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Two-body calculations from the direct radiative reactions D(p,⋎)He³(⋎,p) and O¹⁶(p,⋎)F¹⁷Donnelly, Thomas William January 1967 (has links)
The direct radiative capture reactions D(p,⋎)He³ and O¹⁶(p,⋎)F¹⁷, both of which are of interest in astrophysical processes, have been studied theoretically using a simple two-body direct radiative capture model in order to estimate the
cross sections at low energies. In addition, the time inverse
of the first reaction, namely the photodisintegration of He³,
has been studied for high excitation energies in He³ by applying
the reciprocity relations to the direct capture theory. The calculations involve taking matrix elements of the particle-radiation interaction Hamiltonian between bound and continuum states and using first-order perturbation theory to obtain the cross sections. Bound state wave functions are generated in simple potentials involving square-well and Saxon-Woods forms with appropriate Coulomb barriers and with one free parameter which is adjusted to fit the binding energy. The potential parameters for the continuum state wave functions are adjusted to fit available scattering data.
For the reaction O¹⁶(p,⋎)F¹⁷ the cross sections for transitions
to both the ground and first excited states are in good agreement with the somewhat limited experimental data from 150 KeV to 2.5 MeV and the astrophysical S-factors are shown to be energy dependent even at energies below 100 KeV. The photodisintegration cross section for the reaction He³(⋎,p)D is well fitted in the neighbourhood of the peak at around 11
MeV as well as at lower energies. The D(p,⋎)He³ direct capture
cross sections in the energy range around 1 MeV are shown to be
sensitive to admixtures of ²S-state of mixed symmetry and of
⁴D-state in the ground state of He³, which is predominantly
Symmetric ²S. The same model including the ²S-state of mixed
symmetry leads to a capture cross section for thermal neutrons by deuterons in good agreement with the experimental value. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
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A stability study of the Gribov-Levin-Ryskin equation, and its phenomenological implications = Estudo da estabilidade da equação Gribov-Levin-Ryskin e suas implicações fenomenológicas / Estudo da estabilidade da equação Gribov-Levin-Ryskin e suas implicações fenomenológicasRivera Gambini, Guillermo Gerardo, 1984- 30 August 2018 (has links)
Orientador: Donato Giorgio Torrieri / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-30T22:50:16Z (GMT). No. of bitstreams: 1
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Previous issue date: 2016 / Resumo: A equação de Gribov, Levin e Ryskin (GLR) é uma equação de evolução para as funções de distribuição dos gluons que respeita o limite de Froissart. Motivado pelo fato do fluxo elíptico v2 apresentar scaling no momento transversal, na rapidez, no tamanho do sistema, etc. e pela similaridade que esses scalings possuem com o scaling de Bjorken, modificamos a equação GLR adicionando uma dependência angular a ela. Dessa maneira, temos uma equação diferencial parcial não linear do tipo 2+1 que pode apresentar instabilidades nas soluções, gerando v2. A forma geral das soluções foi inspirada pela descomposição de Fourier para a distribuição de momentos das partículas produzidas em colisões entre íons pesados. Duas soluções para os modos instáveis são obtidas e seus significados físicos discutidos / Abstract: The Gribov-Levin-Ryskin (GLR) equation is an evolution equation for gluon distribution functions which respects Froissart's bound. Motivated by the non-obviousness of elliptic flow v2 scaling in transverse momentum, rapidity, system size, etc. being explained by Hydrodynamics, and the similarity they have with Bjorken scaling, the GLR equation is modified by adding an angular dependence to it; therefore, turning it into a 2+1 nonlinear partial differential equation, which can present instabilities in its solutions, generating v2. The general form of the solutions was inspired by the Fourier decomposition for the momentum distribution of produced particles in heavy-ion collisions. Two solutions for the unstable modes are found and their physical meaning is discussed / Mestrado / Física / Mestre em Física / 1370446/2014 / 151922/2014-4 / CAPES / CNPQ
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Etude des propriétés de transport et d'équilibration de la matière nucléaire dans le domaine de l'énergie de Fermi / Study of the transport and equilibration properties of the nuclear matter in the Fermi energy domainHenri, Maxime 19 October 2018 (has links)
L’équation d’état de la matière nucléaire est un outil primordial dans la description des collisions entreions lourds, mais également dans la description de la formation d’objets ou de phénomènes astrophysiques(structure des étoiles à neutrons, fusion d’étoiles à neutron). Établir l’équation d’état de la matière nucléairerequiert de définir de manière précise les conditions thermodynamiques (densité, température, asymétrie pro-ton/neutron) dans lesquelles le systèmes évolue. Dans ce travail, nous abordons la problématique de l’étatd’équilibration maximal qui est atteint dans les collisions entre ions lourds, en terme d’énergie et d’isospin.Pour cela, nous utilisons la base de données expérimentale du multi-détecteur INDRA construite par lacollaboration au cours de ces 25 dernières années, en nous intéressant plus particulièrement aux collisionscentrales dans le domaine de l’énergie de Fermi, entre 10 et 100 MeV/nucléon. Nous présentons ainsi dansce document, comment à l’aide de simulation dédiées, il nous a été possible de relier le pouvoir d’arrêt de lamatière nucléaire à la section efficace de collision nucléon-nucléon dans la matière nucléaire. Nous apportonségalement des éléments de réponse au regard du transport de l’isospin dans les collisions centrales à l’aidedes rapports isobariques A = 3 construits à partir des tritons et des hélium-3. Ces différents résultats nouspermettent de mettre en avant le nouveau dispositif expérimental mis en place par les collaborations INDRAet FAZIA : le multi-détecteur FAZIA. Ce dernier est le résultat d’une période de recherche et développementde dix ans, ayant abouti à un multi-détecteur embarquant son électronique numérique sous vide, avec desperformances d’identification accrues (mesure de la charge Z et de la masse A jusqu’à Z = 25) par rapportaux multi-détecteurs des générations précédentes. / The nuclear matter equation of the state is an essential tool in the description of heavy ion collisions,but also in the description of the formation of astrophysical objects or phenomena (neutron star structure,neutron stars fusion). Establishing the nuclear matter equation of state requires a proper definition of thethermodynamic conditions (density, temperature, proton/neutron asymmetry) in which the system evolves.In this work, we address the issue of equilibration reached in heavy ion collisions, in terms of energy andisospin. To do this, we use the experimental database of the INDRA array built by the collaboration over thepast 25 years, focusing on central collisions in the Fermi energy domain, between 10 and 100 MeV/nucleon.In this document, we present how, with the help of dedicated simulations, it has been possible to link thestopping power of nuclear matter to the in-medium nucleon-nucleon cross-section. We also provide someanswers regarding isospin transport in central collisions using the isobaric ratios A = 3 based on the tritonsand helium-3 particles. These different results allow us to highlight the new experimental apparatus devel-loped by the INDRA and FAZIA collaborations : the FAZIA array. The latter is the result of a ten-yearperiod of research and development, resulting in an array embedded its digital electronic under vacuum, withincreased identification performance (measurement of the Z charge and A mass up to Z = 25) compared tothe previous generations arrays.
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J/Ψ suppression in ultra-relativistic heavy ion collisionsRitchie, Robert Alexander 24 March 2017 (has links)
No description available.
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Near-resonant rotation-vibration energy transfer in atom-diatom collisionsSmith, Wesley Dexter 01 August 1973 (has links)
In this dissertation, a theory of vibration-rotation (V-R) energy transfer in atom-vibrating-rotor collisions is formulated by a simple extension of the Arthurs and Dalgarno atom-rigid-rotor theory, and V-R transition probabilities, cross sections and rate constants are found from solutions to a set of coupled differential equations. The theory is tested on two near-resonant V-R energy transfer processes. First, the rate constant for the (υ=0, j=20 <– υ=1, j=15) transition in Ar-OH(A^2 Σ^+) is calculated in the infinite-order sudden approximation and in the distorted-wave approximation at 360°K. The results agree with experiment and indicate that the transition is direct and first-order. Second, cross sections for the (υ=1, j=7 <– υ=0, j=11) excitation in Li^+ -H_2(X^1 Σ_g^+) are obtained in the exponential distorted-wave approximation at 14,000°K. The calculated cross sections are larger than those of neighboring off-resonant V-R and non-V-R transitions. It is concluded that near-resonant V-R energy transfer is an important process in atom-diatom collisions.
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ΛK and Ξ<sup>−</sup>K<sup>±</sup> Femtoscopy in Pb-Pb Collisions at √<i>s</i><sub>NN</sub> = 2.76 TeV from the LHC ALICE CollaborationBuxton, Jesse Thomas 29 August 2019 (has links)
No description available.
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Ortho- and perikinetic studies of latex hydrosol stability : a thesisTakamura, Koichi. January 1980 (has links)
No description available.
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Penetrating probes in relativistic heavy ion collisionsQin, GuangYou. January 2008 (has links)
No description available.
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Nuclear dynamics in the mean field Vlasov equationGan, Hin Hark January 1986 (has links)
No description available.
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Differential Model and Impact Response of a Flexible Beam Attached to a Rigid Supporting StructureChandra, Harish 20 May 2008 (has links)
No description available.
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