Speaker
Description
Exploring anomalous objects from beyond standard model (BSM) signatures is one important mission of the LHC experiments. Recently, new particles in the sub-GeV scale have received more and more attention. The light pseudo-scalar such as axion-like particles (ALPs) and light scalar such as dark Higgs are proposed by many BSM models and can be taken as mediators of some sub-GeV dark matter models as well. Except for the fixed target and B factories experiments, the light pseudo-scalar and scalar can also be searched via Higgs boson exotic decays and ALP/dark Higgs strahlung processes at the LHC.
In this talk, we will focus on Higgs boson exotic decays and introduce a Higgs portal simplified model with both a light scalar s and pseudo-scalar a and both h→aa and h→ss interactions are included. For the mass range of ms,a < 1 GeV, s,a→γγ, s→π0π0 and a→π0π0π0 can become dominant decay modes. As the scalar and pseudoscalar are highly boosted from the Higgs boson decay, the generated photons in the final states are collimated and non-isolated such that they are recorded as a single jet-like object, i.e. photon-jet, instead of multi-photons signature by the detector.
Based on the Higgs portal model, we will present the studies of photon-jet signatures in an ATLAS-like electromagnetic calorimeter with a full simulation of the electromagnetic showers using GEANT4. In particular, we will focus on the search of photon-jet signatures with the presence of photon or neutral pion originating from SM backgrounds using deep learning methods. The promising performance of photon-jet reconstruction and SM backgrounds rejection using Boosted Decision Tree technique and Convolutional Neural Network will be highlighted. The sensitivity of LHC to the constraints of h→aa and h→ss couplings will be discussed while these two triscalar couplings cannot be explored at the fixed target and B factories experiments.
Significance
The talk will present novel studies of using BDT and CNN for search of a dedicated new physics signature proposed at the LHC. A manuscript is being prepared for submission.
| Speaker time zone | Compatible with Europe |
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