2,253 research outputs found
Examining the everyday micro-economies of migrant detention in the United States
Securitization of immigration, the rise of interior immigration policing, and forces of carceral privatization have occasioned a remarkable expansion of immigrant detention throughout the United States. Previous studies have drawn attention to the importance of the daily rates paid by the federal government to individual facilities in driving the emphasis on detention. This paper, in contrast, argues that tracing the political and economic geography of money inside detention facilities is also critical for understanding detention expansion and its consequences. We define the processes, mechanisms, and practices of generating profit above and beyond the "per-bed" daily rate as "internal micro-economies" of migrant detention. Drawing on an ongoing examination of migrant detention facilities in the greater New York City metropolitan area, we identify four micro-economies evident in detention facilities: the commissary systems, phone and other forms of communication, detainee labor, and detainee excursions outside detention. These economies show how detained migrants' needs and daily routines are tailored in ways that produce migrants as both captive consumers and laborers. Recognition of multiple micro-economies also highlights the fact that the numbers of individuals and entities invested in the incarceration of immigrants proliferate in tandem with the objectification of detainees. The paper further suggests that attending to relationships embedded in the inner workings of detention exposes economic links across carceral boundaries, rendering visible the porosity between government, private companies, and publics
Evaluation of the space disposal of defense nuclear waste, Phase 2. Volume 1: Executive summary
Evaluation of the space disposal of defense nuclear waste, phase 2. Volume 2: Technical Report
F-theory, GUTs, and the Weak Scale
In this paper we study a deformation of gauge mediated supersymmetry breaking
in a class of local F-theory GUT models where the scale of supersymmetry
breaking determines the value of the mu term. Geometrically correlating these
two scales constrains the soft SUSY breaking parameters of the MSSM. In this
scenario, the hidden SUSY breaking sector involves an anomalous U(1)
Peccei-Quinn symmetry which forbids bare mu and B mu terms. This sector
typically breaks supersymmetry at the desired range of energy scales through a
simple stringy hybrid of a Fayet and Polonyi model. A variant of the
Giudice-Masiero mechanism generates the value mu ~ 10^2 - 10^3 GeV when the
hidden sector scale of supersymmetry breaking is F^(1/2) ~ 10^(8.5) GeV.
Further, the B mu problem is solved due to the mild hierarchy between the GUT
scale and Planck scale. These models relate SUSY breaking with the QCD axion,
and solve the strong CP problem through an axion with decay constant f_a ~
M_(GUT) * mu / L, where L ~ 10^5 GeV is the characteristic scale of gaugino
mass unification in gauge mediated models, and the ratio \mu / L ~
M_(GUT)/M_(pl) ~ 10^(-3). We find f_a ~ 10^12 GeV, which is near the high end
of the phenomenologically viable window. Here, the axino is the goldstino mode
which is eaten by the gravitino. The gravitino is the LSP with a mass of about
10^1 - 10^2 MeV, and a bino-like neutralino is (typically) the NLSP with mass
of about 10^2 - 10^3 GeV. Compatibility with electroweak symmetry breaking also
determines the value of tan(beta) ~ 30 +/- 7.Comment: v3: 94 pages, 9 figures, clarification of Fayet-Polonyi model and
instanton corrections to axion potentia
On the Effective Description of Large Volume Compactifications
We study the reliability of the Two-Step moduli stabilization in the type-IIB
Large Volume Scenarios with matter and gauge interactions. The general analysis
is based on a family of N=1 Supergravity models with a factorizable Kaehler
invariant function, where the decoupling between two sets of fields without a
mass hierarchy is easily understood. For the Large Volume Scenario particular
analyses are performed for explicit models, one of such developed for the first
time here, finding that the simplified version, where the Dilaton and Complex
structure moduli are regarded as frozen by a previous stabilization, is a
reliable supersymmetric description whenever the neglected fields stand at
their leading F-flatness conditions and be neutral. The terms missed by the
simplified approach are either suppressed by powers of the Calabi-Yau volume,
or are higher order operators in the matter fields, and then irrelevant for the
moduli stabilization rocedure. Although the power of the volume suppressing
such corrections depends on the particular model, up to the mass level it is
independent of the modular weight for the matter fields. This at least for the
models studied here but we give arguments to expect the same in general. These
claims are checked through numerical examples. We discuss how the factorizable
models present a context where despite the lack of a hierarchy with the
supersymmetry breaking scale, the effective theory still has a supersymmetric
description. This can be understood from the fact that it is possible to find
vanishing solution for the auxiliary components of the fields being integrated
out, independently of the remaining dynamics. Our results settle down the
question on the reliability of the way the Dilaton and Complex structure are
treated in type-IIB compactifications with large compact manifold volumina.Comment: 23 pages + 2 appendices (38 pages total). v2: minor improvements,
typos fixed. Version published in JHE
FCNC Processes from D-brane Instantons
Low string scale models might be tested at the LHC directly by their Regge
resonances. For such models it is important to investigate the constraints of
Standard Model precision measurements on the string scale. It is shown that
highly suppressed FCNC processes like K0- bar K^0 oscillations or leptonic
decays of the D0-meson provide non-negligible lower bounds on both the
perturbatively and surprisingly also non-perturbatively induced string theory
couplings. We present both the D-brane instanton formalism to compute such
amplitudes and discuss various possible scenarios and their constraints on the
string scale for (softly broken) supersymmetric intersecting D-brane models.Comment: 28 pages, 13 figures, reference added, 1 typo corrected, style file
adde
Preheating After Modular Inflation
We study (p)reheating in modular (closed string) inflationary scenarios, with
a special emphasis on Kahler moduli/Roulette models. It is usually assumed that
reheating in such models occurs through perturbative decays. However, we find
that there are very strong non-perturbative preheating decay channels related
to the particular shape of the inflaton potential (which is highly nonlinear
and has a very steep minimum). Preheating after modular inflation, proceeding
through a combination of tachyonic instability and broad-band parametric
resonance, is perhaps the most violent example of preheating after inflation
known in the literature. Further, we consider the subsequent transfer of energy
to the standard model sector in scenarios where the standard model particles
are confined to a D7-brane wrapping the inflationary blow-up cycle of the
compactification manifold or, more interestingly, a non-inflationary blow up
cycle. We explicitly identify the decay channels of the inflaton in these two
scenarios. We also consider the case where the inflationary cycle shrinks to
the string scale at the end of inflation; here a field theoretical treatment of
reheating is insufficient and one must turn instead to a stringy description.
We estimate the decay rate of the inflaton and the reheat temperature for
various scenarios.Comment: 34 pages, 10 figures. Accepted for publication in JCA
Froggatt-Nielsen models from E8 in F-theory GUTs
This paper studies F-theory SU(5) GUT models where the three generations of
the standard model come from three different curves. All the matter is taken to
come from curves intersecting at a point of enhanced E8 gauge symmetry. Giving
a vev to some of the GUT singlets naturally implements a Froggatt-Nielsen
approach to flavour structure. A scan is performed over all possible models and
the results are filtered using phenomenological constraints. We find a unique
model that fits observations of quark and lepton masses and mixing well. This
model suffers from two drawbacks: R-parity must be imposed by hand and there is
a doublet-triplet splitting problem.Comment: 42 pages; v2:journal version; v3:corrected typo in neutrino masse
Phenomenology of a Pseudo-Scalar Inflaton: Naturally Large Nongaussianity
Many controlled realizations of chaotic inflation employ pseudo-scalar
axions. Pseudo-scalars \phi are naturally coupled to gauge fields through c
\phi F \tilde{F}. In the presence of this coupling, gauge field quanta are
copiously produced by the rolling inflaton. The produced gauge quanta, in turn,
source inflaton fluctuations via inverse decay. These new cosmological
perturbations add incoherently with the "vacuum" perturbations, and are highly
nongaussian. This provides a natural mechanism to generate large nongaussianity
in single or multi field slow-roll inflation. The resulting phenomenological
signatures are highly distinctive: large nongaussianity of (nearly) equilateral
shape, in addition to detectably large values of both the scalar spectral tilt
and tensor-to-scalar ratio (both being typical of large field inflation). The
WMAP bound on nongaussianity implies that the coupling, c, of the pseudo-scalar
inflaton to any gauge field must be smaller than about 10^{2} M_p^{-1}.Comment: 45 pages, 7 figure
Warped Supersymmetry Breaking
We address the size of supersymmetry-breaking effects within
higher-dimensional settings where the observable sector resides deep within a
strongly warped region, with supersymmetry breaking not necessarily localized
in that region. Our particular interest is in how the supersymmetry-breaking
scale seen by the observable sector depends on this warping. We obtain this
dependence in two ways: by computing within the microscopic (string) theory
supersymmetry-breaking masses in supermultiplets; and by investigating how
warping gets encoded into masses within the low-energy 4D effective theory. We
find that the lightest gravitino mode can have mass much less than the
straightforward estimate from the mass shift of the unwarped zero mode. This
lightest Kaluza-Klein excitation plays the role of the supersymmetric partner
of the graviton and has a warped mass m_{3/2} proportional to e^A, with e^A the
warp factor, and controls the size of the soft SUSY breaking terms. We
formulate the conditions required for the existence of a description in terms
of a 4D SUGRA formulation, or in terms of 4D SUGRA together with soft-breaking
terms, and describe in particular situations where neither exist for some
non-supersymmetric compactifications. We suggest that some effects of warping
are captured by a linear dependence in the Kahler potential. We outline
some implications of our results for the KKLT scenario of moduli stabilization
with broken SUSY.Comment: 34 pages, 1 figure. v2 Further discussion of dual interpretation and
gravitino mas
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