The weekly cosmology journal club takes place on Fridays at 11am in the DFTE seminar room (101).
JC organizer: Rodrigo Holanda
- Seminar (next Friday at 11 am), Speaker: Dr. Farinaldo Queiroz. Title: How can we discover the nature of dark matter?
Abstract: We will briefly review dark matter and its methods of detection, and then treat of mechanism capable of retrieving precious information about the nature of dark matter.
- Seminar (Friday at 11 am), Speaker: Dr. Janilo Santos. Title: f(R) Theories of Gravity.
Abstract: One of the key problems at the interface between fundamental physics and cosmology is to understand the physical mechanism behind the late-time acceleration of the Universe. In principle this phenomenon may be the result of unknown physical processes involving either modifications of gravitation theory or the existence of new fields in high energy physics. Although the latter route is most commonly used, which gives rise to the idea of a dark energy matter component in the Universe, the former has recently attracted many attentions as a proposal capable of exhibit naturally an accelerating cosmological expansion without introducing exotic dark energy. Among the various modified gravity proposals, the f(R) gravity framework is the conceptually simplest generalization of Einstein’s gravity, and has attracted the interest of many cosmologists. These theories are constructed by replacing the Ricci scalar curvature R in the Einstein-Hilbert Lagrangian with some arbitrary smooth nonlinear function f(R). In this talk I will briefly present the two different variational approaches that may be followed when we work with f(R) gravity, namely, the metric and the Palatini formalisms, as well as its potentialities, difficulties and similarities with scalar-tensor theories. Also, I present some applications to the flat Friedmann-Robertson-Walker cosmological model in the Palatini formalism.
Mini-course on Modern methods for Scattering Amplitudes in gauge
theories. William J. Torres Bobadilla IFIC (UV-Spain)
The calculation of scattering amplitudes has been playing a very important role in the physics of the LHC. In particular, more accuracy is required to compare our theoretical predictions with the experiments. In this course, I plan to focus on modern techniques for the calculation of tree and multi-loop level amplitudes. In particular, the latter are part of the main ingredients to perform a Next-to-Next-to-Leading order (NNLO) computation, which currently is the main target of the physics community and can be applied also in classical gravity.
Lessons on Tue 11, Wed 12, Fri 14, Mon 17, Wed 19, Thu 20 September at 14:00 until 15:30 in the main auditorium of IIP.
• Computational techniques of scattering amplitudes: QCD scattering amplitudes, colour-ordered amplitudes, spinor-helicity formalism, momentum twistor variables, recursive relations.
• On-shell methods: Britto-Cachazo-Feng-Witten recursive relation, untarity of the S-matrix, optical theorem, generalised unitarity, quadruple cut.
• Feynman integrals: Passarino-Veltman reduction, Loop-tree duality, master integrals, differential equations for master integrals.
• Integrand reduction methods for multi-scattering amplitudes: Ossola-Papadopoulos-Pittau method, adaptive integrand decomposition.