Metodi di calibrazione e ricostruzione degli eventi nell'esperimento MEG

%Il seguente riassunto e' compilabile con un editor LATEX% L'esperimento MEG si propone di ottenere un'evidenza sperimentale della non conservazione del sapore leptonico (in inglese ``Lepton Flavour Violation'', LFV) e si colloca nel filone di ricerca dei decadimenti rari non permessi dal Mo\-del\-lo Standard con neutrini privi di massa; lo scopo dell'esperimento \`e infatti l'osservazione del processo $\mu^{+}\rightarrow e^{+}\gamma$ con una sensibilit\`a sul rapporto di decadimento (in inglese ``Branching Ratio'', BR) pari a BR$_{(\mu\rightarrow e\gamma)}$ $\approx 10^{-13}$, inferiore di due ordini di grandezza rispetto al limite attuale posto dalla collaborazione MEGA (2001).\\ Nel Modello Standard con neutrini massivi, che include le oscillazioni dei neutrini, il processo $\mu^{+}\rightarrow e^{+}\gamma$ $\;$\`e predetto con un rapporto di decadimento non nullo, ma comunque non misurabile sperimentalmente (BR$_{(\mu\rightarrow e\gamma)}<10^{-50}$). I processi LFV sono invece previsti nella quasi totalit\`a delle e\-sten\-sioni supersimmetriche del Modello Standard con valori del rapporto di decadimento molto pi\`u elevati, attorno a $10^{-12}\div10^{-14}$. Un'osservazione del processo $\mu^{+}\rightarrow e^{+}\gamma$ costituirebbe pertanto un'evidenza incontrovertibile in favore dei modelli supersimmetrici, mentre una non osservazione del decadimento sarebbe di grande utilit\`a nel porre limiti sempre pi\`u stringenti ai parametri liberi delle nuove teorie.\\ La segnatura del decadimento $\mu^{+}\rightarrow e^{+}\gamma$ $\;$a riposo \`e data dalla coincidenza di un positrone e di un fotone, emessi simultaneamente, con un angolo relativo di $180$° ed un'energia di circa $52.8$ MeV ciascuno, pari a met\`a della massa del $\mu^{+}$.\\ Nell'esperimento MEG grande importanza rivestono la comprensione ed il controllo degli eventi di fondo, in cui vengono emesse particelle con caratteristiche simili a quelle di segnale e che possono essere rigettati solo grazie ad elevate risoluzioni sperimentali nella misura delle variabili cinematiche e temporali: energie, angolo relativo e tempo relativo dei prodotti di decadimento. Il rag\-giun\-gi\-men\-to di tali risoluzioni \`e una condizione indispensabile per la buona riuscita dell'esperimento. Inoltre, per la realizzazione di una misura di precisione cos\`i spinta come quella richiesta per MEG, \`e necessario tenere sotto controllo tutti i parametri legati ai rivelatori, in modo da minimizzare le incertezze sistematiche dovute ad effetti strumentali. Per ottenere tali risultati \`e dunque necessaria un'accurata e costante operazione di Calibrazione e Monito\-raggio dell'intero apparato.\\ Il presente lavoro di tesi include un'attivit\`a di laboratorio ed una di analisi dati. La prima \`e consistita nella partecipazione alla misura dei parametri caratteristici dei fototubi in una stazione di test a Pisa ed all'allestimento del rivelatore, con particolare riferimento al montaggio delle sorgenti $\alpha$ di calibrazione del calorimetro. La seconda, svolta nell'ambito del gruppo di lavoro che si occupa dello sviluppo del software dell'esperimento, comprende l'implementazione di algoritmi per la ricostruzione delle variabili cinematiche delle particelle nei sottorivelatori e per l'automatizzazione delle procedure di calibrazione, uno studio sistematico della risoluzione temporale dell'apparato ed una prima analisi dei dati raccolti nel 2007, con la possibile identificazione di un campione di eventi di decadimento radiativo del muone. A conclusione della tesi verranno discusse le prospettive dei risultati ottenibili durante l'acquisizione dati prevista nel 2008

The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II

The accurate determination of the Parton Distribution Functions (PDFs) of the proton is an essential ingredient of the Large Hadron Collider (LHC) program. PDF uncertainties impact a wide range of processes, from Higgs boson characterisation and precision Standard Model measurements to New Physics searches. A major recent development in modern PDF analyses has been to exploit the wealth of new information contained in precision measurements from the LHC Run I, as well as progress in tools and methods to include these data in PDF fits. In this report we summarise the information that PDF-sensitive measurements at the LHC have provided so far, and review the prospects for further constraining PDFs with data from the recently started Run II. This document aims to provide useful input to the LHC collaborations to prioritise their PDF-sensitive measurements at Run II, as well as a comprehensive reference for the PDF-fitting collaborations.Comment: 55 pages, 13 figure

A Roadmap for HEP Software and Computing R&D for the 2020s

Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the shear amounts of data to be recorded. In planning for the HL-LHC in particular, it is critical that all of the collaborating stakeholders agree on the software goals and priorities, and that the efforts complement each other. In this spirit, this white paper describes the R&D activities required to prepare for this software upgrade.Peer reviewe

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good