Filtyp
We extend the definition of the star product introduced by Lunin and Maldacena to study marginal deformations of N=4 SYM. The essential difference from the latter is that instead of considering U(1)xU(1) non-R-symmetry, with charges in a corresponding diagonal matrix, we consider two Z_3-symmetries followed by an SU(3) transformation, with resulting off-diagonal elements. From this procedure we ob
In this talk I first discuss the experimental evidence for multiple scattering and the properties of the underlying event. The extensive analyses by Rick Field of data from CDF cannot be reconciled with traditional wisdom concerning multiple collisions and the AGK cutting rules. Data seem to imply some kind of color recombination or unexpectedly strong effects from pomeron vertices. I then discuss
This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.
This talk describes the reasons why $\eta$ and $\eta^\prime$ decays are an interesting topic of study for both theory and experiment. The main part discusses the results of the recent calculation of $\eta\to3\pi$ at two-loop order in ChPT. Some puzzling aspects of the results compared to earlier dispersive calculations are highlighted. I also like to remind the reader of the use of $\eta$ and $\et
There are experimental evidence for the occurrence of colour reconnection, but the mechanisms involved are far from understood. Previous reconnection studies are briefly summarized, and some potential implications for LHC physics are outlined.
A brief overview of the current state of general purpose event generators, focusing on recent developments in extending the precision of QCD to next-to-leading order.
QCD EVENT GENERATORS This report is a survey on QCD Event Generator issues of relevance for LEP 2. It contains four main sections: a summary of experience from LEP 1, extrapolations to LEP 2 energies, Monte Carlo descriptions and standardization issues.
We report on our studies of the neutron-skin effects in high-pT observables at the LHC. We study the impact of the neutron-skin effect on the centrality dependence of inclusive direct photon, highpT hadron and W± production in nuclear collisions at the LHC. The neutron-skin effect refers to the observation that in spherical heavy nuclei, the tail of the neutron distribution extends farther than th
The inclusive and exclusive processes associated with a leading neutron in ep collisions at high energies are described using the color dipole formalism. We demonstrate that the available experimental HERA data on the xL (Feynman momentum) distribution of leading neutrons can be very well described taking into account the nonlinear (saturation) effects in the QCD dynamics. Moreover, we present our
An updated analysis regarding the expected nuclear PDF constraints from the future Large Hadron Electron Collider (LHeC) experiment is presented. The new study is based on a more flexible small-x parametrization which provides less biased uncertainty estimates in the region where there are currently no data constraints. The effect of the LHeC is quantified by directly including a sample of pseudod
This thesis is composed of four papers, which concern Monte Carlo event generators for high energy particle physics. Precise predictions of the outcome of particle collisions are important for the exploration of the Standard Model of particle physics at collider experiments like the LHC at CERN. The papers address the uncertainties of these predictions in different contexts.Paper I presents an alg
In this paper, a model inspired by Grand Unification principles featuring three generations of vector-like fermions, new Higgs doublets and a rich neutrino sector at the low scale is presented. Using the state-of-the-art Deep Learning techniques we perform the first phenomenological analysis of this model focusing on the study of new charged vector-like leptons (VLLs) and their possible signatures
First-order perturbations of homogeneous and hypersurface orthogonal locally rotationally symmetric class II cosmologies with a cosmological constant are considered in the framework of the 1+1+2 covariant decomposition of spacetime. The perturbations, which are of perfect fluid type, include general scalar, vector, and tensor modes and extend some previous works in which vorticity perturbations we
Context. The solar vicinity is currently populated by a mix of stars with various chemo-dynamic properties, including stars with a high metallicity compared to the Sun. Dynamical processes such as churning and blurring are expected to relocate such metal-rich stars from the inner Galaxy to the solar region. Aims. We report the identification of a set of old super-metal-rich (+0.15 ≤ [Fe/H] ≤ +0.50
Context.Gaia's third data release provides radial velocities for 33 million stars and spectroscopically derived atmospheric parameters for more than 5 million targets. When combined with the astrometric data, these allow us to derive orbital and stellar parameters that are key to understanding the stellar populations of the Milky Way and to perform Galactic archaeology. Aims. We used the calibrate
Context. The high quality of the Gaia mission data has allowed for studies of the internal kinematics of the Large Magellanic Cloud (LMC) to be undertaken in unprecedented detail, providing insights into the non-axisymmetric structure of its disc. Recent works by the Gaia Collaboration have already made use of the excellent proper motions of Gaia DR2 and Gaia EDR3 for a first analysis of this sort
Gaia Data Release 3 provides novel flux-calibrated low-resolution spectrophotometry for '220 million sources in the wavelength range 330 nm ≤ λ ≤ 1050 nm (XP spectra). Synthetic photometry directly tied to a flux in physical units can be obtained from these spectra for any passband fully enclosed in this wavelength range. We describe how synthetic photometry can be obtained from XP spectra, illust
