[en] The determination of the ordering of the neutrino masses (the hierarchy) is probably a crucial prerequisite to understand the origin of lepton masses and mixings and to establish their relationship to the analogous properties in the quark sector. In this talk, we follow an alternative strategy to the usual neutrino-antineutrino comparison: we exploit the combination of the neutrino-only data from the NOvA and the T2K experiments by performing these two off-axis experiments at different distances but at the same < E>/L, < E> being the mean neutrino energy and L the baseline. This would require a minor adjustment to the proposed off-axis angle for one or both of the proposed experiments

[en] A suppression in the spectrum of ultrahigh-energy (UHE, (ge) 10¹⁸ eV) neutrinos will be present in extra-dimensional scenarios, due to enhanced neutrino-antineutrino annihilation processes with the supernova relic neutrinos. In this scenario, neutrinos can not be responsible for the highest energy events observed in the UHE cosmic ray spectrum. A direct implication of these extra-dimensional interactions would be the absence of UHE neutrinos in ongoing and future neutrino telescopes

[en] If the value of θ₁₃ is within the reach of the upcoming generation of long-baseline experiments, T2K and NOvA, they show that a low-energy neutrino factory, with peak energy in the few GeV range, would provide a sensitive tool to explore CP-violation and the neutrino mass hierarchy. They consider baselines with typical length 1000-1500 km. The unique performance of the low energy neutrino factory is due to the rich neutrino oscillation pattern at energies between 1 and 4 GeV at baselines Ο(1000) km. They perform both a semi-analytical study of the sensitivities and a numerical analysis to explore how well this setup can measure θ₁₃, CP-violation, and determine the type of mass hierarchy and the θ₂₃ quadrant. A low energy neutrino factory provides a powerful tool to resolve ambiguities and make precise parameter determinations, for both large and fairly small values of the mixing parameter θ₁₃

[en] The determination of the ordering of the neutrino masses (the hierarchy) is probably a crucial prerequisite to understand the origin of lepton masses and mixings and to establish their relationship to the analogous properties in the quark sector. Here, we follow an alternative strategy to the usual neutrino-antineutrino comparison in long baseline neutrino oscillation experiments: we exploit the combination of the neutrino-only data from the NOvA and the T2K experiments by performing these two off-axis experiments at different distances but at the same < E>/L, where < E> is the mean neutrino energy and L is the baseline. This would require a minor adjustment to the proposed off-axis angle for one or both of the proposed experiments

[en] The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse

[en] We consider a Super-NOVA-like experimental configuration based on the use of two detectors in a long-baseline experiment as NOVA. We take the far detector as in the present NOVA proposal and add a second detector at a shorter baseline. The location of the second off-axis detector is chosen such that the ratio L/E is the same for both detectors, being L the baseline and E the neutrino energy. We consider liquid argon and water- Cerenkov techniques for the second off-axis detector and study, for different experimental setups, the detector mass required for the determination of the neutrino mass hierarchy, for different values of θ₁₃. We also study the capabilities of such an experimental setup for determining CP-violation in the neutrino sector. Our results show that by adding a second off-axis detector a remarkable enhancement on the capabilities of the current NOVA experiment could be achieved

[en] Coupled cosmologies, in order to satisfy CMB constraints, predict values for the cosmological parameters today which may differ substantially from the parameters values within non-interacting cosmologies. In order to fit high-precision CMB data available today, coupled cosmologies can hide their effects at very low redshifts. Therefore, low redshift probes are highly complementary and thus powerful to constrain interacting dark sector models. In this talk we focus on near-universe, low-redshift constraints in a variety of coupled dark matter-dark energy models. We find that current data constrain the dimensionless coupling to be |ξ| < 0.2. We also explore the forecasts for future low redshift probes.

[en] The neutrino mixing parameters are presented in a number of different ways by the various experiments, e.g., SuperKamiokande, K2K, SNO, KamLAND, and CHOOZ, and also by the Particle Data Group. In this paper, we argue that presenting the data in terms of sin²θ, where θ is the mixing angle appropriate for a given experiment, has a direct physical interpretation. For current atmospheric, solar, and reactor neutrino experiments, the sin²θ's are effectively the probabilities of finding a given flavor in a particular neutrino mass eigenstate. The given flavor and particular mass eigenstate vary from experiment to experiment; however, the use of sin²θ provides a unified picture of all the data. Using this unified picture we present a graphical way to represent these neutrino mixing parameters which includes the uncertainties. All of this is performed in the context of the present experimental status of three neutrino oscillations

[en] In the overlap region, for the normal and inverted hierarchies, of the neutrino-antineutrino bi-probability space for ν_μ→ν_e appearance, we derive a simple identity between the solutions in the (sin²2θ₁₃, sinδ) plane for the different hierarchies. The parameter sin²2θ₁₃ sets the scale of the ν_μ→ν_e appearance probabilities at the atmospheric δm_atm²≅2.4x10^-3 eV² whereas sinδ controls the amount of CP violation in the lepton sector. The identity between the solutions is that the difference in the values of sinδ for the two hierarchies equals twice the value of √(sin²2θ₁₃) divided by the critical value of √(sin²2θ₁₃). We apply this identity to the two proposed long baseline experiments, T2K and NOvA, and we show how it can be used to provide a simple understanding of when and why fake solutions are excluded when two or more experiments are combined. This identity demonstrates the true complementarity of T2K and NOvA

[en] This note constitutes a Letter of Interest to study the physics capabilities of, and to develop an implementation plan for, a neutrino physics program based on a Low-Energy Neutrino Factory at Fermilab providing a ν beam to a detector at the Deep Underground Science and Engineering Laboratory. It has been over ten years since the discovery of neutrino oscillations (1) established the existence of neutrino masses and leptonic mixing. Neutrino oscillations thus provide the first evidence of particle physics beyond the Standard Model. Most of the present neutrino oscillation data are well described by the 3ν mixing model. While a number of the parameters in this model have already been measured, there are several key parameters that are still unknown, namely, the absolute neutrino mass scale, the precise value of the mixing angles, the CP phase (delta) and hence the presence or absence of observable CP-violation in the neutrino sector. Future measurements of these parameters are crucial to advance our understanding of the origin of neutrino masses and of the nature of flavor in the lepton sector. The ultimate goal of a program to study neutrino oscillations goes beyond a first measurement of parameters, and includes a systematic search for clues about the underlying physics responsible for the tiny neutrino masses, and, hopefully, the origin of the observed flavor structure in the Standard Model, as well as the possible source of the observed matter-antimatter asymmetry in the Universe. To achieve this goal will almost certainly require precision measurements that go well beyond the presently foreseen program. One of the most promising experimental approaches to achieve some of the goals mentioned above is to build a Neutrino Factory and its corresponding detector. The Neutrino Factory produces neutrino beams from muons which have been accelerated to an energy of, for example, 25 GeV. The muons are stored in a race-track shaped decay ring and then decay along the straight sections of the ring. Since the decay of the muon is well understood, the systematic uncertainties associated with a neutrino beam produced in this manner are very small. Beam diagnostics in the decay ring and a specially designed near detector further reduce the systematic uncertainties of the neutrino beam produced at the Neutrino Factory. In addition since the muon (anti-muon) decays produce both muon and anti-electron neutrinos (anti-muon and electron neutrinos), many oscillation channels are accessible from a Neutrino Factory, further extending the reach in the oscillation parameter space. Over the last decade there have been a number of studies (2-5) that have explored the discovery reach of Neutrino Factories in the small mixing angle, θ₁₃, and its capability to determine the mass hierarchy and determine if CP is violated in leptons through observation of phase parameter, (delta). The most recent study to be completed (6), the International scoping study of a future Neutrino Factory and super-beam facility (the ISS), studied the physics capabilities of various future neutrino facilities: super-beam, β-Beam and Neutrino Factory and has determined that the Neutrino Factory with an energy of ∼25 GeV has the best discovery reach for small values of sin²2θ₁₃, reaching an ultimate sensitivity of between 10^-5 and 10^-4. However, for larger values of sin²2θ₁₃ (> 10^-3), the sensitivity of other experimental approaches is competitive to that of the 25 GeV Neutrino Factory. The wide-band neutrino beam (WBB) produced at Fermilab and directed towards DUSEL (7) is one such competitor. For the case where sin²2θ₁₃ (> 10^-3) is large, initial studies have shown that a Low-Energy Neutrino Factory (8-10) with an energy of, for example, 4 GeV, may be both cost-effective and offers exquisite sensitivity. The required baseline for a Low-Energy Neutrino Factory matches Fermilab to DUSEL and, therefore, its physics potential and implementation should be studied in the context of DUSEL along with those for the WBB