9,531 research outputs found
The Lee-Wick Fields out of Gravity
We study the Maxwell-Einstein theory in the framework of effective field
theories. We show that the modified one-loop renormalizable Lagrangian due to
quantum gravitational effects contains a Lee-Wick vector field as an extra
degree of freedom in the theory. Thus gravity provides a natural mechanism for
the emergence of this exotic particle.Comment: 8 pages, 1 figure, typos fixe
The Leptoquark Hunter's Guide: Large Coupling
Leptoquarks have recently received much attention especially because they may
provide an explanation to the and anomalies in rare
meson decays. In a previous paper we proposed a systematic search strategy
for all possible leptoquark flavors by focusing on leptoquark pair production.
In this paper, we extend this strategy to large (order unity) leptoquark
couplings which offer new search opportunities: single leptoquark production
and -channel leptoquark exchange with dilepton final states. We discuss the
unique features of the different search channels and show that they cover
complementary regions of parameter space. We collect and update all currently
available bounds for the different flavor final states from LHC searches and
from atomic parity violation measurements. As an application of our analysis,
we find that current limits do not exclude the leptoquark explanation of the
physics anomalies but that the high luminosity run of the LHC will reach
the most interesting parameter space.Comment: 33 pages + references, 15 figures, 9 tables, v2: references adde
The Epsilon-Expansion from Conformal Field Theory
Conformal multiplets of and recombine at the Wilson-Fisher
fixed point, as a consequence of the equations of motion. Using this fact and
other constraints from conformal symmetry, we reproduce the lowest nontrivial
order results for the anomalous dimensions of operators, without any input from
perturbation theory.Comment: 24 pages; v2 - references added, minor changes; v3 - refs and
comments added, misprints corrected, version to appear in J.Phys.
A flexible and adaptive Simpler GMRES with deflated restarting for shifted linear systems
In this paper, two efficient iterative algorithms based on the simpler GMRES
method are proposed for solving shifted linear systems. To make full use of the
shifted structure, the proposed algorithms utilizing the deflated restarting
strategy and flexible preconditioning can significantly reduce the number of
matrix-vector products and the elapsed CPU time. Numerical experiments are
reported to illustrate the performance and effectiveness of the proposed
algorithms.Comment: 17 pages. 9 Tables, 1 figure; Newly update: add some new numerical
results and correct some typos and syntax error
The effects of KSEA interaction on the ground-state properties of spin chains in a transverse field
The effects of symmetric helical interaction which is called the Kaplan,
Shekhtman, Entin-Wohlman, and Aharony (KSEA) interaction on the ground-state
properties of three kinds of spin chains in a transverse field have been
studied by means of correlation functions and chiral order parameter. We find
that the anisotropic transition of chain in a transverse field (TF)
disappears because of the KSEA interaction. For the other two chains, we find
that the regions of gapless chiral phases in the parameter space induced by the
DM or type of three-site interaction are decreased gradually with
increase of the strength of KSEA interaction. When it is larger than the
coefficient of DM or type of three-site interaction, the gapless
chiral phases also disappear.Comment: 7 pages, 3 figure
The longlived charged massive scalar field in the higher-dimensional Reissner--Nordstr\"{o}m spacetime
The quasinormal resonance frequency of the higher-dimensional
Reissner--Nordstr\"{o}m (RN) black hole due to charged massive scalar field
perturbation is deduced analytically in the eikonal regime. The characteristic
decay timescale of the charged massive scalar perturbation in the background of
the higher-dimensional RN spacetime is then obtained. The result reveals that
longlived charged massive scalar field can exist in higher-dimensional RN
spacetime under a certain condition.Comment: 6 pages, 1 figur
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