With the discovery of a Higgs boson with a mass of 125 gigaelectronvolts (GeV) at the Large Hadron Collider (LHC) at CERN in 2012, the Standard Model (SM) is complete, and despite intensive searches, no new fundamental particle has been observed since then. In fact, a discovery can be challenging without a predictive new physics model because different channels and observables cannot be combined directly and unambiguously. Furthermore, without supporting indirect hints, the signal space to be searched is huge, resulting in diluted significances owing to the look-elsewhere effect. Several LHC processes with multiple leptons in the final state point towards the existence of a new Higgs boson with a mass between 140 GeV to 160 GeV decaying mostly to $\textit{W}$ bosons. While the former strongly reduces the look-elsewhere effect, the latter indicates that it could be a Higgs triplet with zero hypercharge. Within this simple and predictive extension of the SM, we simulate and combine different channels of di-photon production in association with leptons, missing energy, jets, $\textit{etc}$... Using the full run-2 results by ATLAS, including those presented recently at the Moriond conference, an increased significance of 4 standard deviations is obtained for a $\approx$ 152 GeV Higgs. Due to the previously predicted mass range, the look-elsewhere effect is negligible, and this constitutes the highest statistical evidence for a new narrow resonance obtained at the LHC. Furthermore, the model predicts a heavier-than-expected $\textit{W}$ boson, as indicated by the global electroweak fit. If further substantiated, the discovery of a new Higgs would overthrow the SM, provide a compelling case for the construction of future particle colliders, and pave the way to a novel understanding of the known shortcomings of the SM. In particular, the triplet Higgs field can lead to a strong first-order phase transition and could thus be related to the matter anti-matter asymmetry in our Universe.

Switzerland

Andreas Crivellin

China

Saiyad Ashanujjaman

Sumit Banik

Guglielmo Coloretti

India

Siddharth P. Maharathy

South Africa

Bruce Mellado

Growing evidence for a Higgs triplet * The work of Andreas Crivellin is supported by a Professorship Grant from the Swiss National Science Foundation (PP00P21_76884). The work of Saiyad Ashanujjaman is partially supported by the National Natural Science Foundation of China (11835013). Siddharth P. Maharathy acknowledges using the SAMKHYA: High-Performance Computing Facility provided by the Institute of Physics, Bhubaneswar

The electron capture in  $$^{163}\mathrm {Ho}$$  <math> <mrow> <msup> <mrow></mrow> <mn>163</mn> </msup> <mi>Ho</mi> </mrow> </math>   experiment (ECHo) is designed to directly measure the effective electron neutrino mass by analysing the endpoint region of the  $$^{163}\mathrm {Ho}$$  <math> <mrow> <msup> <mrow></mrow> <mn>163</mn> </msup> <mi>Ho</mi> </mrow> </math>   electron capture spectrum. We present a data reduction scheme for the analysis of high statistics data acquired with the first phase of the ECHo experiment, ECHo-1k, to reliably infer the energy of  $$^{163}\mathrm {Ho}$$  <math> <mrow> <msup> <mrow></mrow> <mn>163</mn> </msup> <mi>Ho</mi> </mrow> </math>   events and discard triggered noise or pile-up events. On a first level, the raw data is filtered purely based on the trigger time information of the acquired signals. On a second level, the time profile of each triggered event is analysed to identify the signals corresponding to a single energy deposition in the detector. We demonstrate that events not belonging to this category are discarded with an efficiency above 99.8%, with a minimal loss of  $$^{163}\mathrm {Ho}$$  <math> <mrow> <msup> <mrow></mrow> <mn>163</mn> </msup> <mi>Ho</mi> </mrow> </math>   events of about 0.7%. While the filter using the trigger time information is completely energy independent, a slight energy dependence of the filter based on the time profile is precisely characterised. This data reduction protocol will be important to minimise systematic errors in the analysis of the  $$^{163}\mathrm {Ho}$$  <math> <mrow> <msup> <mrow></mrow> <mn>163</mn> </msup> <mi>Ho</mi> </mrow> </math>   spectrum for the determination of the effective electron neutrino mass.

Germany

Robert Hammann

Arnulf Barth

Andreas Fleischmann

Dennis Schulz

Loredana Gastaldo

Data reduction for a calorimetrically measured  $$^{163}\mathrm {Ho}$$  <math> <mrow> <msup> <mrow></mrow> <mn>163</mn> </msup> <mi>Ho</mi> </mrow> </math>   spectrum of the ECHo-1k experiment