Higher su(N) tensor products

We extend our recent results on ordinary su(N) tensor product multiplicities to higher su(N) tensor products. Particular emphasis is put on four-point couplings where the tensor product of four highest weight modules is considered. The number of times the singlet occurs in the decomposition is the associated multiplicity. In this framework, ordinary tensor products correspond to three-point couplings. As in that case, the four-point multiplicity may be expressed explicitly as a multiple sum measuring the discretised volume of a convex polytope. This description extends to higher-point couplings as well. We also address the problem of determining when a higher-point coupling exists, i.e., when the associated multiplicity is non-vanishing. The solution is a set of inequalities in the Dynkin labels.Comment: 17 pages, LaTe

Less intra-row weeds – experiences with a punch planter and a cycloid hoe based on GPS

Experiences with a punch planter and an intelligent rotary tine weeder are summarized. The objectives were to investigate (1) to what extent punch planting and pre-emergence flame weeding can reduce intra-row weed emergence in direct sown crops like onion, carrot and sugar beet, (2) to what extent an intelligent intra-row weeder, a cycloid hoe based on RTK-GPS technology, can control intra-row weeds without damaging the crop in direct sown crops, (3) and to what extent there exists synergy between punch planting with pre-emergence flame weeding and mechanical intra-row weeding

New State Record and Notable Range Extension for \u3ci\u3eLibellula Semifasciata\u3c/i\u3e (Odonata: Libellulidae)

The painted skimmer, Libellula semifasciata Burmeister (Odonata: Libellulidae), is an eastern species of dragonfly that has never been documented in Iowa. In this note we report two observations and the collection of a voucher for this species in southeast Iowa in the last three years. Based on other records of this species, including those from neighboring states and more northerly latitudes, we propose that these observations are evidence of a range extension

Evidence for Widespread AGN Activity among Massive Quiescent Galaxies at z ~ 2

We quantify the presence of Active Galactic nuclei (AGN) in a mass-complete (M_* >5e10 M_sun) sample of 123 star-forming and quiescent galaxies at 1.5 < z < 2.5, using X-ray data from the 4 Ms Chandra Deep Field-South (CDF-S) survey. 41+/-7% of the galaxies are detected directly in X-rays, 22+/-5% with rest-frame 0.5-8 keV luminosities consistent with hosting luminous AGN (L_0.5-8keV > 3e42 ergs/s). The latter fraction is similar for star-forming and quiescent galaxies, and does not depend on galaxy stellar mass, suggesting that perhaps luminous AGN are triggered by external effects such as mergers. We detect significant mean X-ray signals in stacked images for both the individually non-detected star-forming and quiescent galaxies, with spectra consistent with star formation only and/or a low luminosity AGN in both cases. Comparing star formation rates inferred from the 2-10 keV luminosities to those from rest-frame IR+UV emission, we find evidence for an X-ray excess indicative of low-luminosity AGN. Among the quiescent galaxies, the excess suggests that as many as 70-100% of these contain low- or high-luminosity AGN, while the corresponding fraction is lower among star-forming galaxies (43-65%). The ubiquitous presence of AGN in massive, quiescent z ~ 2 galaxies that we find provides observational support for the importance of AGN in impeding star formation during galaxy evolution.Comment: 9 pages, 3 figures, 3 tables; Accepted for publication in ApJ. Minor editing changes and a few references added. Matches published versio

IceCube Neutrinos from Hadronically Powered Gamma-Ray Galaxies

In this work we use a multi-messenger approach to determine if the high energy diffuse neutrino flux observed by the IceCube Observatory can originate from $\gamma$-ray sources powered by Cosmic Rays interactions with gas. Typical representatives of such sources are Starburst and Ultra-Luminous Infrared Galaxies. Using the three most recent calculations of the non-blazar contribution to the extragalactic $\gamma$-ray background measured by the Fermi-LAT collaboration, we find that a hard power-law spectrum with spectral index $\alpha \leq 2.12$ is compatible with all the estimations for the allowed contribution from non-blazar sources, within 1$\sigma$. Using such a spectrum we are able to interpret the IceCube results, showing that various classes of hadronically powered $\gamma$-ray galaxies can provide the dominant contribution to the astrophysical signal above 100 TeV and about half of the contribution to the energy flux between 10-100 TeV. With the addition of neutrinos from the Galactic plane, it is possible to saturate the IceCube signal at high energy. Our result shows that these sources are still well motivated candidates.Comment: Accepted for publication on JCA

Astrophysical neutrinos flavored with Beyond the Standard Model physics

We systematically study the allowed parameter space for the flavor composition of astrophysical neutrinos measured at Earth, including beyond the Standard Model theories at production, during propagation, and at detection. One motivation is to illustrate the discrimination power of the next-generation neutrino telescopes such as IceCube-Gen2. We identify several examples that lead to potential deviations from the standard neutrino mixing expectation such as significant sterile neutrino production at the source, effective operators modifying the neutrino propagation at high energies, dark matter interactions in neutrino propagation, or non-standard interactions in Earth matter. IceCube-Gen2 can exclude about 90% of the allowed parameter space in these cases, and hence will allow to efficiently test and discriminate models. More detailed information can be obtained from additional observables such as the energy-dependence of the effect, fraction of electron antineutrinos at the Glashow resonance, or number of tau neutrino events.Comment: 21 pages, 9 figures, 3 tables, v2: references added, typos corrected, conclusion unchanged, matches final version in PR