Dissertations / Theses on the topic 'NUCLEON SPIN'
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Cunningham, Elizabeth Sarah. "The effect of spin-spin interactions on nucleon-nucleus scattering." Thesis, University of Surrey, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527010.
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Unrau, Peter. "Spin dependent nucleon structure at intermediate Q²." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38381.
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Tang, Jian 1968. "Spin structure of nucleon in the asymptotic limit." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38418.
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Steffens, Fernando Monti. "The spin and flavour structure of the nucleon /." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phs817.pdf.
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Thesis (Ph. D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1996?Copies of author's previously published articles inserted. Includes bibliographical references (leaves 189-206).
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PUSSIEUX, THIERRY. "Mesures des fonctions de structure en spin du nucleon." Paris 11, 1994. http://www.theses.fr/1994PA112242.
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Cette these est consacree aux mesures des fonctions de structure en spin du proton et du deuton realisees via la diffusion profondement inelastique de muons polarises de hautes energies sur des cibles de protons et de deutons polarises. Nous possedons un cadre theorique pour l'etude de la structure du nucleon: la chromodynamique quantique. La regle de somme de bjorken, invoquant la difference des deux premiers moments des fonctions de structure en spin du proton et du neutron #p#1 - #n#1 = g#a/6, est directement derivee de cette theorie en ne faisant appel qu'a la symetrie d'isospin su(2). La verification experimentale de cette prediction confirmerait notre comprehension de la dynamique interne du nucleon et des processus d'interaction forte. De plus, nous montrons comment nos mesures permettent d'acceder a la contribution des quarks au spin du nucleon dans le modele des partons. Nous faisons ensuite le point sur les situations experimentale et theorique avant le debut de notre experience, suite aux resultats surprenants de la collaboration emc. Experimentalement, ces fonctions de structure sont determinees par la mesure d'une asymetrie de sections efficaces. L'analyse de cette experience commence donc par les programmes de reconstructions de trajectoires donnant la cinematique et la position du vertex de la diffusion et permettant ainsi d'acceder aux asymetries de taux de comptage. Une relation simple les relient a l'asymetrie de sections efficaces de photo-absorption par un nucleon et par consequent aux fonctions de structure en spin du nucleon. Nos resultats permettent d'estimer la fraction de spin du proton portee par les quarks a (q#2 = 10gev#2) = 22% 15% et la polarisation de la mer de quarks etranges a s(q#2 = 10gev#2) = - 12% 6% ce qui confirme les conclusions de emc. Une analyse combinee de toutes les donnees existantes sur le proton nous conduit a (q#2 = 10gev#2) = 27% 13% et s(q#2 = 10gev#2) = - 10% 5%. Une analyse combinee de toutes les donnees publiees sur le proton, le neutron et le deuton confirme la regle de somme de bjorken avec une precision de 10%
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Kämpfer, Burkhard, L. P. Kaptari, A. Yu Umnikov, and K. Yu Kazakov. "The Deuteron Spin-Dependent Structure Function within an Effective Meson-Nucleon Theory." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-32647.
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Eldahoumi, Gamal. "Constituent Quarks and the Gluonic Contribution to the Spin of the Nucleon." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-100441.
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Amir-Ahmadi, Hamid Reza. "Three-nucleon potential effects in spin observables of elastic deuteron-proton scattering." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/292621256.
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Tallini, Hugh Arthur McLaren. "A measurement of the quark spin distributions of the nucleon at HERMES." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367159.
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Kämpfer, Burkhard, L. P. Kaptari, A. Yu Umnikov, and K. Yu Kazakov. "The Deuteron Spin-Dependent Structure Function within an Effective Meson-Nucleon Theory." Forschungszentrum Rossendorf, 1993. https://hzdr.qucosa.de/id/qucosa%3A22091.
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Markoff, Diane Melanie. "Measurement of the parity nonconserving spin-rotation of transmitted cold neutrons through a liquid helium target /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/9743.
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Maheswari, Dhiraj. "QCD Process in Few Nucleon Systems." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3795.
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One of the important issues of Quantum Chromodynamics (QCD) - the fundamental theory of strong interaction, is the understanding of the role of the quark-gluon interactions in the processes involving nuclear targets. One direction in such studies is to explore the onset of the quark gluon degrees of freedom in nuclear dynamics. The other direction is using the nuclear targets as a “micro-labs” in studies of the QCD processes involving protons and neutrons bound in the nucleus. In the proposed research, we work in both directions considering high energy photo- and electro-production reactions involving deuteron and 3 He nuclei.
In the first half of the research, we study the high energy break-up of the 3 He nucleus, caused by a incoming photon, into a proton-deuteron pair at the large center of mass scattering angle. The main motivation of the research is the theoretical interpretation of recent experimental data which revealed the unprecedentedly large exponent s −17 , for the energy dependence of the differential cross section. In the present research, we extend the theoretical formalism of the hard QCD rescattering model to calculate energy and angular dependences of the absolute cross section of the γ 3 He → pd reaction in high momentum transfer limit.
The second half of the research explores the deep-inelastic scattering of a polarized electron off the polarized deuteron and 3 He nuclei, to explore the quark-gluon structure of polarized neutron. The main reason of using deuteron is that it is the most simple and best understood nucleus. While the reason of using polarized 3 He as an effective polarized neutron target is that because of the Pauli-principle, the two protons in the target are in the opposite spin states and thus the neutron has all the polarization of the 3 He nucleus. However this approximation is exact only for the S-state and becomes less accurate with the increase of the internal momentum of the bound nucleons in the nucleus. There are several planned experiments which will be performed during next few years at the kinematics in which the internal momenta of the probed neutron cannot be neglected. Therefore, for the reliable interpretation of the data, all the nuclear effects, especially the effects related to the relativistic treatment of high momentum component of the nuclear wave function, should be taken into account. In this work, we developed a comprehensive theoretical framework for calculation of the all relevant nuclear effects that will allow the accurate extraction of the neutron data from deepinelastic scattering involving deuteron and 3 He targets.
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Grenier, Philippe. "Etude des fonctions de structure en spin du nucleon : l'experience e143 au slac." Clermont-Ferrand 2, 1995. http://www.theses.fr/1995CLF21720.
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Cette these decrit l'experience e143 de diffusion profondement inelastique d'electrons de 29 gev sur des cibles de nh#3 et nd#3 polarisees. Elle s'est deroulee aupres de l'accelerateur de stanford, en californie, et son but etait de mesurer les fonctions de structure polarisees g#1 et g#2 sur le proton et le deuton. Ces fonctions de structure permettent de tester la regle de somme de bjrken, regle fondamentale de la chromodynamique quantique. Elles nous renseignent egalement sur la structure en spin du nucleon et, en particulier, elles permettent d'acceder a la fraction du spin du nucleon portee par les quarks. Experimentalement, on determine les fonctions de structure par la mesure d'asymetries en sections efficaces. Nous obtenons pour le premier moment de g#1, pour le proton et le deuton, des valeurs qui se situent de deux a trois deviations standards en dessous des predictions d'ellis et jaffe, mais nos resultats confirment la validite de la regle de somme de bjrken et permettent d'estimer a environ 30% la contribution des quarks au spin du nucleon. Nos resultats sur g#2 semblent etre bien decrits par l'expression de wandzura et wilczek
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Sabatié, Franck. "Etude des fonctions de structure en spin du nucleon : l'experience e154 au slac." Caen, 1998. http://www.theses.fr/1998CAEN2026.
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L'experience e154 au slac a mesure la fonction de structure en spin du neutron g1n en faisant diffuser des electrons polarises de 50 gev sur une cible d'helium 3 gazeux polarisee. L'integrale de la fonction de structure en spin du neutron par rapport a x pour x de 0. 014 a 0. 7 est alors egale a 0. 0348 plus ou moins 0. 0033 (stat. ) plus ou moins 0. 0043 (syst. ) plus ou moins 0. 0014 (evolution dglap). Nous observons des valeurs de g1n relativement larges a bas x, ce qui remet en question les methodes usuelles d'extrapolation dans cette region ou les quarks de valence ne sont plus dominants : un comportement de type regge a bas x semble en desaccord avec les donnees dans la region en x 0. 014 a 0. 1. Par contre, le comportement predit par la qcd perturbative semble etre compatible avec ces memes donnees. D'autre part, nous avons effectue une analyse a l'ordre sous dominant en qcd perturbative des donnees mondiales sur g1, en octroyant une attention toute particuliere aux differentes hypothese theoriques employees, ainsi qu'au calcul des erreurs. A partir d'une parametrisation simple des distributions de partons polarisees, nous en deduisons une valeur de la fraction de spin portee par les quarks : 0. 29 plus ou moins 0. 06 dans le schema ms barre a 5 gev carre et 0. 37 plus ou moins 0. 07 dans le schema ab. La contribution des gluons au spin du nucleon est tres peu contrainte par les donnees experimentales actuelles, nous pouvons neanmoins affirmer avec un bon degre de confiance qu'elle est comprise entre 0 et 2 a 5 gev carre. L'etude nous permet egalement de deduire le premier moment de g1n et de verifier le bon accord avec la regle de somme de bjorken.
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Wiese, Christian. "Investigating new lattice approaches to the momentum and spin structure of the nucleon." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17522.
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Diese Arbeit beschäftigt sich mit der Berechnung von für die Struktur des Nukleons relevanten Observablen, die experimentell durch inklusive und semi-inklusive Streuexperimente bestimmt werden können. Es werden zwei Pilotstudien erörtert, welche die Spin- und Impulsstruktur des Nukleons mithilfe von Gitter-QCD untersuchen. Hierfür wird der Twisted-Mass-Formalismus mit dynamischen Fermionen verwendet, um sicherzustellen, dass die untersuchten Größen einen verbesserten Kontinuumslimes aufweisen. Der erste Teil dieser Arbeit untersucht die Umsetzbarkeit einer Rechnung, die sich mit dem durchschnittlichen Impulsanteil der Gluonen im Nukleon auseinandersetzt. Diese Größe wurde bisher kaum im Rahmen der Gitter-QCD behandelt. In diesem Zusammenhang werden zwei verschiedene Gittermethoden untersucht: das Feynman-Hellman-Theorem, sowie die direkte Berechnung der relevanten Formfaktoren. Mithilfe der zweiten Methode und mehreren Iterationen des Schmierens der Eichlinks ist es möglich, statistisch aussagekräftige Resultate zu erhalten. Die zweite Studie beschäftigt sich mit der direkten Berechnung der vollständigen Impuls- und Spinverteilung von Quarks und Antiquarks im Nukleon. Hierfür wird untersucht, ob eine kürzlich publizierte Methode praktikabel ist, nach der eine räumliche Quasiverteilung zu berechnen und aus dieser die physikalische Verteilung abzuleiten ist. In diesem Zusammenhang wird der Einfluß des Schmierens der Eichlinks und unterschiedlicher Impulsboosts des Nukleons erprobt. Die anschließend berechneten Isovektor-Quarkverteilungen (unpolarisiert und polarisiert) weisen eine gute qualitative Übereinstimmung mit Verteilungen auf, die mithilfe von phänomenologischen Analysen bestimmt wurden. Zentrale Erkenntnis dieser Arbeit ist der Nachweis, dass es auf dem Gitter prinzipiell möglich ist, beide Observablen zu berechnen. Trotzdem muss noch erheblich mehr Arbeit aufgewendet werden, um verlässliche Resultate für diese Größen zu erhalten.This thesis deals with the theoretical computation of nucleon structure observables as they can be experimentally obtained from inclusive and semi-inclusive scattering experiments. I present two exploratory studies on spin and momentum structure observables of the nucleon in the framework of lattice QCD. Throughout this work, I use the twisted mass formalism with dynamical fermions at maximal twist, which ensures an improved continuum limit scaling for the relevant quantities. In the first part, I investigate the feasibility of a lattice calculation of the gluons’ average momentum fraction in the nucleon, a quantity that is rarely studied in lattice QCD. For this purpose, I study two different methods, namely the Feynman-Hellman theorem and the direct computation of the relevant form factor. Applying the latter method and combining it with several steps of stout gauge link smearing, I obtain a statistically significant results for the gluon content. The second study is concerned with the direct computation of the full momentum and spin distribution of quarks and antiquarks within the nucleon. I investigate the feasibility of a recently published approach proposing the computation of a purely spatial quasi-distribution that can be related to the physical distribution. I test the influence of gauge link smearing and different nucleon momentum boosts on the lattice data. Ultimately, I obtain iso-vector quark distributions for the unpolarized and polarize case that featuring a decent qualitative agreement to quark distributions acquired from phenomenological fits. As a key result of this work, I demonstrate that the demanding calculation of gluon content and the novel approach of computing quark distributions directly within lattice QCD are feasible in principle, although significantly more effort has to be invested into obtaining accurate results with reliable uncertainties.
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Mammei, Juliette Mae. "Parity-Violating Elastic Electron Nucleon Scattering: Measurement of the Strange Quark Content of the Nucleon and Towards a Measurement of the Weak Charge of the Proton." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/27661.
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The experiments discussed in this thesis exploit parity violation in elastic electron proton
scattering in order to measure properties of the nucleon. Both experiments make use of
the high quality, highly polarized electron beam available at Thomas Jefferson National
Accelerator Facility. Qweak will measure the weak mixing angle, sin2θW, via a measurement
of the weak charge of the proton, at a four-momentum transfer, Q2~0.026 GeV2/c2. The
precision of this measurement gives Qweak access to new physics at the scale of 2.3 TeV,
making it a test of the standard model. The G0 experimental program provides the fully
separated contributions of the strange quark to the charge and magnetization distributions of
the nucleon at two different values of four-momentum transfer, Q2 ~ 0.22 and 0.63 GeV2/c2. The measurement of the strange quark content of the proton in the G0 experimental program
and other parity-violating electron scattering experiments provides a measurement of the
hadronic contribution to the asymmetry in Qweak.
In addition, G0 was able to measure the parity-conserving beam normal single spin
asymmetries that provide a measurement of the imaginary part of two photon exchange.
The measurement of this asymmetry is necessary to understand the systematic contribution
to measurements of parity-violating asymmetries, but it is also an important physics result.
Recent theoretical work has shown that higher order radiative effects, such as two photon
exchange, may be able to explain discrepancies between experiments which measure the ratio
of the electric and magnetic form factors of the proton. The measurement of the transverse or
beam normal single spin asymmetries provides a benchmark for theories that estimate the size
of radiative corrections that are important for precision electroweak scattering experiments
such as those described in this thesis. The results of the measurement of the transverse
asymmetries at backward angles in G0 are presented at the two values of Q2 ~ 0.22 and 0.63 GeV2/c2 for hydrogen. Results for deuterium, which can provide the first measurements of the beam normal single spin asymmetries on the neutron, are also presented.Ph. D.
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Matthews, M. T. "A study of nucleon spin structure through polarised muon polarised proton deep inelastic scattering." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233868.
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Wilfert, Malte Christian [Verfasser]. "Investigation of the spin structure of the nucleon at the COMPASS experiment / Malte Christian Wilfert." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/1139217003/34.
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Andrieux, Vincent. "Polarisation of quarks and gluons inside the nucleon." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112244/document.
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Cette thèse présente un travail relatif à l'étude de la structure en spin longitudinal du nucléon. Le but est de déterminer la contribution des constituants du proton, quarks et gluons, à la formation de son spin 1/2. L'analyse s'appuie sur les données de l'expérience COMPASS qui bénéficie d'un faisceau de muons polarisés à 200 GeV diffusé sur les protons polarisés d'une cible d'ammoniac (NH₃) de 1,2 m de long. On mesure l'asymétrie de spin longitudinal des sections efficaces de diffusion profondément inélastique. On extrait la fonction de structure en spin du proton, g₁p, étendant la couverture cinématique mondiale à des régions inexplorées jusqu'à maintenant (0,0036 < x < 0,57; 1,03 < Q² (GeV/c)² < 96 et 23 < W² (GeV/c)² < 320). Les résultats, d'une grande précision statistique, sont inclus dans une analyse des données mondiales de g₁p, g₁d et g₁n (proton, deutéron et neutron) au 2ème ordre de QCD afin de paramétrer les distributions de quarks et de gluons polarisés. L'étendue de la couverture cinématique en x et Q² des données mondiales de g₁, un élément déterminant pour la sensibilité à la polarisation des gluons ΔG, s'avère trop limitée pour constituer une extraction précise de celle-Ci. Néanmoins, l'analyse QCD permet de déterminer la contribution du spin des quarks au spin du proton à 0.26<ΔΣ<0.33 à Q² = 3 (GeV/c)² dans le schéma MSbar. L'étude montre que l'incertitude principale sur ΔΣ est liée au choix des formes fonctionnelles utilisées dans la régression des données. Enfin, la règle de somme de Bjorken, qui constitue un test de QCD, est vérifiée avec une précision de 9% en utilisant les données de COMPASS uniquementThe work presented in this thesis is related to the study of the longitudinal spin structure of the nucleon. The aim is to determine the contribution to the spin 1/2 of the proton in terms of its constituents, quarks and gluons. The analysis is performed on the data taken with the COMPASS experiment, which benefits from a polarised muon beam at 200 GeV scattered off polarised protons from an ammonia target of 1.2 m long. The double longitudinal spin asymmetry of deep inelastic scattering cross-Section. The spin-Dependent structure function of the proton g₁p is derived from these measurements, which extend the kinematic world coverage to unexplored region so far (0,0036 < x< 0,57; 1,03 < Q² (GeV/c)² < 96 and 23 < W² (GeV/c)² < 320).The results obtained with a high statistical precision are included in a Next-To-Leading order QCD analysis of world g₁p, g₁d and g₁n (proton, deuteron and neutron) data to parametrise the polarised quark and gluon distributions. The g₁ world coverage of the x and Q² kinematic domain, which is a key point in the sensitivity to the gluon polarisation ΔG, turns out to be too limited for an accurate ΔG determination. Nevertheless, the QCD analysis allows to determine the quark spin contributions to the proton spin to 0.26<ΔΣ<0.33 at Q² = 3 (GeV/c)² in the MSbar scheme. The dominant uncertainty on ΔΣ is related to the choice of functional forms assumed in the fit. Finally, the Bjorken sum rule, which constitutes a fundamental test of QCD, is verified on the COMPASS data alone with a precision of 9%
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Bernet, Colin. "Caractérisation des micromégas et mesure de la polarisation des gluons sur COMPASS." Paris 7, 2004. http://www.theses.fr/2004PA077205.
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McAndrew, Michael Gabriel. "A measurement of the quark polarisation of the nucleon." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366732.
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Zagrebelnyy, V. [Verfasser]. "Investigation of transverse-momentum-dependent functions(TMD) in azimuthal spin asymmetries of semi-inclusive deep inelastic nucleon scattering / Vitaly Zagrebelnyy." Gießen : Universitätsbibliothek, 2015. http://d-nb.info/1069740691/34.
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Wiese, Christian [Verfasser], Ulrich [Gutachter] Wolff, Karl [Gutachter] Jansen, and Markus [Gutachter] Diehl. "Investigating new lattice approaches to the momentum and spin structure of the nucleon / Christian Wiese. Gutachter: Ulrich Wolff ; Karl Jansen ; Markus Diehl." Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://d-nb.info/1103570692/34.
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Pesaro, Giulia. "Measurement at COMPASS of transverse spin effects on identified hadrons on a transversely polarised proton target." Doctoral thesis, Università degli studi di Trieste, 2011. http://hdl.handle.net/10077/4566.
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2009/2010La sezione d'urto che descrive la diff usione profondamente inelastica di un leptone carico (mu+) su di un nucleone (protone) polarizzato trasversalmente rispetto alla direzione del moto con identifi cazione di almeno un adrone nello stato finale presenta otto modulazioni azimutali, rispetto al piano de finito dallo spin del nucleone bersaglio e dal momento del leptone incidente. Tra queste le meglio conosciute sono dovute all'eff etto Collins e all'eff etto Sivers. Il primo eff etto è la frammentazione di un quark polarizzato trasversalmente in un adrone e l'ampiezza della modulazione è data dalla convoluzione della "trasversità" (ovvero la funzione di distribuzione che descrive i partoni polarizzati parallelamente o antiparallelamente allo spin del nucleone, per nucleoni polarizzati trasversalmente) con la funzione di frammentazione di Collins. L'eff etto Sivers è dovuto alla distribuzione di momento trasverso dei partoni all'interno del nucleone. Le rimanenti sei modulazioni sono dovute ad altre correlazioni tra la polarizzazione o il momento trasverso del partone e lo spin del nucleone. Il lavoro presentato in questa tesi è la misura dell'ampiezza delle modulazioni azimutali (asimmetrie) per i dati raccolti nel 2007 dall'esperimento COMPASS, usando un bersaglio di NH3 per accedere al protone polarizzato, focalizzando l'attenzione sulle asimmetrie di Collins e Sivers. Le asimmetrie sono state misurate sia su un campione di adroni carichi che su adroni identi cati con il rivelatore di luce Cerenkov RICH-1. Ampia parte del lavoro è stata dedicata alla determinazione dell'errore sistematico della misura.
The Semi-Inclusive Deep Inelastic Scattering (SIDIS) cross section, that describes the scattering of a charged lepton (mu+) o a nucleon (proton) transversely polarised with respect to its momentum, and with the detection of a hadron in the final state, has 8 independent azimuthal modulations, that depends on the spin of the target nucleon and on the lepton momentum. Among these modulations, the most famous are due to the Collins and Sivers eff ects. The Collins eff ect is the asymmetric fragmentation of a polarised quark into a hadron, and the amplitude of the modulation is proportional to the Collins fragmentation function with the transversity parton distribution function, that gives the probability difference to find a quark with the polarisation parallel or anti-parallel to the nucleon spin in a transversely polarised nucleon. The Sivers effect is due to the coupling of the quark transverse momentum and the spin in a transversely polarised nucleon. The other six modulations are due to other correlations between the quark polarisation or the quark transverse momentum and the nucleon spin. The work presented in this Thesis is the measurement of the amplitude of the azimuthal modulations (asymmetries) on the data of the COMPASS experiment, collected in 2007 using a NH3 target to access the polarised proton, focusing on the Collins and Sivers asymmetries. The asymmetries have been measured both the charged hadrons and on hadrons identif ied making use of the ring-imaging Cherenkov detector RICH-1 . Large part of the work presented here is devoted to the determination of the systematic error of the measurement.
XXIII Ciclo
1982
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Sodickson, Daniel Kevin. "Spin-spin couplings in two limits : experimental, theoretical, and computational studies of dipole-coupled nuclear spins in solids." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32601.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Whitaker College of Health Sciences and Technology, 1994.Includes bibliographical references (leaves 193-200).
by Daniel Kevin Sodickson.
Ph.D.
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Hasch, Delia. "Messung der polarisierten Strukturfunktion g1(x, Q 2) des Protons mit dem HERMES-Experiment." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 1999. http://dx.doi.org/10.18452/14523.
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Die vorliegende Arbeit beschreibt die Messung der polarisierten Strukturfunktion g1p des Protons in der polarisationsabh"angigen tief inelastischen Positron-Proton-Streuung bei einer Schwerpunktenergie von 7.5 GeV. Die Analyse umfasst die 1997 mit dem Hermes-Experiment am Hera-Positronring aufgezeichneten Daten der Streuung polarisierter Positronen der Energie 27.6 GeV an einem polarisierten Wasserstofftarget. Aus den Z"ahlraten der inklusiv nachgewiesenen, selektierten Positronen f"ur die parallele und die antiparallele Ausrichtung der Spinvektoren von Strahlteilchen und Targetatomen wurde die Streuquerschnitts- Asymmetrie der Positron-Proton-Streuung bestimmt. In verschiedenen Korrekturverfahren wurden Untergrundprozesse, Spektrometereinfl"usse sowie Strahlungskorrekturen ber"ucksichtigt. Die Untergrundkorrekturen wurden aus den Daten, die Spektrometerkorrekturen aus einer Monte-Carlo- Simulation ermittelt. Die Abh"angigkeit der Monte-Carlo- und Strahlungskorrekturen von der gew"ahlten Modell-Asymmetrie zur Beschreibung der polarisationsabh"angigen Effekte wurde durch die Anwendung eines iterativen Verfahrens minimiert. Aus der vollst"andig korrigierten Streuquerschnitts-Asymmetrie wurde die Asymmetrie g1/F1 im kinematischen Bereich 0.021 < x < 0.85 und Q2 > 0.8 GeV^2 mit einer systematischen Unsicherheit von etwa 8% bei einer statistischen Genauigkeit von 6% bis 20%, ansteigend f"ur abnehmende x-Werte, bestimmt. Die aus g1/F1 berechnete polarisierte Strukturfunktion g1p(x,Q2) wird, unter der Annahme einer von q2 unabh"angigen Asymmetry g1/F1, zu einem festen Wert Q2_0 entwickelt. Ihr erstes Moment im gemessenen x-Bereich betr"agt int_{0.021}^{0.85} dx g1p(x,Q2_0) = 0.122 =- 0.003 (stat) =- 0.010 (sys) at Q2_0 = 2.5 GeV^2. Der Vergleich mit den Werten des SMC-Experimentes am CERN und des E143-Experimentes am SLAC f"ur das erste Moment von g1p wurde unter Anwendung des gleichen Integrationsschemas f"ur den jeweils gemeinsam gemessenen x-Bereich sowie f"ur gleiche Q2_0 Werte durchgef"uhrt. Das Ergebnis der vorliegenden Analyse befindet sich, bezogen auf die statistische Genauigkeit der Messungen, in "Ubereinstimmung innerhalb von 0.6 bzw. 1.2 Standardabweichungen mit den Resultaten des E143- bzw. SMC-Experimentes. Durch Extrapolation der Strukturfunktion auf den gesamten x-Bereich [0,1] wird das erste Moment zu \int_{0}^{1} dx g1p(x,Q2_0) = 0.132 +- 0.003 (stat) +- 0.010 (sys) +- 0.006 (extr) bestimmt, wobei der zus"atzliche Fehler die Unsicherheit in der Extrapolation x -> 0 wiedergibt. Die Interpretation der vorliegenden Messung im Rahmen des Quark-Parton-Modells unter Ber"ucksichtigung von QCD-Korrekturen der Ordnung O(alphaS^3) ergibt einen Beitrag der Quarks zum Gesamtspin des Nukleons von (30 +- 10)% f"ur Q2_0 = 2.5 GeV^2. Dieses Ergebnis entspricht einer Abweichung von der Ellis-Jaffe-Vorhersage um 2.5 Standardabweichungen, bezogen auf den angegebenen Gesamtfehler, und f"uhrt im Kontext des Quark-Parton-Modells zur Interpretation negativ polarisierter Strange-Seequarks mit einem Beitrag von (-9 +- 4)% f"ur Q2_0 = 2.5 GeV^2. Von verschiedenen Gruppen werden aus QCD-Analysen unterschiedlicher Datens"atze Beitr"age der Quarks zum Nukleonspin von 19% bis 44% angegeben. Unter Hinzunahme der Hermes-Messung der polarisierten Neutronstrukturfunktion g1n wurde der Wert der fundamentalen Bjorken-Summenregel f"ur Q2_0 = 2.5 GeV^2 bestimmt. Dieser Wert befindet sich, bei einer auf den Gesamtfehler bezogenen Genauigkeit von 13%, innerhalb von 0.5 Standardabweichungen in "Ubereinstimmung mit der theoretischen Vorhersage, berechnet unter Ber"ucksichtigung von QCD-Korrekturen der Ordnung O(\alphaS^3).The subject of this thesis is the measurement of the polarised structure function g1p of the proton in deeply inelastic positron-proton-scattering at a centre of mass energy of 7.5 GeV. The data used in the analysis were recorded during the 1997 running period of the Hermes experiment using a longitudinally nuclear polarised hydrogen target in the 27.6 GeV Hera polarised positron storage ring. The cross section asymmetry of positron-proton-scattering has been measured by counting the number of inclusively reconstructed and selected positrons with target spin vector parallel or antiparallel to the beam spin direction. Background processes, spectrometer effects, and radiative corrections have been taken into account by applying different correction procedures. Here background corrections were determined from data while spectrometer corrections were computed from Monte Carlo simulation. The dependence of Monte Carlo and radiative corrections on the model asymmetry chosen to describe polarisation dependent effects has been minimised by applying an iterative procedure. From the fully corrected cross section asymmetry the asymmetry g1/F1 has been computed in the kinematic region 0.021 < x < 0.85 and Q2 > 0.8 GeV^2 with a systematic uncertainty of 8% and a statistical accuracy of 6% to 20%, raising for decreasing x values. The polarised structure function g1p(x,Q2), determined from the asymmetry g1/F1 , was evoluted to a common Q2_0 value assuming g1/F1 to be independent of Q2. Its first moment evaluated in the measured x region is int_{0.021}^{0.85} dx g1p(x,Q2_0) = 0.122 =- 0.003 (stat) =- 0.010 (sys) at Q2_0 = 2.5 GeV^2. This result has been compared with those from E143 at SLAC and from SMC at CERN, both calculated with the same integration scheme and for the kinematic range of Hermes. With respect to the statistical uncertainties the agreement is better than 0.6 and 1.2 standard deviations, respectively. Extrapolation over the entire x range [0,1] yield for the first moment\int_{0}^{1} dx g1p(x,Q2_0) = 0.132 +- 0.003 (stat) +- 0.010 (sys) +- 0.006 (extr) where the additional error gives the uncertainty in the extrapolation x -> 0. The interpretation of this measurement in the framework of the quark parton model taking QCD corrections of the order O(alphaS^3) into account results in a contribution of the quarks to the total nucleon spin of (30 +- 10)% at Q2_0 = 2.5 GeV^2. This result corresponds to a deviation from the Ellis-Jaffe prediction by 2.5 standard deviation regarding the given total uncertainty. Within the quark parton model the deviation can be interpreted as negative polarisation of the strange sea quarks with a contribution of (-9 +- 4)% at Q2_0 = 2.5 GeV^2. Different groups give contributions of the quarks to the nucleon spin of 19% to 44% which were obtained from QCD analyses of various data sets. The fundamental Bjorken sum rule has been determined at Q2_0 = 2.5 GeV^2 using the Hermes measurement of the polarised neutron structure function g1n. With respect to the experimental accuracy of 13 %, the result agrees within 0.5 standard deviation with the theoretical prediction taking QCD corrections of the order O(alphaS^3) into account.
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Deur, A. "La structure en spin du nucléon." Habilitation à diriger des recherches, Université Blaise Pascal - Clermont-Ferrand II, 2008. http://tel.archives-ouvertes.fr/tel-00407961.
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Ce document décrit les récents résultats expérimentaux sur la structure en spin du nucléon obtenus auprès de l'accélérateur d'électrons Thomas Jefferson National Accelerator Facility (Jefferson Lab) en Virginie. Après avoir discuté la finalité de l'étude la structure en spin du nucléon et donnés les définitions de base, nous expliquons la phénoménologie de la diffusion de leptons. Nous détaillons ensuite certaines règles de somme, un outil central pour l'étude du spin du nucléon à Jefferson Lab, puis exposons la situation expérimentale actuelle. Suivent une présentation et discussion des résultats correspondants puis un exemple de résultat de l'étude du nucléon et ses conséquences sur notre compréhension de l'interaction forte. Nous concluons ce document sur les perspectives expérimentales dans ce domaine de recherche, en particulier avec la prochaine augmentation en énergie de Jefferson Lab.
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Bvumbi, Suzan Phumudzo. "Spin and parity assignment in 152 Gd investigating octupole structures." Thesis, University of Western Cape, 2008. http://hdl.handle.net/11394/3267.
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>Magister Scientiae - MScThe high-spin states of the nucleus 152Gd have been populated via the 152Sm (α, 4n) 152Gd fusion-evaporation reaction at a beam energy of 45MeV. The emitted γ rays were observed with the AFRODITE spectrometer array. The previously known decay scheme of 152Gd was extended. Directional Correlation from Oriented states of nuclei (DCO) and linear polarization measurements were performed in order to assign spins and parities in the 152Gd decay scheme. An alternative interpretation of the first excited Kπ = 0+ band, previously considered to be a β-vibration is discussed.
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Zhu, Leiming. "A study of spin dynamics and molecular structure of nucleic acids by NMR /." Thesis, Connect to this title online; UW restricted, 1994. http://hdl.handle.net/1773/11543.
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Hansen, Rasmus Hvass. "Towards the nuclear spin quantum computer." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442465.
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Khandogin, Yang. "Nonrelativistic and scalar relativistic nuclear spin-spin couplings in density functional theory." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0017/MQ48017.pdf.
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RIBEIRO, HUGO [Verfasser]. "Nuclear-Spin Induced Electron Spin Decoherence In Semiconductor Quantum dots / Hugo Ribeiro." Konstanz : Bibliothek der Universität Konstanz, 2012. http://d-nb.info/1023210444/34.
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Kim, Jungtaek. "Electron-nuclear spin control and carrier spin dynamics in II-VI semiconductor." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17524.
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Diese Dissertation besteht aus zwei Teilen von Studien. Der erste Teil demonstriert die Steuerung der Elektron-Kern-Spin-Systems in II-VI Halbleiter Quantum Dots (QDs) durch elektrische Ströme über Mikrospulen. Mikrometer-große Leiterschleifen sind auf der Oberseite von Heterostrukturen mit geladenen CdSe/ZnS QDs hergestellt worden. Eine Strominjektion erzeugt magnetische Felder im Bereich von einige 10 mT, welche stark genug sind, um die Hyperfeinwechselwirkung in CdSe QDs modulieren zu können. Der Durchmesser des Spulen im Mikrometer-Bereich ermöglicht die Generation von schnellen Feld transienten im Bereich von wenigen ns. Mit diesen Vorteilen der Mikrospulen werden die Steuerungs des Spins der residenten Elektronen sowie das Auslesen des Kernspinzustandes durch elektrische Impulse nachgewiesen. Der zweite Teil befasst sich mit der Ladungsträger-Spindynamik in ZnO Quantum Well (QW) Strukturen und Epitaxieschichten, die mittels des optischen Übergang von negativ geladenen Exzitonen X− beziehungsweise des am neutralen Donator gebunden Exziton D0X untersucht werden. Der Loch-Spin kann direkt über die zirkular polarisierten Photolumineszenz der beiden Komplexe zurückverfolgt werde. Die Spin-Relaxationszeit von QW und Epiplyer verfolgt werden. Der Spin des Donatorelektronens wird über die Ausbleichung des Spin-selektive Anregungprozesses nachgewiesen. Es werden longitudinale Loch-Spinrelaxationszeiten von 80 bis 140 ps für D0X und X− gefunden. Deutlich längere longitudinalen Elektronen-Spin-Relaxationszeiten in Bereich von mehreren 100 ns werden gefunden, wenn die Hyperfeinwechselwirkung durch ein geeignetes externes Magnetfeld unterdrückt wird. Eine Feldstärke von 2 mT ist groß genug. Dies zeigt den extrem kleinen Wert des Overhauser-Feldes in ZnO auf, der durch die sehr begrenzte Anzahl von magnetischen Kernen in Wechselwirkung mit dem Elektronen innerhalb des Volumens des Donators verursacht wird.This work is composed of two parts of studies. The first part represents an electron-nuclear spin control in II-VI semiconductor quantum dots (QDs) by electrical currents via micro coils. Micrometer single turn coils are fabricated on top of heterostructures with charged CdSe/ZnSe QDs. Current injection creates magnetic fields in the range of some 10 mT which is strong enough to modulate the hyperfine interaction in CdSe. The micrometer-range diameter of coil allows for generation of fast field transient in the range of few ns. Using these advantages of micro coils, local control of the resident electron spin as well as read out of the nuclear spin state are demonstrated by electrical pulses. The second part presents charged carrier spin dynamics in ZnO quantum wells and epilayers using the optical transition of the negatively charged exciton X− and the neutral donor bound exciton D0X, respectively. The hole spin can be directly traced by the circular polarized photoluminescence of both complexes. The spin relaxation of the resident electrons and donor electrons is accessed via the bleaching of the spin selective excitation process. Longitudinal hole spin relaxation times of 80 and 140 ps are found for D0X and X−, respectively. Much longer longitudinal electron spin relaxation times in the several 100 ns range are uncovered if the hyperfine interaction is suppressed by a proper external magnetic field. A field strength of 2 mT is large enough proving that the extremely small value of the Overhauser field in ZnO caused by the very restricted number of magnetic nuclei interacting with the electron inside the donor volume.
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Tilles, P. F. C. [UNESP]. "Quantização de partículas com spin." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/138360.
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000855913.pdf: 421119 bytes, checksum: af9ecbafa30255e17d4d849d32b01ab5 (MD5)Uma partícula clássica relativística é descrita utilizando-se o formalismo de Dirac para sistemas vinculados devido à invariança sob transformações de reparametrizações requerida por uma teoria explícitamente covariante. Nós introduzimos os graus de liberdade de spin via variáveis de Grassman, que levam diretamente ao conceito de supersimetria presente na teoria. As equações de movimento e a quantização são consideradas tanto para as teorias livres de spin 0 e 1/2, como para a teoria com interação eletromagnética. A álgebra dos vínculos de primeira classe é extendida para descrever partículas de spin N/2, que incluem as representações de spin 1. A teoria quântica obtida é comparada com a teoria clássica de campos
Aclassical relativistic particleis described by means of Dirac's formalism for constrained systems, where the constraints come from the reparametrization invariance required by an explicitly covariant theory. We introduce spin degrees of freedom via Grassman variables, which leads directly to the concept of supersymmetry in the theory. The equations of motion and quantization are considered both for the spin 0 and 1/2 free theories, and for the eletromagnetic interaction. The first class constraints algebra is extended to describe spin N/2 particles, which include spin 1 representations. The quantum theory obtained is compared to the classical theory of fields
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Tilles, Paulo Fernando Coimbra. "Quantização de partículas com spin /." São Paulo, 2007. http://hdl.handle.net/11449/138360.
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Orientador: Nathan Jacob BerkovitsBanca: Bruto Max Pimentel Escobar
Banca: Ricardo Ivan Medina Bascur
Resumo: Uma partícula clássica relativística é descrita utilizando-se o formalismo de Dirac para sistemas vinculados devido à invariança sob transformações de reparametrizações requerida por uma teoria explícitamente covariante. Nós introduzimos os graus de liberdade de spin via variáveis de Grassman, que levam diretamente ao conceito de supersimetria presente na teoria. As equações de movimento e a quantização são consideradas tanto para as teorias livres de spin 0 e 1/2, como para a teoria com interação eletromagnética. A álgebra dos vínculos de primeira classe é extendida para descrever partículas de spin N/2, que incluem as representações de spin 1. A teoria quântica obtida é comparada com a teoria clássica de campos
Abstract: Aclassical relativistic particleis described by means of Dirac's formalism for constrained systems, where the constraints come from the reparametrization invariance required by an explicitly covariant theory. We introduce spin degrees of freedom via Grassman variables, which leads directly to the concept of supersymmetry in the theory. The equations of motion and quantization are considered both for the spin 0 and 1/2 free theories, and for the eletromagnetic interaction. The first class constraints algebra is extended to describe spin N/2 particles, which include spin 1 representations. The quantum theory obtained is compared to the classical theory of fields
Mestre
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Giri, Rakshyakar. "Electron and nuclear spin dynamics in GaAs microcavities." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20037/document.
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Nous avons obtenu des angles de rotation Faraday (RF) allant jusqu'à 19° par orientation optique d'un gaz d'électrons dans GaAs de type n inclus dans une microcavité (Q=19000), sans champ magnétique. Cette forte rotation est obtenue en raison des multiples allers-retours de la lumière dans la cavité. Nous avons également démontré la commutation optique rapide de la RF à l'échelle sub-microseconde en échantillonnant le signal de RF sous excitation impulsionnelle mono-coup. De la dépolarisation de la RF en champ magnétique transverse, nous avons déduit un temps de relaxation de spin de 160 ns. Le concept de section efficace de RF, coefficient de proportionnalité entre l'angle RF, la densité de spin électronique, et le chemin parcouru, a été introduit. La section efficace de RF, qui définit l'efficacité du gaz d'électrons à produire une RF, a été estimée quantitativement, et comparée avec la théorie. Nous avons également démontré la possibilité de mesurer de manière non destructive l'aimantation nucléaire dans GaAs-n, via la RF amplifiée par la cavité. Contrairement aux méthodes existantes, cette détection ne nécessite pas la présence d'électrons hors équilibre. Par cette technique nous avons étudié la dynamique de spin nucléaire dans GaAs-n avec différents dopages. Contrairement à ce qu'on pourrait attendre, le déclin de la RF nucléaire est complexe et consiste en deux composantes ayant des temps de relaxation très différents. Deux effets à l'origine de la RF nucléaire sont identifiés: le splitting de spin de la bande de conduction, et la polarisation en spin des électrons localisés, tous deux induits par le champ Overhauser. Le premier effet domine la RF nucléaire dans les deux échantillons étudiés, tandis que la RF induite par les électrons localisés n'a été observée que dans l'échantillon métalliqueWe obtained Faraday rotation (FR) up to 19° by using optical orientation of electron gas in n-doped bulk GaAs confined in a microcavity (Q=19000), in the absence of magnetic field. This strong rotation is achieved because the light makes multiple round trips in the microcavity. We also demonstrated fast optical switching of FR in sub-microsecond time scale by sampling the FR in a one-shot experiment under pulsed excitation. From the depolarization of FR by a transverse magnetic field, we deduce electron spin relaxation time of about 160 ns. A concept of FR cross-section as a proportionality coefficient between FR angle, electron spin density and optical path is introduced. This FR cross-section which defines the efficiency of spin polarized electrons in producing FR was estimated quantitatively and compared with theory. We also demonstrated non-destructive measurement of nuclear magnetization in n-GaAs via cavity enhanced FR. In contrast with the existing optical methods, this detection scheme does not require the presence of detrimental out-of-equilibrium electrons. Using this technique, we studied nuclear spin dynamics in n-GaAs with different doping concentrations. Contrary to simple expectation, the nuclear FR is found to be complex, and consists of two components with vastly different time constants. Two effects at the origin of FR have been identified: the conduction band spin splitting and the localized electron spin polairzation both induced by the Overhauser field. The first effect dominates the FR in both studied samples, while the FR induced by the localized electrons has been observed only in the metallic sample
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Dumez, Jean-Nicolas. "Many body dynamics in nuclear spin diffusion." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2011. http://tel.archives-ouvertes.fr/tel-00657067.
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Since its introduction by Bloembergen in 1949, nuclear spin diffusion has been a topic of significant interest in magnetic resonance. Spin diffusion, which can be defined as the transfer of spin polarisation induced by the dipolar interaction, is a ubiquitous transport mechanism in solids. Experimental observations of spin diffusion contain structural information. However, the many-body nature of the problem makes it difficult to describe from first principles. The central goal of this thesis is to obtain a quantitative description of the spin diffusion phenomenon from first-principles, through the development of suitable models of the underlying many-body dynamics. To that end we first consider an extension of an existing approach that relies on a master equation to describe the polarisations, for the case of proton-driven carbon-13 spin diffusion (PDSD). Second, a novel approach is introduced for the simulation of the time evolution of selected observables for large strongly coupled nuclear spin systems, using low-order correlations in Liouville space (LCL). Following the introduction of this new simulation method, Liouville-space reduction in solids is analysed in more detail, in order to identify the conditions under which the LCL approximation is valid. Finally, using the LCL model, simulations of proton spin diffusion (PSD) and PDSD are performed, directly from crystal geometry and with no adjustable parameters, and are found to be in excellent agreement with experimental measurements for polycrystalline organic solids.
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Shi, Junhui. "Nuclear spin optical rotation in organic liquids." Thesis, Princeton University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3604505.
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Nuclear spin induced optical rotation (NSOR) is a novel technique for the detection of nuclear magnetic resonance (NMR) via optical rotation instead of conventional pick-up coil. Originating from hyperfine interactions between nuclei and orbital electrons, NSOR provides a new method to reveal nuclear chemical environments in different molecules. Previous experiments of NSOR detection have poor signal-to-noise ratio (SNR), which limits the application of NSOR in chemistry. In this work, based on a continuous-wave NMR scheme at a low magnetic field (5 G), we employ a multi-pass cavity and a 405 nm laser to improve the sensitivity of NSOR. By performing precision measurements of NSOR detection in a range of pure liquid organic chemicals, we demonstrate the capability of NSOR to distinguish 1H signals in different chemicals, in agreement with the first-principles quantum mechanical calculations. The NSOR of 19F is also measured at low fields with high SNR, showing that heavy nuclei have higher optical rotation signals than light nuclei.
In addition, in order to obtain NSOR at different chemical sites in the same molecule via chemical shift, we make efforts to develop a novel scheme based on liquid-core hollow fiber for the detection of NSOR under high magnetic fields. By coiling a long liquid-core fiber densely for many loops around a small rod combined with RF coils, it is possible to measure optical rotation signals inside a narrow-bore superconducting magnet. Manufactured by filling liquids into capillary tubings, those liquid-core fibers perform like multimode step-index fibers, and thereby exhibit linear birefringence and depolarization, significantly reducing the light polarization for the measurement of optical rotation. According to our attempts, it is possible to suppress the linear birefringence by filling chiral liquids in hollow fibers, and approach near single-mode operation by means of launching light beam into the fiber core under the mode match condition. Although some issues of hollow fibers obstruct the final measurement of high-frequency NSOR, our work on the liquid-core fiber provides the basis for future fiber-based NSOR experiments under high magnetic fields.
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Nikolaou, Panayiotis. "SPECTROSCOPIC STUDIES OF NUCLEAR SPINS POLARIZED VIA SPIN EXCHANGE OPTICAL PUMPING AND DYNAMIC COUPLING IN CRYPTOPHANE HOST-GUEST COMPLEXES." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/dissertations/185.
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NMR is a powerful analytical spectroscopic tool used to perform detailed studies of structure and dynamics of molecules in solution. However, despite NMR's excellent spectral sensitivity, most NMR methods suffer from low detection sensitivity. This low detection sensitivity results largely from extremely small (Boltzmann) nuclear spin polarization at thermal equilibrium--in even the strongest of magnets. This dissertation focuses on selected research areas that maybe used to combat the limitations presented by NMR and measure weak spectral responses with atomic-scale precision. In particular, these methods involve the use of laser-polarized xenon, liquid crystals, and polarization transfer (cross-polarization) techniques to enhance NMR sensitivity and/or measure weak interactions. The potential use of these tools to study host-guest interactions is of particular interest. In certain systems the sensitivity problem of conventional NMR/MRI can be overcome by applying optical pumping (OP) methods to enhance nuclear spin polarization. For instance, OP of noble gases (such as xenon) is employed to dramatically increase their nuclear spin polarization by transferring angular momentum of laser light to electronic and then nuclear spins. Next, cryptophane complexes are ideal choices for fundamental studies of prototypical host-guest interactions. Of general interest when studying host-guest interactions is how (1) physical confinement at the nanoscale and (2) interactions between guest and host may affect the properties, dynamics, interactions, and/or reactivity of a trapped molecule and the host/guest complex as a whole. As a more specific example, we are interested in probing host-guest dynamic coupling, which refers to the relative motion of the guest within the host, determined by the relative sizes and geometries--as well as the interactions involved. With the development of new NMR methods and techniques, we hope to gain insight into mechanisms that underlie complex formation by probing the structures, dynamics and energetic contributions involved in ligand binding, where molecular contributions such as: orientational and motional freedom of the guest; and structure, dynamics, and ordering of the host can influence the behavior of inclusion complexes.
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Ohlsson, Tommy. "Dynamics of quarks and leptons : theoretical Studies of Baryons and Neutrinos." Doctoral thesis, KTH, Fysik, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2991.
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The Standard Model of Elementary Particle Physics (SM) is the present theoryfor the elementary particles and their interactions and is a well-established theorywithin the physics community. The SM is a combination of Quantum Chromodynamics(QCD) and the Glashow{Weinberg{Salam (GWS) electroweak model. QCDis a theory for the strong force, whereas the GWS electroweak model is a theoryfor the weak and electromagnetic forces. This means that the SM describes allfundamental forces in Nature, except for the gravitational force. However, the SMis not a nal theory and some of its problems will be discussed in this thesis.In the rst part of this thesis, several properties of baryons are studied suchas spin structure, spin polarizations, magnetic moments, weak form factors, andnucleon quark sea isospin asymmetries, using the chiral quark model (QM). TheQM is an eective chiral eld theory developed to describe low energy phenomena of baryons, since perturbative QCD is not applicable at low energies. The resultsof the QM are in good agreement with experimental data.The second part of the thesis is devoted to the concept of quantum mechanicalneutrino oscillations. Neutrino oscillations can, however, not occur within the GWSelectroweak model. Thus, this model has to be extended in some way. All studiesincluding neutrino oscillation are done within three avor neutrino oscillationmodels. Both vacuum and matter neutrino oscillations are considered. Especially,global ts to all data of candidates for neutrino oscillations are presented and alsoan analytical formalism for matter enhanced three avor neutrino oscillations usingtime evolution operators is derived. Furthermore, investigations of matter eectswhen neutrinos traverse the Earth are included.The thesis begins with an introductory review of the QM and neutrino oscillationsand ends with the research results, which are given in the nine accompanyingscientic articles.QC 20100616
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Fushitani, Mizuho. "Nuclear Spin Selection Rule in Photoinduced Reaction of Methyl Radical and Nuclear Spin Conversion of Methane in Solid Parahydrogen." 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/150022.
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Cravey, Robin Lee. "Propagators for higher spin particles." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/27904.
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Notbohm, Susanne. "Spin dynamics of quantum spin-ladders and chains." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/403.
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Netshiya, Adivhaho Andrew. "Octupole and quadrupole structures in the N=88 nucleus 152Gd." University of the Western Cape, 2018. http://hdl.handle.net/11394/6577.
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>Magister Scientiae - MScThe focus for this work is on 152Gd produced by the 150Sm( , 2n)152Gd reaction at a beam energy of 25 MeV. The nucleus has been previously studied for both low spin states and high spin states at di erent energies. The most recent work on 152Gd was done by S. P. Bvumbi using the 152Sm( , 4n)152Gd reaction at a beam energy of 45 MeV where she was able to populate low spin states and assign spins and parities to the levels as shown in Fig. 1.1. The nucleus 152Gd, with proton number Z=64 subshell closure, belongs to a set of isotones having N=88 in the transitional region with just 6 neutrons outside the N=82 closed shell and lies just before the N=90 permanently deformed region. The isotope 152Gd is in the transitional region, consequently its nuclear collective motion will quickly evolve from vibrational to rotational motion. The low lying K =0+2 bands in N=88 and 90 nuclei appear at low excitation energies and are poorly understood. Key to these studies is the crucial question about the legitimacy of the low lying K =0+2 bands being described as vibrations along the symmetry axis. The current work examines the K =0+2 band with the objective of providing more understanding. Previous studies of N=88 isotones saw consistent E1 transitions both from and to the K =0+2 bands and octupole bands, namely 144Ba, 146Ce, 148Nd, 150Sm and 154Dy nuclei. The experimental systematics of the low lying negative parity states in N=88 isotones are remarkably well reproduced by theoretical calculations of the quadrupole octupole coupling (QOC) modelas shown in Fig. 1.2.
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Rizzutto, Marcia de Almeida. "Estados de spin elevado em \'ANTPOT.130 La." Universidade de São Paulo, 1989. http://www.teses.usp.br/teses/disponiveis/43/43131/tde-08112013-101544/.
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Estados de spin elevado do núcleo duplamente ímpar ANTPOT.130 La foram estudados através de técnicas de espectroscopia gama em linha utilizando reações do tipo fusão-evaporação. Os raios gama de ANTPOT.130 La foram inicialmente identificados pelo método de reações cruzadas: ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La e ANTPOT.124 Te (ANTPOT.10 B, 4n) ANTPOT.130 La. Foram realizadas medidas de função de excitação, distribuição angular e coincidência --t para a reação ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La com energia de feixe de 54 MeV. Duas bandas rotacionais foram observadas com configurações h IND.11/2 g IND. 7/2 e h IND.11/2 g IND. 11/2 onde a segunda banda mostra um pequeno valor de signature splitting ( 50 KeV) que pode indicar uma forma ligeiramente triaxial. Os resultados experimentais serão comparados com os núcleos vizinhos ímpares e ímpar-ímpar e também interpretados segundo modelos de Roto mais duas quasipartículas e Cranked Shell Model.High-spin states in the doubly odd nucleus ANTPOT.130 La have been studied using in-beam spectroscopy techinques with fusion evaporation reactions. The ganma rays of ANTPOT.130 La were initially identified by cross-beam reactions ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La and ANTPOT.124 Te (ANTPOT.10 B, 4n) ANTPOT.130 La. Excitation functions, angular distributions and --t coincidences were measured using the reaction ANTPOT.121 Sb (ANTPOT.12 C, 3n) ANTPOT.130 La at E IND.BEAM = 54 MeV. Two rotational bands were observed with the configuration h IND.11/2 g IND. 7/2 and h IND.11/2 g IND. 11/2. The second band shows a small signature splitting of 50 KeV which could indicate a slightly triaxial shape. The results will be compared with the framework of Triaxial Rotor plus Two-Quasiparticule Model as well as Cranked Shell Model.
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Lv, Bingfeng. "Chirality in the ¹³⁶Nd and ¹³⁵Nd nuclei." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS353/document.
Full textAbstract:
Le mode d’excitation collective exotique appelé chiralité a été étudié et des isomères de longue durée de vie ont été recherchés dans les noyaux ¹³⁶Nd et ¹³⁵Nd. Cinq paires de bandes Δ I=1 presque dégénérées et de même parité ont été identifiées à des spins élevés dans ¹³⁶Nd Les bandes observées ont été étudiées en utilisant la théorie de la fonctionnelle de densité covariante contrainte et rotation autour d'une axe incliné, et par un nouveau modèle de rotor plus particules développé pour décrire le couplage de particules dans quatre couches j à un rotor triaxial. Les propriétés de ces bandes doublet sont en bon accord avec les résultats des calculs théoriques. Par conséquent, l'existence de bandes chirales multiples (MχD) dans le noyau ¹³⁶Nd a été établie. Il s'agit de la première preuve expérimentale de l'existence de bandes chirales dans des noyaux pairs. Les cinq paires de bandes chirales constituent le plus grand ensablé de bandes chirales observé jusqu'à présent dans un seul noyau. De plus, le schéma de niveaux de ¹³⁶Nd a été considérablement étendu aux spins bas, moyens et très élevés. Les configurations possibles de toutes les bandes rotationnelles ont été attribuées á l'aide du modèle Nilsson-Strutinsky en rotation. La structure de ¹³⁶Nd a été clarifiée et les divers types d'excitations uni-particule et collectives ont été bien compris. Une nouvelle paire de bandes chirales á parité positive a été identifiée dans. Les caractéristiques des bandes soutiennent leur interprétation en termes de bandes chirales. Des bandes chirales à parité négative ayant été identifiées précédemment, la présence de multiple bandes chirales dans ¹³⁵Nd est ainsi établie. Les bandes chirales observées ont été étudiées en utilisant la théorie avec fonctionnelle de densité covariante contrainte et avec le modèle rotor plus particules; elles reproduisent fidèlement les données expérimentales, confirmant ainsi le phénomène MχD dans ce noyau. Les bandes chirales nouvellement observées dans ¹³⁵Nd représentent une étape importante dans la confirmation de l'existence du phénomène MχD dans les noyaux. La recherche d'états isométriques à longue durée de vie dans ¹³⁵Nd et ¹³⁶Nd a été aussi effectuée, mais n'a pas permis d'identifier de nouveaux isomères. Cependant, nous avons pu confirmer la présence des isomères déjà identifiés dans les noyaux ¹³⁸Nd, ¹³⁴Ce, ¹³⁶Pr, et ¹³⁷Pr dans nos donnéesThe exotic collective excitation mode called chirality has been investigated and long-lived isomers have been searched for in the ¹³⁶Nd and ¹³⁵Nd nuclei. Five pairs of nearly degenerate Δ I=1 bands with the same parity have been identified at high spins in ¹³⁶Nd. The observed bands were investigated by the constrained and tilted axis cranking covariant density functional theory and a new developed four single-j shells particle-rotor model. It was found that the properties of these doublet bands are in good agreement with results of the model calculations. Therefore, the multiple chiral doublets (MχD) phenomenon in the nucleus ¹³⁶Nd was confirmed. This was the first experimental evidence for the MχD bands in even-even nuclei. The five pairs of chiral doublet bands is the largest observed in a single nucleus until now. In addition, the level scheme of the ¹³⁶Nd has been extended significantly at low, medium, and very high spins. Possible configurations of all rotational bands have been assigned by using the cranked Nilsson-Strutinsky model. The band structure of ¹³⁶Nd was clarified and the various types of single-particle and collective excitations were well understood. A new pair of positive-parity chiral doublet bands has been identified in ¹³⁵Nd. The characteristics of the doublet bands support the chiral interpretation. Together with the previously reported negative-parity chiral doublet bands show the presence of MχD bands in ¹³⁵Nd. The observed doublet bands were compared with constrained covariant density functional theory and particle-rotor model calculations which nicely reproduce the experimental data, confirming the MχD phenomenon in this nucleus. The newly observed MχD bands in ¹³⁵Nd represent an important milestone in supporting the existence of MχD in nuclei. The search for long-lived isomeric states in ¹³⁵Nd and ¹³⁶Nd has also been performed. This did not lead to the identification of new isomers, but we could confirm the existence of the previously reported isomers in the nuclei ¹³⁸Nd, ¹³⁴Ce, ¹³⁶Pr, and ¹³⁷Pr in our data
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Windham, Gordon. "Spin dependence in heavy ion induced nuclear reactions." Thesis, University of Surrey, 1986. http://epubs.surrey.ac.uk/843452/.
Full textAbstract:
The interest of this work is to explore the spin dependent effects of projectile structure in nuclear heavy ion induced reactions. The projectiles are considered to consist of two clusters which remain inert, the intercluster wavefunctions are obtained by the use of the orthogonality condition model. Excitation to the low lying projectile states is included by the use of coupled channels calculations. The projectile excited states are included by allowing excitation in the inter cluster wavefunctions. Coupling to the excited states is performed by multipole terms arising from a single folding model, which is used consistently throughout the work. The effects of projectile excitation are considered in two areas, elastic and inelastic scattering, and transfer reactions. It is found that the inclusion of the projectile excited states has a very strong effect on the spin dependent elastic observables, in particular the vector analysing powers. In contrast to earlier analysis it is found that projectile excitation plays a dominant role in reproducing the experimentally observed vector analysing powers for the elastic scattering of 6Li from 16O and 28Si at 22.8 MeV. Projectile excitation is also seen to produce strong spin dependent effects in the elastic scattering of Li from 120Sn at 44 MeV and of 19Ffrom 28Si at 60 MeV. The inclusion of projectile excitation via CCBA calculations produces changes in the transfer cross section for the 28Si (19F, 16O)31P(1/2+ ,g.s.) reaction. The observed changes can be understood in terms of the effects of spin dependence in the reaction path. The inclusion of projectile excitation however does not significantly improve the quality of the agreement with experimental data.
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Skiba-Szymanska, Joanna. "Electron nuclear spin interaction in semiconductor quantum dots." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500176.
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Yeung, R. R. "Nuclear spin relaxation and morphology of solid polyolefins." Thesis, University of East Anglia, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356619.
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Harper, R. E. "Anomalous nuclear spin-lattice relaxation peaks in InSb." Thesis, University of St Andrews, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373036.
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