Mass Uncertainty Research Articles

Resbos2 and the CDF W mass measurement

The recent collider detector at fermilab (CDF) W mass measurement of 80,433±9 MeV is the most precise direct measurement. However, this result deviates from the Standard Model predicted mass of 80,359.1±5.2 MeV by 7σ. The CDF experiment used an older version of the esos code that was only accurate at NNLL+NLO, while the esos2 code is able to make predictions at N3LL+NNLO accuracy. We determine that the data-driven techniques used by CDF capture most of the higher order corrections, and using higher order corrections would have an impact on the CDF result in total at the 10 MeV level. Additionally, we investigate the effects from handling the width of the W boson on the mass, PDF correlations, and scale uncertainties. We find that these contributions are consistent with those obtained by CDF. Published by the American Physical Society 2024

Quantification of contaminant mass discharge and uncertainties: Method and challenges in application at contaminated sites

Contaminant mass discharge (CMD) estimation involves combining multilevel concentration and flow measurements to quantify the contaminant mass passing through a control plane downgradient of a point source. However, geological heterogeneities and limited data introduce uncertainties that complicate CMD estimation and risk assessment. Although CMD is increasingly used in groundwater management, methods for quantifying and handling these uncertainties are still needed. This study develops and tests a CMD estimation method based on Bayesian geostatistics to quantify CMD uncertainties using data from a control plane perpendicular to the contaminant plume.By combining geostatistical conditional simulations of the spatial concentration distribution with the flow, an ensemble of CMD realizations is generated, from which a cumulative distribution function is derived. A key element of this approach is the use of a macrodispersive transport model to simulate the spatial concentration trend. This ensures that the estimated concentration reflects the expected physical behavior of the contaminant plume while also allowing the integration of site-specific conceptual information.The method is applicable to plumes with dissolved contaminants, such as chlorinated solvents, petroleum hydrocarbons, Per- and polyfluoroalkyl substances (PFAS) and pesticides. Site-specific conceptual understanding is used to inform the prior probability density functions of the structural model parameters and to define acceptable simulated concentration limits. We applied the method at three sites contaminated with chlorinated ethenes, demonstrating its robustness across varying information levels and data availability.Our results shows that strong site-specific conceptual knowledge and high sampling density constrain the CMD uncertainty (CV = 21 %) and results in estimated model parameters and a spatial concentration distribution that agrees well with the conceptual model. For a site with less data and limited conceptual knowledge, CMD and concentration distribution estimates are still feasible, though with higher uncertainty (CV = 41 %). Extending the method to account for multiple source zones and complex plume migration improved parameter identification and reduced the 95 % CMD confidence interval by 11 % ([4950–8750] to [5090–8480] g yr−1), while also providing a spatial concentration distribution in better agreement with the plume conceptualization.This study highlights the importance of integrating site-specific conceptual knowledge in CMD estimation, particularly for less-sampled sites. The method can furthermore assist in identifying remediation targets, evaluating remedial effectiveness, and optimizing sampling strategies.

An Absolute Mass, Precise Age, and Hints of Planetary Winds for WASP-121A and b from a JWST NIRSpec Phase Curve

We have conducted a planetary radial velocity measurement of the ultrahot Jupiter WASP-121b using JWST NIRSpec phase curve data. Our analysis reveals the Doppler shift of the planetary spectral lines across the full orbit, which shifts considerably across the detector (∼10 pixels). Using cross-correlation techniques, we have determined an overall planetary velocity amplitude of K p = 215.7 ± 1.1 km s−1, which is in good agreement with the expected value. We have also calculated the dynamical mass for both components of the system by treating it as an eclipsing double-line spectroscopic binary, with WASP-121A having a mass of M ⋆ = 1.330 ± 0.019 M ⊙, while WASP-121b has a mass of M p = 1.170 ± 0.043 M Jup. These dynamical measurements are ∼3× more precise than previous estimates and do not rely on any stellar modeling assumptions that have a ∼5% systematic floor mass uncertainty. Additionally, we used stellar evolution modeling constrained with a stellar density and parallax measurement to determine a precise age for the system, found to be 1.11 ± 0.14 Gyr. Finally, we observed potential velocity differences between the two NIRSpec detectors, with NRS1 lower by 5.5 ± 2.2 km s−1. We suggest that differences can arise from day/night asymmetries in the thermal emission, which can lead to a sensitivity bias favoring the illuminated side of the planet, with planetary rotation and winds both acting to lower a measured K P. The planet’s rotation can account for 1 km s−1 of the observed velocity difference, with 4.5 ± 2.2 km s−1 potentially attributable to vertical differences in wind speeds.

Adaptive Sliding Mode Control for Trajectory Tracking of Quadrotor Unmanned Aerial Vehicles Under Input Saturation and Disturbances

This paper addresses the challenging issue of trajectory tracking for uncertain quadrotor unmanned aerial vehicles (UAVs), particularly under the constraints of input saturation and external disturbances. It introduces adaptive laws for managing uncertainties in mass and inertia moments without requiring prior knowledge, ensuring effective control even with varying system parameters. To counteract the effects of input saturation, the study incorporates an auxiliary system designed to compensate for these limitations. Additionally, a disturbance observer (DO) is utilized to manage and mitigate the impact of time-varying external disturbances. The proposed control strategy integrates a sliding mode adaptive control approach with an inner–outer loop structure, enhancing robustness and adaptability. Numerical simulations demonstrate the effectiveness of the designed control strategy.

Online and Remote Community-Engaged Facilitation: Pedagogical and Ethical Considerations and Commitments

In the early days of the COVID-19 pandemic, many community-engaged practitioners struggled with how to meaningfully and ethically build, maintain or sustain relationships, partnerships, or community-engaged projects, amidst mass upheaval, loss, and uncertainty. Prior to the pandemic, workshops, meetings or community events happened in community drop-ins, social service organizations, or in neighbourhood meeting places. Due to social distancing restrictions, these physical environments abruptly changed to online meeting and messaging applications, phone, and even postal mail. This drastically impacted how community-engaged practitioners approached their facilitation work with communities. This rapid shift also amplified many ethical complexities, like privacy and confidentiality, equitable access, and safety, for those facilitating workshops or programs in non-profit, community-based and participatory research contexts. This article explores findings from a participatory study on how community-engaged practitioners (i.e., community artists, community facilitators, participatory researchers, and participatory visual methods practitioners) across Canada adapted their facilitation approaches to online or remote platforms in the context of COVID-19. We briefly describe our process of doing participatory research online during a pandemic and share findings on how community-engaged practitioners articulated the ethical commitments they brought to their facilitation practice as well as pedagogical and ethical considerations identified for online or remote (i.e., phone, mail) community-engaged facilitation. We conclude by offering reflections on what might be gleaned about online and remote community-engaged facilitation for the present moment. We hope that this article - and the illustrations enclosed - will serve as a guide for emerging and established community-engaged practitioners to reflect on their ‘how and why’ of facilitation when working with and alongside communities for social change.

Arts Community Resilience in Malaysia during the Time of COVID-19: Five Arts Centre’s Open House Initiative

The intrusion of COVID-19 in Malaysia had resulted in the disruption of many art projects for the whole year of 2020. Due to the country’s countermeasures to combat the disease’s ongoing spread, several art groups and art projects were facing mass postponements, cancellations, and uncertainty—arts communities were vulnerable to economic losses, social and environmental limitations during the volatile period. However, there were few art groups that managed to adapt their practices and work around the pandemic constraints they’ve encountered. Five Arts Centre arts collective was sampled and interviewed for this year-long study which looks at the preliminary impacts and responses of COVID-19 on the arts communities in Kuala Lumpur. The results indicate Malaysian arts communities were able to remain resilient against the pandemic mostly due to their social connectedness across the arts practitioners and institutions within the arts ecosystem. Added with their intuitive instrumentalisation of existing resources to meet the environmental limitations that the COVID-19 presented. The research findings are analysed through the utilisation of an adapted resilience framework to help explain the sampled art groups’ experiences through the pandemic period.

The Effect of Job Insecurity on Turnover Intention among Employees at Startup Companies in Jabodetabek

Winter tech refers to a significant decline in business activity and investment, leading to mass layoffs, bankupties, and uncertainty or instability. One of the impact of an unstable work environment is the increased level of job insecurity, which can influence employees intention to leave their jobs, known as turnover intention. Therefore, this study aims to identify the influence of job insecurity on employees turnover intention amid this phenomenon. The study employs a quantitative approach with a questionnaire as the data collection instrument and uses sample regression analysis to examine the influence between the two variables. The data collection technique used is purposive sampling, with respondents consisting of contract and permanent employees at company X, totaling 55 employees. The results of this study show a positive influence of job insecurity on employees turnover intention at company X by 34.9% with the remaining 65.1% influenced by other variables not tested in this study. In other words, if job insecurity increases, the intention to leave the job will increase, and conversely, if job insecurity dreases, the intention to leave the job will also decrease.

Exploring dark forces with multimessenger studies of extreme mass ratio inspirals

The exploration of dark sector interactions via gravitational waves (GWs) from binary inspirals has been a subject of recent interest. We study dark forces using extreme mass ratio inspirals (EMRIs), pointing out two issues of interest. Firstly, the innermost stable circular orbit (ISCO) of the EMRI, which sets the characteristic length scale of the system and hence the dark force range to which it exhibits enhanced sensitivity, probes force mediator masses that complement those studied with supermassive black hole (SMBH) or neutron star binaries. The LISA mission (the proposed μAres detector) will probe mediators with masses m V ∼ 10-16 eV (m V ∼ 10-18 eV), corresponding to ISCOs of 106 M ⊙ (108 M ⊙) central SMBHs. Secondly, while the sensitivity to dark couplings is typically limited by the uncertainty in the binary component masses, independent mass measurements of the central SMBH through reverberation mapping campaigns or the motion of dynamical tracers enable one to break this degeneracy. Our results therefore highlight the necessity for coordinated studies, loosely referred to as “multimessenger”, between future μHz- mHz GW observatories and ongoing and forthcoming SMBH mass measurement campaigns, including OzDES-RM, SDSS-RM, and SDSS-V Black Hole Mapper.

PNG-UNITsims: Halo clustering response to primordial non-Gaussianities as a function of mass

This paper presents the PNG-UNITSIMS suite, which includes the largest full N-body simulation to date with local primordial non-Gaussianities (local PNG), the PNG-UNIT. The amplitude of the PNGs is given by f localNL=100. The simulation follows the evolution of 40963 particles in a periodic box with Lbox = 1 h−1 Gpc, resulting in a mass resolution of mp = 1.24 × 109 h−1 M⊙, enough to finely resolve the galaxies targeted by stage-IV spectroscopic surveys. The PNG-UNIT has fixed initial conditions with phases also matching the pre-existing UNIT simulation with Gaussian initial conditions. The fixed and matched initial conditions reduce the simulation uncertainty significantly. In this first study of the PNG-UNITSIMS, we measure the PNG response parameter, p, as a function of the halo mass. halos with masses between 1 × 1012 and 5 × 1013 h−1 M⊙ are well described by the universality relation, given by p = 1. For halos with masses between 2 × 1010 and 1 × 1012 h−1 M⊙ we find that p < 1, at a significance between 1.5 and 3.1σ. Combining all the halos between 2 × 1010 and 5 × 1013 h−1 M⊙, we find p consistent with a value of 0.955 ± 0.013, which is 3σ away from the universality relation. We demonstrate that these findings are robust to mass resolution, scale cuts and uncertainty estimation. We also compare our measurements to separate universe simulations, finding that the PNG-UNITSIMS constraints outperform the former for the setup considered. Using a prior on p as tight as the one reported here for DESI-like forecast can result in fNL constraints comparable to fixing p. At the same time, fixing p to a wrong value (p = 1) may result in up to 2σ biases on fNL.

Adaptive sliding mode control for quadrotor transport systems with uncertain parameters and disturbances

SummaryQuadrotor transportation systems have been widely utilized in both commercial and civilian fields. However, challenges arise due to the variable payload mass and unpredictable wind disturbances during cargo transport, potentially leading to excessive payload swinging and system instability. To tackle this issue, this article proposes an adaptive sliding mode control approach that concurrently achieves trajectory tracking for the quadrotor and mitigates payload swinging. In the outer loop subsystem, the quadrotor dynamics model is partitioned into two components that is, actuated and underactuated components. Sliding surfaces are designed based on this divided system model, and two adaptive laws are designed to compensate for payload mass uncertainty and unknown wind disturbances. The system's asymptotic stability is assured through the application of the Lyapunov theorem. In the inner loop subsystem, a disturbance rejection controller is formulated. Comparative simulation results conclusively demonstrate the outstanding performance of the proposed method in terms of trajectory tracking and robustness.

A low-mass sub-Neptune planet transiting the bright active star HD 73344

Context. Planets with radii of between 2 and 4 R⊕ closely orbiting solar-type stars are of significant importance for studying the transition from rocky to giant planets, and are prime targets for atmospheric characterization by missions such as JWST and ARIEL. Unfortunately, only a handful of examples with precise mass measurements are known to orbit bright stars. Aims. Our goal is to determine the mass of a transiting planet around the very bright F6 star HD 73344 (Vmag = 6.9). This star exhibits high activity and has a rotation period that is close to the orbital period of the planet (Pb = 15.6 days). Methods. The transiting planet, initially a K2 candidate, is confirmed through TESS observations (TOI 5140.01). We refined its parameters using TESS data and rule out a false positive with Spitzer observations. We analyzed high-precision radial velocity (RV) data from the SOPHIE and HIRES spectrographs. We conducted separate and joint analyses of K2, TESS, SOPHIE, and HIRES data using the PASTIS software. Given the star’s early type and high activity, we used a novel observing strategy, targeting the star at high cadence for two consecutive nights with SOPHIE to understand the short-term stellar variability. We modeled stellar noise with two Gaussian processes: one for rotationally modulated stellar processes, and one for short-term stellar variability. Results. High-cadence RV observations provide better constraints on stellar variability and precise orbital parameters for the transiting planet: a radius of Rb = 2.88−0.07+0.08 R⊕ and a mass of Mb = 2.98−1.90+2.50 M⊕ (upper-limit at 3σ is <10.48 M⊕). The derived mean density suggests a sub-Neptune-type composition, but uncertainties in the planet’s mass prevent a detailed characterization. In addition, we find a periodic signal in the RV data that we attribute to the signature of a nontransiting exoplanet, without totally excluding the possibility of a nonplanetary origin. This planetary candidate would have a minimum mass of about Mc sin ic = 116.3 ± −13.0+12.8 M⊕ and a period of Pc = 66.45−0.25+0.10 days. Dynamical analyses confirm the stability of the two-planet system and provide constraints on the inclination of the candidate planet; these findings favor a near-coplanar system. Conclusions. While the transiting planet orbits the bright star at a short period, stellar activity prevented us from precise mass measurements despite intensive RV follow-up. Long-term RV tracking of this planet could improve this measurement, as well as our understanding of the activity of the host star. The latter will be essential if we are to characterize the atmosphere of planets around F-type stars using transmission spectroscopy.

Dynamic analysis of the tethered satellite system considering uncertain but bounded parameters

Dynamic analysis of the tethered satellite system (TSS) can provide a fundamental guideline to the evaluation of performance and robust design of the system examined. Uncertainties inherited with the parameters would induce unexpected variation of the response and deteriorate the reliability of the system. In this work, the effect of uncertain mass of the satellites on the deployment and retrieval dynamics of the TSS is investigated. First the interval mode is employed to take the variation of mass of satellite into account in the processes of deployment and retrieval. Then, the Chebyshev interval method is used to obtain the lower and upper response bounds of the TSS. To achieve a smooth and reliable implementation of deployment and retrieval, the nonlinear programming based on the Gauss pseudo-spectral method is adopted to obtain optimal trajectory of tether velocity. Numerical results show that the uncertainties of mass of the satellites have a distinct influence on the response of tether tension in the processes of deployment and retrieval.

Location of the neutron drip line for Sn and its impact on r-process abundances

Nuclear physical inputs are critical for predicting the abundance of r-process elements. Extensive sensitivity studies have recently been performed to gauge the impact of the individual properties of nuclei on the r-process. In this work, we investigate the impact of the large uncertainties in the theoretical predictions of the masses of neutron-rich Sn isotopes and the location of the neutron drip line on the abundance of r-process abundances. The uncertainties in the predicted r-process abundances are obtained through large-scale network calculations by simultaneously varying the masses and reaction rates of Sn within the predicted mass uncertainties. The calculations use a generally indicative astrophysical trajectory of neutron-star mergers and are based on three different mass models. The results indicate that the large uncertainty in the location of the neutron drip line for Sn can significantly and asymmetrically affect the predicted abundances of nuclei after the second peak, in particular around A=140−155, sometimes accompanied by a delayed freeze-out.

Strengthening nuclear symmetry energy constraints using multiple resonant shattering flares of neutron stars with realistic mass uncertainties

ABSTRACT With current and planned gravitational-wave (GW) observing runs, coincident multimessenger timing of resonant shattering flares (RSFs) and GWs may soon allow for neutron star (NS) asteroseismology to be used to constrain the nuclear symmetry energy, an important property of fundamental nuclear physics that influences the composition and equation of state of NSs. In this work, we examine the effects of combining multiple RSF detections on these symmetry energy constraints, and consider how realistic uncertainties in the masses of the progenitor NSs may weaken them. We show that the detection of subsequent multimessenger events has the potential to substantially improve constraints beyond those obtained from the first, and that this improvement is insensitive to the mass of the NSs that produce the RSFs and its uncertainty. This sets these asteroseismic constraints apart from bulk NS properties such as radius, for which the NS mass is highly important, meaning that any multimessenger RSF and GW events can equally improve our knowledge of fundamental physics.

Active suspension hierarchical control with parameter uncertainty and external disturbance of electro-hydraulic actuators

In order to improve the ride comfort and handling stability of the electro-hydraulic active suspension system, a hierarchical control strategy is proposed. For the active suspension system with body mass uncertainty and safety constraints, an enhanced constraint adaptive backstepping controller is designed to generate the target force of body vertical motion. When dealing with constraints, nonlinear filters are introduced, backstepping technology and quadratic Lyapunov function are used to combine the control target and domain constraints, and the vertical displacement of the body and the suspension deflection control index are synthesized into a single controlled variable, so that the control variable converging to zero meets the suspension dynamic displacement limit. The ride comfort and safety of the active suspension system are improved. Secondly, stability analysis is conducted on the zero dynamic error system to ensure that all safety performance indicators are bounded. The effects of external disturbances, parameter uncertainties and modelling errors on the force tracking accuracy of asymmetric cylinder electrohydraulic systems are addressed. A backstepping dynamic surface control method based on a nonlinear perturbation observer is proposed, which estimates the composite perturbation terms such as modelling error and external perturbation, and uses the estimated value of the nonlinear observer to design a feedforward compensating control term to offset the effect of the composite perturbation on the system performance. In addition, the dynamic surface control method is used to calculate the derivative of the target force input, which avoids the derivative explosion phenomenon and reduces the computational complexity of the system. Simulation test results show that this method reduces the computational complexity of the system and improves the control performance. And under random and bumpy road conditions, the root-mean-square value of sprung mass acceleration performance index is reduced by 48.354 % and 72.677 % compared with passive suspension, which improves the ride comfort of the vehicle.

The Implications of Thermal Hydrodynamic Atmospheric Escape on the TRAPPIST-1 Planets

JWST observations of the seven-planet TRAPPIST-1 system will provide an excellent opportunity to test outcomes of stellar-driven evolution of terrestrial planetary atmospheres, including atmospheric escape, ocean loss, and abiotic oxygen production. While most previous studies use a single luminosity evolution for the host star, we incorporate observational uncertainties in stellar mass, luminosity evolution, system age, and planetary parameters to statistically explore the plausible range of planetary atmospheric escape outcomes. We present probabilistic distributions of total water loss and oxygen production as a function of initial water content, for planets with initially pure water atmospheres and no interior–atmosphere exchange. We find that the interior planets are desiccated for initial water contents below 50 Earth oceans. For TRAPPIST-1e, f, g, and h, we report maximum water-loss ranges of 8.0−0.9+1.3 , 4.8−0.4+0.6 , 3.4−0.3+0.3 , and 0.8−0.1+0.2 Earth oceans, respectively, with corresponding maximum oxygen retention of 1290−75+75 , 800−40+40 , 560−25+30 , and 90−10+10 bars. We explore statistical constraints on initial water content imposed by current water content, which could inform evolutionary history and planet formation. If TRAPPIST-1b is airless while TRAPPIST-1c possesses a tenuous oxygen atmosphere, as initial JWST observations suggest, then our models predict an initial surface water content of 8.2 −1.0+1.5 Earth oceans for these worlds, leading to the outer planets retaining >1.5 Earth oceans after entering the habitable zone. Even if TRAPPIST-1c is airless, surface water on the outer planets would not be precluded.

Enhancing Exoplanet Ephemerides by Leveraging Professional and Citizen Science Data: A Test Case with WASP-77 A b

We present an updated ephemeris, and physical parameters, for the exoplanet WASP-77 A b. In this effort, we combine 64 ground- and space-based transit observations, 6 space-based eclipse observations, and 32 radial velocity observations to produce this target's most precise orbital solution to date aiding in the planning of James Webb Space Telescope and Ariel observations and atmospheric studies. We report a new orbital period of 1.360029395 ± 5.7 × 10−8 days, a new mid-transit time of 2459957.337860 ± 4.3 × 10−5 Barycentric Julian Date in the Barycentric Dynamical Timescale (BJDTDB) and a new mid-eclipse time of 2459956.658192 ± 6.7 × 10−5 BJDTDB. Furthermore, the methods presented in this study reduce the uncertainties in the planet's mass 1.6654 ± 4.5 × 10−3 M Jup and orbital period 1.360029395 ± 5.7 × 10−8 days by factors of 15.1 and 10.9, respectively. Through a joint fit analysis comparison of transit data taken by space-based and citizen science-led initiatives, our study demonstrates the power of including data collected by citizen scientists compared to a fit of the space-based data alone. Additionally, by including a vast array of citizen science data from ExoClock, Exoplanet Transit Database, and Exoplanet Watch, we can increase our observational baseline and thus acquire better constraints on the forward propagation of our ephemeris than what is achievable with Transiting Exoplanet Survey Satellite data alone.

Top-quark pole mass extraction at NNLO accuracy, from total, single- and double-differential cross sections for tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} + X production at the LHC

We extract the top-quark mass value in the on-shell renormalization scheme from the comparison of theoretical predictions for pp → tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} + X at next-to-next-to-leading order (NNLO) QCD accuracy with experimental data collected by the ATLAS and CMS collaborations for absolute total, normalized single-differential and double-differential cross-sections during Run 1, Run 2 and the ongoing Run 3 at the Large Hadron Collider (LHC). For the theory computations of heavy-quark pair-production we use the MATRIX framework, interfaced to PineAPPL for the generation of grids of theory predictions, which can be efficiently used a-posteriori during the fit, performed within xFitter. We take several state-of-the-art parton distribution functions (PDFs) as input for the fit and evaluate their associated uncertainties, as well as the uncertainties arising from renormalization and factorization scale variation. Fit uncertainties related to the datasets are also part of the extracted uncertainty of the top-quark mass and turn out to be of similar size as the combined scale and PDF uncertainty. Fit results from different PDF sets agree among each other within 1σ uncertainty, whereas some datasets related to tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} decay in different channels (dileptonic vs. semileptonic) point towards top-quark mass values in slight tension among each other, although still compatible within 2.5 σ accuracy. Our results are compatible with the PDG 2022 top-quark pole-mass value. Our work opens the road towards more complex simultaneous NNLO fits of PDFs, the strong coupling αs(MZ) and the top-quark mass, using the currently most precise experimental data on tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} + X total and multi-differential cross sections from the LHC.

The Sloan Digital Sky Survey Reverberation Mapping Project: Key Results

We present the final data from the Sloan Digital Sky Survey (SDSS) Reverberation Mapping (RM) project, a precursor to the SDSS-V Black Hole Mapper RM program. This data set includes 11 yr photometric and 7 yr spectroscopic light curves for 849 broad-line quasars over a redshift range of 0.1 < z < 4.5 and a luminosity range of L bol = 1044−47.5 erg s−1, along with spectral and variability measurements. We report 23, 81, 125, and 110 RM lags (relative to optical continuum variability) for broad Hα, Hβ, Mg ii, and C iv using the SDSS-RM sample, spanning much of the luminosity and redshift ranges of the sample. Using 30 low-redshift RM active galactic nuclei with dynamical-modeling black hole masses, we derive a new estimate of the average virial factor of logf=0.62±0.07 for the line dispersion measured from the rms spectrum. The intrinsic scatter of individual virial factors is 0.31 ± 0.07 dex, indicating a factor of 2 systematic uncertainty in RM black hole masses. Our lag measurements reveal significant R–L relations for Hβ and Mg ii at high redshift, consistent with the latest measurements based on heterogeneous samples. While we are unable to robustly constrain the slope of the R–L relation for C iv given the limited dynamic range in luminosity, we found substantially larger scatter in C iv lags at fixed L 1350. Using the SDSS-RM lag sample, we derive improved single-epoch (SE) mass recipes for Hβ, Mg ii, and C iv, which are consistent with their respective RM masses as well as between the SE recipes from two different lines, over the luminosity range probed by our sample. The new Hβ and Mg ii recipes are approximately unbiased estimators at given RM masses, but there are systematic biases in the C iv recipe. The intrinsic scatter of SE masses around RM masses is ∼0.45 dex for Hβ and Mg ii, increasing to ∼0.58 dex for C iv.

Cosmic-ray diffusion in two local filamentary clouds

Context. Hadronic interactions between cosmic rays (CRs) and interstellar gas have been probed in γ rays across the Galaxy. A fairly uniform CR distribution is observed up to a few hundred parsecs from the Sun, except in the Eridu cloud, which shows an unexplained 30–50% deficit in GeV to TeV CR flux. Aims. To explore the origin of this deficit, we studied the Reticulum cloud, which shares notable traits with Eridu: a comparable distance in the low-density region of the Local Valley and a filamentary structure of atomic hydrogen extending along a bundle of ordered magnetic-field lines that are steeply inclined to the Galactic plane. Methods. We measured the γ-ray emissivity per gas nucleon in the Reticulum cloud in the 0.16–63 GeV energy band using 14 years of Fermi-LAT data. We also derived interstellar properties that are important for CR propagation in both the Eridu and Reticulum clouds, at the same parsec scale. Results. The γ-ray emissivity in the Reticulum cloud is fully consistent with the average spectrum measured in the solar neighbourhood, but this emissivity, and therefore the CR flux, is 1.57 ± 0.09 times larger than in Eridu across the whole energy band. The difference cannot be attributed to uncertainties in gas mass. Nevertheless, we find that the two clouds are similar in many respects: both have magnetic-field strengths of a few micro-Gauss in the plane of the sky; both are in approximate equilibrium between magnetic and thermal pressures; they have similar turbulent velocities and sonic Mach numbers; and both show magnetic-field regularity with a dispersion in orientation lower than 10°–15° over large zones. The gas in Reticulum is colder and denser than in Eridu, but we find similar parallel diffusion coefficients around a few times 1028 cm2 s−1 in both clouds if CRs above 1 GV in rigidity diffuse on resonant, self-excited Alfvén waves that are damped by ion-neutral interactions. Conclusions. The loss of CRs in Eridu remains unexplained, but these two clouds provide important test cases to further study how magnetic turbulence, line tangling, and ion-neutral damping regulate CR diffusion in the dominant gas phase of the interstellar medium.