160 research outputs found
Uniformity Of The 2000 Test Beam Module With The New Optimal Filtering Coefficients
An original method to reconstruct electron and pion signals in the Liquid ARGon barrel calorimeter (LARG) is applied to test beam data collected at the H8 line of the CERN North Area in July and August 2000. The method is based on the use of optimal filtering coefficients and takes into account the electrical description of the read-out electronics in the reconstruction of the physics pulses. Results on improvements in the LARG response and in particular on the energy uniformity of the calorimeter are shown
Mesure de la section efficace différentielle de production du boson Z se désintégrant en paires électron-position, dans l'expérience ATLAS
La première mesure du spectre en phi*_eta du boson Z à 7 TeV a été réalisée dans cette thèse. Cette variable permet de sonder la dynamique de production des Z de façon fine. L échantillon complet des données enregistrées par ATLAS en 2011 a été utilisé ce qui correspond à 4.7/fb de luminosité intégrée. Les résultats de cette mesure sont publiés dans la Ref. [18] fondé sur la note interne Ref. [69]. La section efficace différentielle de Z->ee en fonction phi*_eta a été mesurée et comparée aux calculs perturbatifs à ordre fixé, avec/sans resommation pour la région des petits phi*_eta. Le code RESBOS fournit la meilleure description des données, cependant il est incapable de reproduire, à mieux de 4%, la forme détaillée de la section efficace mesurée. La section efficace différentielle a également été comparée aux prédictions de différents générateurs Monte Carlo interfacés avec un algorithme de parton shower. Les meilleures descriptions du spectre en phi*_eta mesuré sont données par les générateurs SHERPA et POWHEG+PYTHIA8. La mesure précise de la section efficace différentielle en phi*_eta fournit des informations précieuses pour l ajustement des codes Monte Carlo. La précision expérimentale typique de cette mesure (~0.5%) est dix fois meilleure que la précision des calculs théoriques et elle est donc aussi précieuse pour contraindre la théorie. La mesure du spectre en ptZ a également été faite pour quantifier l incertitude systématique de cette mesure en utilisant la grande statistique de l échantillon de données. Cela permet de comparer deux mesures qui traitent de l impulsion transverse du boson Z. Dans la plupart du domaine en phi*_eta l incertitude systématique de la mesure de ptZ est deux fois plus grande que celle de la mesure de phi*_eta. Cette comparaison confirme l intérêt de la variable phi*_eta. Les résultats présentés dans cette thèse ont beaucoup d implications pour les études futures. Ajustant les générateurs Monte Carlo en utilisant les résultats de la mesure précise du spectre en phi*_eta minimisera l incertitude sur leurs paramètres. Une mesure de la section efficace doublement différentielle en ptZ et phi*_eta est intéressante pour mieux comprendre la corrélation entre ces deux variables. La mesure précise du spectre en ptZ utilisant la variable phi*_eta peut être appliquée au spectre en ptW et on sait que des mesures plus fines du ptW sont importante pour une détermination précise de la masse du boson W. De plus, une compréhension précise du spectre en ptZ est importante pour comprendre les propriétés cinématiques de la production du boson de Higgs.The first measurement of the phi*_eta spectrum of Z bosons at 7 TeV of pp collisions has been studied in this thesis, which is an alternative way to probe the transverse momentum of Z bosons. The full data sample recorded by the ATLAS detector during 2011 run of the LHC was used, which corresponds with 4.7/fb integrated luminosity. The results of this measurement were reported in Ref. [18] supported by the internal note in Ref. [69]. The differential cross section of Z->ee as a function of phi*_eta has been measured and compared to fixed order perturbative QCD calculations with/without a resummation for the low phi*_eta region. Calculations using RESBOS provide the best descriptions of the data. However, they are unable to reproduce the detailed shape of the measured cross section to better than 4%. The differential cross section was also compared to predictions from different Monte Carlo generators interfaced to a parton shower algorithm. The best descriptions of the measured phi*_eta spectrum are provided by SHERPA and POWHEG+PYTHIA8 Monte Carlo event generators. The precise measurement of the differential cross section as a function of phi*_eta provides valuable information for the tuning of MC generators. The typical experimental precision of this measurement (~0.5%) is ten times better than the typical theoretical precision and therefore is valuable to constrain the theoretical predictions further. The ptZ measurement has been also studied to quantify the systematic uncertainty of this measurement using the high statistic data sample. This allows to compare two measurements which both address the physics issues of the Z transverse momentum. In most of the phi*_eta range, the systematic uncertainty of the ptZ measurement is two times larger than the one of the phi*_eta measurement. This comparison confirms the interest for the phi*_eta variable. The measurements presented in this thesis has many implications for future studies. Tuning MC generators using the result of the precise measurement of the phi*_eta spectrum will minimize the uncertainty on the tuned parameters. A double differential cross section measurement as a function of ptZ and phi*_eta is interesting to understand the correlation between ptZ and phi*_eta variables. The precise measurement of the ptZ spectrum using the new variable phi*_eta can be applied to ptZ. More precise measurement of ptZ are important to obtain precise measurements of the W mass. In addition, a precise understanding of the ptZ spectrum is important to understand kinematic properties of Higgs boson production.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF
Averaging lifetimes for B hadron species
The measurement of the lifetimes of the individual B species are of great interest. Many of these measurements are well below the 10 level of precision. However, in order to reach the precision necessary to test the current theoretical predictions, the results from different experiments need to be averaged. Therefore, the relevant systematic uncertainties of each measurement need to be well defined in order to understand the correlations between the results from different experiments. \par In this paper we discuss the dominant sources of systematic errors which lead to correlations between the different measurements. We point out problems connected with the conventional approach of combining lifetime data and discuss methods which overcome these problems
Passive seismology and deep structure in central Italy
n the last decade temporary teleseismic transects have become a powerful tool for investigating the crustal and upper mantle structure. In order to gain a clearer picture of the lithosphere-asthenosphere structure in peninsular Italy, between 1994 and 1996, we have deployed three teleseismic transects in northern, central, and southern Apennines, in the framework of the project GeoModAp (European Community contract EV5V-CT94–0464). Some hundreds of teleseisms were recorded at each deployment which lasted between 3 and 4 months. Although many analyses are still in progress, the availability of this high quality data allowed us to refine tomographic images of the lithosphere-asthenosphere structure with an improved resolution in the northern and central Apennines, and to study the deformation of the upper mantle looking at seismic anisotropy through shear-wave splitting analysis. Also, a study of the depth and geometry of the Moho through the receiver function technique is in progress. Tomographic results from the northernmost 1994 and the central 1995 teleseismic experiments confirm that a high-velocity anomaly (HVA) does exist in the upper 200–250 km and is confined to the northern Apenninic arc. This HVA, already interpreted as a fragment of subducted lithosphere is better defined by the new temporary data, compared to previous works, based only on data from permanent stations. No clear high-velocity anomalies are detected in the upper 250 km below the central Apennines, suggesting either a slab window due to a detachment below southern peninsular Italy, or a thinner, perhaps continental slab of Adriatic lithosphere not detectable by standard tomography. We found clear evidence of seismic anisotropy in the uppermost mantle, related to the main tectonic processes which affected the studied regions, either NE–SW compressional deformation of the lithosphere beneath the mountain belt, or arc-parallel asthenospheric flow (both giving NW–SE fast polarization direction), and successive extensional deformation ( E–W trending) in the back-arc basin of northern Tyrrhenian and Tuscany. Preliminary results of receiver function studies in the northern Apennines show that the Moho depth is well defined in the Tyrrhenian and Adriatic regions while its geometry underneath the mountain belt is not yet well constrained, due to the observed high complexity.Published479-4934T. Sismicità dell'ItaliaJCR Journa
Bollettino Sismico Italiano: Analisys of Early Aftershocks of the 2016 MW 6.0 Amatrice, MW 5.9 Visso and MW 6.5 Norcia earthquakes in Central Italy
The Amatrice-Visso-Norcia seismic sequence is the most important of the last 30 years in Italy. The seismic sequence started on 24 August, 2016 and still is ongoing in central Apennines. At the end of February 2017 more than 57,000 events were located, 80,000 events up to the end of September 2017 (Fig. 1). The mainshocks of the sequence occurred on 24 August 2016 (Mw 6.0 and Mw 5.4), 26 October 2016 (Mw 5.4 and Mw 5.9), 30 October 2016 (Mw 6.5), 18 January 2017 (four earthquakes Mw≥ 5.0).
In this seismic sequence, all the waveforms recorded by temporary stations deployed by the SISMIKO emergency group (stations T12**; Moretti et al., 2016) where available in real- time at the surveillance room of INGV. Because of the high level of seismicity and the dense seismic network installed in the region, more than 150 events per day were located at the end of February 2017; still 60 events per day were located up to the end of August 2017.The Amatrice-Visso-Norcia is the most important seismic sequence since 2015, the time when the analysis procedures of the BSI group (Bollettino Sismico Italiano) were revised (Nardi et al., 2015). BSI is now available every four months on the web: bulletins contain revised earthquakes (location and magnitude) with ML≥ 1.5, quasi-real time revision of ML≥ 3.5 earthquakes and phase arrivals from waveforms recorded on seismic stations available from the European Integrated Data Archive (EIDA), (Mazza et al., 2012).
These last procedures allow the integration of signals from temporary seismic stations (Moretti et al., 2014) installed by the emergency group SISMIKO (Moretti and Sismiko working group, 2016), even when they are not in real time transmission, if they are rapidly archived in EIDA, together with real time signals from the seismic stations of the permanent INGV network.
The analysis strategy of the BSI group for the Amatrice -Visso - Norcia seismic sequence (AVN.s.s in the following) was to select the earthquakes located in the box with min/max latitude: 42.2/43.2 - and min/max longitude: 12.4/14.1 to prepare a special volume of BSI on the seismic sequence.PublishedTrieste, Italy1SR. TERREMOTI - Servizi e ricerca per la Societ
Bollettino Sismico Italiano gennaio – aprile 2019
Nel periodo che va dal 1 gennaio al 30 aprile 2019, gli analisti del BSI hanno revisionato tutti gli eventi di magnitudo M≥1.5, mentre i parametri dei terremoti di magnitudo inferiore a tale soglia di revisione sono stati calcolati in tempo reale, nella sala di sorveglianza sismica di Roma.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat
Bollettino Sismico Italiano settembre – dicembre 2018
Gli analisti del BSI hanno revisionato tutti gli eventi di magnitudo M≥1.5, localizzati dal 1 settembre al 31 dicembre 2018. I parametri dei terremoti di magnitudo inferiore a tale soglia di revisione, sono quelli calcolati in tempo reale, nella sala di sorveglianza sismica di Roma.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat
Bollettino Sismico Italiano gennaio – aprile 2018
Nel primo quadrimestre 2018 si sono verificati in Italia cinque eventi di magnitudo superiore o
uguale a 4.0, di cui nessuno di magnitudo superiore a 5.0. Due di essi, avvenuti il 4 (MW 4.0) e il
10 aprile (MW 4.6), hanno interessato la zona della sequenza dell’Italia centrale, in provincia di
Macerata. Un terremoto di magnitudo MW 4.3 è avvenuto in provincia di Campobasso, il 25 aprile,
ad una profonditĂ di 29 km. Infine due terremoti profondi, avvenuti il 12 febbraio (ML 4.4, con
profonditĂ di 379 km) e il 7 marzo (ML 4.0, con profonditĂ di 294 km), hanno interessato il Tirreno
Meridionale, al largo della costa calabra.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat
Performance of the ATLAS Electromagnetic Calorimeter End-cap Module 0
The construction and beam test results of the ATLAS electromagnetic end-cap calorimeter pre-production module 0 are presented. The stochastic term of the energy resolution is between 10% GeV^1/2 and 12.5% GeV^1/2 over the full pseudorapidity range. Position and angular resolutions are found to be in agreement with simulation. A global constant term of 0.6% is obtained in the pseudorapidity range 2.5 < eta < 3.2 (inner wheel)
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