Coherent elastic neutrino-nucleus scattering -- First constraints/observations and future potential

The detection of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) opens new possibilities for neutrino physics within and beyond the Standard Model. Following the initial discovery in 2017, several experimental attempts have emerged allowing this reaction channel to be studied with the full repertoire of modern detection technologies. As one of several reactor experiments, CONUS aims for an observation with antineutrinos emitted from the powerful $3.9$ GW$_{th}$ reactor of the nuclear power plant in Brokdorf (Germany). In particular, the application of ultra-low threshold, high-purity germanium detectors within a sophisticated shield design in close proximity to a nuclear reactor core represents an important step towards high-statistics neutrino detection with small-scale detectors. In addition to the conventional interaction, typical extensions of the Standard Model neutrino sector can be investigated with data provided from different neutrino sources and several target materials. Among these, new neutrino interactions as well as electromagnetic neutrino properties are of particular interest. This talk gives an overview of existing CE$\nu$NS results and highlights the advantage of using different neutrino sources and target materials. The example of CONUS is used to demonstrate the various capabilities of recent and future CE$\nu$NS measurements

Leptonic CP violation in the minimal type-I seesaw model : Bottom-up phenomenology & top-down model building

This work deals with a minimal realization of the type-I seesaw model with only two right-handed Majorana neutrinos, which is investigated from two perspectives; bottom-up and top-down. In a data-driven approach, the manifestation of certain hierarchies in the neutrino Yukawa matrix is analyzed in the context of realizable approximate two-zero textures. A general method for the investigation of Yukawa structures is developed and applied to the minimal seesaw model. Besides a robustness study of the obtained results, theoretical error bars are assigned to this model's predictions. In a top-down ansatz, a high-energy embedding of the minimal seesaw model is built that exhibits minimal degrees of freedom. A minimal SU(5) Froggatt-Nielsen avor model is chosen and assuming approximate exchange symmetries in the heavy neutrino sector helps to reduce the model's free parameter. Demanding consistency with electroweak naturalness and leptogenesis leads to a most minimal type-I seesaw model, that emerges from a high-energy theory and predicts at the same time all measured neutrino observables

Coherent elastic neutrino-nucleus scattering -- First constraints/observations and future potential

The detection of coherent elastic neutrino-nucleus scattering (CE$\nu$NS)opens new possibilities for neutrino physics within and beyond the StandardModel. Following the initial discovery in 2017, several experimental attemptshave emerged allowing this reaction channel to be studied with the fullrepertoire of modern detection technologies. As one of several reactorexperiments, CONUS aims for an observation with antineutrinos emitted from thepowerful $3.9$ GW$_{th}$ reactor of the nuclear power plant in Brokdorf(Germany). In particular, the application of ultra-low threshold, high-puritygermanium detectors within a sophisticated shield design in close proximity toa nuclear reactor core represents an important step towards high-statisticsneutrino detection with small-scale detectors. In addition to the conventionalinteraction, typical extensions of the Standard Model neutrino sector can beinvestigated with data provided from different neutrino sources and severaltarget materials. Among these, new neutrino interactions as well aselectromagnetic neutrino properties are of particular interest. This talk givesan overview of existing CE$\nu$NS results and highlights the advantage of usingdifferent neutrino sources and target materials. The example of CONUS is usedto demonstrate the various capabilities of recent and future CE$\nu$NSmeasurements.<br

Canonical Transformation Approach to the Ultrafast Non-linear Optical Dynamics of Semiconductors

We develop a theory describing the effects of many-particle Coulomb correlations on the coherent ultrafast nonlinear optical response of semiconductors and metals. Our approach is based on a mapping of the nonlinear optical response of the ``bare'' system onto the linear response of a ``dressed'' system. The latter is characterized by effective time-dependent optical transition matrix elements, electron/hole dispersions, and interaction potentials, which in undoped semiconductors are determined by the single-exciton and two-exciton Green functions in the absence of optical fields. This mapping is achieved by eliminating the optically-induced charge fluctuations from the Hamiltonian using a Van Vleck canonical transformation. It takes into account all many-body contributions up to a given order in the optical fields as well as important Coulomb-induced quantum dynamics to all orders in the optical field. Our approach allows us to distinguish between optical nonlinearities of different origins and provides a physically-intuitive interpretation of their manifestations in ultrafast coherent nonlinear optical spectroscopy.Comment: 24 page

\u3ci\u3eAcrobasis\u3c/i\u3e Shoot Moth (Lepidoptera: Pyralidae) Infestation-Tree Height Link in a Young Black Walnut Plantation

Acrobasis shoot moth infestations were evaluated in a young black walnut progeny test for 4 years, from ages 3 to 6. Infestation levels were greatest on the largest trees in the fourth and fifth year after plantation establishment, and were declining by the sixth year. Acrobasis infestation appears to be a problem primarily on young trees less than 2.5 m in height. There was no evidence for genetic resistance to Acrobasis infestation in black walnut

Constraints on pseudo-Dirac neutrinos using high-energy neutrinos from NGC 1068

Neutrinos can be pseudo-Dirac in Nature - they can be Majorana fermions whilebehaving effectively as Dirac fermions. Such scenarios predict active-sterileneutrino oscillation driven by a tiny mass-squared difference $(\delta m^2)$,which is an outcome of soft-lepton number violation. Oscillations due to tiny$\delta m^2$ can take place only over astrophysical baselines and hence are notaccessible in terrestrial neutrino oscillation experiments. This implies thathigh-energy neutrinos coming from large distances can naturally be used to testthis scenario. We use the recent observation of high-energy neutrinos from theactive galactic nuclei NGC 1068 by the IceCube collaboration to constrain$\delta m^2 \leq 10^{-18}{\rm eV}^2$ at more than $90\%$ confidence level - oneof the strongest limits to date on the values of $\delta m^2$.<br

Kolmogorov condition near hyperbolic singularities of integrable Hamiltonian systems

In this paper we show that, if an integrable Hamiltonian system admits a nondegenerate hyperbolic singularity then it will satisfy the Kolmogorov condegeneracy condition near that singularity (under a mild additional condition, which is trivial if the singularity contains a fixed point)Comment: revised version, 11p, accepted for publication in a sepecial volume in Regular and Chaotic Dynamics in honor of Richard Cushma

Neutron-induced background in the CONUS experiment

CONUS is a novel experiment aiming at detecting elastic neutrino nucleus scattering in the fully coherent regime using high-purity Germanium (Ge) detectors and a reactor as antineutrino ($\bar\nu$) source. The detector setup is installed at the commercial nuclear power plant in Brokdorf, Germany, at a very small distance to the reactor core in order to guarantee a high flux of more than 10$^{13}\bar\nu$/(s$\cdot$cm$^2$). For the experiment, a good understanding of neutron-induced background events is required, as the neutron recoil signals can mimic the predicted neutrino interactions. Especially neutron-induced events correlated with the thermal power generation are troublesome for CONUS. On-site measurements revealed the presence of a thermal power correlated, highly thermalized neutron field with a fluence rate of (745$\pm$30)cm$^{-2}$d$^{-1}$. These neutrons that are produced by nuclear fission inside the reactor core, are reduced by a factor of $\sim$10$^{20}$ on their way to the CONUS shield. With a high-purity Ge detector without shield the $\gamma$-ray background was examined including highly thermal power correlated $^{16}$N decay products as well as $\gamma$-lines from neutron capture. Using the measured neutron spectrum as input, it was shown, with the help of Monte Carlo simulations, that the thermal power correlated field is successfully mitigated by the installed CONUS shield. The reactor-induced background contribution in the region of interest is exceeded by the expected signal by at least one order of magnitude assuming a realistic ionization quenching factor of 0.2.Comment: 28 pages, 28 figure