Making Education Work For Latinas in the U.S.

This study examines the existing knowledge base about promoting Latina educational success, defined as completing high school and then going on to secure a college degree. It also adds to existing research by examining two large data sets - one national, and one California-based for predictors of successful educational outcomes for representative samples of Latina youth who have recently been in high school and college. Finally, after identifying important predictors of success from the existing literature, and the examination of current data, the study incorporates case studies of seven young Latinas who illustrate pathways of women who are finding their way to educational success through high school, community college, and four year universities. Their stories provide a deeper understanding of the challenges that young Latinas encounter in our culture, as well as the promise they represent

Holography with Schroedinger Potentials

We examine the analogue one-dimensional quantum mechanics problem associated with bulk scalars and fermions in a slice of AdS_5. The ``Schroedinger'' potential can take on different qualitative shapes depending on the values of the mass parameters in the bulk theory. Several interesting correlations between the shape of the Schroedinger potential and the holographic theory exist. We show that the quantum mechanical picture is a useful guide to the holographic theory by examining applications from phenomenology.Comment: 22 pages, 4 figure

Non-Standard Neutrino Interactions from a Triplet Seesaw Model

We investigate non-standard neutrino interactions (NSIs) in the triplet seesaw model featuring non-trivial correlations between NSI parameters and neutrino masses and mixing parameters. We show that sizable NSIs can be generated as a consequence of a nearly degenerate neutrino mass spectrum. Thus, these NSIs could lead to quite significant signals of lepton flavor violating decays such as \mu^- \to e^- \nu_e anti\nu_\mu and \mu^+ \to e^+ anti\nu_e \nu_\mu at a future neutrino factory, effects adding to the uncertainty in determination of the Earth matter density profile, as well as characteristic patterns of the doubly charged Higgs decays observable at the Large Hadron Collider.Comment: 4 pages, 3 figures and 1 table; v2: minor corrections, Sect. IV revise

Combining Direct & Indirect Kaon CP Violation to Constrain the Warped KK Scale

The Randall-Sundrum (RS) framework has a built in protection against flavour violation, but still generically suffers from little CP problems. The most stringent bound on flavour violation is due to epsilon_K, which is inversely proportional to the fundamental Yukawa scale. Hence the RS epsilon_K problem can be ameliorated by effectively increasing the Yukawa scale with a bulk Higgs, as was recently observed in arXiv:0810.1016. We point out that incorporating the constraint from epsilon'/\epsilon_K, which is proportional to the Yukawa scale, raises the lower bound on the KK scale compared to previous analyses. The bound is conservatively estimated to be 5.5 TeV, choosing the most favorable Higgs profile, and 7.5 TeV in the two-site limit. Relaxing this bound might require some form of RS flavour alignment. As a by-product of our analysis, we also provide the leading order flavour structure of the theory with a bulk Higgs.Comment: 15 pages, 2 figure

The precision electroweak data in warped extra-dimension models

The Randall-Sundrum scenario with Standard Model fields in the bulk and a custodial symmetry is considered. We determine the several minimal quark representations allowing to address the anomalies in the forward-backward b-quark asymmetry A^b_FB, while reproducing the bottom and top masses via wave function overlaps. The calculated corrections of the Zbb coupling include the combined effects of mixings with both Kaluza-Klein excitations of gauge bosons and new b'-like states. It is shown that the mechanism, in which the left-handed doublet of third generation quarks results from a mixing on the UV boundary of introduced fields Q_1L and Q_2L, is necessary for phenomenological reasons. Within the obtained models, both the global fit of R_b with A^b_FB [at the various center of mass energies] and the fit of last precision electroweak data in the light fermion sector can simultaneously be improved significantly with respect to the pure Standard Model case, for M_KK = 3,4,5 TeV (first KK gauge boson) and a best-fit Higgs mass m_h > 115 GeV i.e. compatible with the LEP2 direct limit. The quantitative analysis of the oblique parameters S,T,U even shows that heavy Higgs mass values up to ~500 GeV may still give rise to an acceptable quality of the electroweak data fit, in contrast with the Standard Model. The set of obtained constraints on the parameter space, derived partly from precision electroweak data, is complementary of a future direct exploration of this parameter space at the LHC. In particular, we find that custodians, like b' modes, can be as light as ~1200 GeV i.e. a mass lying possibly in the potential reach of LHC.Comment: 24 pages, 8 figures. Added references, corrected typos and Higgs mass dependence discussion complete

Semi-Analytic Calculation of the Gravitational Wave Signal From the Electroweak Phase Transition for General Quartic Scalar Effective Potentials

Upcoming gravitational wave (GW) detectors might detect a stochastic background of GWs potentially arising from many possible sources, including bubble collisions from a strongly first-order electroweak phase transition. We investigate whether it is possible to connect, via a semi-analytical approximation to the tunneling rate of scalar fields with quartic potentials, the GW signal through detonations with the parameters entering the potential that drives the electroweak phase transition. To this end, we consider a finite temperature effective potential similar in form to the Higgs potential in the Standard Model (SM). In the context of a semi-analytic approximation to the three dimensional Euclidean action, we derive a general approximate form for the tunneling temperature and the relevant GW parameters. We explore the GW signal across the parameter space describing the potential which drives the phase transition. We comment on the potential detectability of a GW signal with future experiments, and physical relevance of the associated potential parameters in the context of theories which have effective potentials similar in form to that of the SM. In particular we consider singlet, triplet, higher dimensional operators, and top-flavor extensions to the Higgs sector of the SM. We find that the addition of a temperature independent cubic term in the potential, arising from a gauge singlet for instance, can greatly enhance the GW power. The other parameters have milder, but potentially noticeable, effects.Comment: accepted by JCAP, revisions: removed turbulence contribution, minor changes to experimental sensitivity, fixed various minor typos and text revisions, added references, made it clear we consider only detonations; 17 pages, 4 figures, revtex

Dirac Neutrino Masses with Planck Scale Lepton Number Violation

It is shown how pure Dirac neutrino masses can naturally occur at low energies even in the presence of Planck scale lepton number violation. The geometrical picture in five dimensions assumes that the lepton number symmetry is explicitly broken on the Planck brane while the right-handed neutrino is localised on the TeV brane. This physical separation in the bulk causes the global lepton number to be preserved at low energies. A small wavefunction overlap between the left-handed and right-handed neutrinos then naturally leads to a small Dirac Yukawa coupling. By the AdS/CFT correspondence there exists a purely four-dimensional dual description in which the right-handed neutrino is a composite CFT bound state. The global lepton number is violated at the Planck scale in a fundamental sector whose mixing into the composite sector is highly suppressed by CFT operators with large anomalous dimensions. A similar small mixing is then also responsible for generating a naturally small Dirac Yukawa coupling between the fundamental left-handed neutrino and the composite right-handed neutrino.Comment: 12 pages, LaTeX; v2: references added; v3: another reference adde

Grand Unification in RS1

We study unification in the Randall-Sundrum scenario for solving the hierarchy problem, with gauge fields and fermions in the bulk. We calculate the one-loop corrected low-energy effective gauge couplings in a unified theory, broken at the scale M_GUT in the bulk. We find that, although this scenario has an extra dimension, there is a robust (calculable in the effective field theory) logarithmic dependence on M_GUT, strongly suggestive of high-scale unification, very much as in the (4D) Standard Model. Moreover, bulk threshold effects are naturally small, but volume-enhanced, so that we can accommodate the measured gauge couplings. We show in detail how excessive proton decay is forbidden by an extra U(1) bulk gauge symmetry. This mechanism requires us to further break the unified group using boundary conditions. A 4D dual interpretation, in the sense of the AdS/CFT correspondence, is provided for all our results. Our results show that an attractive unification mechanism can combine with a non-supersymmetric solution to the hierarchy problem.Comment: Latex, 23 pages. In the revised version, Eq. (3.3) has been modified with no change in the central result of the paper and a reference has been adde