Search for the Standard Model Higgs->ZZ(*)->4leptons in ATLAS

The sensitivity of the ATLAS experiment to possible discovery channels has been recently re-evaluated using complete - ``as built'' - detector simulation, latest theoretical cross-section calculations, optimized selection criteria and appropriate statistical treatment. In this contribution, the sensitivity to H->ZZ(*)->4l, which covers the Standard Model Higgs discovery in the mass range from ~120 GeV to ~700 GeV, is presented. The four lepton signature makes this channel very promising, even for the detector start-up phase, while it poses stringent requirements in terms of lepton identification and measurement capabilities

Route to Direct Multiphoton Multiple Ionization

We address the concept of direct multiphoton multiple ionization in atoms exposed to intense, short wavelength radiation and explore the conditions under which such processes dominate over the sequential. Their contribution is shown to be quite robust, even under intensity fluctuations and interaction volume integration, and reasonable agreement with experimental data is also found.Comment: Close to the version to be published in Phys. Rev. A. Additional supplementary material can be found ther

Search for light dark matter with NEWS-G

The NEWS-G collaboration is searching for light dark matter candidates using a spherical proportional counter. Light gases, such as hydrogen, helium, and neon, are used as targets, providing access in the 0.1-10 GeV mass range. First results obtained with SEDINE, a 60 cm in diameter detector, in the Underground Laboratory of Modane yielded a 90% confidence level upper limit of 4.4x 10^{37} cm^2 on the nucleon-dark matter interaction cross-section for a candidate with 0.5 GeV mass. Recent developments in several aspects of the detector instrumentation are presented, along with the construction of a new, 140 cm in diameter, detector with new compact shielding.Comment: 10 pages, 10 figures, 15th Topical Seminar on Innovative Particle and Radiation Detectors, 14-17 October 2019, Siena, Ital

A unified approach of catastrophic events

Although there is an accumulated charge of theoretical, computational, and numerical work, like catastrophe theory, bifurcation theory, stochastic and deterministic chaos theory, there is an important feeling that these matters do not completely cover the physics of real catastrophic events. Recent studies have suggested that a large variety of complex processes, including earthquakes, heartbeats, and neuronal dynamics, exhibits statistical similarities. Here we are studying in terms of complexity and non linear techniques whether isomorphic signatures emerged indicating the transition from the normal state to the both geological and biological shocks. In the last 15 years, the study of Complex Systems has emerged as a recognized field in its own right, although a good definition of what a complex system is, actually is eluded. A basic reason for our interest in complexity is the striking similarity in behaviour close to irreversible phase transitions among systems that are otherwise quite different in nature. It is by now recognized that the pre-seismic electromagnetic time-series contain valuable information about the earthquake preparation process, which cannot be extracted without the use of important computational power, probably in connection with computer Algebra techniques. This paper presents an analysis, the aim of which is to indicate the approach of the global instability in the pre-focal area. Non-linear characteristics are studied by applying two techniques, namely the Correlation Dimension Estimation and the Approximate Entropy. These two non-linear techniques present coherent conclusions, and could cooperate with an independent fractal spectral analysis to provide a detection concerning the emergence of the nucleation phase of the impending catastrophic event. In the context of similar mathematical background, it would be interesting to augment this description of pre-seismic electromagnetic anomalies in order to cover biological crises, namely, epileptic seizure and heart failure

Muon Energy Loss Upsteam of the Muon Spectrometer

A method for the estimation of the muon energy loss downstream of the Muons Spectrometer is presented. The method provides an improved and updated parametrization of the muon energy loss in ATLAS, along with an estimation based on the actual energy deposition in the calorimeters. The latter aims to account, on an event-by-event basis, for the statistical fluctuations of the energy loss. The final implementation of the presented method combines both the energy loss parametrization and the calorimeter information. This hybrid method provides on average a 5% improvement on the muon stand-alone momentum resolution, reaching 10% for , and reduces the non-gaussian tails. The method is implemented inside the ATHENA framework, in the MuidCaloEnergyTools package

Solving the m-mixing problem for the three-dimensional time-dependent Schr\"{o}dinger equation by rotations: application to strong-field ionization of H2+

We present a very efficient technique for solving the three-dimensional time-dependent Schrodinger equation. Our method is applicable to a wide range of problems where a fullly three-dimensional solution is required, i.e., to cases where no symmetries exist that reduce the dimensionally of the problem. Examples include arbitrarily oriented molecules in external fields and atoms interacting with elliptically polarized light. We demonstrate that even in such cases, the three-dimensional problem can be decomposed exactly into two two-dimensional problems at the cost of introducing a trivial rotation transformation. We supplement the theoretical framework with numerical results on strong-field ionization of arbitrarily oriented H2+ molecules.Comment: 5 pages, 4 figure