Discovery Potential of R-hadrons with the ATLAS Detector at the LHC

R-hadrons are predicted in a range of supersymmetric scenarios including split-supersymmetry and gauge-mediated supersymmetry breaking. In this paper, the discovery potential of the ATLAS experiment for gluino and stop-based R-hadrons is outlined. A range of final state observables such as high transverse momentum muon-like objects and information on ionization energy loss are used. It is shown that ATLAS would be able to discover such particles at comparatively modest amounts of luminosity (1fb-1) for masses up to 1 TeV.R‐hadrons are predicted in a range of supersymmetric scenarios including split‐supersymmetry and gauge‐mediated supersymmetry breaking. In this paper, the discovery potential of the ATLAS experiment for gluino and stop‐based R‐hadrons is outlined. A range of final state observables such as high transverse momentum muon‐like objects and information on ionization energy loss is used. It is shown that ATLAS would be able to discover such particles at comparatively modest amounts of luminosity (1fb−1) for masses up to 1 TeV.R-hadrons are predicted in a range of supersymmetric scenarios including split-supersymmetry and gauge-mediated supersymmetry breaking. In this paper, the discovery potential of the ATLAS experiment for gluino and stop-based R-hadrons is outlined. A range of final state observables such as high transverse momentum muon-like objects and information on ionization energy loss is used. It is shown that ATLAS would be able to discover such particles at comparatively modest amounts of luminosity (1fb-1) for masses up to 1 TeV

Cadre géologique et environnemental

Pfyngut: Geologischer Rahmen und natürliches Umfeld Dieses Kapitel ist der Geologie der Region gewidmet, unter besonderer Beachtung der Schichtabfolge von Pfyngut. Die Fundstelle befindet sich im alpinen Raum, am Oberlauf der Rhone, zwischen Siders und Leuk. Sie liegt auf einem Schuttkegel, der sich am Fusse des Illgrabens gebildet hat, einer tief in die penninischen Decken eingeschnittenen Schlucht mit carbonatreichen Gesteinen und Quarziten. Die untersuchten Schichtabfolgen liegen auf der linken Seite des Rhonetals, rund 20 m über der Überschwemmungsebene, und bestehen hauptsächlich aus Wildbachablagerungen und durch Oberflächenwasser verlagerten Feinsedimenten, zwischen denen sich fossile Böden erhalten haben. Diese Ablagerungen erreichen eine Gesamtmächtigkeit von maximal 2,50 m und liegen über den pedogen verwitterten Schottern (cambisol) des Illgrabenfächers. Die Sequenz beginnt an der Basis mit einer Abfolge fossiler Böden. Mikromorphologische Untersuchungen, in Kombination mit den Ergebnissen der Pollenanalysen und Makrorestuntersuchungen belegen, dass der menschliche Einfluss ab der frühen Eisenzeit das lokale Landschaftsbild zu verändern begann : nach einer Rodungsphase, setzte Erosion ein, auf die ackerbauliche Nutzung folgt. Pollen von Weizen und Ruderalplanzen sprechen für eine ausgedehnte Bewirtschaftung der Gegend ab der späten Eisenzeit. Ein weiterer starker menschlicher Eingriff stellt der Bau einer grossen Fernverkehrsstrasse in frührömischer Zeit dar. Sie wird mehfach aufwändig erneuert und nach Aufgabe von feinkörnigen Überflutungssedimenten überdeckt. An deren Oberfläche bildet sich wiederum ein humöser Oberboden, der Pflugspuren eines ausgedehnten Ackerbaus aufweist und ins Mittelalter datiert. Nach dem 12. Jh. wird die gesamte Westflanke des Kegels wiederholt von Bachgeschiebe und Murgangsedimenten überdeckt, was auf eine Destabilisierung der Berghangs hinweist. Der oberste Bereich der Schichtabfolge besteht hauptsächlich aus feinen Ablagerungen, wie sie bei der Bewässerung der Wiesen mittels Suonen entstehen. Darüber folgt der Humushorizont der heutigen Bodenoberfläche. Die Untersuchung der Pflanzenreste erbrachte ausschliesslich den Nachweis von Wildpflanzen, die wohl alle aus der nahen Umgebung stammen. Sie zeigt zudem, dass die Waldföhre bereits in der Eisenzeit die dominante Baumart im Gebiete des Pfynwalds war. Die Landschaft war relativ offen und besass Wiesen- und Weideflächen. Das Fehlen von Kulturpflanzen, wie auch von typischen Ackerunkräutern lässt den Schluss zu, dass in dieser frühen Zeit kaum Ackerstandorte in unmittelbarer Nähe des Fundorts lagen, und mit den untersuchten Proben auch keine Siedlungsbereiche erfasst worden sind, wo Nahrungsmittel gelagert oder verarbeitet wurden

Non-collider searches for stable massive particles

The theoretical motivation for exotic stable massive particles (SMPs) and the results of SMP searches at non-collider facilities are reviewed. SMPs are defined such that they would be sufficiently long-lived so as to still exist in the cosmos either as Big Bang relics or secondary collision products, and sufficiently massive to be beyond the reach of any conceivable accelerator-based experiment. The discovery of SMPs would address a number of important questions in modern physics, such as the origin and composition of dark matter in the Universe and the unification of the fundamental forces. This review outlines the scenarios predicting SMPs and the techniques used at non-collider experiments to look for SMPs, eg in cosmic rays and bound in matter. The limits so far obtained on the fluxes and matter densities of SMPs which possess various detection-relevant properties such as electric and magnetic charge are given

A High Pressure Time Projection Chamber with Optical Readout

Measurements of proton-nucleus scattering and high resolution neutrino-nucleus interaction imaging are key to reduce neutrino oscillation systematic uncertainties in future experiments. A High Pressure Time Projection Chamber (HPTPC) prototype has been constructed and operated at Royal Holloway University of London and CERN as a first step in the development of a HPTPC capable of performing these measurements as part of a future long-baseline neutrino oscillation experiment such as the Deep Underground Neutrino Experiment. In this paper we describe the design and operation of the prototype HPTPC with an argon based gas mixture. We report on the successful hybrid charge and optical readout, using four CCD cameras, of signals from Am-241 sources.Comment: 40 pages, 24 figure

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Research and Development for Near Detector Systems Towards Long Term Evolution of Ultra-precise Long-baseline Neutrino Experiments

With the discovery of non-zero value of $\theta_{13}$ mixing angle, the next generation of long-baseline neutrino (LBN) experiments offers the possibility of obtaining statistically significant samples of muon and electron neutrinos and anti-neutrinos with large oscillation effects. In this document we intend to highlight the importance of Near Detector facilities in LBN experiments to both constrain the systematic uncertainties affecting oscillation analyses but also to perform, thanks to their close location, measurements of broad benefit for LBN physics goals. A strong European contribution to these efforts is possible