2,201 research outputs found
Simulating Nonlinear Tax Rules and Nonstandard Behavior: An Application to the Tax Treatment of Charitable Contributions
This paper examines how the tax simulation method can be extended to incorporate nonlinear budget constraints and nonstandard economic behavior. We simulate the effect of extending the charitable deduction to nonitemizers and study the effect of alternative "floors". The specific simulations indicate that the econometric evidence on charitable giving implies that extending the charitable deduction to nonitemizers would raise individual giving by about 12 percent of the existing total amount or 4.1 billion. A floor of $300 or 3 percent of AGI would reduce the revenue loss by 30 to 40 percent, even if there is significant bunching. The effect of the floor on increased giving depends critically on whether taxpayers' behavior is guided by conventional demand principles or by the net altruism rule. A reasonable conclusion is that a floor would reduce giving by less than the increased revenue but that the difference between them would not be very large.
Comments and Discussion [The Measurement and Determination of Loanable-Funds Saving]
macroeconomics, saving, capital formation, interest
The Effective Field Theory of Dark Matter Direct Detection
We extend and explore the general non-relativistic effective theory of dark
matter (DM) direct detection. We describe the basic non-relativistic building
blocks of operators and discuss their symmetry properties, writing down all
Galilean-invariant operators up to quadratic order in momentum transfer arising
from exchange of particles of spin 1 or less. Any DM particle theory can be
translated into the coefficients of an effective operator and any effective
operator can be simply related to most general description of the nuclear
response. We find several operators which lead to novel nuclear responses.
These responses differ significantly from the standard minimal WIMP cases in
their relative coupling strengths to various elements, changing how the results
from different experiments should be compared against each other. Response
functions are evaluated for common DM targets - F, Na, Ge, I, and Xe - using
standard shell model techniques. We point out that each of the nuclear
responses is familiar from past studies of semi-leptonic electroweak
interactions, and thus potentially testable in weak interaction studies. We
provide tables of the full set of required matrix elements at finite momentum
transfer for a range of common elements, making a careful and fully
model-independent analysis possible. Finally, we discuss embedding
non-relativistic effective theory operators into UV models of dark matter.Comment: 32+23 pages, 5 figures; v2: some typos corrected and definitions
clarified; v3: some factors of 4pi correcte
Social Security
This paper, a forthcoming chapter in the Handbook of Public Economics, reviews the theoretical and empirical issues dealing with Social Security pensions. The first part of the paper discusses pure pay-as-you-go plans. It considers the effects of introducing such a plan on the present value of consumption, the optimal level of benefits in such plans, and the emprical research on the effects of pay-as-you-go pension systems on labor supply and saving. The second part of the paper discusses the transition to investment-based systems, analyzing the effect on the present value of consumption of such a transition and considering such issues as the distributional effects and risk associated with such systems.
A Simple Explanation for DAMA with Moderate Channeling
We consider the possibility that the DAMA signal arises from channeled events
in simple models where the dark matter interaction with nuclei is suppressed at
small momenta. As with the standard WIMP, these models have two parameters (the
dark matter mass and the size of the cross-section), without the need to
introduce an additional energy threshold type of parameter. We find that they
can be consistent with channeling fractions as low as about ~ 15%, so long as
at least ~70% of the nuclear recoil energy for channeled events is deposited
electronically. Given that there are reasons not to expect very large
channeling fractions, these scenarios make the channeling explanation of DAMA
much more compelling.Comment: 6 pages, 2 figure
Density Perturbations and the Cosmological Constant from Inflationary Landscapes
An anthropic understanding of the cosmological constant requires that the
vacuum energy at late time scans from one patch of the universe to another. If
the vacuum energy during inflation also scans, the various patches of the
universe acquire exponentially differing volumes. In a generic landscape with
slow-roll inflation, we find that this gives a steeply varying probability
distribution for the normalization of the primordial density perturbations,
resulting in an exponentially small fraction of observers measuring the COBE
value of 10^-5. Inflationary landscapes should avoid this "\sigma problem", and
we explore features that can allow them to do that. One possibility is that,
prior to slow-roll inflation, the probability distribution for vacua is
extremely sharply peaked, selecting essentially a single anthropically allowed
vacuum. Such a selection could occur in theories of eternal inflation. A second
possibility is that the inflationary landscape has a special property: although
scanning leads to patches with volumes that differ exponentially, the value of
the density perturbation does not vary under this scanning. This second case is
preferred over the first, partly because a flat inflaton potential can result
from anthropic selection, and partly because the anthropic selection of a small
cosmological constant is more successful.Comment: 23 page
Puzzles of Dark Matter - More Light on Dark Atoms?
Positive results of dark matter searches in experiments DAMA/NaI and
DAMA/LIBRA confronted with results of other groups can imply nontrivial
particle physics solutions for cosmological dark matter. Stable particles with
charge -2, bound with primordial helium in O-helium "atoms" (OHe), represent a
specific nuclear-interacting form of dark matter. Slowed down in the
terrestrial matter, OHe is elusive for direct methods of underground Dark
matter detection using its nuclear recoil. However, low energy binding of OHe
with sodium nuclei can lead to annual variations of energy release from OHe
radiative capture in the interval of energy 2-4 keV in DAMA/NaI and DAMA/LIBRA
experiments. At nuclear parameters, reproducing DAMA results, the energy
release predicted for detectors with chemical content other than NaI differ in
the most cases from the one in DAMA detector. Moreover there is no bound
systems of OHe with light and heavy nuclei, so that there is no radiative
capture of OHe in detectors with xenon or helium content. Due to dipole Coulomb
barrier, transitions to more energetic levels of Na+OHe system with much higher
energy release are suppressed in the correspondence with the results of DAMA
experiments. The proposed explanation inevitably leads to prediction of
abundance of anomalous Na, corresponding to the signal, observed by DAMA.Comment: Contribution to Proceedings of XIII Bled Workshop "What Comes beyond
the Standard Model?
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