Measuring spin and CP from semi-hadronic ZZ decays using jet substructure

We apply novel jet techniques to investigate the spin and CP quantum numbers of a heavy resonance X, singly produced in pp -> X -> ZZ -> l(+)l(-)jj at the LHC. We take into account all dominant background processes to show that this channel, which has been considered unobservable until now, can qualify under realistic conditions to supplement measurements of the purely leptonic decay channels X -> ZZ -> 4l. We perform a detailed investigation of spin- and CP-sensitive angular observables on the fully-simulated final state for various spin and CP quantum numbers of the state X, tracing how potential sensitivity communicates through all the steps of a subjet analysis. This allows us to elaborate on the prospects and limitations of performing such measurements with the semihadronic final state. We find our analysis particularly sensitive to a CP-even or CP-odd scalar resonance, while, for tensorial and vectorial resonances, discriminative features are diminished in the boosted kinematical regime.Comment: 12 pages, 7 figures, 2 tables, published versio

Propagation of Ultra High Energy Cosmic Rays in Extragalactic Magnetic Fields: A view from cosmological simulations

We use the CRPropa code to simulate the propagation of ultra high energy cosmic rays (with energy $\geq 10^{18} \rm eV$ and pure proton composition) through extragalactic magnetic fields that have been simulated with the cosmological ENZO code.We test both primordial and astrophysical magnetogenesis scenarios in order to investigate the impact of different magnetic field strengths in clusters, filaments and voids on the deflection of cosmic rays propagating across cosmological distances. We also study the effect of different source distributions of cosmic rays around simulated Milky-Way like observers. Our analysis shows that the arrival spectra and anisotropy of events are rather insensitive to the distribution of extragalactic magnetic fields, while they are more affected by the clustering of sources within a $\sim 50$ Mpc distance to observers. Finally, we find that in order to reproduce the observed degree of isotropy of cosmic rays at $\sim$ EeV energies, the average magnetic fields in cosmic voids must be $\sim 0.1 \rm \ nG$, providing limits on the strength of primordial seed fields.Comment: 13 pages, 20 figure

Language and Meter

In Language and Meter, Dieter Gunkel and Olav Hackstein unite fifteen linguistic studies on a variety of poetic traditions, including the Homeric epics, the hieratic hymns of the Ṛgveda, the Gathas of the Avesta, early Latin and the Sabellic compositions, Germanic alliterative verse, Insular Celtic court poetry, and Tocharian metrical texts. The studies treat a broad range of topics, including the prehistory of the hexameter, the nature of Homeric formulae, the structure of Vedic verse, rhythm in the Gathas, and the relationship between Germanic and Celtic poetic traditions. The volume contributes to our understanding of the relationship between language and poetic form, and how they change over time.https://scholarship.richmond.edu/bookshelf/1318/thumbnail.jp

Introduction

The present volume unites fifteen studies on language and meter. For the most part, the articles began as lectures delivered during the interdisciplinary conference on Language and Meter in Diachrony and Synchrony, which was hosted in Munich from September 2nd-4th, 2013 by the Department of Historical and Indo-European Linguistics at the Ludwig-Maximilians-Universität München. The study of language and meter has profited from numerous advances over the last several hundred years. Scholars have produced accurate editions of poetic texts, added linguistic theory to description, utilized quantitative methods to test hypotheses, and provided descriptions and analyses of a relatively broad range of metrical traditions. To quote an influential handbook article on meter (Brogan 1993: 781), Linguistics, texts, theory, and data- these are the essential preliminaries. At the turn of the 21st c., pretty much everything still remains to be done. In our view, the contributions to this volume make a respectable amount of headway on numerous fronts. In the following overview, we intend to give a sense of the breadth of topics and traditions treated in the contributions as well as their relationship to previous scholarship

Sharpening up Galactic all-sky maps with complementary data - A machine learning approach

Galactic all-sky maps at very disparate frequencies, like in the radio and $\gamma$-ray regime, show similar morphological structures. This mutual information reflects the imprint of the various physical components of the interstellar medium. We want to use multifrequency all-sky observations to test resolution improvement and restoration of unobserved areas for maps in certain frequency ranges. For this we aim to reconstruct or predict from sets of other maps all-sky maps that, in their original form, lack a high resolution compared to other available all-sky surveys or are incomplete in their spatial coverage. Additionally, we want to investigate the commonalities and differences that the ISM components exhibit over the electromagnetic spectrum. We build an $n$-dimensional representation of the joint pixel-brightness distribution of $n$ maps using a Gaussian mixture model and see how predictive it is: How well can one map be reproduced based on subsets of other maps? Tests with mock data show that reconstructing the map of a certain frequency from other frequency regimes works astonishingly well, predicting reliably small-scale details well below the spatial resolution of the initially learned map. Applied to the observed multifrequency data sets of the Milky Way this technique is able to improve the resolution of, e.g., the low-resolution Fermi LAT maps as well as to recover the sky from artifact-contaminated data like the ROSAT 0.855 keV map. The predicted maps generally show less imaging artifacts compared to the original ones. A comparison of predicted and original maps highlights surprising structures, imaging artifacts (fortunately not reproduced in the prediction), and features genuine to the respective frequency range that are not present at other frequency bands. We discuss limitations of this machine learning approach and ideas how to overcome them

Boosting Higgs discovery - the forgotten channel

Searches for a heavy Standard Model Higgs boson focus on the 'gold plated mode' where the Higgs decays to two leptonic Z bosons. This channel provides a clean signature, in spite of the small leptonic branching ratios. We show that using fat jets the semi-leptonic ZZ mode significantly increases the number of signal events with a similar statistical significance as the leptonic mode.Comment: 12 pages, 3 figure