Search for right-handed W bosons and heavy neutrinos with the ATLAS experiment

A search for heavy right-handed Majorana or Dirac neutrinos (NR) and heavy right-handed W gauge bosons (WR) participating in the Keung-Senjanovi´c process has been performed in events with a pair of energetic electrons or muons, with opposite-sign charges, and two energetic jets. Events were selected from pp collision data with an integrated luminosity of 36.1fb−1 collected by the ATLAS detector at √s = 13TeV. No significant deviations from the Standard Model expectation were observed. The results were interpreted within the theoretical frameworks of two forms of Left-Right Symmetric Model and lower limits were set on masses in the heavy right-handed W and neutrino mass plane, as well as upper limits on the Keung-Senjanovi´c process cross section multiplied by the branching fraction to eejj or µµjj. The excluded region extends to mWR = 4.7TeV for both Majorana and Dirac NR neutrinos. The mNR > mWR region is explored for the first time by a search for the Keung-Senjanovi´c process at the LHC

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Trigger Menu-aware Monitoring for the ATLAS experiment

Changes in the trigger menu, the online algorithmic event-selection of the ATLAS experiment at the LHC, are followed by adjustments to the ATLAS trigger monitoring systems. During Run 1, and so far in Run 2, ATLAS has deployed monitoring updates with the installation of new software releases at Tier-0, the first level of the ATLAS computing grid. Having to wait for a new software release to be installed at Tier-0, in order to update ATLAS offline trigger monitoring configurations, results in a lag with respect to the modification of the trigger menu. We present the design and implementation of a `trigger menu-aware' monitoring system that aims to simplify the ATLAS operational workflows by allowing monitoring configuration changes to be made at the Tier-0 site by utilising an Oracle SQL database.We present a“trigger menu-aware” monitoring system designed for the Run-2 data-taking of the ATLAS experiment at the LHC. Unlike Run-1, where a change in the trigger menu had to be matched by the installation of a new software release at Tier-0, the new monitoring system aims to simplify the ATLAS operational workflows. This is achieved by integrating monitoring updates in a quick and flexible manner via an Oracle DB interface. We present the design and the implementation of the menu-aware monitoring, along with lessons from the operational experience of the new system with the 2016 collision data

A mechanistic mathematical model of initiation and malignant transformation in sporadic vestibular schwannoma

BACKGROUND: A vestibular schwannoma (VS) is a relatively rare, benign tumour of the eighth cranial nerve, often involving alterations to the gene NF2. Previous mathematical models of schwannoma incidence have not attempted to account for alterations in specific genes, and could not distinguish between nonsense mutations and loss of heterozygosity (LOH). METHODS: Here, we present a mechanistic approach to modelling initiation and malignant transformation in schwannoma. Each parameter is associated with a specific gene or mechanism operative in Schwann cells, and can be determined by combining incidence data with empirical frequencies of pathogenic variants and LOH. RESULTS: This results in new estimates for the base-pair mutation rate u = 4.48 × 10(−10) and the rate of LOH = 2.03 × 10(−6)/yr in Schwann cells. In addition to new parameter estimates, we extend the approach to estimate the risk of both spontaneous and radiation-induced malignant transformation. DISCUSSION: We conclude that radiotherapy is likely to have a negligible excess risk of malignancy for sporadic VS, with a possible exception of rapidly growing tumours

A mechanistic mathematical model of initiation and malignant transformation in sporadic vestibular schwannoma

AbstractA vestibular schwannoma (VS) is a relatively rare, benign tumour of the eighth cranial nerve, often involving alterations to the gene NF2. Previous mathematical models of schwannoma incidence have not attempted to account for alterations in specific genes, and could not distinguish between point mutations and loss of heterozygosity (LOH). Here, we present a mechanistic approach to modelling initiation and malignant transformation in Schwannoma. Each parameter is associated with a specific gene or mechanism operative in Schwann cells, and can be determined by combining incidence data with empirical frequencies of pathogenic variants and LOH. This results in new estimates for the base pair mutation rate u = 4.48 × 10−10 and the rate of LOH = 2.03 × 10−6/yr in Schwann cells. In addition to new parameter estimates, we extend the approach to estimate the risk of both spontaneous and radiation-induced malignant transformation. We conclude that radiotherapy is likely to have a negligible excess risk of malignancy for sporadic VS, with a possible exception of rapidly growing tumours.</jats:p