34,049 research outputs found
Lepton non-universality in decays and fermion mass structure
We consider the possibility that the neutral-current anomalies are due to
radiative corrections generated by Yukawa interactions of quarks and leptons
with new vector-like quark and lepton electroweak doublets and new Standard
Model singlet scalars. We show that the restricted interactions needed can
result from an underlying Abelian family symmetry and that the same symmetry
can give rise to an acceptable pattern of quark and charged lepton masses and
mixings, providing a bridge between the non-universality observed in the
B-sector and that of the fermion mass matrices. We construct two simple models,
one with a single singlet scalar in which the flavour changing comes from quark
and lepton mixing and one with an additional scalar in which the flavour
changing can come from both fermion and scalar mixing. We show that for the
case the new quarks are much heavier than the new leptons and scalars the
anomalies can be due to box diagrams with couplings in the perturbative regime
consistent with the bounds coming from , and mixing as well as other lepton family number violating processes. The
new states can be dark matter candidates and, in the two scalar model with a
light scalar of O(60) GeV and vector-like lepton of O(100) GeV, there can be a
simultaneous explanation of the B-anomalies, the muon anomalous magnetic moment
and the dark matter abundance.Comment: Replacement contains few additional reference
Genetic braid optimization: A heuristic approach to compute quasiparticle braids
In topologically-protected quantum computation, quantum gates can be carried
out by adiabatically braiding two-dimensional quasiparticles, reminiscent of
entangled world lines. Bonesteel et al. [Phys. Rev. Lett. 95, 140503 (2005)],
as well as Leijnse and Flensberg [Phys. Rev. B 86, 104511 (2012)] recently
provided schemes for computing quantum gates from quasiparticle braids.
Mathematically, the problem of executing a gate becomes that of finding a
product of the generators (matrices) in that set that approximates the gate
best, up to an error. To date, efficient methods to compute these gates only
strive to optimize for accuracy. We explore the possibility of using a generic
approach applicable to a variety of braiding problems based on evolutionary
(genetic) algorithms. The method efficiently finds optimal braids while
allowing the user to optimize for the relative utilities of accuracy and/or
length. Furthermore, when optimizing for error only, the method can quickly
produce efficient braids.Comment: 6 pages 4 figure
One-dimensional in-plane edge domain walls in ultrathin ferromagnetic films
We study existence and properties of one-dimensional edge domain walls in
ultrathin ferromagnetic films with uniaxial in-plane magnetic anisotropy. In
these materials, the magnetization vector is constrained to lie entirely in the
film plane, with the preferred directions dictated by the magnetocrystalline
easy axis. We consider magnetization profiles in the vicinity of a straight
film edge oriented at an arbitrary angle with respect to the easy axis. To
minimize the micromagnetic energy, these profiles form transition layers in
which the magnetization vector rotates away from the direction of the easy axis
to align with the film edge. We prove existence of edge domain walls as
minimizers of the appropriate one-dimensional micromagnetic energy functional
and show that they are classical solutions of the associated Euler-Lagrange
equation with Dirichlet boundary condition at the edge. We also perform a
numerical study of these one-dimensional domain walls and uncover further
properties of these domain wall profiles
Flavor Delta(54) in SU(5) SUSY Model
We design a supersymmetric SU (5) GUT model using \Delta (54), a finite
non-abelian subgroup of SU (3)f . Heavy right handed neutrinos are introduced
which transform as three-dimensional repre-sentation of our chosen family
group. The model successfully reproduces the mass hierarchical mass structures
of the Standard Model, and the CKM mixing matrix. It then provides predictions
for the light neutrino with a normal hierarchy and masses such that m{\nu},1
\approx 5\times10-3 eV, m{\nu}, 2 \approx 1\times 10-2 eV, and m{\nu},3 \approx
5 \times 10-2 eV. We also provide predictions for masses of the heavy
neutrinos, and correc- tions to the tri-bimaximal matrix that fit within
experimental limits, e.g. a reactor angle of -7.31o. A simple modification to
our model is introduced at the end and is shown to also produce predictions
that fall well within those limits.Comment: 22 page
Increasing levels of the endocannabinoid 2-AG is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease
Date of Acceptance: 28/07/2015 The authors are grateful to the staff of the Medical Research Facility for their help with the animal care. This work was supported by the NHS Endowment fund 09/03 and the Wellcome Trust (WT080782MF). We thank Merck & Co. Inc., Rathway NJ, USA for the supply of DFU.Peer reviewedPublisher PD
Comparison of research framing preferences and information use of state legislators and advocates involved in cancer control, United States, 2012–2013
INTRODUCTION: Evidence-based policy plays an important role in prevention of cancer and other chronic diseases. The needs of actors involved in policy decision-making should inform knowledge translation strategies. This study examines the differences between state legislators and advocates in how they seek and use information and what their preferences are for how research information is framed. METHODS: We conducted a cross-sectional comparison of survey responses by US advocates (n = 77) and state legislators (n = 265) working on issues related to cancer control. RESULTS: Advocates differed significantly from legislators on all demographic characteristics. Advocates reported seeking and using information more frequently than legislators, though legislators used legislative research bureaus more often (0.45 point difference, P = .004). Both legislators and advocates prioritized the presentation and timeliness of research information similarly but reported different preferences for source (information bias, information relevance, delivery of information by trusted person) of research information. Several differences between advocates and legislators were modified by participant age. CONCLUSION: Our study provides insights for development of knowledge translation strategies to enhance evidence-based policy making for cancer control that are tailored to state-level legislators and advocates. Additional research efforts should evaluate the effectiveness of such knowledge translation strategies, particularly among advocates
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