CERN Accelerating science

ATLAS

Stephanie Zimmermann (1973 – 2020)

  We have been deeply saddened to hear about the passing of Stephanie Zimmermann, an outstanding physicist, who has made a long-lasting contributions to the ATLAS experiment. Stephanie was involved in the Muon Detector Control System activities and…

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Machine learning ushers in a new paradigm for particle searches at the LHC

Searching for physics beyond the Standard Model (BSM) is a major part of the research programme at the LHC experiments. Nearly all of these searches pick a signal model that addresses one or more of the experimental (e.g., dark matter) or…

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What is the likelihood function, and how is it used in particle physics?

In statistical data analysis, “likelihood” is a key concept that is closely related to, but crucially distinct from, the concept of “probability”, which is often a synonym in everyday English. In this article, I first lay some necessary foundations…

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ATLAS New Small Wheel Upgrade – activities resumed after down-time from COVID-19

 As discussed in a previous issue of the EP Newsletter (The ATLAS New Small Upgrade – entering new waters, preparing to install and commission its first sector, October 2019), the New Small Wheel (NSW) Upgrade is the most challenging and complex one…

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CERN experiments find first evidence for rare Higgs boson decay

The strength of the interaction between the Higgs field and a particle determines the mass it obtains from the Higgs and it is a mystery why the interaction strength is different for different particles. This puzzle is exacerbated as the leptons,…

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How to search for new physics without knowing about it?

BSM searches at the LHC increasingly profit from ML techniques since this approach allows more general searches that minimise the probability of missing evidence of new physics. Very recently, the ATLAS collaboration has published a novel approach […

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ATLAS results: from precision to rarity

 Two recent ATLAS results that showcase the full range of the ATLAS physics potential, from precision to rarity, were shown at LHCP and presented at a recent CERN LHC seminar. A test of the universality of τ and μ lepton couplings in W boson decays…

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LHC experiments ramp-up activities

Around the world,research centres, laboratories and universities have closed as a response to the COVID-19 pandemic — forcing an increasing number of researchers to work from home. Researchers teleworking coordinated with colleagues who had to…

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Exploring new ways to see the Higgs boson

The ATLAS and CMS collaborations presented their latest results on new signatures for detecting the Higgs boson at CERN’s Large Hadron Collider. These include searches for rare transformations of the Higgs boson into a Z boson – which is a carrier…

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ATLAS experiment revamps activities

  ATLAS entered the COVID-19 lock down on the 17th of March 2020; the closing of  the activities was very fast and efficient. During the lock down, still many activities were performed remotely, among them the development of the firmware for two of…

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