# Journal of High Energy Physics

Published by Springer Verlag (Germany)

Online ISSN: 1029-8479

Print ISSN: 1126-6708

Published by Springer Verlag (Germany)

Online ISSN: 1029-8479

Print ISSN: 1126-6708

Publications

We present a practical three-step procedure of using the Standard Model
effective field theory (SM EFT) to connect ultraviolet (UV) models of new
physics with weak scale precision observables. With this procedure, one can
interpret precision measurements as constraints on the UV model concerned. We
give a detailed explanation for calculating the effective action up to one-loop
order in a manifestly gauge covariant fashion. This covariant derivative
expansion method dramatically simplifies the process of matching a UV model
with the SM EFT, and also makes available a universal formalism that is easy to
use for a variety of UV models. A few general aspects of RG running effects and
choosing operator bases are discussed. Finally, we provide mapping results
between the bosonic sector of the SM EFT and a complete set of precision
electroweak and Higgs observables to which present and near future experiments
are sensitive. Many results and tools which should prove useful to those
wishing to use the SM EFT are detailed in several appendices.

…

It has been suggested that for QCD at finite baryon density the distribution
of the phase angle, i.e. the angle defined as the imaginary part of the
logarithm of the fermion determinant, has a simple Gaussian form. This
distribution provides the density in the density of states approach to the sign
problem. We calculate this phase angle distribution using i) the hadron
resonance gas model; and ii) a combined strong coupling and hopping parameter
expansion in lattice gauge theory. While the former model leads only to a
Gaussian distribution, in the latter expansion we discover terms which cause
the phase angle distribution to deviate, by relative amounts proportional to
powers of the inverse lattice volume, from a simple Gaussian form. We show that
despite the tiny inverse-volume deviation of the phase angle distribution from
a simple Gaussian form, such non-Gaussian terms can have a substantial impact
on observables computed in the density of states/reweighting approach to the
sign problem.

…

We present precise predictions for four-lepton plus jets production at the
LHC obtained within the fully automated Sherpa+OpenLoops framework. Off-shell
intermediate vector bosons and related interferences are consistently included
using the complex-mass scheme. Four-lepton plus 0- and 1-jet final states are
described at NLO accuracy, and the precision of the simulation is further
increased by squared quark-loop NNLO contributions in the gg -> 4l, gg -> 4l+g,
gq -> 4l+q, and qq -> 4l+g channels. These NLO and NNLO contributions are
matched to the Sherpa parton shower, and the 0- and 1-jet final states are
consistently merged using the MEPS@NLO technique. Thanks to Sudakov
resummation, the parton shower provides improved predictions and uncertainty
estimates for exclusive observables. This is important when jet vetoes or jet
bins are used to separate four-lepton final states arising from Higgs decays,
diboson production, and top-pair production. Detailed predictions are presented
for the ATLAS and CMS H->WW analyses at 8 TeV in the 0- and 1-jet bins.
Assessing renormalisation-, factorisation- and resummation-scale uncertainties,
which reflect also unknown subleading Sudakov logarithms in jet bins, we find
that residual perturbative uncertainties are as small as a few percent.

…

We study the linear sigma model subspace of the moduli space of (0,2)
superconformal world-sheet theories obtained by deforming (2,2) theories based
on Calabi-Yau hypersurfaces in reflexively plain toric varieties. We describe a
set of algebraic coordinates on this subspace, formulate a (0,2) generalization
of the monomial-divisor mirror map, and show that the map exchanges principal
components of singular loci of the mirror half-twisted theories. In
non-reflexively plain examples the proposed map yields a mirror isomorphism
between subfamilies of linear sigma models.

…

We use simple current techniques and their relation to orbifolds with
discrete torsion for studying the (0,2) CFT/geometry duality with non-rational
internal N=2 SCFTs. Explicit formulas for the charged spectra of heterotic
SO(10) GUT models are computed in terms of their extended Poincar\'{e}
polynomials and the complementary Poincar\'{e} polynomial which can be computed
in terms of the elliptic genera. While non-BPS states contribute to the charged
spectrum, their contributions can be determined also for non-rational cases.
For model building, with generalizations to SU(5) and SM gauge groups, one can
take advantage of the large class of Landau-Ginzburg orbifold examples.

…

We study the stability of heterotic compactifications described by (0,2) gauged linear sigma models with respect to worldsheet instanton corrections to the space-time superpotential following the work of Beasley and Witten [1]. We show that generic models elude the vanishing theorem proved there, and may not determine supersymmetric heterotic vacua. We then construct a subclass of linear models for which a vanishing theorem holds, generating an extensive list of consistent heterotic backgrounds.

…

We construct supersymmetric compactifications of E_8 \times E_8 heterotic
string theory which realise exactly the massless spectrum of the Minimal
Supersymmetric Standard Model (MSSM) at low energies. The starting point is the
standard embedding on a Calabi-Yau threefold which has Hodge numbers
(h^11,h^21) = (1,4) and fundamental group Z_12, which gives an E_6 grand
unified theory with three net chiral generations. The gauge symmetry is then
broken to that of the standard model by a combination of discrete Wilson lines
and continuous deformation of the gauge bundle. On eight distinct branches of
the moduli space, we find stable bundles with appropriate cohomology groups to
give exactly the massless spectrum of the MSSM.

…

We show that recently proposed linear sigma models with torsion can be
obtained from unconventional branches of conventional gauge theories. This
observation puts models with log interactions on firm footing. If non-anomalous
multiplets are integrated out, the resulting low-energy theory involves log
interactions of neutral fields. For these cases, we find a sigma model geometry
which is both non-toric and includes brane sources. These are heterotic sigma
models with branes. Surprisingly, there are massive models with compact complex
non-Kahler target spaces, which include brane/anti-brane sources. The simplest
conformal models describe wrapped heterotic NS5-branes. We present examples of
both types.

…

We enumerate massless E6 singlets for (0,2)-compactifications of the
heterotic string on a Calabi-Yau threefold with the "standard embedding" in
three distinct ways. In the large radius limit of the threefold, these singlets
count deformations of the Calabi-Yau together with its tangent bundle. In the
"small-radius" limit we apply Landau-Ginzburg methods. In the orbifold limit we
use a combination of geometry and free field methods. In general these counts
differ. We show how to identify states between these phases and how certain
states vanish from the massless spectrum as one deforms the complex structure
or Kaehler form away from the Gepner point. The appearance of extra singlets
for particular values of complex structure is explored in all three pictures,
and our results suggest that this does not depend on the Kaehler moduli.

…

We compute instanton corrections to correlators in the genus-zero topological subsector of a (0,2) supersymmetric gauged linear sigma model with target space P1xP1, whose left-moving fermions couple to a deformation of the tangent bundle. We then deduce the theory's chiral ring from these correlators, which reduces in the limit of zero deformation to the (2,2) ring. Finally, we compare our results with the computations carried out by Adams et al.[ABS04] and Katz and Sharpe[KS06]. We find immediate agreement with the latter and an interesting puzzle in completely matching the chiral ring of the former. Comment: AMSLatex, 30 pages, one eps figure. V4: typos corrected, final version appearing in JHEP

…

We study (0,2) deformations of a (2,2) supersymmetric gauged linear sigma
model for a Calabi-Yau hypersurface in a Fano toric variety. In the non-linear
sigma model these correspond to some of the holomorphic deformations of the
tangent bundle on the hypersurface. Combinatorial formulas are given for the
number of these deformations, and we show that these numbers are exchanged by
mirror symmetry in a subclass of the models.

…

We study the topological heterotic ring in (0,2) Landau-Ginzburg models without a (2,2) locus. The ring elements correspond to elements of the Koszul cohomology groups associated to a zero-dimensional ideal in a polynomial ring, and the computation of half-twisted genus zero correlators reduces to a map from the first non-trivial Koszul cohomology group to complex numbers. This map is a generalization of the local Grothendieck residue. The results may be applied to computations of Yukawa couplings in a heterotic compactification at a Landau-Ginzburg point. Comment: 25 pages; typos fixed; published version

…

In this paper we explore basic aspects of nonabelian (0,2) GLSM's in two
dimensions for unitary gauge groups, an arena that until recently has largely
been unexplored. We begin by discussing general aspects of (0,2) theories,
including checks of dynamical supersymmetry breaking, spectators and weak
coupling limits, and also build some toy models of (0,2) theories for bundles
on Grassmannians, which gives us an opportunity to relate physical anomalies
and trace conditions to mathematical properties, as well as to study some
simple dualities. We then turn to Calabi-Yau and related examples, studying
dualities and supersymmetry breaking. We then apply these ideas to study (0,2)
theories on Pfaffians, applying recent perturbative constructions of Pfaffians
of Jockers et al. We then turn to a more systematic study of dualities in these
theories. We begin with dualities in (2,2) nonabelian gauge theories, and give
a geometric picture of Seiberg-like duality for U(k) gauge theories with both
fundamentals and antifundamentals. We also discuss a duality between (2,2)
GLSM's for Grassmannians and certain Pfaffians, motivated by mathematics. We
describe a general duality between (0,2) theories with dual gauge bundles, and
apply it to outline the geometry underlying recent (0,2) dualities and
trialities discussed by Gadde-Gukov-Putrov. We then outline how duality works
in open strings in unitary gauge theories, and also describe why, in general
terms, we expect analogous dualities in (0,2) theories to be comparatively
rare.

…

In the framework of (0,2) gauged linear sigma models, we systematically
generate sets of perturbatively dual heterotic string compactifications. This
target space duality is first derived in non-geometric phases and then
translated to the level of GLSMs and its geometric phases. In a landscape
analysis, we compare the massless chiral spectra and the dimensions of the
moduli spaces. Our study includes geometries given by complete intersections of
hypersurfaces in toric varieties equipped with SU(n) vector bundles defined via
the monad construction.

…

In this paper we compute spaces of chiral operators in general two-dimensional (0,2) nonlinear sigma models, both in theories twistable to the A/2 or B/2 model, as well as in non-twistable theories, and apply them to check recent duality conjectures. The fact that in a nonlinear sigma model, the Fock vacuum can act as a section of a line bundle on the target space plays a crucial role in our (0,2) computations, so we begin with a review of this property. We also take this opportunity to show how even in (2,2) theories, the Fock vacuum encodes in this way choices of target space spin structures, and discuss how such choices enter the A and B model topological field theories. We then compute chiral operators in general (0,2) nonlinear sigma models, and apply them to the recent Gadde-Gukov-Putrov triality proposal, which says that certain triples of (0,2) GLSMs should RG flow to nontrivial IR fixed points. We find that different UV theories in the same proposed universality class do not necessarily have the same space of chiral operators — but, the mismatched operators do not contribute to elliptic genera and are in non-integrable representations of the proposed IR affine symmetry groups, suggesting that the mismatched states become massive along RG flow. We find this state matching in examples not only of different geometric phases of the same GLSMs, but also in phases of different GLSMs, indirectly verifying the triality proposal, and giving a clean demonstration that (0,2) chiral rings are not topologically protected. We also check proposals for enhanced IR affine E
6 symmetries in one such model, verifying that (matching) chiral states in phases of corresponding GLSMs transform as 27’s, \( \overline{\mathbf{27}}'\mathrm{s} \).

…

We study the role of accidental symmetries in two-dimensional (0,2)
superconformal field theories obtained by RG flow from (0,2) Landau-Ginzburg
theories. These accidental symmetries are ubiquitous, and, unlike in the case
of (2,2) theories, their identification is key to correctly identifying the IR
fixed point and its properties. We develop a number of tools that help to
identify such accidental symmetries in the context of (0,2) Landau-Ginzburg
models and provide a conjecture for a toric structure of the SCFT moduli space
in a large class of models. We also give a self-contained discussion of aspects
of (0,2) conformal perturbation theory.

…

Conformal field theories with (0,4) worldsheet supersymmetry and K3 target
can be used to compactify the E8xE8 heterotic string to six dimensions in a
supersymmetric manner. The data specifying such a model includes an appropriate
configuration of 24 gauge instantons in the E8xE8 gauge group to satisfy the
constraints of anomaly cancellation. In this note, we compute twining genera -
elliptic genera with appropriate insertions of discrete symmetry generators in
the trace - for (0,4) theories with various instanton embeddings. We do this by
constructing linear sigma models which flow to the desired conformal field
theories, and using the techniques of localization. We present several examples
of such twining genera which are consistent with a moonshine relating these
(0,4) models to the finite simple sporadic group M24.

…

We discuss a marginal deformation of the SL(2,R) x SU(2) x U(1)^4 WZW model,
which describes string theory on AdS_3 x S^3 x T^4, that corresponds to warping
the S^3 factor. This deformation breaks part of the N=(4,4) supersymmetry of
the undeformed dual CFT to N=(0,4) supersymmetry. In the spirit of work by
Giveon, Kutasov, and Seiberg, we construct the asymptotic spacetime symmetry
algebra from worldsheet operators and find a restoration of (4,4) supersymmetry
at discrete values of the deformation parameter. We explain this result from
various perspectives: the worldsheet, supergravity, and from the singular D1-D5
CFT. The supergravity analysis includes an asymptotic symmetry computation of
the level of the affine SU(2) R-symmetry, which arises purely from B-field
contributions.

…

The energy flow, dE/d(eta), is studied at large pseudorapidities in
proton-proton collisions at the LHC, for centre-of-mass energies of 0.9 and 7
TeV. The measurements are made in the pseudorapidity range 3.15 < |eta| < 4.9,
for both minimum-bias events and events with at least two high-momentum jets,
using the CMS detector. The data are compared to various pp Monte Carlo event
generators whose theoretical models and input parameter values are sensitive to
the energy-flow measurements. Inclusion of multiple-parton interactions in the
Monte Carlo event generators is found to improve the description of the
energy-flow measurements.

…

- The CMS collaboration
- Vardan Khachatryan
- Albert Sirunyan
- [...]
- M. Weinberg

Measurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton
collisions at centre-of-mass energies of Ös = 0.9 \sqrt {s} = 0.9 , 2.36, and 7 TeV, in five pseudorapidity ranges from |η| < 0.5 to |η| < 2.4. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and
the 7 TeV run in 2010. The multiplicity distribution at
Ös = 0.9\textTeV \sqrt {s} = 0.9\;{\text{TeV}} is in agreement with previous measurements. At higher energies the increase of the mean multiplicity with Ös \sqrt {s} is underestimated by most event generators. The average transverse momentum as a function of the multiplicity is also presented.
The measurement of higher-order moments of the multiplicity distribution confirms the violation of Koba-Nielsen-Olesen scaling
that has been observed at lower energies.
KeywordsHadron-Hadron Scattering

…

- The CMS collaboration
- Vardan Khachatryan
- Albert Sirunyan
- [...]
- M. Weinberg

Bose-Einstein correlations between identical particles are measured in samples of proton-proton collisions at 0.9 and 7 TeV
centre-of-mass energies, recorded by the CMS experiment at the LHC. The signal is observed in the form of an enhancement of
number of pairs of same-sign charged particles with small relative momentum. The dependence of this enhancement on kinematic
and topological features of the event is studied. Anticorrelations between same-sign charged particles are observed in the
region of relative momenta higher than those in the signal region.
KeywordHadron-Hadron Scattering

…

- The CMS Collaboration
- Sergey Chatrchyan
- Vardan Khachatryan
- [...]
- M. Weinberg

A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed in proton-proton collisions at \( \sqrt {s} = 0.9 \) and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |η| < 2 and transverse momentum p
T
> 0.5 GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-p
T
sum of the particles in the transverse region is observed with increasing p
T
of the leading track-jet, followed by a much slower rise above a few GeV/c. For track-jet p
T
larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in pythia are compared to the data.

…

Dubovsky and Sibiryakov recently proposed a scenario in which particles of different species propagate with different speeds due to their direct couplings to ghost condensate. It was argued that this extended version of ghost condensate allows a gedanken experiment leading to violation of the generalized second law. However, in the original ghost condensate scenario, difference in propagation speeds is suppressed by M^2/M_{Pl}^2, where M is the order parameter of spontaneous Lorentz breaking and M_{Pl} is the Planck scale. In this case the energy transfer necessary for the gedanken experiment is so slow that the timescale of decrease of entropy, if any, is always longer than the Jeans timescale of ghost condensate. Hence the generalized second law is not violated by the gedanken experiment in the original ghost condensate scenario. This conclusion trivially extends to gauged ghost condensation by taking into account accretion of gauged ghost condensate into a black hole. Comment: 17 pages; comment on negative energy added, gauged ghost condensation considered (v2); version accepted for publication in JHEP (v3)

…

We study possibilities of string theory embeddings of the gravity
duals for non-relativistic Lifshitz-like theories with anisotropic
scale invariance. We search classical solutions in type IIA and
eleven-dimensional supergravities which are expected to be dual to
(2+1)-dimensional Lifshitz-like theories. Under reasonable
ansätze, we prove that such gravity duals in the supergravities
are not possible. We also discuss a possible physical reason behind this.

…

A model of an exact gravity dual of a gapless superconductor is presented in which the condensate is provided by a charged scalar field coupled to a bulk black hole of hyperbolic horizon in asymptotically AdS spacetime. Below a critical temperature, the black hole acquires its hair through a phase transition while an electromagnetic perturbation of the background Maxwell field determines the conductivity of the boundary theory. Comment: 21 pages, 8 figures, a section on the stability of the MTZ black hole is added, references are added, version to be published in JHEP

…

We investigate the quantitative impact that data from the second oscillation maximum has on the performance of wide band beam neutrino oscillation experiments. We present results for the physics sensitivities to standard three flavor oscillation, as well as results for the sensitivity to non-standard interactions. The quantitative study is performed using an experimental setup similar to the Fermilab to DUSEL Long Baseline Neutrino Experiment (LBNE). We find that, with the single exception of sensitivity to the mass hierarchy, the second maximum plays only a marginal role due to the experimental difficulties to obtain a statistically significant and sufficiently background-free event sample at low energies. This conclusion is valid for both water Čerenkov and liquid argon detectors. Moreover, we confirm that non-standard neutrino interactions are very hard to distinguish experimentally from standard three-flavor effects and can lead to a considerable loss of sensitivity to θ
13, the mass hierarchy and CP violation.

…

In the time-space symmetric version of dynamical triangulation, a
non-perturbative version of quantum Einstein gravity, numerical simulations
without matter have shown two phases, with spacetimes that are either crumpled
or elongated like branched polymers, with strong evidence of a first-order
transition between them. These properties have generally been considered
unphysical. Using previously unpublished numerical results, we give an
interpretation in terms of continuum spacetimes that have constant positive and
negative curvature, respectively in the 'elongated' and 'crumpled' phase. The
magnitude of the positive curvature leads naturally to average spacetimes
consisting solely of baby-universes in a branched-polymer structure, whereas
the negative curvature accommodates easily a large mother universe, albeit with
a crumpling singularity. Nevertheless, there is evidence for scaling in the
crumpled phase, which we compare with the well-known scaling in the elongated
phase. Using constraint effective-action models we analyze existing numerical
susceptibility-data of the phase transition and determine the behavior of the
average Regge-curvature. We propose a renormalization of the Regge curvature
and compare it to the curvature of the above continuum spacetimes, and also to
the curvature implied by the Gauss-Bonnet theorem in the continuum. The latter
involves a more benign multiplicative renormalization and suggests that
simulations at larger volumes are needed to settle the order of the phase
transition.

…

In a Dark left-right gauge model, the neutral component of right-handed lepton doublet is odd under generalized R-parity and thus the lightest one serves as the dark matter (DM) candidate. The coannihilation of the dark matter with the singly charged Higgs triplet produces the correct relic abundance. We explain AMS-02 positron excess by the annihilation of 800 GeV dark matter into μ
+μ
−γ, through a t-channel exchange of the additional charged triplet Higgs boson. The DM is leptophilic which is useful for explaining the non-observation of any antiproton excess which would generically be expected from DM annihilation. The large cross-section needed to explain AMS-02 also requires an astrophysical boost. In addition, we show that the muon (g − 2) receives required contribution from singly and doubly charged triplet Higgs in the loops.

…

We studied an extension of the standard model with a vector lepton doublet to
explain the discrepancy in the muon $g-2$ and explain the positron excess seen
in the AMS-02 experiment. We introduced a gauge $\rm SU(2)_H$ horizontal
symmetry between the muon family and the 4th generation leptons. The neutral
components of the 4th generation lepton doublet act as inelastic pseudo-Dirac
dark matter. In this leptophilic model no antiproton excess predicted and the
direct detection constraints are evaded. We get a boost factor of order 100
needed to explain the AMS-02 positron flux by dark matter annihilation into
muons, by a Sommerfeld enhancement from $Z$ exchange.

…

The AMS-02 collaboration has recently reported an excess of the cosmic-ray
positron fraction, which turned out to be consistent with previous results
reported by the PAMELA and Fermi-LAT collaborations. A decaying dark matter
with the mass around 1 TeV can be responsible for the excess of the positron
fraction when it is interpreted as a dark matter signal. Interestingly, the
pure gravity mediation model provides such a dark matter, namely an almost pure
neutral wino dark matter, when a tiny R-parity violation through $LLE^c$
interactions is introduced. We show that the decaying wino dark matter well
reproduces the energy spectrum of the fraction with being consistent with
constraints from cosmic-ray anti-proton and gamma-ray observations.

…

We propose a definition of asymptotically plane wave spacetimes in
vacuum gravity in terms of the asymptotic falloff of the metric, and
discuss the relation to previously constructed exact solutions. We
construct a well-behaved action principle for such spacetimes, using
the formalism developed by Mann and Marolf. We show that this action
is finite on-shell and that the variational principle is
well-defined for solutions of vacuum gravity satisfying our
asymptotically plane wave falloff conditions.

…

We present models of flavorful supersymmetry in higher dimensions. The Higgs fields and the supersymmetry breaking field are localized in the same place in the extra dimension(s). The Yukawa couplings and operators generating the supersymmetry breaking parameters then receive the same suppression factors from the wavefunction profiles of the matter fields, leading to a specific correlation between these two classes of interactions. The resulting phenomenology is very rich, while stringent experimental constraints from the low-energy flavor and CP violating processes can all be satisfied. We construct both unified and non-unified models in this framework, which can be either strongly or weakly coupled at the cutoff scale. We analyze one version in detail, a strongly coupled unified model, which addresses various issues of supersymmetric grand unification. The models presented here provide an explicit example in which the supersymmetry breaking spectrum can be a direct window into the physics of flavor at a very high energy scale. Comment: 31 pages, 2 figures; references and comments added

…

We present solutions for the higher genus topological string amplitudes on Calabi-Yau-manifolds, which are realized as complete intersections in Grassmannians. We solve the B-model by direct integration of the holomorphic anomaly equations using a finite basis of modular invariant generators, the gap condition at the conifold and other local boundary conditions for the amplitudes. Regularity of the latter at certain points in the moduli space suggests a CFT description. The A-model amplitudes are evaluated using a mirror conjecture for Grassmannian Calabi-Yau by Batyrev, Ciocan-Fontanine, Kim and Van Straten. The integrality of the BPS states gives strong evidence for the conjecture.

…

Can supersymmetric models with a moderate stop mass be made consistent with the negative Higgs boson searches at LEP, while keeping perturbative unification manifest? The NMSSM achieves this rather easily, but only if extra matter multiplets filling complete SU(5) representations are present at intermediate energies. As a concrete example which makes use of this feature, we give an analytic description of the phenomenology of a constrained NMSSM close to a Peccei-Quinn symmetry point. The related pseudo-Goldstone boson appears in decays of the Higgs bosons and possibly of the lightest neutralino, and itself decays into (b anti-b) and (tau anti-tau).

…

In the work [1, 2], black hole spectroscopy has been successfully reproduced in the tunneling picture. As a result, the derived entropy spectrum of black hole in different gravity (including Einstein’s gravity, Einstein-Gauss-Bonnet gravity and Hořava-Lifshitz gravity) are all evenly spaced, sharing the same forms as S
n
= n, where physical process is only confined in the semiclassical framework. However, the real physical picture should go beyond the semiclassical approximation. In this case, the physical quantities would undergo higher-order quantum corrections, whose effect on different gravity shares in different forms. Motivated by these facts, in this paper we aim to observe how quantum corrections affect black hole spectroscopy in different gravity. The result shows that, in the presence of higher-order quantum corrections, black hole spectroscopy in different gravity still shares the same form as S
n
= n, further confirming the entropy quantum is universal in the sense that it is not only independent of black hole parameters, but also independent of higher-order quantum corrections. This is a desiring result for the forthcoming quantum gravity theory.

…

In recent work (arXiv:0712.2456, arXiv:0712.2451) the energy-momentum tensor for the N=4 SYM fluid was computed up to second derivative terms using holographic methods. The aim of this note is to propose an entropy current (accurate up to second derivative terms) consistent with this energy-momentum tensor and to explicate its relation with the existing theories of relativistic hydrodynamics. In order to achieve this, we first develop a Weyl-covariant formalism which simplifies the study of conformal hydrodynamics. This naturally leads us to a proposal for the entropy current of an arbitrary conformal fluid in any spacetime (with d>3). In particular, this proposal translates into a definite expression for the entropy flux in the case of N=4 SYM fluid. We conclude this note by comparing the formalism presented here with the conventional Israel-Stewart formalism.

…

We investigate the construction of five-dimensional, three-charge supergravity solutions that only have a rotational U(1) isometry. We show that such solutions can be obtained as warped compactifications with a singular ambi-polar hyper-Kahler base space and singular warp factors. We show that the complete solution is regular around the critical surface of the ambi-polar base. We illustrate this by presenting the explicit form of the most general supersymmetric solutions that can be obtained from an Atiyah-Hitchin base space and its ambi-polar generalizations. We make a parallel analysis using an ambi-polar generalization of the Eguchi-Hanson base space metric. We also show how the bubbling procedure applied to the ambi-polar Eguchi-Hanson metric can convert it to a global AdS_2xS^3 compactification.

…

Recently, an interesting work, which reformulates the tunneling framework to
directly produce the Hawking emission spectrum and entropy spectroscopy in the
tunneling picture, has been received a broad attention. However, during the
emission process, most related observations have not incorporated the effects
of back reaction on the background spacetime, whose derivations are therefore
not the desiring results for the real physical process. With this point as a
central motivation, in this paper we suitably adapt the \emph{reformulated}
tunneling framework so that it can well accommodate the effects of back
reaction to produce the Hawking emission spectrum and entropy spectroscopy.
Consequently, we interestingly find that, when back reaction is considered, the
Parikh-Wilczek's outstanding observations that, an isolated radiating black
hole has an unitary-evolving emission spectrum that is \emph{not} precisely
thermal, but is related to the change of the Bekenstein-Hawking entropy, can
also be reproduced in the reformulated tunneling framework, meanwhile the
entropy spectrum has the same form as that without inclusion of back reaction,
which demonstrates the entropy quantum is \emph{independent} of the effects of
back reaction. As our final analysis, we concentrate on the issues of the black
hole information, but \emph{unfortunately} find that, even including the
effects of back reaction and higher-order quantum corrections, such tunneling
formalism can still not provide a mechanism for preserving the black hole
information.

…

In this paper we show that the polynomial structure of the topological string partition function found by Yamaguchi and Yau for the quintic holds for an arbitrary Calabi-Yau manifold with any number of moduli. Furthermore, we generalize these results to the open topological string partition function as discussed recently by Walcher and reproduce his results for the real quintic. 1 Introduction and Summary The holomorphic anomaly equation of the topological string [1, 2] relates the anti-holomorphic derivative of the genus g topological string partition function F (g) with covariant derivatives of the partition functions of lower genus. This enables one to recursively determine the partition function at each genus up to a holomorphic ambiguity which has to be fixed

…

We study a system of $N_c$ $D3$-branes intersecting $D7$-branes and $O7$-planes in 1+1-dimensions. We use anomaly cancellation and string dualities to argue that there must be chiral fermion zero-modes on the $D3$-branes which are localized near the $O7$-planes. Away from the orientifold limit we verify this by using index theory as well as explicit construction of the zero-modes. This system is related to F-theory on K3 and heterotic matrix string theory, and the heterotic strings are related to Alice string defects in $\mathcal{N}=4$ Super-Yang-Mills. In the limit of large $N_c$ we find an $AdS_3$ dual of the heterotic matrix string CFT. Comment: 44 pages, typos corrected, version published in JHEP

…

We study geometries produced by brane intersections preserving eight supercharges. Typical examples of such configurations are given by fundamental strings ending on Dp branes and we construct gravity solutions describing such intersections. The geometry is specified in terms of two functions obeying coupled differential equations and the boundary conditions are determined by distributions of D branes. We show that a consistency of type IIB supergravity constrains the allowed positions of the branes. The shapes of branes derived from gravity are found to be in a perfect agreement with profiles predicted by the DBI analysis. We also discuss related 1/4-BPS systems in M theory.

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We show how Newtonian gravity emerges on 4-dimensional non-commutative spacetime branes in Yang-Mills matrix models. Large matter clusters such as galaxies are embedded in large-scale harmonic deformations of the space-time brane, which screen gravity for long distances. On shorter scales, the local matter distribution reproduces Newtonian gravity via local deformations of the brane and its metric. The harmonic ``gravity bag'' acts as a halo with effective positive energy density. This leads in particular to a significant enhancement of the orbital velocities around galaxies at large distances compared with the Newtonian case, before dropping to zero as the geometry merges with a Milne-like cosmology. Besides these ``harmonic'' solutions, there is another class of solutions which is more similar to Einstein gravity. Thus the IKKT model provides an accessible candidate for a quantum theory of gravity. Comment: 35 pages, 4 figures. V2: Minor corrections and discussion added, published version

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We show that all IIB supergravity backgrounds which admit more than 28 Killing spinors are maximally supersymmetric. In particular, we find that for all N> 28 backgrounds the supercovariant curvature vanishes, and that the quotients of maximally Recently, it has been realized that there are restrictions on the existence of type II and eleven-dimensional supergravity backgrounds with near maximal number of supersymmetries. This was initiated in [1] where it was shown that IIB backgrounds with N = 31 supersymmetries are maximally supersymmetric. Later this was extended to IIA backgrounds

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Martin has proposed a scenario dubbed ``compressed supersymmetry'' (SUSY) where the MSSM is the effective field theory between energy scales M_{\rm weak} and M_{\rm GUT}, but with the GUT scale SU(3) gaugino mass M_3<< M_1 or M_2. As a result, squark and gluino masses are suppressed relative to slepton, chargino and neutralino masses, leading to a compressed sparticle mass spectrum, and where the dark matter relic density in the early universe may be dominantly governed by neutralino annihilation into ttbar pairs via exchange of a light top squark. We explore the dark matter and collider signals expected from compressed SUSY for two distinct model lines with differing assumptions about GUT scale gaugino mass parameters. For dark matter signals, the compressed squark spectrum leads to an enhancement in direct detection rates compared to models with unified gaugino masses. Meanwhile, neutralino halo annihilation rates to gamma rays and anti-matter are also enhanced relative to related scenarios with unified gaugino masses but, depending on the halo dark matter distribution, may yet be below the sensitivity of indirect searches underway. In the case of collider signals, we compare the rates for the potentially dominant decay modes of the stop_1 which may be expected to be produced in cascade decay chains at the LHC: \tst_1\to c\tz_1 and \tst_1\to bW\tz_1. We examine the extent to which multilepton signal rates are reduced when the two-body decay mode dominates. For the model lines that we examine here, the multi-lepton signals, though reduced, still remain observable at the LHC. Comment: 22 pages including 24 eps figures

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We study the smooth non-supersymmetric three-charge microstates of Jejjala, Madden, Ross and Titchener [hep-th/0504181] using Kaluza-Klein reductions of the solutions to five and four dimensions. Our aim is to improve our understanding of the relation between these non-supersymmetric solutions and the well-studied supersymmetric cases. We find some surprising qualitative differences. In the five-dimensional description, the solution has orbifold fixed points which break supersymmetry locally, so the geometries cannot be thought of as made up of separate half-BPS centers. In the four-dimensional description, the two singularities in the geometry are connected by a conical singularity, which makes it impossible to treat them independently and assign unambiguous brane charges to these centers.

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We investigate boundary dynamics of orbifold conformal field theory involving T-duality twists. Such models typically appear in contexts of non-geometric string compactifications that are called monodrofolds or T-folds in recent literature. We use the framework of boundary conformal field theory to analyse the models from a microscopic world-sheet perspective. In these backgrounds there are two kinds of D-branes that are analogous to bulk and fractional branes in standard orbifold models. The bulk D-branes in T-folds allow intuitive geometrical interpretations and are consistent with the classical analysis based on the doubled torus formalism. The fractional branes, on the other hand, are `non-geometric' at any point in the moduli space and their geometric counterparts seem to be missing in the doubled torus analysis. We compute cylinder amplitudes between the bulk and fractional branes, and find that the lightest modes of the open string spectra show intriguing non-linear dependence on the moduli (location of the brane or value of the Wilson line), suggesting that the physics of T-folds, when D-branes are involved, could deviate from geometric backgrounds even at low energies. We also extend our analysis to the models with SU(2) WZW fibre at arbitrary levels. Comment: 38 pages, no figure, ams packages. Essentially the published version

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We propose gauge theory operators built using a complex Matrix scalar which are dual to brane-anti-brane systems in $AdS_5 \times S^5 $, in the zero coupling limit of the dual Yang-Mills. The branes involved are half-BPS giant gravitons. The proposed operators dual to giant-anti-giant configurations satisfy the appropriate orthogonality properties. Projection operators in Brauer algebras are used to construct the relevant multi-trace Matrix operators. These are related to the ``coupled representations'' which appear in 2D Yang-Mills theory. We discuss the implications of these results for the quantum mechanics of a complex matrix model, the counting of non-supersymmetric operators and the physics of brane-anti-brane systems. The stringy exclusion principle known from the properties of half-BPS giant gravitons, has a new incarnation in this context. It involves a qualitative change in the map between brane-anti-brane states to gauge theory operators. In the case of a pair of sphere giant and anti-giant this change occurs when the sum of the magnitudes of their angular momenta reaches $N$. Comment: 52 pages, 10 figures

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In this paper, we first use semi-classical methods to study quantum field theoretical aspects of the integrable
noncommutative sine-Gordon model proposed in [hep-th/0406065]. In particular, we examine the fluctuations at quadratic order around the static kink solution using the background field method. We derive equations of motion for the fluctuations and argue that at O(θ2) the spectrum of fluctuations remains essentially the same as that of the corresponding commutative theory. We compute the one-loop two-point functions of the sine-Gordon field and the additional scalar field present in the model and exhibit logarithmic divergences, only some of which lead to UV/IR mixing. We briefly discuss the one-loop renormalization in Euclidean signature and comment on the obstacles in determining the noncommutativity corrections to the quantum mass of the kink.

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We study the dynamics of the finite-temperature phase transition for warped Randall-Sundrum(RS)-like throat models related to the Klebanov-Tseytlin solution. We find that, for infrared branes stabilized near the tip of the throat, the bounce action has a mild N^2 dependence, where N(y) \sim [M_5 L(y)]^{3/2} is the effective number of degrees of freedom of the holographic dual QFT, and where L(y) is the local curvature radius, which decreases in the infrared. In addition, the bounce action is not enhanced by large numbers. These features allow the transition to successfully complete over a wider parameter range than for Goldberger-Wise stabilized RS models. Due to the increase of L(y) in the ultraviolet, the throat has a reliable gravitational description even when the number of infrared degrees of freedom is small. We also comment on aspects of the thermal phase transition in Higgsless models, where the gauge symmetry breaking is achieved via boundary conditions. Such models include orbifold-GUT models and the Higgsless electroweak symmetry breaking theories of Csaki et al., with Standard Model gauge fields living in the bulk.

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We show how the well-known classical field equations
as Einstein and Yang-Mills ones, which arise as the conformal invariance conditions of certain two-dimensional theories,
expanded up to the second order in the formal parameter, can be reformulated as Generalized/formal Maurer-Cartan equations
(GMC), where the differential is the BRST operator of String theory. We introduce the bilinear operations which
are present in GMC, and study their properties,
allowing us to find the symmetries of the resulting equations which will be naturally identified
with the diffeomorphism and gauge symmetries of Einstein and Yang-Mills equations correspondingly.

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