Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

Search for supersymmetry in final states with two or three soft leptons and missing transverse momentum in proton-proton collisions at s\sqrt{s} = 13 TeV

A search for supersymmetry in events with two or three low-momentum leptons and missing transverse momentum is performed. The search uses proton-proton collisions at $\sqrt{s}$ = 13 TeV collected in the three-year period 2016–2018 by the CMS experiment at the LHC and corresponding to an integrated luminosity of up to 137 fb$^{-1}$. The data are found to be in agreement with expectations from standard model processes. The results are interpreted in terms of electroweakino and top squark pair production with a small mass difference between the produced supersymmetric particles and the lightest neutralino. For the electroweakino interpretation, two simplified models are used, a wino-bino model and a higgsino model. Exclusion limits at 95% confidence level are set on $_{X2/X1}^{~0 ~+-}$ masses up to 275 GeV for a mass difference of 10 GeV in the wino-bino case, and up to 205(150) GeV for a mass difference of 7.5 (3) GeV in the higgsino case. The results for the higgsino are further interpreted using a phenomenological minimal supersymmetric standard model, excluding the higgsino mass parameter μ up to 180 GeV with the bino mass parameter M1 at 800 GeV. In the top squark interpretation, exclusion limits are set at top squark masses up to 540 GeV for four-body top squark decays and up to 480 GeV for chargino-mediated decays with a mass difference of 30 GeV

Search for supersymmetry in final states with two or three soft leptons and missing transverse momentum in proton-proton collisions at root s=13 TeV

ArXiv ePrint: 2111.06296 (https://arxiv.org/abs/2111.06296).Copyright © 2022 CERN, for the benefit of the CMS Collaboration. A search for supersymmetry in events with two or three low-momentum leptons and missing transverse momentum is performed. The search uses proton-proton collisions at s√ = 13 TeV collected in the three-year period 2016–2018 by the CMS experiment at the LHC and corresponding to an integrated luminosity of up to 137 fb−1. The data are found to be in agreement with expectations from standard model processes. The results are interpreted in terms of electroweakino and top squark pair production with a small mass difference between the produced supersymmetric particles and the lightest neutralino. For the electroweakino interpretation, two simplified models are used, a wino-bino model and a higgsino model. Exclusion limits at 95% confidence level are set on χ∼02/χ∼±1 masses up to 275 GeV for a mass difference of 10 GeV in the wino-bino case, and up to 205(150) GeV for a mass difference of 7.5 (3) GeV in the higgsino case. The results for the higgsino are further interpreted using a phenomenological minimal supersymmetric standard model, excluding the higgsino mass parameter μ up to 180 GeV with the bino mass parameter M1 at 800 GeV. In the top squark interpretation, exclusion limits are set at top squark masses up to 540 GeV for four-body top squark decays and up to 480 GeV for chargino-mediated decays with a mass difference of 30 GeV.SCOAP3

Search for supersymmetry in final states with two or three soft leptons and missing transverse momentum in proton-proton collisions at root s=13 TeV

A search for supersymmetry in events with two or three low-momentum leptons and missing transverse momentum is performed. The search uses proton-proton collisions at s√ = 13 TeV collected in the three-year period 2016–2018 by the CMS experiment at the LHC and corresponding to an integrated luminosity of up to 137 fb−1. The data are found to be in agreement with expectations from standard model processes. The results are interpreted in terms of electroweakino and top squark pair production with a small mass difference between the produced supersymmetric particles and the lightest neutralino. For the electroweakino interpretation, two simplified models are used, a wino-bino model and a higgsino model. Exclusion limits at 95% confidence level are set on χ∼02/χ∼±1 masses up to 275 GeV for a mass difference of 10 GeV in the wino-bino case, and up to 205(150) GeV for a mass difference of 7.5 (3) GeV in the higgsino case. The results for the higgsino are further interpreted using a phenomenological minimal supersymmetric standard model, excluding the higgsino mass parameter μ up to 180 GeV with the bino mass parameter M1 at 800 GeV. In the top squark interpretation, exclusion limits are set at top squark masses up to 540 GeV for four-body top squark decays and up to 480 GeV for chargino-mediated decays with a mass difference of 30 GeV

Patterns and processes of larval fish supply to the coral reefs of the upper Florida Keys

To identify temporal and spatial patterns in the supply of late-stage fish larvae to the coral reefs of the upper Florida Keys, 3 replicate light traps that collect larvae in the process of settling were deployed at each of 2 reefs from May 2002 to February 2004. Traps were deployed every other night from May through October and twice monthly from November through April to examine cross-shelf (2002 and 2003) and alongshore (2002 and 2004) patterns. The nightly abundance of settling larvae was compared to concurrently collected environmental data to assess the relationships between these variables and temporal patterns of larval supply. In total, 26 185 fish larvae from 55 families were collected during 174 nights of sampling. Seasonally, the supply of larvae peaked in the late winter to early spring and reached a minimum in late fall. Within-season supply of late-stage larvae was cyclic and strongly related to the lunar cycle, and to a lesser extent, the maximum tidal amplitude cycle. Strong negative correlations between larval supply and both moon illumination and maximum tidal amplitude each night resulted in peak supply of fish larvae between the third quarter moon/minimum amplitude tides and the new moon/maximum amplitude tides. While these cyclic environmental cues provided a high degree of temporal predictability of larval pulses, the magnitude of pulses was stochastic, with some variability related to the passage of mesoscale frontal eddies by the upper Florida Keys. However, the effects of these physical features on larval supply were not consistent over time. Spatial variability (kilometer-scale) was greater in the cross-shelf direction than in the alongshore direction: the supply of larval fishes was significantly greater to the fringing reef site (French Reef) than to the inshore patch reef (White Banks), due to either active larval avoidance of inshore environments or depletion of larvae originating offshore as they pass over and settle on the fringing reef

Environmental conditions and paternal care determine hatching synchronicity of coral reef fish larvae

For all fishes, hatching is a short but crucial event, and the conditions under which it occurs considerably influence the success of the larvae. For coral reef fish, hatching is even more important because it marks the beginning of the dispersal phase. The timing of hatching dictates the conditions that the larvae will encounter, potentially influencing their survival and dispersal. Despite this importance, very few studies have looked at hatching of marine fishes in the natural environment because of important technical constrains. In this study, we directly examined the temporal pattern of hatching during the night. Using remote night vision cameras and infrared lights to avoid disturbances, we successfully documented in situ hatching events of three coral reef fish species, all benthic brooders (Abudefduf saxatilis, Stegastes partitus, and Elacatinus lori). Hatching timing, rate, and duration were computed from the observations, and highlight different hatching strategies used by the fish species. The analysis of the fish behaviors shows that the males display parental care beyond the incubation period of the eggs and increase activity during the hatching events. With this study, we can relate the hatching events to the environmental context, giving us a better understanding of the factors influencing the beginning of the larval phase. These observations highlight the benefit of in situ studies to better understand the characteristics and potential consequences of hatching

Celestial patterns in marine soundscapes

Soundscape ecology is the study of the acoustic characteristics of habitats, and aims to discern contributions from biological and non-biological sound sources. Acoustic communication and orientation are important for both marine and terrestrial organisms, which underscores the need to identify salient cues within soundscapes. Here, we investigated temporal patterns in coral reef soundscapes, which is necessary to further understand the role of acoustic signals during larval settlement. We used 14 mo simultaneous acoustic recordings from 2 reefs, located 5 km apart in the Florida Keys, USA to describe temporal variability in the acoustic environment on scales of hours to months. We also used weather data from a nearby NOAA buoy to examine the influence of environmental variables on soundscape characteristics. We found that high acoustic frequencies typically varied on daily cycles, while low frequencies were primarily driven by lunar cycles. Some of the daily and lunar cycles in the acoustic data were explained by environmental conditions, but much of the temporal variability was caused by biological sound sources. The complexity of the soundscape had strong lunar periodicity at one reef, while it had a strong diurnal period at the other reef. At both reefs, the highest sound levels (~130 dB re: 1 μPa) occurred during new moons of the wet season, when many larval organisms settle on the reefs. This study represents an important example of recently-developed soundscape ecology tools that can be applied to any ecosystem, and the patterns uncovered here provide valuable insights into natural acoustic phenomena that occur in these highly diverse, yet highly threatened ecosystems

Sequencing Bait: Nuclear and Mitogenome Assembly of an Abundant Coastal Tropical and Subtropical Fish, Atherinomorus stipes

Genetic data from nonmodel species can inform ecology and physiology, giving insight into a species’ distribution and abundance as well as their responses to changing environments, all of which are important for species conservation and management. Moreover, reduced sequencing costs and improved long-read sequencing technology allows researchers to readily generate genomic resources for nonmodel species. Here, we apply Oxford Nanopore long-read sequencing and low-coverage (∼1x) whole genome short-read sequencing technology (Illumina) to assemble a genome and examine population genetics of an abundant tropical and subtropical fish, the hardhead silverside ( Atherinomorus stipes ). These fish are found in shallow coastal waters and are frequently included in ecological models because they serve as abundant prey for commercially and ecologically important species. Despite their importance in sub-tropical and tropical ecosystems, little is known about their population connectivity and genetic diversity. Our A. stipes genome assembly is about 1.2 Gb with comparable repetitive element content (∼47%), number of protein duplication events, and DNA methylation patterns to other teleost fish species. Among five sampled populations spanning 43 km of South Florida and the Florida Keys, we find little population structure suggesting high population connectivity