This dissertation presents muon charge asymmetry, fiducial differential cross section and CMS single muon trigger efficiency measurements as a function of muon pseudorapidity for inclusive W→μν events produced in proton-proton collisions at the LHC. The data were recorded by the CMS detector at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of 18.8 fb-1. Several comparisons are performed to cross-check the experimental results. Muon efficiency measurements are compared to estimated values from Monte Carlo simulations and reference values recommended by CMS physics object groups. The differential cross section and the charge asymmetry measurements are compared to theoretical predictions based on next-to-leading order and next-to-next-to-leading order QCD calculations with different PDF models. Inputs from the charge asymmetry and the differential cross section measurements for the determination of the next generation of PDF sets are expected to bring different predictions closer together and aid in reducing PDF uncertainties. The impact of the charge asymmetry on PDFs has been investigated by putting the asymmetry results into a QCD analysis at next-to-leading order and next-to-next-leading order with inclusive deep-inelastic scattering data from HERA. Significant improvement of the accuracy on the valence-quark distributions is observed. This measurement is recommended for more accurate constraints in future PDF determinations. More precise measurements of PDFs will improve LHC predictions.

<p>A facility for studies of elastic neutron scattering in the 50–130 MeV range has been developed. In addition to elastic neutron scattering, it has been used for (n,p) and (n,d) reaction experiments. The performance of the device has been illustrated in measurements of the (n,p) and (n,n) cross sections on ¹H and ¹²C.</p><p>Elastic neutron scattering from ¹²C and ²⁰⁸Pb has been studied at 96 MeV in the 10–70 degree interval. The achieved energy resolution, 3.7 MeV, is about one order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, 3 %, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target.</p><p>The results are compared with modern optical model predictions, based on phenomenology or microscopic nuclear theory. The data on ²⁰⁸Pb are in general in good agreement with the theory models.</p><p>All theory models fail to describe the ¹²C data in the 30–50 degree interval, where the models predict a saddle structure not displayed by the present experimental data. Various reasons for this discrepancy have been investigated. For the other parts of the angular range studied, the agreement is good.</p><p>These measurements have to a large degree been motivated by needs in various application areas, i.e., nuclear waste incineration by fast neutrons and biomedical effects caused by neutrons. The implications of the present results on these applications are discussed.</p>

A facility for studies of elastic neutron scattering in the 50–130 MeV range has been developed. In addition to elastic neutron scattering, it has been used for (n,p) and (n,d) reaction experiments. The performance of the device has been illustrated in measurements of the (n,p) and (n,n) cross sections on 1H and 12C. Elastic neutron scattering from 12C and 208Pb has been studied at 96 MeV in the 10–70 degree interval. The achieved energy resolution, 3.7 MeV, is about one order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, 3 %, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions, based on phenomenology or microscopic nuclear theory. The data on 208Pb are in general in good agreement with the theory models. All theory models fail to describe the 12C data in the 30–50 degree interval, where the models predict a saddle structure not displayed by the present experimental data. Various reasons for this discrepancy have been investigated. For the other parts of the angular range studied, the agreement is good. These measurements have to a large degree been motivated by needs in various application areas, i.e., nuclear waste incineration by fast neutrons and biomedical effects caused by neutrons. The implications of the present results on these applications are discussed.

In this work an analysis of the CHORUS (anti-)neutrino-nucleon scattering data taken on lead--scintillator calorimeter during the 1998 run is presented. The differential cross-sections are measured in the range of $0.01le xle 0.7$, $0.05le y le 0.95$, $10le E_nu le 200 GeV$ for both anti-neutrino and neutrino beam modes. The anti-neutrino and neutrino--nucleon structure functions Fone, Ftwo and Fthree is extracted by making 2, 3 and 6-parameter fits to the measured differential cross-sections. The comparisons of these results with the earlier experiments, CDHSW and CCFR is given.

Une étude théorique et expérimentale sur la simple et double ionisation de petites molécules par impact électronique a été effectuée dans le présent travail. Des expériences de simple ionisation des trois orbitales de valence de l'ammoniac pour une énergie incidente de l'ordre de 600 eV ont été réalisées à Orsay (ISMO). Ces expériences, notées (e,2e), consistent à détecter les électrons diffusé et éjecté en coïncidence. Nous avons comparé les expériences correspondantes à des théories perturbatrices telles que la première approximation de Born : 1CW (One Coulomb Wave) et 1DW (One Distorted Wave). Ainsi que le modèle BBK (pour l'acronyme Brauner, Briggs and Klar). Nos résultats ont montré un accord raisonnable entre l'expérience et la théorie en ce qui concerne la distribution du lobe binaire. Par contre, le lobe de recul est largement sous-estimé. L'application du modèle BBK incluant la prise en compte des déphasages à courte portée est une intéressante perspective pour la description de l'ionisation simple de la molécule d'ammoniac. De même, nous avons étudié les processus d'ionisation du méthane par impact d'électrons. Pour la simple ionisation du méthane, nous avons fourni des approches théoriques pour décrire la distribution angulaire des sections efficaces doublement et triplement différentielle. Nos résultats ont été comparés aux expériences réalisées à Afyon en Turquie. Pour la double ionisation du méthane, nous avons réalisé des expériences (e,3-1e) (dans laquelle l'électron diffusé et un des éjectés sont détectés en coïncidence) pour la couche externe 1t2 à Orsay (ISMO). La théorie que nous avons appliquée est du premier ordre et ne peut pas décrire complétement les deux lobes. Par conséquent, le développement d'un modèle dans le cadre de la deuxième approximation de Born s'avère nécessaire. / A theoretical and experimental study on simple and double ionization of small molecules by electron impact is reported in the present work. Experiments of simple ionization of the three valence orbitals of ammonia with an incident energy of about 600 eV were performed in Orsay (ISMO). These experiments, named (e,2e), consist in the detection of the scattered and ejected electrons in coincidence. We compared the correspondent experiments to perturbative theories such as first Born approximation: 1CW (One Coulomb Wave) and 1DW (One Distorted Wave). In addition to the BBK model (for the acronym Brauner, Briggs and Klar). Our results show a reasonable agreement between the experiment and the theory concerning the distribution of the binary lobe. On the contrary, the recoil lobe was largely under-estimated. The application of the BBK model by taking into account the short range phases will be an interesting perspective for the description of simple ionization of ammonia molecule. In addition, we studied the ionization process of methane by electron impact. For the simple ionization of methane, we developed theoretical approaches in order to describe the angular distribution of double and triple differential cross sections. Our results were compared to experimental data performed in Afyon in Turkey. For the double ionization of methane, we performed experiments for the external shell 1t2 in Orsay (ISMO) by using the (e,3-1e), during which the scattered and one of the two ejected electrons are detected in coincidence. The theory which we applied is of first order and it could not describe completely the two lobes. Consequently, the development of a second order model sounds necessary.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-09T13:42:42Z No. of bitstreams: 1 helensilvamarinho.pdf: 3306567 bytes, checksum: a26c4de3a06861aae569017b37ca14e2 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-27T13:25:33Z (GMT) No. of bitstreams: 1 helensilvamarinho.pdf: 3306567 bytes, checksum: a26c4de3a06861aae569017b37ca14e2 (MD5) / Made available in DSpace on 2017-06-27T13:25:33Z (GMT). No. of bitstreams: 1 helensilvamarinho.pdf: 3306567 bytes, checksum: a26c4de3a06861aae569017b37ca14e2 (MD5) Previous issue date: 2009-05-05 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Neste trabalho foram realizadas medidas de Seção de Choque Diferencial Elástica (SCDE) para o espalhamento de elétrons de baixa energia por moléculas poliatômicas, utilizando uma nova versão do Método de Fluxo Relativo (MFR) associado a uma fenda acoplada a um tubo móvel como fonte de gás. Tal técnica foi desenvolvida por M. A. Khakoo et al. Neste novo MFR, as SCDEs são obtidas sem nenhum conhecimento prévio do diâmetro molecular cinético dos gases estudados. Esta modificação permite que o novo MFR seja mais preciso e rápido do que o MFR convencional e também capaz ser aplicado a uma série de compostos que não eram possíveis de serem estudados anteriormente. As medidas da SCDE foram obtidas para as moléculas dos álcoois metanol, etanol, n-propanol e n-butanol, cujos diâmetros cinéticos não são conhecidos na literatura, gerando dados inéditos sobre estes alvos. A região energética trabalhada foi entre 1 e 100 eV e os ângulos de espalhamento entre 5 e 130°. Medidas adicionais de SCDE foram obtidas para as moléculas de H2 e N2 a fim ratificar o novo MFR utilizado. Os dados dessas duas moléculas mostraram-se em ótima concordância com dados da literatura, tanto teóricos quanto experimentais, evidenciando a excelência da nova técnica e o desempenho do espectrômetro. Em um teste adicional para o MFR, medidas de SCDE para o vapor de água também foram registradas. Porém, as medidas encontradas se mostraram em grande desacordo quantitativo com experimentos realizados no passado, que utilizaram o MFR convencional. Esta discrepância encontrada levou ao questionamento das medidas de SCDE da água publicadas anteriormente na literatura, sugerindo à comunidade científica que dados de SCDE para moléculas da água fossem revisados, uma vez que o diâmetro cinético encontrado por estes experimentos realizados se mostraram substancialmente maiores (1,8 vezes) àqueles utilizados para medidas anteriormente publicadas. / In this work were performed measurements of Elastic Differential Cross Section (EDCS) for low energy by polyatomic molecules electron scattering using a new version of Relative Flow Method (RFM) associated to an aperture coupled in a movable tube as a source of gas. This technique was developed by M. A. Khakoo et al. In this new RFM the EDCSs are obtained without any previous information about kinetic molecular diameter of the gas in study. That modification allowed us apply the new RFM more accurately and faster than the conventional RFM and also, apply it to several compounds which were not possible to be studied previously. The measurements of EDCS were obtained for alcohols molecules as methanol, ethanol, n-propanol e n-butanol, whose molecular diameters were not published in the literature, generating new information about these targets. The energetic range worked was from 1 to 100 eV and the scattering angles from 5 to 130°. Additional measurements of EDCS were obtained for H2 e N2 to provide a excellent test to the new RFM. The data for these molecules are in excellent agreement with compared data from literature, thus theoretical as experimental showing the excellence of the new technique and the performance of spectrometer. In an additional test for the RFM, measurements of EDCS for water vapor were registered. However, these measurements are in a big quantitative disagreement with experiments developed in the past witch applied the conventional RFM. This discrepancy took to questioning of the measurements of EDCS previously published for water in the literature suggesting to the scientific community that EDCS data for water be revised despite the kinetic molecular diameter found in our experiment showed bigger (1.8 times) than those published in the past.

Title: Measurement of the top quark properties Author: Mgr. Jaroslava Schovancová Department: Institute of Physics, Academy of Sciences of the Czech Re- public Supervisor: RNDr. Jiří Chudoba, Ph.D., Institute of Physics, Academy of Sciences of the Czech Republic Abstract: This Thesis presents the ATLAS experiment measurement of the top quark differential cross-section as a function of pT, mass and rapidity of the t¯t system. A sample of approx. 4.7 fb−1 of the 2011 pp collision data at the center-of-mass energy of 7 TeV was analyzed. The differential spectra shapes in the t¯t system are consistent with the Standard Model and reason- ably described by the event generators. Several activities in the scope of ATLAS Distributed Computing are pre- sented, particularly in the area of operations, monitoring, automation, and development of the PanDA Workload Management System. Such activities aim to improve efficiency and facilitate the use of distributed computing re- sources and therefore contribute in supporting the ATLAS Physics Program. Keywords: ATLAS, top quark, differential cross-section, missing transverse energy, ATLAS Distributed Computing

Le Modèle Standard de la physique des particules décrit les particules elementaires et leurs interactions avec une grande précision. Il décrit trois des quatre interactions fondamentales connues entre les particules elementaires : les interactions faibles, fortes et électromagnétiques. Le Modèle standard fournit aussi une description précise des interactions électrofaibles jusqu’à des échelles d’énergie qui ont été étudies dans les expériences de physique de haute énergie. Les interactions ainsi que les désintégrations d'un grand nombre de particules découvert et observe tout au long des expériences différentes dans les 50 dernières années sont également décrites. En dépit de son succès, le Modèle Standard est loin d’être une théorie complète des interactions fondamentales car il n’intègre pas la théorie complète de la gravitation telle que décrite par la relativité générale, ni la prédiction de l’accélération de l'expansion de l'univers (qui pourrait être décrite par l’énergie noire). La théorie ne contient aucune particule de matière noire viable qui possède toutes les propriétés déduites de la cosmologie observationnelle. Également, elle ne prend pas en compte les oscillations de neutrinos (et leurs masses non nulles). On pense que la nouvelle physique doit exister conduisant a de nouvelles particules et phénomènes. L’échelle a laquelle cette nouvelle physique devrait appara&#305;tre n'est pas bien connue, cependant plusieurs arguments soulignent l’échelle du TeV et nécessitent une très haute énergie et des puissants collisionneurs de hadrons. Le Large Hadron Collider (LHC) est le plus grand accélérateur et collisionneur de particules existant. / The Standard Model of particle physics is very successful in describing elementary particles and their interactions with a great precision. It describes three of the four known fundamental interactions between elementary particles : the weak, the strong and the electromagnetic interactions. The Standard Model also provides an accurate description of the electroweak interactions up to energy scales that have been explored in high energy physics experiments. The interaction and decay of a large number of particles discovered and observed throughout different experiments in the last 50 years are also described. Despite its great success, the Standard Model falls short of being a complete theory of fundamental interactions because it does not incorporate the full theory of gravitation as described by general relativity, or predict the accelerating expansion of the universe (as possibly described by dark energy). The theory does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology. It also does not account for neutrino oscillations (and their non-zero masses). It is thought that new physics should exist leading to new particles and phenomena. The scale at which this new physics should appear is not well known, though several arguments point to the TeV scale and require a very high energy and powerful hadron collider. The Large Hadron Collider (LHC) is the biggest existing particle accelerator and collider. It is designed to provide proton-proton collisions with an unprecedented center-of-mass energy of 14 TeV, with instantaneous luminosities up to 10^{34} cm&#8722;2s&#8722;1.

<p>A beam of 250A MeV ¹⁷O ions was scattered from argon and xenon targets. The large excess of fast neutrons compared with statistical model calculations that was observed earlier for xenon, was confirmed and found for argon as well. Analysis and calculations show that a considerable fraction of these neutrons can be interpreted as coming from direct knock-out reactions.</p><p>The angular distributions do not support the suggestion of using fast heavy ion scattering as a probe for the study of the neutron skin in nuclei. While the basic idea that a heavy projectile tends to sample the neutron wave function near the surface of the nucleus is sound, the measured neutron distribution is not as distinct as suggested by the previous experiment. This makes it difficult to distinguish direct reactions from other channels, such as semi-direct decay of giant resonances.</p><p>The improvements in the experimental methods have made the concept of using the CELSIUS storage and cooler ring as an internal magnetic spectrometer attractive for other of experiments presently being prepared.</p>

<p>Two aspects of applied nuclear physics have been studied in this thesis; Monte Carlo simulations for high-sensitivity monitoring of radioactive xenon and high-accuracy neutron-proton scattering measurements for neutron physics applications and fundamental physics.</p><p>The Monte Carlo simulations have been performed for two systems for detection of radioactive xenon, using the MCNP code. These systems, designed for monitoring of violations of the Comprehensive Nuclear-Test-Ban Treaty, are based on coincident detection of electrons and gamma rays, emitted in beta decay of xenon nuclides produced in nuclear weapons explosions. In general, the simulations describe test data well, and the deviations from experimental data are understood. </p><p>The neutron-proton scattering measurements have been performed by measuring the differential <i>np</i> scattering cross section at 96 MeV in the angular range θ_c.m.= 20° – 76°. Together with an earlier data set at the same energy, covering the angles θ_c.m.= 74° – 180°, a new data set has been formed in the angular range θ_c.m.= 20° – 180°. This extended data set has been normalised to the experimental total <i>np</i> cross section, resulting in a renormalisation of the earlier data of 0.7 %, which is well within the stated normalisation uncertainty for that experiment. The results on forward <i>np</i> scattering are in reasonable agreement with theory models and partial wave analyses and have been compared with data from the literature.</p>