Field Theory Approaches to Nonequilibrium Dynamics

It is explained how field-theoretic methods and the dynamic renormalisation group (RG) can be applied to study the universal scaling properties of systems that either undergo a continuous phase transition or display generic scale invariance, both near and far from thermal equilibrium. Part 1 introduces the response functional field theory representation of (nonlinear) Langevin equations. The RG is employed to compute the scaling exponents for several universality classes governing the critical dynamics near second-order phase transitions in equilibrium. The effects of reversible mode-coupling terms, quenching from random initial conditions to the critical point, and violating the detailed balance constraints are briefly discussed. It is shown how the same formalism can be applied to nonequilibrium systems such as driven diffusive lattice gases. Part 2 describes how the master equation for stochastic particle reaction processes can be mapped onto a field theory action. The RG is then used to analyse simple diffusion-limited annihilation reactions as well as generic continuous transitions from active to inactive, absorbing states, which are characterised by the power laws of (critical) directed percolation. Certain other important universality classes are mentioned, and some open issues are listed.Comment: 54 pages, 9 figures, Lecture Notes for Luxembourg Summer School "Ageing and the Glass Transition", submitted to Springer Lecture Notes in Physics (www.springeronline/com/series/5304/

Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector

This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 &lt; kappa(lambda) &lt; 12.0 (-5.8 &lt; kappa(lambda) &lt; 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p

Prompt and non-prompt J/psi elliptic flow in Pb plus Pb collisions at root S-NN=5.02 TeV with the ATLAS detector

The elliptic flow of prompt and non-prompt J/ \u3c8 was measured in the dimuon decay channel in Pb+Pb collisions at sNN=5.02&nbsp;TeV with an integrated luminosity of 0.42nb-1 with the ATLAS detector at the LHC. The prompt and non-prompt signals are separated using a two-dimensional simultaneous fit of the invariant mass and pseudo-proper decay time of the dimuon system from the J/ \u3c8 decay. The measurement is performed in the kinematic range of dimuon transverse momentum and rapidity 9 &lt; pT&lt; 30 GeV , | y| &lt; 2 , and 0\u201360% collision centrality. The elliptic flow coefficient, v2, is evaluated relative to the event plane and the results are presented as a function of transverse momentum, rapidity and centrality. It is found that prompt and non-prompt J/ \u3c8 mesons have non-zero elliptic flow. Prompt J/ \u3c8v2 decreases as a function of pT, while for non-prompt J/ \u3c8 it is, with limited statistical significance, consistent with a flat behaviour over the studied kinematic region. There is no observed dependence on rapidity or centrality

Search for squarks and gluinos in final states with hadronically decaying tau-leptons, jets, and missing transverse momentum using pp collisions at root s = 13 TeV with the ATLAS detector

A search for supersymmetry in events with large missing transverse momentum, jets, and at least one hadronically decaying τ-lepton is presented. Two exclusive final states with either exactly one or at least two τ-leptons are considered. The analysis is based on proton-proton collisions at √s=13  TeV corresponding to an integrated luminosity of 36.1  fb⁻¹ delivered by the Large Hadron Collider and recorded by the ATLAS detector in 2015 and 2016. No significant excess is observed over the Standard Model expectation. At 95% confidence level, model-independent upper limits on the cross section are set and exclusion limits are provided for two signal scenarios: a simplified model of gluino pair production with τ-rich cascade decays, and a model with gauge-mediated supersymmetry breaking (GMSB). In the simplified model, gluino masses up to 2000 GeV are excluded for low values of the mass of the lightest supersymmetric particle (LSP), while LSP masses up to 1000 GeV are excluded for gluino masses around 1400 GeV. In the GMSB model, values of the supersymmetry-breaking scale are excluded below 110 TeV for all values of tanβ in the range 2 ≤ tanβ ≤ 60, and below 120 TeV for tanβ > 30.M. Aaboud … D. Duvnjak … P. Jackson … J.L. Oliver … A. Petridis … A. Qureshi … A.S. Sharma … M.J. White … et al. [The ATLAS Collaboration

Uncertainty and sensitivity analysis of a coastal flood risk modelling chain

This paper describes the application of uncertainty and sensitivity analysis techniques to a coastal flood risk modelling chain to a site on the south coast of England. The modelling chain comprises multivariate extreme value modelling of sea conditions. Whilst this technique is now well-established, it is well-known that significant uncertainties arise when extrapolating historical datasets to extremes. Whilst these uncertainties can, to a certain extent, be evaluated through the statistical model fitting process, the resulting confidence limits are rarely utilised in practice. The analysis described here evaluates the uncertainty associated with the statistical extrapolation to extremes. This uncertainty is then propagated through a modelling chain that comprises: Wave transformation; Wave overtopping; Flood inundation; Economic damage. Each model component within a model chain has uncertainty associated with it. This includes uncertainty relating to the input data and the formulation of the model component itself, sometimes referred to as model structural uncertainty. To date, however, the overall uncertainty associated with the output of a chain of coastal flood models is not well understood. In this study the uncertainty associated with the multivariate extreme value model has been combined with uncertainty from these other model components, to provide estimates of uncertainty on flood risk. Sensitivity analysis is related to uncertainty analysis. The objective of the sensitivity analysis undertaken in this context is to gain an insight into which sources of uncertainty (both model components and data) within the modelling chain are most important in terms of contributing to the overall output uncertainty. So, for example, at the site analysed, it is possible to answer questions like “is the uncertainty associated with the multivariate extrapolation to extremes more influential than the uncertainty associated with the wave transformation model?” This information can then be used to support decisions relating to prioritisation of data collection and model component improvement activities. A generic technique, Variance Based Sensitivity Analysis (VBSA), has been applied to the modelling chain. The analysis shows that at this site the uncertainty associated with the wave overtopping model dominates all other sources

The application of XRF and PIXE in the analysis of rice shoot and compositional screening of genotypes

The analytical performance of Particle Induced X-ray Emission (PIXE) and X-ray Fluorescence (XRF) techniques was assessed in the determination of fourteen elements (Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Br, Rb and Sr) in plant samples. The quality of the results – in terms of accuracy, associated uncertainty and correlation between the two methods – was evaluated with regard to their usability for compositional classification of different rice genotypes with known tolerance levels to salinity stress. Plant uptake of essential elements was explored by Principal Component Analysis, which illuminated patterns between treatments (salt and control treatments) and across the rice genotypes tested