Quaero@H1: An Interface to High-pT HERA Event Data

Distributions from high-pT HERA event data analyzed in a general search for new physics at H1 have been incorporated into Quaero, an algorithm designed to automate tests of specific hypotheses with high energy collider data. The use of Quaero@H1 to search for leptoquarks, R-parity violating supersymmetry, and excited quarks provides examples to develop intuition for the algorithm's performance.Comment: Submitted to Eur. Phys. J.

Electronic and phonon excitations in {\alpha}-RuCl3_3

We report on THz, infrared reflectivity and transmission experiments for wave numbers from 10 to 8000 cm$^{-1}$ ($\sim$ 1 meV - 1 eV) and for temperatures from 5 to 295 K on the Kitaev candidate material {\alpha}-RuCl$_3$. As reported earlier, the compound under investigation passes through a first-order structural phase transition, from a monoclinic high-temperature to a rhombohedral low-temperature phase. The phase transition shows an extreme and unusual hysteretic behavior, which extends from 60 to 166 K. In passing this phase transition, in the complete frequency range investigated we found a significant reflectance change, which amounts almost a factor of two. We provide a broadband spectrum of dielectric constant, dielectric loss and optical conductivity from the THz to the mid infrared regime and study in detail the phonon response and the low-lying electronic density of states. We provide evidence for the onset of an optical energy gap, which is of order 200 meV, in good agreement with the gap derived from measurements of the DC electrical resistivity. Remarkably, the onset of the gap exhibits a strong blue shift on increasing temperatures.Comment: 18 pages, 7 figure

Forage Grass in Static Gas Exchange Chambers Deployed In Southern Amazon Influences Field Measurement of Soil N2O Emissions.

Abstract: Static chambers are used to estimate the exchange of greenhouse gases between the soil and the atmosphere, but the presence of plants inside such chambers can alter gas fluxes. This study aimed to determine the influence of forage grass on N2O fluxes emanating from an oxisol in the southern Amazon region of Brazil. A randomized experiment comprising two treatments, namely static gas exchange Chambers with Grass (CWG) and Chambers with No Grass (CNG) with six replicates of each was performed to determine N2O fluxes over a period of one year. Soil N2O fluxes in the CWG were higher (19.08 µg N2O-N m-2 h-1) than those in the CNG (9.05 µg N2O-N m-2 h-1), most especially during the wet season. Cumulative N2O emissions were 1.60 and 0.72 kg N2O-N ha-1 for the CWG and CNG, respectively. The higher N2O estimates in the CWG may be attributed to the plant transpiration stream and/or to changes in soil attributes induced by the plants. Measurement of N2O emissions from a grass-covered oxisol inside gas exchange chambers may overestimate soil N2O flux in the tropical humid climate of the Southern Amazon

On the embedding of spacetime in five-dimensional Weyl spaces

We revisit Weyl geometry in the context of recent higher-dimensional theories of spacetime. After introducing the Weyl theory in a modern geometrical language we present some results that represent extensions of Riemannian theorems. We consider the theory of local embeddings and submanifolds in the context of Weyl geometries and show how a Riemannian spacetime may be locally and isometrically embedded in a Weyl bulk. We discuss the problem of classical confinement and the stability of motion of particles and photons in the neighbourhood of branes for the case when the Weyl bulk has the geometry of a warped product space. We show how the confinement and stability properties of geodesics near the brane may be affected by the Weyl field. We construct a classical analogue of quantum confinement inspired in theoretical-field models by considering a Weyl scalar field which depends only on the extra coordinate.Comment: 16 pages, new title and references adde

Dirac and Majorana heavy neutrinos at LEP II

The possibility of detecting single heavy Dirac and Majorana neutrinos at LEP II is investigated for heavy neutrino masses in the range $M_N=(\sqrt s/2, \sqrt s)$. We study the process $e^+e^- \longrightarrow \nu_{\ell} \ell q_i \bar q_j$ as a clear signature for heavy neutrinos. Numerical estimates for cross sections and distributions for the signal and the background are calculated and a Monte Carlo reconstruction of final state particles after hadronization is presented.Comment: 4 pages, 8 figure