Rozprawy doktorskie na temat „Lhcd”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Lhcd”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Liang, Anshu. "Understanding the low to high confinement transition in tokamak plasmas". Electronic Thesis or Diss., Aix-Marseille, 2023. http://theses.univ-amu.fr.lama.univ-amu.fr/230112_LIANG_826zuy182lisgpn946fzpk544n_TH.pdf.
Pełny tekst źródłaThe works presented in this thesis are devoted to understand the physical mechanism of the L-H transition. The driving mechanism of the velocity shear in the plasma edge has been studied using lower hybrid current drive (LHCD) power injection on the HL-2A tokamak in China. It has been shown that the increase of the velocity shear is mainly driven by the ion diamagnetic term of the radial electric field Er. During the L-H transition, it is observed that the ion diamagnetic term of the radial electric field Er plays a dominant role in the increase of velocity shear, while the contributions of the poloidal and toroidal velocity terms are negligible. The velocity shear must reach a critical value to allow the L-H transition to occur. This means that the critical value plays a role as a velocity shear threshold for the L-H transition. In addition, the stimulated effect of supersonic molecular beam injection (SMBI) on the L-H transition has also been investigated on HL-2A. The results suggest that SMBI could be a reliable method for reducing the L-H transition power threshold and controlling the L-H transition in future fusion reactors. Finally, efforts have been made on the optimization of LHCD coupling on the WEST tokamak in France and an analysis of the LH wave coupling in WEST plasmas has been carried out. The analysis shows that the toroidal reshaping of the fully-active-multijunction launcher carried out before its installation in WEST was successful. The experiments have also shown that the reshaping of the passive-active-multijunction launcher is necessary in order to avoid overheating on the launcher front in long pulses
Sierchio, Jennifer Marie. "The effect of ICRF and LHCD waveguide and launcher location on tritium breeding ratio and radiation damage in fusion reactors". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103703.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (pages 73-76).
In most tokamak fusion reactor designs, ICRF (Ion Cyclotron Range of Frequencies) and LH (Lower Hybrid) radio frequency (RF) waves used to heat the plasma and drive current are launched from the low-field, outboard side where there is more access space. It has recently been proposed to launch these waves from the high-field side [1-3], which increases current-drive efficiency, allows for better wave penetration, and has favorable scrape-off-layer and plasma material interaction characteristics [4]. However the poloidal location and size of RF launchers will also affect important aspects of the neutronics of the tokamak fusion design, i.e. how the 14.1 MeV neutrons born out of the deuterium-tritium (D-T) fusion reaction interact with the surrounding blanket and structures. The goal of this thesis is to assess the dependence of RF launcher poloidal location on the important neutronics parameters of tritium fuel breeding, launcher damage and activation. To determine the effects of waveguide and antenna location on Tritium Breeding Ratio (TBR), damage, and activation, the MCNP Transport Code was used, as well as the EASY 2010 activation package to analyze the activation of the vacuum vessel components. A simple geometry was designed for MCNP, based on the original ARC model [1]. Seven locations for the waveguides and antenna were chosen: the inner and outer midplane, the inner and outer upper corners, two spaces between the midplane (inboard and outboard), and a central location directly above the vacuum vessel. TBR, DPA, and helium concentration were calculated at all seven points to find the optimal location for the waveguides and antenna. Four blanket materials were chosen: two liquid blankets (FliBe and Pb-17Li) and two solid blankets (Li4SiO4 and Li2TiO3). This was to test whether or not blanket material affects the optimal location of the launchers. We find that from the neutronics point of view the overall optimal location is the inboard upper corner, which minimizes DPA and helium concentration in the antenna and waveguide, and maximizes TBR. DPA in the waveguide was minimized when placed in the outboard upper corner, although the difference in DPA between the two locations was small. While TBR was maximized at the top of the vacuum vessel, the differences in TBR between all locations was less than 1%. These results reinforce the choice of inside, upper corner launch as the optimal location for current drive, launcher protection and neutronics. Activation was also assessed for the vacuum vessel, both without and with the waveguides and antenna, assuming irradiation times of one week, one month, and one year. Overall, activation was significant in the vacuum vessel, as expected, due to the use of Inconel 718. The IAEA recycling limit could be achieved, regardless of irradiation time. The dominant isotopes present after irradiation differed when the irradiation time was one week versus one month or one year. Activation was also assessed in the waveguides and antenna for the cases of the launchers being placed at the outboard midplane versus the inboard corner. The activation in the antenna was shown to be reduced by a factor of two and in the waveguides by a factor of four, when the launchers were placed in the inboard corner.
by Jennifer Marie Sierchio.
S.M.
McCarthy, James. "Search for rare baryonic b decays with the LHCb experiment at the LHC". Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6247/.
Pełny tekst źródłaManuzzi, Daniele. "Measure of the branching ratio of the B0→D∗−τ+ντ decay at LHCb: a preliminary study for RD∗(q2) in 3-prong τ decays". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15841/.
Pełny tekst źródłaMELONI, SIMONE. "Test of lepton flavour universality with the simultaneous measurement of R(D+) and R (D*+) with τ→ μνν decays at the LHCb experiment". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/364128.
Pełny tekst źródłaIn the Standard Model of particle physics, the coupling of the electroweak gauge bosons to the leptons is independent of the lepton flavour. This property, known as Lepton Flavour Universality, is an accidental symmetry of the Standard Model, which can be tested in semileptonic b-meson decays. The variables used to test the Lepton Flavour Universality hypothesis are ratios of branching fractions between decays with the τ lepton and the ones with the μ lepton in the final state: R(Hc) = B(B → Hc τ ν) / B(B → Hc μν) with Hc a charmed meson produced in the decay. Any sign of deviation with respect to the Standard Model predictions in these variables could be a clear sign of New Physics effects. A tension at the level of 3σ with respect to the Standard Model predictions has been observed in the combination of the measurements of R(D) and R(D*) performed by the Belle, BaBar and LHCb collaborations. At the time of writing of this thesis, no measurement of the R(D) parameter has been performed by any hadron collider experiment. This thesis reports a simultaneous measurement of the R(D+) and R(D*+) parameters performed using B → D(*)lν decays. This measurement exploits leptonic decays of the τ lepton, τ → μνν , using a data sample corresponding to an integrated luminosity of 2.0 /fb collected in proton-proton collisions at a centre-of-mass energy of 13 TeV at the LHCb experiment during the 2015 and 2016 data taking years. All the steps of the analysis have been performed and all the main systematic uncertainties have been studied. The value of the measured parameters is still blinded and the analysis is in internal review within the LHCb collaboration. The expected uncertainty on the parameters of interest is given by R(D+) = xxx ± 0.033(stat.) ± 0.037(syst.), R(D*+)= xxx ± 0.040(stat.) ± 0.070(syst.).
Roselló, Canal Maria del Mar. "Control de l'escintil·lador SPD del calorímetre d'LHCb". Doctoral thesis, Universitat Ramon Llull, 2009. http://hdl.handle.net/10803/9152.
Pełny tekst źródłaL'LHC és un accelerador orientat a estudiar els constituents de la matèria on LHCb n'és un dels detectors. El calorímetre és aquella part del detector destinada a mesurar l'energia de les partícules que el travessen. En el nostre cas l'SPD discrimina entre partícules carregades i no carregades contribuint així en les decisions del calorímetre.
En l'electrònica de l'SPD trobareu diferenciades dues parts: l'electrònica en contacte directe amb el subdetector (Very Front End, VFE) i l'electrònica de gestió de l'SPD (la Control Board, CB). L'objectiu d'aquesta tesi és la descripció d'aquesta darrera així com la integració de l'SPD en el sistema de control del calorímetre.
El VFE realitza un primer processat de les dades del detector determinant un nivell digital el qual indica si s'ha rebut una partícula carregada o no. La CB és l'encarregada en canvi de la monitorització i el control del sistema SPD: és capaç d'enviar dades de configuració als VFE i a la vegada en monitoritza el correcte funcionament.
Veureu que el document es troba organitzat en 5 parts. A la primera part trobareu descrites les característiques principals del calorímetre, les seves funcions i la seva estructura. La part segona, tercera i quarta són dedicades integrament a la CB: a la part 2 tenim descrit el hardware, a la part 3 el sistema de control i a la quarta part hi trobarem comentats els diferents testos i proves realitzades tan sobre el hardware com amb el sistema de control. Finalment a la cinquena part hi trobarem resumits els objectius aconseguits amb el nostre disseny i les aportacions d'aquest en la globalitat de l'experiment.
En esta tesis se describe la electrónica y la gestión de la placa de control del SPD. SPD son las siglas correspondientes a Scintillator Pad Detector, parte del calorímetro de LHCb del acelerador LHC.
LHC es un acelerador orientado al estudio de los constituyentes de la materia donde LHCb es uno de los detectores. El calorímetro es aquella parte del detector destinada a medir la energía de las partículas que lo traviesan. En nuestro caso el SPD discrimina entre partículas cargadas y neutras contribuyendo así a las decisiones del calorímetro.
En la electrónica del SPD encontraréis diferenciadas dos partes: la electrónica en contacto directo con el detector (Very Front End, VFE) y la electrónica de gestión del SPD (la Control Board, CB). El objetivo de esta tesis es precisamente la descripción de esta última parte así como la integración del SPD en el sistema de control del calorímetro.
El VFE realiza un primer procesado de los datos del detector determinando un nivel digital el cual indica si la partícula detectada está cargada o no. La CB es en cambio la encargada de la monitorización y el control del sistema SPD: es capaz de enviar datos de configuración a los VFE y a la vez monitorizar su correcto funcionamiento.
Veréis que el documento se encuentra organizado en 5 partes. En la primera parte encontraréis descritas las características principales del calorímetro, sus funciones y su estructura. La segunda parte, la tercera y la cuarta están plenamente dedicadas a la CB: en la parte 2 tenemos descrito el hardware, en la parte 3 el sistema de control y en la cuarta encontraremos los diferentes tests y pruebas realizadas sobre el hardware y el sistema de control. Finalmente en la quinta parte tenemos resumidos los objetivos conseguidos con nuestro diseño y las aportaciones de este en la globalidad del experimento.
In this thesis you will have described the electronics and management of the SPD. SPD stands for Scintillator Pad Detector which is part of the LHCb calorimeter of the LHC accelerator.
LHC is an accelerator oriented to study the matter constitution and LHCb is one of the detectors designed for this challenge. The LHCb part oriented to measure the particles energy is the calorimeter. The SPD is designed to discriminate between charged and neutral particles contributing in the calorimeter decisions.
In the SPD electronics description we can distinguish between to parts: the electronics in contact with the subdetector (Very Front End, VFE) and the electronics in charge of the SPD management (the Control Board, CB). The goal of this thesis is the description of the last and also the integration of the SPD with the calorimeter control system.
The VFE captures the data from the detector and makes a first digital decision depending on if the particle detected is charged or not. The CB is in charge of the monitoring and control of the SPD system: is able to send configuration data to the VFE and also monitors parameters to assure a proper behaviour.
You will see that the document is divided in 5 parts. In the first, you will find described the calorimeter, its functionalities and its structure. Part 2, part 3 and part 4 are fully dedicated to the CB: in part 2 we will find the CB hardware, in part 3 the control system and finally in part 4 the different tests performed with the hardware and the control system. The document ends with part 5 where the main objectives of this work are summarized and also the contribution of the SPD design in the LHCb project.
Hopchev, Plamen. "Mesures de la luminosité absolue à l'expérience LHCb". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00684982.
Pełny tekst źródłaAlessio, Federico. "Beam, Background and Luminosity Monitoring in LHCb and Upgrade of the LHCb Fast Readout Control". Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22044/document.
Pełny tekst źródłaThere are two main central topics in the thesis: the LHCb beam, background and luminosity monitoring systems and the LHCb optimization systems of experimental conditions. These systems are heavily connected to each other, as improving the machine beam, background and luminosity conditions will automatically improve global operation by maximizing the ratio of luminosity recorded over signal background. At the same time, improving the operation of the experiment will help improve luminosity, by studying more accurately the beam and background conditions and therefore improving the LHC machine settings. In this thesis, the systems to accomplish the requirements of these two main topics are described in detail
Kochebina, Olga. "Study of Rare Charm Decays with the LHCb Detector at CERN". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112208/document.
Pełny tekst źródłaRare charm decays proceed mostly through the c -> u Flavor Changing Neutral Current (FCNC), which is possible only at loop level in the Standard Model (SM). In charmed decays, FCNCs are subject to a very efficient GIM suppression, leading to very rare processes. Consequently, rare charm decays are good tools to probe to New Physics (NP) beyond the SM. NP particles could become detectable by causing observables such as branching ratios and CP or angular asymmetries to deviate from the SM predictions. The main subject of this thesis is the measurement of the branching ratio of the D0 -> K-π+ ρ/ω (->µ+µ-) mode. It will be precious in the future, in particular as a normalization mode in the study of all: D0 -> h-h’+ µ+µ- decays D0 -> K-π+µ+µ-, D0 -> π+π-µ+µ-, D0 -> K+K-µ+µ- and D0 -> K+π-µ+µ-. Using 2/fb of 2012 LHCb data we find: B(D0 -> K-π+ ρ/ω (->µ+µ-)) = (4.37± 0.12(stat.) ±0.53(syst.)) ×10^-6. This is the first measurement of this mode. We also determined sensitivities to total and partial branching fractions and asymmetries in D0 -> h-h’+ µ+µ- decays with future LHCb datasets. In addition, the systematic uncertainties affecting the searches for the 3-body decays, D+(s) -> π+µ+µ- and D+(s) -> π-µ+µ+, carried out by LHCb based on the data collected in 2011 (1/fb). Finally, the results of the tests of front-end electronic board for the Upgrade of LHCb are presented
Laubser, J. "Conception et réalisation de l'unité de décision du système de déclenchement de premier niveau du détecteur LHCb au LHC". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2007. http://tel.archives-ouvertes.fr/tel-00283775.
Pełny tekst źródłaFitzpatrick, Conor Thomas. "Measurement of the CP-violating phase φs in the decay Bo/s →J/ψ/φ". Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7723.
Pełny tekst źródłaFerrari, Fabio. "Measurement of CP asymmetries in $\lambda^0_b \to pk^-$ and $\lambda^0_b \to p \pi^-$ decays at LHCb". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7041/.
Pełny tekst źródłaLaubser, Julien. "Conception et réalisation de l'unité de décision du système de déclenchement de premier niveau du détecteur LHCb au LHC". Phd thesis, Clermont-Ferrand 2, 2007. https://tel.archives-ouvertes.fr/tel-00283775.
Pełny tekst źródłaVallier, Alexis. "Measurement of the CKM angle gamma in the B⁰->DK*⁰ decays using the Dalitz method in the LHCb experiment at CERN and photon reconstruction optimisation for the LHCb detector upgrade". Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112175/document.
Pełny tekst źródłaQuark mixing is described in the standard model of particle physics with the Cabibbo-Kobayashi-Maskawa mecanism. The angle gamma of the unitarity triangle is one of the parameters of this mecanism that is still determined with a large uncertainty. It can be measured without significant contribution of new physics, making it a standard model key measurement. The current precision of the best direct measurement of gamma is approximately 10°, whereas the global fits of the CKM parameters determine this angle up to a few degrees. Therefore precise measurement of this quantity is needed to further constrain the Unitarity Triangle of the CKM matrix, and check the consistency of the theory. This thesis reports a measurement of gamma with a Dalitz analysis of the B0->DK*0 channel where the D meson decays into K0Spipi, based on the 3 fb⁻¹ of proton-proton collision data collected by LHCb during the LHC Run I, at the centre-of-mass energy of 7 and 8 TeV. This channel is sensitive to gamma through the interference between the b->u and b->c transitions. The CP violation observables are measured to be x- = -0.09 ^{+0.13}_{-0.13} ± 0.09 ± 0.01 , x+ = -0.10 ^{+0.27}_{-0.26} ± 0.06 ± 0.01 , y- = 0.23 ^{+0.15}_{-0.16} ± 0.04 ± 0.01 , y+ = -0.74 ^{+0.23}_{-0.26} ± 0.07 ± 0.01 , where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is the systematic uncertainty due to the Dalitz model. A frequentist interpretation of these observables leads to rB0 = 0.39±0.13 , deltaB0 = ( 186^{+24}_{-23} )°, gamma = ( 77^{+23}_{-24} )° , where rB0 is the magnitude of the ratio between the suppressed and favoured decays and deltaB0 the strong phase difference between these two decays. In addition, the work performed on the optimisation of the photon reconstruction for the upgraded LHCb detector is reported. During LHC Run III, the LHCb instantaneous luminosity will be increased by a factor five, implying a larger shower overlap in the electromagnetic calorimeter. The study shows that reducing the cluster size used in the photon reconstruction limits the effect of the overlap between the showers, without inducing a significant energy leakage. With some dedicated corrections, the new cluster reconstruction improves the Bs->Phi gamma mass resolution by 7 to 12%, depending on the calorimeter region
Adrover, Pacheco Cosme. "Vers une première mesure du rapport de branchement $B^{0}_{(s)} \to\mu^+ \mu^-$ avec le détecteur LHCb au LHC". Phd thesis, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00740781.
Pełny tekst źródłaSABATINO, GIOVANNI. "Charmonium production at LHCb: measurement of the psi' to J/psi production ratio with the first data". Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1244.
Pełny tekst źródłaLHCb is an experiment dedicated to precise measurements of CP violating and rare decays of $b$-hadrons. It will exploit the proton-proton collisions at an energy of 14 TeV in the centre-of-mass system, produced by the LHC collider (CERN-Geneva), and will operate at a luminosity of $2\times 10^{32}$ cm$^{-2}$s$^{-1}$. The expected number of pairs $b\overline{b}$ produced by the LHC collisions is N$_{b\overline{b}}\approx10^{12}$/year. LHCb is designed with a robust and efficient trigger whose purpose is to reduce the event rate in input ($\approx10$ MHz) to a manageable event rate, enriched in content of heavy flavour quarks, to be written to storage ($\approx2$ kHz). The rate reduction is achieved in two trigger levels, L0 (Level 0) and HLT (High Level Trigger), that will be widely discussed in this thesis. A good particle identification as well as efficient tracks and vertexes reconstruction, are fundamental requirements for the reconstruction of the $b$-hadron decays and proper time measurement.\\ LHCb aims to improve the current precision on the CKM parameters and to search for any possible inconsistency with the Standard Model predictions in order to find out eventual ``New Physics'' effects. The LHCb detector is fully installed, commissioned and ready for data taking: the LHC start-up is expected by the end of 2009.\\ In the first periods of data taking, the understanding of the apparatus, as well as the preparatory measures, are necessary steps for the future analyses on the $b$-hadrons. In particular the charmonium states will be largely produced either as prompt or from $b$$\rightarrow$$c$ transitions. Their well known properties make these resonances ideal for alignment and calibration studies. On the other hand the observation of charmonium states and the measurement, per example, of the prompt cross section ratio between $\psi(2S)$ and $J/\psi$ can give some interesting informations about the production mechanisms.\\ The hadroproduction of $J/\psi$ and $\psi(2S)$ is not yet completely understood. Early models could not describe the cross section of directly produced $J/\psi$ mesons. Such models underestimated the measurements by a factor of approximately 50 and did not adequately describe the cross section shape as a function of $p_T$. With the advent of Non-Relativistic QCD (NRQCD) it has been possible to give a better theoretical description of charmonium production through the introduction of the Color Octet model. Nevertheless there are still a lot of issues and open problems: the spin alignment of $\psi$ mesons predicted by NRQCD theories is totally in disagreement with the CDF findings (polarization puzzle); moreover recent NL0 and NNL0 calculations in the Color Singlet model have shown that the amount of the Color Octet needed so far to explain data could be overestimated. Further measurements with $J/\psi$ and other charmonia states are needed to discriminate between the models and clarify the situation.\\ In this thesis the measurement of the prompt cross section ratio between $\psi(2S)$ and J/$\psi$, with the first data of LHCb, is described. Simulation studies have been performed to assess the acceptances, the efficiencies and the systematic errors introduced by the apparatus. Particular emphasis is given to the polarization of the $\psi$'s and to the systematic induced. This measure is a starting point for the subsequent absolute cross section measurements.\\ In chapters I-II-III of this thesis essentially we give a detailed description of the LHCb experiment including the trigger and the online monitoring system. In chapter IV we discuss the theory of charmonium production and the expectations at LHCb. In the chapters V-VI, we present a study on Monte Carlo data in which the measurement of the prompt cross section ratio between $\psi(2S)$ and $J/\psi$, in the dimuon channel, is described. Finally, in the chapter VII we will discuss some further prospects on charmonium measurements.
Gazzoni, Giulio. "Search for time-integrated cp violation in $d^0 \rightarrow k^+k^-$ and $d^0 \rightarrow \pi^+\pi^-$ decays at lhcb". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/6706/.
Pełny tekst źródłaQian, W. "J/ψ production study at the LHCb experiment". Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00525609.
Pełny tekst źródłaLeroy, O. "Trigger à muons, étiquetage de la saveur et performances physiques de l'expérience LHCb". Habilitation à diriger des recherches, Université de la Méditerranée - Aix-Marseille II, 2007. http://tel.archives-ouvertes.fr/tel-00235815.
Pełny tekst źródłaPearce, Alex. "Measurements of charm production and CP violation with the LHCb detector". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/measurements-of-charm-production-and-cp-violation-with-the-lhcb-detector(5379ce11-0da4-4cb3-bc31-d2790d82f696).html.
Pełny tekst źródłaAmhis, Y. "Alignement en temps des calorimètres électromagnetique et hadronique, sélection des canaux $B\rightarrow D^{-}\rho(770)^{+}, B_{s}\rightarrow D_{s}^{-}\rho(770)^{+}$ and $B_{s}\rightarrow D_{s}^{-}K^{*+}(892)$ avec le détecteur LHCb". Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00425102.
Pełny tekst źródłaPagani, Luca. "Misura dell'angolo γ a LHCb". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9090/.
Pełny tekst źródła钱Qian, 文斌Wenbin. "J/ψ production study at the LHCb experimentJ/ψ production study at the LHCb experiment". Paris 11, 2010. http://www.theses.fr/2010PA112109.
Pełny tekst źródłaIn this thesis, the study of the J/ψ production at the LHCb is presented, based on a sample of fully simulated Monte Carlo events. The procedure developped in this thesis will be use to analyze real data when enough statistics will be accumulated. J/ψ events are reconstructed using selection criteria optimized to reach the best discrimitaion against background processes. The stude done shows that 6. 5 million J/ψ can be reconstructed per pb-1 of data. The production cross section of prompt J/ψ and of J/ψ from b is measured in pT and η 28 bins covering the region 0 < pT < 7 GeV/c and 3 < η < 5. In each bin, a variable is defined to distinguish prompt J/ψ and b decays. The analysis show also that J/ polarization plays an important role in the cross section determination. It can contribute to a systematic error up to 30% in some of the bins. Such an effect can be greatly reduced if a J/ψ polarization analysis is done simultaneously. The measurement of the polarization parameters will also help to understand J/ψ production mechanisms. The LHCb experiment already recorded 14 nbֿ¹ of data, part of the analysis can already be done. Approximately 3000 J/ψ candidates are reconstructed. Using this sample, the cross section as a function of pT is measured. The preliminary measurement of the J/ψ cross section in the region pT between 0 and 9 GeV/c and y between 2. 5 and 4 is 7. 6±0. 3 µb where only the statistical error is reported
Veronesi, Michele. "Measurement of $D^{0}-\overline{D}^{0}$ mixing and search for CP violation in $D^{0}\toK^{\pm}\pi^{\mp}$ decays at LHCb". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13439/.
Pełny tekst źródłaEijk, Rutger Mark van der. "Track reconstruction in the LHCb experiment". [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/66446.
Pełny tekst źródłaSimmons, Brinick Matthew Christophe. "Ring imaging Cherenkov counters for LHCb". Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412002.
Pełny tekst źródłaCook, Andrew David. "Double J/u production at LHCb". Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682360.
Pełny tekst źródłaMcSkelly, Ben. "WW dibosons at the LHCb experiment". Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2011180/.
Pełny tekst źródłaHennequin, Arthur. "Performance optimization for the LHCb experiment". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS031.
Pełny tekst źródłaThe LHCb experiment, at CERN, is preparing a major upgrade of its detector and a change from an hardware-based to a fully software-based trigger system. It is now facing the challenge of being able to process incoming events at a rate of 30 million events per second. To cope with this massive data input, the software must be optimized to use the processing power of the filtering farm more efficiently. This thesis focus on the first algorithm of LHCb's High Level Trigger software: the Vertex Locator (VELO) reconstruction algorithm. The VELO is the first detector encountered by particles, directly surrounding the interaction region. Its goal is to find the initial track candidate that are then followed through the other layers of the LHCb detector with a good enough resolution that they could also be used to locate the origin of the collisions. The first step of this algorithm is to prepare the data by grouping pixels of the silicon sensors into hits; this process is called connected component analysis (CCA). This thesis presents multiple new CCA algorithms for both CPU and GPU architectures. A new VELO reconstruction algorithm using SIMD is presented, that enable LHCb to process events in real time and improve the quality of the reconstruction. The SIMDWrapper library, developed for the new VELO algorithm, is now part of LHCb's software and is used in other algorithms
Molson, James. "Proton scattering and collimation for the LHC and LHC luminosity upgrade". Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/proton-scattering-and-collimation-for-the-lhc-and-lhc-luminosity-upgrade(3c4fab61-2d9d-4575-8874-15d91c95523f).html.
Pełny tekst źródłaSobczak, Krzysztof Grzegorz. "Study of charmless three-body decays of neutral B mesons with the LHCb spectrometer". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00686906.
Pełny tekst źródłaMichel, Hanspeter. "Charakterisierung des LHC 2 und der LHC 2-Apoproteine in Chlamydomonas reinhardii /". [S.l : s.n.], 1985. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Pełny tekst źródłaMirarchi, Daniele. "Crystal collimation for LHC". Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/29207.
Pełny tekst źródłaD'AGNOLO, RAFFAELE TITO. "Naturalness at the LHC". Doctoral thesis, Scuola Normale Superiore, 2013. http://hdl.handle.net/11384/85873.
Pełny tekst źródłaGrabalosa, Gándara Marc. "Flavour Tagging developments within the LHCb experiment". Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/84088.
Pełny tekst źródłaMachefert, F. "LHCb calorimeter electronics. Photon identification. Calorimeter calibration". Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00583998.
Pełny tekst źródłaSmith, Andrew Cameron. "LHCb data management on the computing grid". Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3018.
Pełny tekst źródłaGreening, Edward. "Rare and challenging charm decays at LHCb". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:0f960d89-76a1-4222-9d11-922fd7516339.
Pełny tekst źródłaMorda, Alessandro. "Rare dileptonic B meson decays at LHCb". Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4042/document.
Pełny tekst źródłaThe B0(s)→ll decays are generated by Flavor Changing Neutral Currents, hence they can proceed only through loop processes. For this reason, and because of an additional helicity suppression, their branching ratios are predicted to be very small in the Standard Model (SM). A part of the original work presented in this thesis has been devoted to the optimization of the Multi Variate Analysis classifier for the search of the B0(s)→μμ with the full dataset collected at LHCb. This dataset has also been combined with the one collected from CMS to obtain the first observation of B0(s)→μμ has been obtained. In view of the update of the analysis aiming to improve the sensitivity for the B0(s)→μμ mode, a new isolation variable, exploiting a topological vertexing algorithm, has been developed and additional studies for a further optimization of the MVA classifier performances have been done. The presence of two ν in the final state of the decay makes the reconstruction of the τ momenta of the two τ. Nevertheless the possibility of measuring the two decay vertexes of the τ, as well as the B candidate production vertex, allows to impose geometrical constraints that can be used in the reconstruction of the τ momenta. In particular, a new algorithm for the full reconstruction of each event of these momenta and of related variables has been presented and discussed
Soomro, Fatima. "Radiative decays of B mesons at LHCb". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6968.
Pełny tekst źródłaQuagliani, Renato. "Study of double charm B decays with the LHCb experiment at CERN and track reconstruction for the LHCb upgrade". Thesis, University of Bristol, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752741.
Pełny tekst źródłaMartens, Aurélien. "Towards a measurement of the angle γ of the Unitarity Triangle with the LHCb detector at the LHC (CERN) : calibration of the calorimeters using an energy flow technique and first observation of the Bs0 -> D0K*0". Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00634057.
Pełny tekst źródłaNicol, Michelle. "Analysis of the rare decay B->K*ee at LHCb". Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112354/document.
Pełny tekst źródłaThe high bb cross section produced by the LHC offers an excellent opportunity for thestudy of flavour changing neutral current B decays, where the effects of new physics can be probed. This thesis presents an analysis of the rare decay B->K*ee which can be used to measure the polarisation of the photon in the b -> s transition. When the dilepton mass is low, the ee pair comes predominantly from a virtual photon, and the polarisation can be accessed via an angular analysis. It is predicted to be predominantly left handed in the Standard Model, and therefore an enhanced right handed amplitude would be a sign of new physics. A first step is to measure the branching fraction in the dilepton mass range, 30 MeV to 1 GeV. This decay has not yet been observed in this region, due to its small branching ratio. The analysis involves electrons with low transverse momentum, and is thus experimentally complex in the hadronic environment at the LHC. The branching ratio is measured relative to that of B->J/Psi(ee)K*, which eliminates both certain experimental effects, and the need to determine absolute effciencies. The result is obtained with an integrated luminosity of 1 fb-1 of pp collisions, collected by LHCb during 2011 and is found to be:B(B->K*ee)30-1000MeV = (3:19+0:75-0:68(stat) +/- 0:21(syst) =/-0.15(PDG) x10-7 when using the PDG value for the B->J/Psi(ee)K* branching ratio. The last part of the thesis presents Monte Carlo studies, showing that with the inclusion of the 2012 data sample, the expected sensitivity on the fraction of right handed polarisation is approximately 0.1, which is comparable with the world average obtained with different methods
Rose, A. W. "The level-1 Trigger of the CMS experiment the LHC and the Super-LHC". Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516181.
Pełny tekst źródłaBadalov, Alexey Pavlovich. "Coprocessor integration for real-time event processing in particle physics detectors". Doctoral thesis, Universitat Ramon Llull, 2016. http://hdl.handle.net/10803/396128.
Pełny tekst źródłaLa física de altas energías dispone actualmente de aceleradores con energías mayores, sensores más precisos y métodos de recopilación de datos más flexibles que nunca. Su rápido progreso necesita aún más potencia de cálculo; el hardware masivamente paralelo, como las unidades de procesamiento gráfico, nos brinda esta potencia a un coste mucho más bajo que las CPUs tradicionales. Sin embargo, para usar eficientemente este hardware necesitamos algoritmos nuevos y nuevos enfoques de organización de datos difíciles de integrarse con el software existente. En este trabajo, se investiga cómo se pueden usar estos algoritmos paralelos en las infraestructuras de software ya existentes y que están orientadas a CPUs. Se propone una solución en forma de un servicio que comunica con los diversos pipelines que procesan los eventos de las correspondientes colisiones de particulas, reúne los datos en lotes y se los entrega a los algoritmos paralelos acelerados por hardware. Este servicio se integra con Gaudí — la infraestructura del entorno de software que usan dos de los cuatro gran experimentos del Gran Colisionador de Hadrones. Se examinan los costes añadidos por el servicio en los algoritmos paralelos. Se estudia un caso de uso del servicio para ejecutar un algoritmo paralelo para el VELO Pixel (el subdetector encargado de la localización de vértices en el upgrade del experimento LHCb) y se estudian las características de rendimiento de los distintos tamaños de lotes de datos. Finalmente, las conclusiones se contextualizan dentro la perspectiva de los requerimientos para el sistema de trigger de LHCb.
High-energy physics experiments today have higher energies, more accurate sensors, and more flexible means of data collection than ever before. Their rapid progress requires ever more computational power; and massively parallel hardware, such as graphics cards, holds the promise to provide this power at a much lower cost than traditional CPUs. Yet, using this hardware requires new algorithms and new approaches to organizing data that can be difficult to integrate with existing software. In this work, I explore the problem of using parallel algorithms within existing CPU-orientated frameworks and propose a compromise between the different trade-offs. The solution is a service that communicates with multiple event-processing pipelines, gathers data into batches, and submits them to hardware-accelerated parallel algorithms. I integrate this service with Gaudi — a framework underlying the software environments of two of the four major experiments at the Large Hadron Collider. I examine the overhead the service adds to parallel algorithms. I perform a case study of using the service to run a parallel track reconstruction algorithm for the LHCb experiment's prospective VELO Pixel subdetector and look at the performance characteristics of using different data batch sizes. Finally, I put the findings into perspective within the context of the LHCb trigger's requirements.
Puig, Navarro Albert. "First measurements of radiative B decays in LHCb". Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/81945.
Pełny tekst źródłaLes desintegracions dels mesons B són interessants per a l'estudi de Física més enllà del Model Estàndard, ja que són un bon exemple de Corrents Neutres amb Canvi de Sabor, molt sensibles a nova Física a altes energies a través del loop. L'experiment LHCb, dedicat a l'estudi de la física d'hadrons b i c a l'LHC, és un candidat ideal per a l'estudi d'aquest tipus de desintegracions. Tot i així, per a poder estudiar d'una manera efectiva les desintegracions radiative de mesons B a LHCb és necessària una bona resposta del trigger de l'experiment. S'han estudiat dues estratègies de trigger, una d'exclusiva i una d'inclusiva: per un costat, les línies exclusives ja existents han estat modificades, i, per l'altre, s'ha introduït un nou conjunt de línies topològiques específic per a desintegracions radiatives. S'ha estudiat el seu rendiment durant 2011 i, basant-se en els resultats obtinguts, s'ha dissenyat l'estratègia de trigger per a 2012. A més, s'han usat les dades preses per LHCb durant tot 2011 per a extreure la raó de les fraccions d'embrancament BR(B → K∗γ)/BR(Bs → ϕγ), obtenint el resultat de 1.31 ± 0.08(est) ± 0.04(sist) ± 0.10(fs/fd). A partir d'aquest resultat, i fent servir el valor ben mesurat de BR(B → K∗γ), s'ha trobat una raó d'embrancament per a Bs → ϕγ de (3.3 ± 0.3 )x10−5, millorant significativament els resultat anteriors. Aquest treball posa les bases per a futurs desenvolupaments dins del grup de desintegracions radiatives a LHCb, ja que per un costat fixa l'estratègia de trigger i, per l'altre, proporciona un estudi detallat de les diferents fonts de contaminació en la selecció de les desintegracions estudiades. Això resultarà molt útil en futurs anàlisis, tals com les mesures d'asimetria CP en B → K∗γ o la polarització del fotó en Bs → ϕγ.
Sexauer, Edgar. "Development of radiation hard readout electronics for LHCb". [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961823666.
Pełny tekst źródłaPaterson, Stuart Keble. "LHCb distributed data analysis on the computing grid". Thesis, University of Glasgow, 2006. http://theses.gla.ac.uk/1077/.
Pełny tekst źródłaChamonal, Reinhardt Julien Ulrich. "Multianode photomultiplier tubes for the LHCb RICH photodetectors". Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/13348.
Pełny tekst źródłaCurrie, Robert Andrew. "CP-violation in beautiful-strange oscillations at LHCb". Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9669.
Pełny tekst źródła