A search for the resonant production of a heavy scalar X decaying into a Higgs boson and a new lighter scalar S is performed through the process X→ S (bb) H(γγ). The search is conducted using 140 fb−1 of LHC Run 2 data recorded by ATLAS. The mass space investigated in the analysis is 170 ≤ mX ≤ 1000 GeV and 15 ≤ mS ≤ 500 GeV. Parameterised Neural Networks (PNN) are used to enhance the signal purity and to achieve continuous sensitivity in a domain of the (mX, mS) mass plane.
A log-likelihood fit is performed on the PNN score distribution to look for an excess with respect to expected background compatible with X→ S (bb) H(γγ) signal.
If no excess is found, model independent upper limits will be set on the cross section times branching ratio.
The analysis of redshift-space distortions (RSD) aims to measure the growth-rate of structures by quantifying the anisotropies in the clustering of galaxies. In RSD analysis, it is crucial to accurately model the complete shape of the clustering. To accurately describe the density down to non linear scale, we used one-loop perturbation theory with effective corrections for small scale effects to model the requisite velocity statistics. This model allows us to model the 2-point statistics in either Fourier space or Configuration space. This implies that from the same catalog of galaxy we can conduct two analysis : one in Configuration Space and one in Fourier Space. Our work has been to establish a method to produce a consensus results from both analysis which might be different.
Similar to RSD analysis, peculiar velocity analysis aims to measure the growth rate of structure, specially at low redshifts. We will present our ongoing study focuses on velocity correlation statistics derived from SN Ia and galaxy measurements revealing a significant role for the properties of galaxies in peculiar velocity surveys.
Being forbidden in the Standard Model, Lepton Flavor Violating (LFV) decays are a powerful probe for new physics. Current limits on τ → e l l decays are close to predictions of Beyond Standard Model theories.
The Belle II experiment operates at the collision point of SuperKekB, an e+e- collider with a center of mass energy of 10.58 GeV and already has collected 424 fb-1. Thanks to its clean environment, hermetic detector and high τ pair production cross section, it is perfectly suited to study τ decays.
The search for τ → e l l decays, (l = e,\mu) is performed using an untagged analysis, and relying on machine learning techniques to reject background events. An unbinned fit is then performed to extract the upper limit on the branching ratio.
