The LHCb experiment at CERN is dedicated to the study of matter-antimatter asymmetries and rare decays in the Beauty and Charm sectors. It provides important tests of the Standard Model of particle physics and searches for new physics effects, complementary to the direct searches by the LHC general purpose detectors. Following an introduction to the LHCb experiment and its physics potential, recent results from the broad LHCb physics program with emphasis on flavour physics will be presented. This will include a discussion on how the results compare to the Standard Model predictions, as well as a brief outlook into the future of LHCb and its expected performance.
Soon after the discovery of Jupiter-sized planets in extremely close orbits around Sun-like stars, it has been proposed that these "hot Jupiters" cannot have formed in situ but that they must have migrated from the cold, icy regions of the protoplanetary disk at several AU from the star. Competing theories have been put forward as to what stops their inward migration: tidal halting, magnetorotational instabilities that evacuate the close-in protoplanetary disk, planet-disk magnetic interactions, the Kozai mechanism of a distant perturber, planet traps, planet-planet scattering, or high-eccentricity migration. It remained unclear, however, why (1) hot Jupiters pile up near 0.05 AU around sun-like stars (at least in radial velocity surveys), (2) why this pile-up is missing in the Kepler data, (3) why hot Jupiters prevent orbital destruction due to tidal dissipation in the star over billions of years, (4) why the hot Jupiter occurrence rate around sun-like stars is rather low (near 1%). I will present a new star-planet-disk model that reproduces these observations. The key is in the evolution of the star's tidal dissipation efficiency and of its rotation period, the latter of which determines the co-rotation radius beyond which planet migration can be stopped.
Based on a previous work on scenarios where the Standard Model
and dark matter particles share a common asymmetry through effective
operators at early time in the Universe and later on decouple from each other (not car), in this work, we study in detail the collider
phenomenology of these scenarios. In particular, we use the experimental results from the Large Hadron Collider (LHC) to constrain the viable parameter space. Besides effective operators, we also constrain the parameter space of some representative ultraviolet complete models with experimental results from both the LHC and the Large Electron-Positron Collider. Specifically, we use measurements related to jets + missing transverse energy (MET), di-jets and photon + MET. In the case of ultraviolet models, depending on the assumptions on the couplings and masses of mediators, the derived constraints can become more or less stringent. We consider also the situation where one of the mediators has mass below 100~GeV, in this case we use the ultraviolet model to construct a new effective operator responsible for the sharing of the asymmetry and study its phenomenology.
Generic, clean quantum many-body systems approach a thermal equilibrium after a long time evolution. In order to reach a global equilibrium, conserved quantities have to be transported across the whole system which is a rather slow process governed by diffusion. By contrast, the scrambling of quantum information is ballistic and hence can be characterized by a "butterfly" velocity. One way of describing the propagation of quantum information is to study out-of-time ordered (OTO) correlation functions, which are unconventional correlation functions with time arguments that are not time ordered. Using matrix-product-state based numerical simulations, we compute such correlators at high temperatures in a one-dimensional Bose-Hubbard model, where well defined quasi-particles cease to exist. Finally, we will discuss ways of experimentally characterizing these unconventional OTO correlation functions in synthetic quantum matter.
Accretion disks (ADs) in active galactic nuclei (AGNs) are unresolved by current instruments, and indirect imaging methods, such as reverberation mapping are required to probe their physics. We have started an automatized photometric monitoring of active galactic nuclei using the 46cm telescope of the Wise Observatory in Israel. The telescope is specially equipped with narrowband filters to perform
high-fidelity photometric reverberation mapping of the ADs in V < 17 mag sources and up to z ~ 0.1. Here, we describe the capability and accuracy of the experiment and present the first science verification data obtained for the nearby Seyfert 1 galaxy Mrk279. With a sub-day sampling over more than two months, and typical flux measurement uncertainties of ~1%, we are able to robustly measure inter-band time-delays of up to ~2 days across the optical range. The implications of our findings for the physics, structure, and phenomenology of AGN are discussed.
Materials made of arrays of quantum spins forming well-defined lattices serve
as model systems to study the phases of correlated magnetic quantum matter
like spin Luttinger-liquids, magnon Bose-Einstein condensates, or spin super-
solids. Neutron and X-ray scattering are unique tools for high-precision
studies of such phases and of their correlations and excitations with high
energy and momentum resolution. The results will be discussed in the context
of recent developments in computational physics and exciting new
opportunities that free electron lasers will offer to study the time-dependence
and out-of- equilibrium dynamics of such systems.