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  1. null (Ed.)
    Element-calcium ratios in the skeleton of cold-water coral Desmophyllum dianthus represent potential archives for paleo-reconstruction of several ocean properties including temperature and nutrient concentrations. However, relatively large uncertainties in these proxy calibrations and heterogeneity in the skeletal composition have limited its application to date. We address these issues by analyzing corals cultured under systematically varied seawater conditions (phosphate, barium, temperature, pH, feeding frequency) over a two-year period, and refine the calibration of P/Ca, Ba/Ca, U/Ca, and Li/Mg proxies for seawater phosphate, barium, carbonate ion concentration, and temperature, respectively. Composition of the corals is determined using laser-ablation ICPMS, with robust plasma conditions established using the Normalized Argon Index [1], and proxy element incorporation is evaluated for influences of temperature, pH, and feeding frequency. The aragonite precipitated during the stages of the culturing experiment is identified using fluorescent and geochemical labelling of the skeleton through calcein and lead isotopes, respectively. This approach allows us to resolve monthly and annual increments in these slow growing (1-2mm/year) organisms, and also to evaluate the influence of calcification rate on the composition. We address the issue of heterogeneity by adapting methods for LA-ICPMS imaging to create macroscale images to reveal the full pattern of skeletogenesis and related compositional variability of D. dianthus. Preliminary images suggest that heterogeneity stems from the asymmetric precipitation of aragonite, and from centers of calcification (also known as early mineralization zones) that complicate the interpretation of elemental signals throughout the skeleton, but also help to identify new skeletal regions suitable for proxy measurement. Finally, we also discuss the role of endolithic organisms in some of these specimens. [1] Fietzke, J. & Frische, M. (2016), J. Anal. At. Spectrom. 31, 234–244. 
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  2. Abstract

    Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger.

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    Free, publicly-accessible full text available May 1, 2025
  3. A<sc>bstract</sc>

    A search for new physics in top quark production with additional final-state leptons is performed using data collected by the CMS experiment in proton-proton collisions at$$ \sqrt{s} $$s= 13 TeV at the LHC during 2016–2018. The data set corresponds to an integrated luminosity of 138 fb1. Using the framework of effective field theory (EFT), potential new physics effects are parametrized in terms of 26 dimension-six EFT operators. The impacts of EFT operators are incorporated through the event-level reweighting of Monte Carlo simulations, which allows for detector-level predictions. The events are divided into several categories based on lepton multiplicity, total lepton charge, jet multiplicity, and b-tagged jet multiplicity. Kinematic variables corresponding to the transverse momentum (pT) of the leading pair of leptons and/or jets as well as thepTof on-shell Z bosons are used to extract the 95% confidence intervals of the 26 Wilson coefficients corresponding to these EFT operators. No significant deviation with respect to the standard model prediction is found.

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    Free, publicly-accessible full text available December 1, 2024
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  7. Abstract

    A description is presented of the algorithms used to reconstruct energy deposited in the CMS hadron calorimeter during Run 2 (2015–2018) of the LHC. During Run 2, the characteristic bunch-crossing spacing for proton-proton collisions was 25 ns, which resulted in overlapping signals from adjacent crossings. The energy corresponding to a particular bunch crossing of interest is estimated using the known pulse shapes of energy depositions in the calorimeter, which are measured as functions of both energy and time. A variety of algorithms were developed to mitigate the effects of adjacent bunch crossings on local energy reconstruction in the hadron calorimeter in Run 2, and their performance is compared.

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    Free, publicly-accessible full text available November 1, 2024
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