Gluon saturation and energy loss in hadronic collisions

Neste trabalho usamos o Interacting glúon Model (IGM), um modelo que descreve bem o fluxo de energia em colisões hadrônicas, para estudar o espectro de partícula dominante quando são incluídos os efeitos da saturação dos glúons. Os espectros de partícula dominante são obtidos para várias energias do centro de massa (s^1/2), usando funções de distribuição dos glúons com e sem efeitos de saturação. Verificamos que, em qualquer caso, há um \"amolecimento\"do espectro, mas os espectros obtidos com saturação variam mais suavemente com a energia do que os que não incluem saturação. Comparamos nossos resultados com outras estimativas feitas na literatura.In this work we use the Interacting Gluon Model (IGM), a model that describes quite well the energy flow in hadronic collisions, to study the leading particle spectrum when gluon saturation effects are included. The leading particle spectrum is calculated for several center of mass energies (s^1/2), using gluon distribution functions with and without saturation effects. In both cases the resulting spectrum becomes softer for increasing energies. With saturation the softening is less pronounced than without

A study about directed flow

Nesta tese estudamos o fluxo dirigido, a primeira componente na expansão de Fourier da distribuição azimutal das partículas emitidas. Diferente do fluxo elíptico, que é muito bem estudado e descrito na literatura, a física que gera este observável ainda não é muito conhecida. Mostramos que este observável é altamente sensível a condições iniciais, comparando vários resultados numéricos para diferentes condições iniciais, entre analíticas e numéricas. Propomos que o fluxo dirigido também é sensível à aceleração longitudinal e formulamos um modelo analítico baseado nesta hipótese. Este modelo sugere quais ingredientes são relevantes para o fluxo dirigido. Ele é confrontado com sucesso com cálculos numéricos, resultados experimentais e cálculos que não incluem a aceleração longitudinal.In this thesis we study the directed flow, the first component in the Fourier\'s expansion of the azimuthal distribution of emitted particles. Unlike the elliptic flow, which is well studied and described in the literature, the physics that generates this observable is not yet well described. We show that this observable is highly sensible to the initial conditions, comparing several numeric results with different initial conditions, between analytic and numeric ones. We propose that the directed flow is also sensitive to the longitudinal acceleration and we formulate an analytic model based in this hypothesis. This model suggests which ingredients are relevant to the directed flow. It is confronted with success against numeric calculus, experimental results, and calculus that do not include the longitudinal acceleration

Guidelines for sound design in computer games

The inconsequential exploitation of sound in most computer games, both in extent and nature, contrasts with its prominence in our daily lives and with the kind of associations that have been explored in domains such as music and cinema. Sound design remains the craft of a talented minority and the unavailability of a public body of knowledge on the subject has greatly contributed to this state of affairs. This leads to a mix of alienation and best-judgment improvisation in the broader development community. A sensitivity to the potential of sound for the enrichment of the experience—with emphasis on game specifics—is, therefore, necessary. This study presents a contribution to the practice of sound design for computer games. An approach to intentional sound design, informed by multi-disciplinary interpretations of concepts including emotion, context, acoustic ecology, soundscape, resonance, and entrainment, is distilled into a set of design guidelines that holistically address the different sound layers

FLUCTUATIONS AND INITIAL STATE GRANULARITY IN HEAVY ION COLLISIONS AND THEIR EFFECTS ON OBSERVABLES FROM HYDRODYNAMICS

A comparison is made between results obtained using smooth initial conditions and event-by-event initial conditions in the hydrodynamical description of relativistic nuclear collisions. Some new results on directed flow are also included