Light stop squarks and b-tagging

A significant part of the parameter space for light stop squarks still remains unconstrained by collider searches. For both R-Parity Conserving (RPC) and R-Parity Violating (RPV) scenarios there are regions in which the stop mass is around or below the top quark mass that are particularly challenging experimentally. Here we review the status of light stop searches, both in RPC and RPV scenarios. We also propose strategies, generally based on exploiting b-tagging, to cover the unconstrained regions.Comment: To appear in the Proceedings of the Corfu Summer Institute 2014 "School and Workshops on Elementary Particle Physics and Gravity", Corfu, Greec

Spot the stop with a b-tag

The LHC searches for light compressed stop squarks have resulted in considerable bounds in the case where the stop decays to a neutralino and a charm quark. However, in the case where the stop decays to a neutralino, a bottom quark and two fermions via an off-shell W-boson, there is currently a significant unconstrained region in the stop-neutralino mass plane, still allowing for stop masses in the range 90-140 GeV. In this paper we propose a new monojet-like search for light stops, optimized for the four-body decay mode, in which at least one $b$-tagged jet is required. We show that, already by using the existing 8 TeV LHC data set, such a search would cover the entire unconstrained region. Moreover, in the process of validating our tools against an ATLAS monojet search, we show that the existing limit can be extended to exclude also stop masses below 100 GeV.Comment: 6 pages, 1 figure, 2 tables, revtex4 latex style; v2: matches the version published in PRL with the title "Monojetlike Searches for Top Squarks with a b Tag

Computational Approach to Aluminum Biochemistry and Development of New Chelation Strategies

299 p.DIPC:Donostia International Physics Center SmartLigs Bioinformatica Universidade do Port

Inverse diffraction for the Atmospheric Imaging Assembly in the Solar Dynamics Observatory

The Atmospheric Imaging Assembly in the Solar Dynamics Observatory provides full Sun images every 1 seconds in each of 7 Extreme Ultraviolet passbands. However, for a significant amount of these images, saturation affects their most intense core, preventing scientists from a full exploitation of their physical meaning. In this paper we describe a mathematical and automatic procedure for the recovery of information in the primary saturation region based on a correlation/inversion analysis of the diffraction pattern associated to the telescope observations. Further, we suggest an interpolation-based method for determining the image background that allows the recovery of information also in the region of secondary saturation (blooming)

Alcuni problemi di class field theory

Oggetto di studio di questa tesi sono alcuni problemi che riguardano le estensioni abeliane di campi di numeri. Inizialmente esponiamo alcuni risultati fondamentali di teoria algebrica dei numeri, che costituiscono la base per il seguito del lavoro. Introduciamo poi il concetto di divisore di un campo di numeri in modo da poter enunciare i principali teoremi di class field theory nella formulazione più classica. Il primo problema che affrontiamo riguarda la costruzione esplicita dell'Hilbert class field del ventinovesimo campo ciclotomico. A tal scopo richiamiamo alcune delle proprietà che caratterizzano i campi ciclotomici, in particolare quelle riguardanti il gruppo delle unità. Pur essendo un problema essenzialmente di tipo computazionale, la maggior parte del lavoro consiste nel produrre un insieme sufficientemente piccolo di candidati generatori dell'estensione, da cui sia possibile estrarre rapidamente, grazie all'utilizzo di un calcolatore, gli elementi cercati. Calcoliamo quindi il gruppo di Galois assoluto dell'Hilbert class field in modo indipendente da come abbiamo costruito l'estensione. Presentiamo poi la teoria dei nodi di Scholz con alcune importanti conseguenze e studiamo l'$\ell$-rango del gruppo delle classi di ideali di un campo di numeri, dove $\ell$ è un primo dispari, nel caso di estensioni cicliche assolute di grado $\ell$. Proponiamo infine una nuova dimostrazione di un risultato del $2007$ di Nomura che riguarda una condizione necessaria affinché la lunghezza dell'Hilbert $3$-class field tower di un campo ciclico cubico assoluto sia strettamente maggiore di $1$

Deep Brain Stimulation in Treatment-Refractory Addiction

Surgical treatment for addiction has been proposed after the successful efficacy of deep brain stimulation (DBS) for the treatment of neurological movement disorders such as Parkinson’s disease (PD). In the field of psychiatric diseases, DBS has been used firstly for obsessive compulsive disorder (OCD) and treatment-resistant depression. The role in addiction has been proposed only recently. The target areas for DBS in treatment-refractory addiction are nucleus accumbens (NAcc), lateral hypothalamus (LH), amigdala, lateral habenula (LHb), dorsal striatum, prefrontal cortex (PFC) and subthalamic nucleus (STN). A well-documented rationale for the choice of the target is required in order to investigate the effectiveness, safety and feasibility. NAcc appears to be the most effective and safe target for DBS followed by STN; PFC is another promising target but needs further exploration to establish its suitability for clinical purposes. DBS is not free of risks, so every patient has to be carefully evaluated and precise ethical standards must be defined in the form of inclusion and exclusion criteria

CO2 Hydrogenation Induced by Mechanochemical Activation of Olivine With Water Under CO2 Atmosphere

A study on the mechanochemical activation of the olivine in presence of H2O and under CO2 atmosphere have been approached, focusing both on the structural nature of the transformation and the conversion of CO2 to methane and light hydrocarbons. The mechanochemical process was carried out by high energy laboratory mills, with milling vials properly modified in order to be used as batch reactors. Chemical reactivity and reaction rates were investigated under different experimental conditions, evidencing increased performance with respect to the thermally activated process reported in literature. Mechanical treatment induced H2O and olivine activation, with consequent release of molecular H2 which, in turn, allowed hydrogenation of activated CO2. This last reaction also led, through a competitive process, to the precipitation of carbonate phases, whose composition and structural features were dependent of the CO2/H2O ratio.Fil: Farina, Valeria. Università Degli Studi Di Sassari; ItaliaFil: Gamba, Nadia Soledad. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Gennari, Fabiana Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada; ArgentinaFil: Garroni, Sebastiano. Università Degli Studi Di Sassari; ItaliaFil: Torre, Francesco. Università Degli Studi Di Cagliari; ItaliaFil: Taras, Alessandro. Università Degli Studi Di Sassari; ItaliaFil: Enzo, Stefano. Università Degli Studi Di Sassari; ItaliaFil: Mulas, Gabriele. Università Degli Studi Di Sassari; Itali