3,658 research outputs found
Probing Compressed Top Squarks at the LHC at 14 TeV
A feasibility study is presented for the search of the lightest top squark in
a compressed scenario, where its mass is approximately equal to the sum of the
masses of the top quark and the lightest neutralino. The study is performed in
the final state of two b-jets, one lepton, large missing energy, and two
high- jets with large separation in pseudo-rapidity, in opposite
hemispheres, and with large dijet mass. The LHC could discover compressed top
squarks with mass up to approximately 340 GeV (390 GeV) with an integrated
luminosity of 1000 ifb (3000 ifb).Comment: Version updated with major changes: (a) 3-body stop decay (to b+W+n1)
analyzed for first time (b) systematics calculation and discussion
significantly upgraded (c) new kinematic and mass reach plots for the 3-body
decay scenario added (d) discussions clarified throughou
Post-Newtonian gravitational radiation and equations of motion via direct integration of the relaxed Einstein equations. IV. Radiation reaction for binary systems with spin-spin coupling
Using post-Newtonian equations of motion for fluid bodies that include
radiation-reaction terms at 2.5 and 3.5 post-Newtonian (PN) order O[(v/c)^5]
and O[(v/c)^7] beyond Newtonian order), we derive the equations of motion for
binary systems with spinning bodies, including spin-spin effects. In particular
we determine the effects of radiation-reaction coupled to spin-spin effects on
the two-body equations of motion, and on the evolution of the spins. We find
that radiation damping causes a 3.5PN order, spin-spin induced precession of
the individual spins. This contrasts with the case of spin-orbit coupling,
where there is no effect on the spins at 3.5PN order. Employing the equations
of motion and of spin precession, we verify that the loss of total energy and
total angular momentum induced by spin-spin effects precisely balances the
radiative flux of those quantities calculated by Kidder et al.Comment: 10 pages, coincides with published versio
Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
We study a class of metric-variation f(R) models that accelerates the
expansion without a cosmological constant and satisfies both cosmological and
solar-system tests in the small-field limit of the parameter space.
Solar-system tests alone place only weak bounds on these models, since the
additional scalar degree of freedom is locked to the high-curvature
general-relativistic prediction across more than 25 orders of magnitude in
density, out through the solar corona. This agreement requires that the
galactic halo be of sufficient extent to maintain the galaxy at high curvature
in the presence of the low-curvature cosmological background. If the galactic
halo and local environment in f(R) models do not have substantially deeper
potentials than expected in LCDM, then cosmological field amplitudes |f_R| >
10^{-6} will cause the galactic interior to evolve to low curvature during the
acceleration epoch. Viability of large-deviation models therefore rests on the
structure and evolution of the galactic halo, requiring cosmological
simulations of f(R) models, and not directly on solar-system tests. Even small
deviations that conservatively satisfy both galactic and solar-system
constraints can still be tested by future, percent-level measurements of the
linear power spectrum, while they remain undetectable to cosmological-distance
measures. Although we illustrate these effects in a specific class of models,
the requirements on f(R) are phrased in a nearly model-independent manner.Comment: 13 pages, 10 figures. Submitted to Phys. Rev.
On the Intergenerational Transmission of Health Inequality
Cumulating evidence from social science has indicated the intergenerational transmission of inequality is majorly derived from the economic imbalance. In line with this, the same thing happens in health, and emerging evidence has been documenting its transmissible property. No matter the genetic or non-genetic causes, health inequality inevitably plays its role in contributing to the underlying health-associated despoliation in life. Each individual shows an eventual health state where equality and inequality reach a time-dependent temporary condition in which the balancing point fluctuates back and forth. To promote the overall health status, it is crucial to promote and optimize the positive health characteristics to get equilibrium between positive and negative. This review discussed the underlying mechanisms of intergenerational transmission of health inequality by focusing on different types of contributors to the inequality and providing prospective insights into the potentially beneficial strategies that can optimize overall individual health
Optimal Redshift Weighting For Redshift Space Distortions
The low statistical errors on cosmological parameters promised by future
galaxy surveys will only be realised with the development of new, fast,
analysis methods that reduce potential systematic problems to low levels. We
present an efficient method for measuring the evolution of the growth of
structure using Redshift Space Distortions (RSD), that removes the need to make
measurements in redshift shells. We provide sets of galaxy-weights that cover a
wide range in redshift, but are optimised to provide differential information
about cosmological evolution. These are derived to optimally measure the
coefficients of a parameterisation of the redshift-dependent matter density,
which provides a framework to measure deviations from the concordance
CDM cosmology, allowing for deviations in both geometric and/or
growth. We test the robustness of the weights by comparing with alternative
schemes and investigate the impact of galaxy bias. We extend the results to
measure the combined anisotropic Baryon Acoustic Oscillation (BAO) and RSD
signals.Comment: 10 pages, 5 figures, submitted to MNRA
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