VBF $Y_2\to \gamma \gamma$ search is expected to achieve a discovery reach with signal significance greater than 5$\sigma$ for $Y_2$ masses up to 4.4 TeV and ${\kappa }_V$ couplings down to 0.5.

9 pages, 15 figures

References in corpus (11)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• FeynRules - Feynman rules made easy
• Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions
• Search for new phenomena in high-mass diphoton final states using 37 fb${}^{-1}$ of proton-proton collisions collected at $\sqrt{s}=13$ TeV with the ATLAS detector
• Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search
• Vector Boson Fusion Processes as a Probe of Supersymmetric Electroweak Sectors at the LHC
• Probing Compressed Sleptons at the LHC using Vector Boson Fusion Processes
• Expanding the Reach of Heavy Neutrino Searches at the LHC
• Searching for New Heavy Neutral Gauge Bosons using Vector Boson Fusion Processes at the LHC

Cited by in corpus (2)

• Search for supersymmetry with a compressed mass spectrum in events with a soft $\tau$ lepton, a highly energetic jet, and large missing transverse momentum in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Long-term LHC Discovery Reach for Compressed Higgsino-like Models using VBF Processes