U(2)-like Flavor Symmetries and Approximate Bimaximal Neutrino Mixing

Models involving a U(2) flavor symmetry, or any of a number of its non-Abelian discrete subgroups, can explain the observed hierarchy of charged fermion masses and CKM angles. It is known that a large neutrino mixing angle connecting second and third generation fields may arise via the seesaw mechanism in these models, without a fine tuning of parameters. Here we show that it is possible to obtain approximate bimaximal mixing in a class of models with U(2)-like Yukawa textures. We find a minimal form for Dirac and Majorana neutrino mass matrices that leads to two large mixing angles, and show that our result can quantitatively explain atmospheric neutrino oscillations while accommodating the favored, large angle MSW solution to the solar neutrino problem. We demonstrate that these textures can arise in models by presenting a number of explicit examples.Comment: 20 pages RevTex4, 2 figure

Maximal Neutrino Mixing from a Minimal Flavor Symmetry

We study a number of models, based on a non-Abelian discrete group, that successfully reproduce the simple and predictive Yukawa textures usually associated with U(2) theories of flavor. These models allow for solutions to the solar and atmospheric neutrino problems that do not require altering successful predictions for the charged fermions or introducing sterile neutrinos. Although Yukawa matrices are hierarchical in the models we consider, the mixing between second- and third-generation neutrinos is naturally large. We first present a quantitative analysis of a minimal model proposed in earlier work, consisting of a global fit to fermion masses and mixing angles, including the most important renormalization group effects. We then propose two new variant models: The first reproduces all important features of the SU(5)xU(2) unified theory with neither SU(5) nor U(2). The second demonstrates that discrete subgroups of SU(2) can be used in constructing viable supersymmetric theories of flavor without scalar universality even though SU(2) by itself cannot.Comment: 34 pages LaTeX, 1 eps figure, minor revisions and references adde

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data

A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector

Search for supersymmetry in events with b-tagged jets and missing transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector

A search for the supersymmetric partners of the Standard Model bottom and top quarks is presented. The search uses 36.1 fb−1 of pp collision data at √s = 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Direct production of pairs of bottom and top squarks (b˜1 and t˜1) is searched for in final states with b-tagged jets and missing transverse momentum. Distinctive selections are defined with either no charged leptons (electrons or muons) in the final state, or one charged lepton. The zero-lepton selection targets models in which the b˜1 is the lightest squark and decays via b˜1 → bχ˜01 , where ˜χ01 is the lightest neutralino. The one-lepton final state targets models where bottom or top squarks are produced and can decay into multiple channels, b˜1 → bχ˜01 and b˜1 → tχ˜±1, or t˜1 → tχ˜01 and t˜1→ bχ˜±1, where ˜χ±1 is the lightest chargino and the mass difference mχ˜±1 − mχ˜01 is set to 1 GeV. No excess above the expected Standard Model background is observed. Exclusion limits at 95% confidence level on the mass of third-generation squarks are derived in various supersymmetry-inspired simplified models

Search for supersymmetry in final states with two same-sign or three leptons and jets using 36 fb⁻¹ of √s=13 TeV pp collision data with the ATLAS detector

A search for strongly produced supersymmetric particles using signatures involving multiple energetic jets and either two isolated same-sign leptons (e or μ), or at least three isolated leptons, is presented. The analysis relies on the identification of b-jets and high missing transverse momentum to achieve good sensitivity. A data sample of proton-proton collisions at s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 and 2016, corresponding to a total integrated luminosity of 36.1 fb −1 , is used for the search. No significant excess over the Standard Model prediction is observed. The results are interpreted in several simplified supersymmetric models featuring R-parity conservation or R-parity violation, extending the exclusion limits from previous searches. In models considering gluino pair production, gluino masses are excluded up to 1.87 TeV at 95% confidence level. When bottom squarks are pair-produced and decay to a chargino and a top quark, models with bottom squark masses below 700 GeV and light neutralinos are excluded at 95% confidence level. In addition, model-independent limits are set on a possible contribution of new phenomena to the signal region yields.[Figure not available: see fulltext.]

A search for top squarks with R-parity-violating decays to all-hadronic final states with the ATLAS detector in √s = 8 TeV proton-proton collisions

A search for the pair production of top squarks, each with R-parity-violating decays into two Standard Model quarks, is performed using 17.4 fb−1 of √s = 8 TeV proton-proton collision data recorded by the ATLAS experiment at the LHC. Each top squark is assumed to decay to a b- and an s-quark, leading to four quarks in the final state. Background discrimination is achieved with the use of b-tagging and selections on the mass and substructure of large-radius jets, providing sensitivity to top squark masses as low as 100 GeV. No evidence of an excess beyond the Standard Model background prediction is observed and top squarks decaying to b¯ s¯ are excluded for top squark masses in the range 100 ≤ mt≤ 315 GeV at 95% confidence level

Search for supersymmetry in events with large missing transverse momentum, jets, and at least one tau lepton in 20 fb−1 of √s=8 TeV proton-proton collision data with the ATLAS detector

A search for supersymmetry (SUSY) in events with large missing transverse momentum, jets, at least one hadronically decaying tau lepton and zero or one additional light leptons (electron/muon), has been performed using 20.3fb−1 of proton-proton collision data at √s= 8 TeV recorded with the ATLAS detector at the Large Hadron Collider. No excess above the Standard Model background expectation is observed in the various signal regions and 95% confidence level upper limits on the visible cross section for new phenomena are set. The results of the analysis are interpreted in several SUSY scenarios, significantly extending previous limits obtained in the same final states. In the framework of minimal gauge-mediated SUSY breaking models, values of the SUSY breaking scale Λ below 63 TeV are excluded, independently of tan β. Exclusion limits are also derived for an mSUGRA/CMSSM model, in both the R-parity-conserving and R-parity-violating case. A further interpretation is presented in a framework of natural gauge mediation, in which the gluino is assumed to be the only light coloured sparticle and gluino masses below 1090 GeV are excluded

Ensilaje de caña de azúcar integral enriquecido con porcinaza fresca

The present study was aimed at evaluating competitive strategies for incorporating pig manure in to whole ground sugar cane (WGSC)silage for feeding cows; the work was carried out at the University de Caldas' Instituto de Biotecnología Agropecuaria. An 8x3x2 factorial design was used (8 fermentation times, 20-30 and 40% pig manure and no prior fermentation), in completely random blocks, 3 repeats per treatment and 2.5 Kg PVC microsiles as experimental unit. Prior fermentation affected reducing sugar (RS) (p≤0.01), pH, total ash (TA) and Cu content (p≤0.05). The percentage of pig manure (PM) incorporation (p≤0.01) affected total protein (TP), total fat (TF), CT, P, K and Mg. Regarding fermentation time (FT), there was a slight drop (p>0.05) in RS and MS between day 3 and 21 and more strongly so (p≤0.01)from day21 to 50.ThepH fell between the third and sixth days (p≤0.01), remaining constant until day 21 and tending to increase after 50 days (p>0.05); on thecontrary,TF became higher after day 3 (p≤0.05). Normal values were recorded for both variables. TA became reduced (p≤0.05) between day 3 and 6, and remained constant from there on. Adding fresh pig manure to WGSC silage improved its main nutrition al quality indicators, the mixture containing 40% pig manure having outstanding performance (having been subjected to prior fermentation) after day 15 of fermentation.O propósito do presente estudo foi avaliar as estratégias competitivas de incorporação de porcinaza em silagens de cana de açúcar integral moída (CAIM), para alimentação de bovinos. Trabalho realizado no Instituto de Biotecnologia Agropecuária da Universidad de Caldas. Utilizou-se um desenho fatorial de 8x3x2 (8 tempos de fermentação; 20-30 e 40% de porcinaza; e com e sem fermentação prévia), em blocos completos ao acaso, 3 replicações por tratamento e um microsilo de PVC, de 2,5 kg, como unidade experimental. A fermentação prévia afetou o conteúdo de acúcares redutores (AR) (P≤0,01), o pH, as cinzas totais (CT) e o Cu (P≤0,05). A porcentagem de incorporação de porcinaza (IP) afetou (P≤0,01) proteína total (PT), gordura total (GT), CT, P, K, e Mg. Com respeito ao tempo de fermentação (TF), houve um leve decréscimo (P>0,05) em AR e MS dos dias 3 a 21, e mais forte (P≤0,01), dos dias 21 a 50. O pH diminuiu entre o terceiro e o sexto dias (P≤0,01), permaneceu constante até o dia 21 e teve a tendência de aumentar aos 50 dias (P>0,05). Ao contrário, a GT elevou-se a partir do dia 3 (P≤0,05). Ambas variáveis registraram valores normais. As CT diminuíram (P≤0,05) nos dias 3 e 6, e permaneceram constantes a partir daí. A adição de porcinaza fresca à silagem de CAIM melhorou os principais indicadores de qualidade nutricional desta, com um comportamento superior da mistura com 40% de porcinaza, submetida à fermentação prévia, a partir do 15° dia de fermentação.El propósito del presente estudio fue evaluar estrategias competitivas de incorporación de porcinaza en ensilajes de caña de azúcar integral molida (CAIM), para alimentación de bovinos, el trabajo se realizó en el Instituto de Biotecnología Agropecuaria de la Universidad de Caldas. Se utilizó un diseño factorial de 8x3x2 (8 tiempos de fermentación; 20-30 y 40% de porcinaza; y con y sin fermentación previa), en bloques completos al azar, 3 replicaciones por tratamiento y un microsilo de PVC, de 2.5 Kg, como unidad experimental. La fermentación previa afectó el contenido de azúcares reductores (AR) (P≤0.01), el pH, las cenizas totales (CT) y el Cu (P≤0.05). El porcentaje de incorporación de porcinaza (IP) afectó (P≤0.01) proteína total (PT), grasa total (GT), CT, P, K, y Mg. Respecto al tiempo de fermentación (TF), hubo un descenso leve (P>0.05) en AR y MS del día 3 al 21, y más fuerte (P≤0.01), del 21 al 50. El pH bajó entre tercero y sexto día (P≤0.01), permaneció constante hasta el día 21 y tendió a aumentar a los 50 días (P>0.05); Por el contrario, la GT se elevó a partir del día 3 (P≤0.05). Ambas variables registraron valores normales. Las CT disminuyeron (P≤0.05) entre el día 3 y 6, y permanecieron constantes desde allí. La adición de porcinaza fresca al ensilaje de CAIM mejoró los principales indicadores de calidad nutricional de este, con un comportamiento sobresaliente de la mezcla con 40% de porcinaza, sometida a fermentación previa, a partir del día 15 de fermentación