Split-Family SUSY, U(2)^5 Flavour Symmetry and Neutrino Physics

In split-family SUSY, one can use a U(2)^3 symmetry to protect flavour observables in the quark sector from SUSY contributions. However, attempts to extend this procedure to the lepton sector by using an analogous U(2)^5 symmetry fail to reproduce the neutrino data without introducing some form of fine-tuning. In this work, we solve this problem by shifting the U(2)^2 symmetry acting on leptons towards the second and third generations. This allows neutrino data to be reproduced without much difficulties, as well as protecting the leptonic flavour observables from SUSY. Key signatures are a $\mu\to e\gamma$ branching ratio possibly observable in the near future, as well as having selectrons as the lightest sleptons.Comment: 9 pages, 3 figures; v2: improved discussion of LFV processes, results unchanged; v3: Minor changes, version accepted for publication in EPJ

RGE Behaviour of SUSY with a U(2)^3 symmetry

The first LHC results seem to disfavour, from the point of view of naturalness, any constrained MSSM realization with universal conditions at the SUSY-breaking scale. A more motivated scenario is given by split-family SUSY, in which the first two generations of squarks are heavy, compatible with a U(2)^3 flavour symmetry. We consider this flavour symmetry to be broken at a very high scale and study the consequences at low energies through its RGE evolution. Initial conditions compatible with a split scenario are found, and the preservation of correlations from minimal U(2)^3 breaking are checked. The various chiral operators in $\Delta F=2$ processes are analyzed, and we show that, due to LHC gluino bounds, the (LL)(RR) operators can not always be neglected. Finally, we also study a possible extension of the U(2)^3 model compatible with the lepton sector.Comment: 22 pages, 9 Figures; v2: minor corrections, improved discussion on (LL)(RR) operators, main results unchange

Revising the Solution of the Neutrino Oscillation Parameter Degeneracies at Neutrino Factories

In the context of neutrino factories, we review the solution of the degeneracies in the neutrino oscillation parameters. In particular, we have set limits to $\sin^2 2\theta_{13}$ in order to accomplish the unambiguous determination of $\theta_{23}$ and $\delta$. We have performed two different analysis. In the first, at a baseline of 3000 km, we simulate a measurement of the channels $\nu_e\to\nu_\mu$, $\nu_e\to\nu_\tau$ and $\bar{\nu}_\mu\to\bar{\nu}_\mu$, combined with their respective conjugate ones, with a muon energy of 50 GeV and a running time of five years. In the second, we merge the simulated data obtained at L=3000 km with the measurement of $\nu_e\to\nu_\mu$ channel at 7250 km, the so called 'magic baseline'. In both cases, we have studied the impact of varying the $\nu_\tau$ detector efficiency-mass product, $(\epsilon_{\nu_\tau}\times M_\tau)$, at 3000 km, keeping unchanged the $\nu_\mu$ detector mass and its efficiency. At L=3000 km, we found the existance of degenerate zones, that corresponds to values of $\theta_{13}$, which are equal or almost equal to the true ones. These zones are extremely difficult to discard, even when we increase the number of events. However, in the second scenario, this difficulty is overcomed, demostrating the relevance of the 'magic baseline'. From this scenario, the best limits of $\sin^2 2\theta_{13}$, reached at $3\sigma$, for $\sin^2 2\theta_{23}=0.95$, 0.975 and 0.99 are: 0.008, 0.015 and 0.045, respectively, obtained at $\delta=0$, and considering $(\epsilon_{\nu_\tau}\times M_\tau) \approx 125$, which is five times the initial efficiency-mass combination.Comment: 40 pages, 18 figures; added references, corrected typos, updated Eq (15c

Neutrino masses and LFV from minimal breaking of U(3)^5 and U(2)^5 flavor symmetries

We analyze neutrino masses and Lepton Flavor Violation (LFV) in charged leptons with a minimal ansatz about the breaking of the U(3)^5 flavor symmetry, consistent with the U(2)^3 breaking pattern of quark Yukawa couplings, in the context of supersymmetry. Neutrino masses are expected to be almost degenerate, close to present bounds from cosmology and $0\nu\beta\beta$ experiments. We also predict $s_{13} \approx s_{23} |V_{td}|/|V_{ts}| \approx 0.16$, in perfect agreement with the recent DayaBay result. For slepton masses below 1 TeV, barring accidental cancellations, we expect \cB(\mu \to e \gamma) > 10^{-13} and \cB(\tau \to \mu \gamma) > 10^{-9}, within the reach of future experimental searches.Comment: 10 pages, 7 figures, v2: Minor change

How Nutrient Trading Could Help Restore the Chesapeake Bay

The largest estuary in the United States, the Chesapeake Bay is a vital economic, cultural, and ecological resource for the region and the nation. Excess runoff and discharges of nutrients -- particularly nitrogen and phosphorus -- from farms, pavement, wastewater treatment plants (WWTPs), and other sources have placed the bay on the Environmental Protection Agency's (EPA's) List of Impaired Waters. This nutrient pollution is responsible for creating large algal blooms that lead to "dead zones" in the bay (Chesapeake Bay Program, 2009b). Despite decades of restoration efforts, progress has been slow, and the rivers and streams that drain into the Bay remain polluted (Chesapeake Bay Program, 2009b)

How Baywide Nutrient Trading Could Benefit Maryland Farms

Outlines pending legislation to improve the health of the Chesapeake Bay watershed, including a nutrient trading program that allows farms that reduce runoff of nutrients to below target to sell "credits." Estimates costs, credits, and credit revenue

How Baywide Nutrient Trading Could Benefit Pennsylvania Farms

Outlines how legislation to make the Chesapeake Bay watershed healthier, including a program allowing farms that reduce runoff of nutrients to below target to sell "credits," would benefit Pennsylvania farms through cost-sharing funds and new revenues

Constraining sleptons at the LHC in a supersymmetric low-scale seesaw scenario

We consider a scenario inspired by natural supersymmetry, where neutrino data is explained within a low-scale seesaw scenario. We extend the Minimal Supersymmetric Standard Model by adding light right-handed neutrinos and their superpartners, the R-sneutrinos, and consider the lightest neutralinos to be higgsino-like. We consider the possibilities of having either an R-sneutrino or a higgsino as lightest supersymmetric particle. Assuming that squarks and gauginos are heavy, we systematically evaluate the bounds on slepton masses due to existing LHC data.Comment: 26 pages, 8 figures, 2 appendices; v2: Minor changes, version accepted for publication in EPJ