pinecone/core-2020-05-10-deduplication huggingface dataset:
Forward-Backward Asymmetry as a Discovery Tool for Z' Bosons at the LHC

The Forward-Backward Asymmetry (AFB) in Z' physics is commonly only perceived
as the observable which possibly allows one to interpret a Z' signal by
distinguishing different models of such (heavy) spin-1 bosons. In this paper,
we examine the potential of AFB in setting bounds on or even discovering a Z'
boson at the Large Hadron Collider (LHC) and show that it might be a powerful
tool for this purpose. We analyse two different scenarios: Z' bosons with a
narrow and wide width, respectively. We find that, in the first case, the
significance of the AFB search can be comparable with that of the bump search
usually adopted by the experimental collaborations; however, being a ratio of
(differential) cross sections the AFB has the advantage of reducing
systematical errors. In the second case, the AFB search can win over the bump
search in terms of event shape, as the structure of the AFB distribution as a
function of the invariant mass of the reconstructed Z'boson could nail down the
new broad resonance much better than the event counting strategy usually
adopted in such cases.Comment: 27 pages, 17 figure
Multifield Dynamics in Higgs-otic Inflation

In Higgs-otic inflation a complex neutral scalar combination of the $h^0$ and
$H^0$ MSSM Higgs fields plays the role of inflaton in a chaotic fashion. The
potential is protected from large trans-Planckian corrections at large inflaton
if the system is embedded in string theory so that the Higgs fields parametrize
a D-brane position. The inflaton potential is then given by a DBI+CS D-brane
action yielding an approximate linear behaviour at large field. The inflaton
scalar potential is a 2-field model with specific non-canonical kinetic terms.
Previous computations of the cosmological parameters (i.e. scalar and tensor
perturbations) did not take into account the full 2-field character of the
model, ignoring in particular the presence of isocurvature perturbations and
their coupling to the adiabatic modes. It is well known that for generic
2-field potentials such effects may significantly alter the observational
signatures of a given model. We perform a full analysis of adiabatic and
isocurvature perturbations in the Higgs-otic 2-field model. We show that the
predictivity of the model is increased compared to the adiabatic approximation.
Isocurvature perturbations moderately feed back into adiabatic fluctuations.
However, the isocurvature component is exponentially damped by the end of
inflation. The tensor to scalar ratio varies in a region $r=0.08-0.12$,
consistent with combined Planck/BICEP results.Comment: 35 pages, 11 figure
Charged Black Hole Solutions in Gauss-Bonnet-Massive Gravity

Motivated by high interest in the close relation between string theory and
black hole solutions, in this paper, we take into account the
Einstein-Gauss-Bonnet Lagrangian in the context of massive gravity. We examine
the possibility of black hole in this regard, and discuss the types of
horizons. Next, we calculate conserved and thermodynamic quantities and check
the validity of the first law of thermodynamics. In addition, we investigate
the stability of these black holes in context of canonical ensemble. We show
that number, type and place of phase transition points may be significantly
affected by different parameters. Next, by considering cosmological constant as
thermodynamical pressure, we will extend phase space and calculate critical
values. Then, we construct thermodynamical spacetime by considering mass as
thermodynamical potential. We study geometrical thermodynamics of these black
holes in context of heat capacity and extended phase space. We show that
studying heat capacity, geometrical thermodynamics and critical behavior in
extended phase space lead to consistent results. Finally, we will employ a new
method for obtaining critical values and show that the results of this method
are consistent with those of other methods.Comment: Revised version: 22 pages, 18 figure
The spontaneous $\mathbb{Z}_2$ breaking Twin Higgs

The Twin Higgs model seeks to address the little hierarchy problem by making
the Higgs a pseudo-Goldstone of a global $SU(4)$ symmetry that is spontaneously
broken to $SU(3)$. Gauge and Yukawa couplings, which explicitly break $SU(4)$,
enjoy a discrete $\mathbb{Z}_2$ symmetry that accidentally maintains $SU(4)$ at
the quadratic level and therefore keeps the Higgs light. Contrary to most
beyond the Standard Model theories, the quadratically divergent corrections to
the Higgs mass are cancelled by a mirror sector, which is uncharged under the
Standard Model groups. However, the Twin Higgs with an exact $\mathbb{Z}_2$
symmetry leads to equal vevs in the Standard Model and mirror sectors, which is
phenomenologically unviable. An explicit $\mathbb{Z}_2$ breaking potential must
then be introduced and tuned against the $SU(4)$ breaking terms to produce a
hierarchy of vevs between the two sectors. This leads to a moderate but
non-negligible tuning. We propose a model to alleviate this tuning, without the
need for an explicit $\mathbb{Z}_2$ breaking sector. The model consists of two
$SU(4)$ fundamental Higgses, one whose vacuum preserves $\mathbb{Z}_2$ and one
whose vacuum breaks it. As the interactions between the two Higgses are turned
on, the $\mathbb{Z}_2$ breaking is transmitted from the broken to the unbroken
sector and a small hierarchy of vevs is naturally produced. The presence of an
effective tadpole and feedback between the two Higgses lead to a sizable
improvement of the tuning. The resulting Higgs boson is naturally very Standard
Model like.Comment: 17 pages, 6 figures, references update
Power-law and intermediate inflationary models in f(T)-gravity

We study inflation in the framework of $f(T)$-gravity in the presence of a
canonical scalar field. After reviewing the basic equations governing the
background cosmology in $f(T)$-gravity, we turn to study the cosmological
perturbations and obtain the evolutionary equations for the scalar and tensor
perturbations. Solving those equations, we find the power spectra for the
scalar and tensor perturbations. Then, we consider a power-law form for the
$f(T)$ function in the action and examine the inflationary models with the
power-law and intermediate scale factors. We see that in contrast with the
standard inflationary scenario based on the Einstein gravity, in the considered
$f(T)$-gravity scenario, the power-law and intermediate inflationary models can
be compatible with the observational results of Planck 2015 at 68\% CL. In our
$f(T)$-gravity setting, the potentials responsible for both the power-law and
intermediate inflationary models have the power-law form $V(\phi ) \propto
{\phi ^m}$ but the power $m$ is different for them. Therefore, we can refine
some of power-law inflationary potentials in the framework of $f(T)$-gravity
while they are disfavored by the observational data in the standard
inflationary scenario. Interestingly enough, the self-interacting quartic
potential $V(\phi ) \propto {\phi ^4}$ which has special reheating properties,
can be consistent with the Planck 2015 data in our $f(T)$-gravity scenario
while it is ruled out in the standard inflationary scenario.Comment: 30 pages, 3 figure
On section conditions of E7(7) exceptional field theory and
  superparticle in N=8 central charge superspace

We study the properties of section conditions of the E7(7) exceptional field
theory from the perspective of superparticle model in N=8 D=4 superspace
enlarged by additional bosonic coordinates related to the central charge of the
maximal supersymmetry superalgebra. In particular, the superparticle model
suggests that only a part of the section conditions corresponding to generators
of SU(8) subgroup of E7(7) is independent, and we show that this part indeed
suffices to obtain the (classical counterpart of the) general solution of the
strong section condition.Comment: 17 pages. V2. misprint corrected, references adde
New Spinor Fields on Lorentzian 7-Manifolds

This paper deals with the classification of spinor fields according to the
bilinear covariants in 7 dimensions. The previously investigated Riemannian
case is characterized by either one spinor field class, in the real case of
Majorana spinors, or three non-trivial classes in the most general complex
case. In this paper we show that by imposing appropriate conditions on spinor
fields in 7d manifolds with Lorentzian metric, the formerly obtained
obstructions for new classes of spinor fields can be circumvented. New spinor
fields classes are then explicitly constructed. In particular, on 7-manifolds
with asymptotically flat black hole background, these spinors can define a
generalized current density which further defines a time Killing vector at the
spatial infinity.Comment: 13 pages, improved, to match the final version accepted in JHE
Late time behavior of non-conformal plasmas

We determine analytically the dependence of the approach to thermal
equilibrium of strongly coupled plasmas on the breaking of scale invariance.
The theories we consider are the holographic duals to Einstein gravity coupled
to a scalar with an exponential potential. The coefficient in the exponent,
$X$, is the parameter that controls the deviation from the conformally
invariant case. For these models we obtain analytic solutions for the plasma
expansion in the late-time limit, under the assumption of boost-invariance, and
we determine the scaling behaviour of the energy density, pressure, and
temperature as a function of time. We find that the temperature decays as a
function of proper time as $T\sim \tau^{-s/4}$ with $s$ determined in terms of
the non-conformality parameter $X$ as $s=4(1-4X^2)/3$. This agrees with the
result of Janik and Peschanski, $s=4/3$, for the conformal plasmas and
generalizes it to non-conformal plasmas with $X\neq 0$. We also consider more
realistic potentials where the exponential is supplemented by power-law terms.
Even though in this case we cannot have exact solutions, we are able under
certain assumptions to determine the scaling of the energy, that receives
logarithmic corrections.Comment: 31 page
Compactifications of Deformed Conifolds, Branes and the Geometry of
  Qubits

We present three families of exact, cohomogeneity-one Einstein metrics in
$(2n+2)$ dimensions, which are generalizations of the Stenzel construction of
Ricci-flat metrics to those with a positive cosmological constant. The first
family of solutions are Fubini-Study metrics on the complex projective spaces
$CP^{n+1}$, written in a Stenzel form, whose principal orbits are the Stiefel
manifolds $V_2(R ^{n+2})=SO(n+2)/SO(n)$ divided by $Z_2$. The second family are
also Einstein-K\"ahler metrics, now on the Grassmannian manifolds
$G_2(R^{n+3})=SO(n+3)/((SO(n+1)\times SO(2))$, whose principal orbits are the
Stiefel manifolds $V_2(R^{n+2})$ (with no $Z_2$ factoring in this case). The
third family are Einstein metrics on the product manifolds $S^{n+1}\times
S^{n+1}$, and are K\"ahler only for $n=1$. Some of these metrics are believed
to play a role in studies of consistent string theory compactifications and in
the context of the AdS/CFT correspondence. We also elaborate on the geometric
approach to quantum mechanics based on the K\"ahler geometry of Fubini-Study
metrics on $CP^{n+1}$, and we apply the formalism to study the quantum
entanglement of qubits.Comment: 31 page
Aspects of Entanglement Entropy for Gauge Theories

A definition for the entanglement entropy in a gauge theory was given
recently in arXiv:1501.02593. Working on a spatial lattice, it involves
embedding the physical state in an extended Hilbert space obtained by taking
the tensor product of the Hilbert space of states on each link of the lattice.
This extended Hilbert space admits a tensor product decomposition by definition
and allows a density matrix and entanglement entropy for the set of links of
interest to be defined. Here, we continue the study of this extended Hilbert
space definition with particular emphasis on the case of Non-Abelian gauge
theories.
  We extend the electric centre definition of Casini, Huerta and Rosabal to the
Non-Abelian case and find that it differs in an important term. We also find
that the entanglement entropy does not agree with the maximum number of Bell
pairs that can be extracted by the processes of entanglement distillation or
dilution, and give protocols which achieve the maximum bound. Finally, we
compute the topological entanglement entropy which follows from the extended
Hilbert space definition and show that it correctly reproduces the total
quantum dimension in a class of Toric code models based on Non-Abelian discrete
groups.Comment: Discussion of Non-Abelian Toric code corrected to agree with
  arXiv:1511.04369; some related comments revised and typos corrected; 45
  pages, 2 figure
Scalar-Vector Bootstrap

We work out all of the details required for implementation of the conformal
bootstrap program applied to the four-point function of two scalars and two
vectors in an abstract conformal field theory in arbitrary dimension. This
includes a review of which tensor structures make appearances, a construction
of the projectors onto the required mixed symmetry representations, and a
computation of the conformal blocks for all possible operators which can be
exchanged. These blocks are presented as differential operators acting upon the
previously known scalar conformal blocks. Finally, we set up the bootstrap
equations which implement crossing symmetry. Special attention is given to the
case of conserved vectors, where several simplifications occur.Comment: 76 pages, v3 moved several details into appendices, expanded
  discussion of mixed symmetry projecto
U(1) axial symmetry and Dirac spectra in QCD at high temperature

We derive some exact results concerning the anomalous U(1)$_A$ symmetry in
the chirally symmetric phase of QCD at high temperature. We discuss the
importance of topology and finite-volume effects on the U(1)$_A$ symmetry
violation characterized by the difference of chiral susceptibilities. In
particular, we present a reliable method to measure the anomaly strength in
lattice simulations with fixed topology. We also derive new spectral sum rules
and a novel Banks-Casher-type relation. Through our spectral analysis we arrive
at a simple alternative proof of the Aoki-Fukaya-Taniguchi "theorem" on the
effective restoration of the U(1)$_A$ symmetry at high temperature.Comment: 28 pages, 2 figures; v2: Section 2 was substantially rewritten and
  Section 4 was omitted. published versio
Witten Diagrams Revisited: The AdS Geometry of Conformal Blocks

We develop a new method for decomposing Witten diagrams into conformal
blocks. The steps involved are elementary, requiring no explicit integration,
and operate directly in position space. Central to this construction is an
appealingly simple answer to the question: what object in AdS computes a
conformal block? The answer is a "geodesic Witten diagram," which is
essentially an ordinary exchange Witten diagram, except that the cubic vertices
are not integrated over all of AdS, but only over bulk geodesics connecting the
boundary operators. In particular, we consider the case of four-point functions
of scalar operators, and show how to easily reproduce existing results for the
relevant conformal blocks in arbitrary dimension.Comment: 54 pages + ref
Holographic Competition of Phases and Superconductivity

We use a holographic theory to model and study the competition of four
phases: an antiferromagnetic phase, a superconducting phase, a metallic phase
and a striped phase, using as control parameters temperature and a doping-like
parameter. We analyse the various instabilities and determine the possible
phases. One class of phase diagrams, that we analyse in detail, is similar to
that of high-temperature superconductors as well as other strange metal
materials.Comment: 73 pages, 24 figures; v2: references added; v3: Two appendices are
  moved to the main text. Comments and figures added, typos fixed, to appear in
  JHE
Global symmetries of Yang-Mills squared in various dimensions

Tensoring two on-shell super Yang-Mills multiplets in dimensions $D\leq 10$
yields an on-shell supergravity multiplet, possibly with additional matter
multiplets. Associating a (direct sum of) division algebra(s) $\mathbb{D}$ with
each dimension $3\leq D\leq 10$ we obtain formulae for the algebras
$\mathfrak{g}$ and $\mathfrak{h}$ of the U-duality group $G$ and its maximal
compact subgroup $H$, respectively, in terms of the internal global symmetry
algebras of each super Yang-Mills theory. We extend our analysis to include
supergravities coupled to an arbitrary number of matter multiplets by allowing
for non-supersymmetric multiplets in the tensor product.Comment: 25 pages, 2 figures, references added, minor typos corrected, further
  comments on sec. 2.4 included, updated to match version to appear in JHE
Realizing the relaxion from multiple axions and its UV completion with
  high scale supersymmetry

We discuss a scheme to implement the relaxion solution to the hierarchy
problem with multiple axions, and present a UV-completed model realizing the
scheme. All of the $N$ axions in our model are periodic with a similar decay
constant $f$ well below the Planck scale. In the limit $N\gg 1$, the relaxion
$\phi$ corresponds to an exponentially long multi-helical flat direction which
is shaped by a series of mass mixing between nearby axions in the compact field
space of $N$ axions. With the length of flat direction given by $\Delta \phi
=2\pi f_{\rm eff} \sim e^{\xi N} f$ for $\xi={\cal O}(1)$, both the scalar
potential driving the evolution of $\phi$ during the inflationary epoch and the
$\phi$-dependent Higgs boson mass vary with an exponentially large periodicity
of ${\cal O}(f_{\rm eff})$, while the back reaction potential stabilizing the
relaxion has a periodicity of ${\cal O}( f)$. A natural UV completion of our
scheme can be found in high scale or (mini) split supersymmetry (SUSY) scenario
with the axion scales generated by SUSY breaking as $f\sim \sqrt{m_{\rm
SUSY}M_*}$, where the soft SUSY breaking scalar mass $m_{\rm SUSY}$ can be well
above the weak scale, and the fundamental scale $M_*$ can be identified as the
Planck scale or the GUT scale.Comment: 20 pages, 2 figures; v2: a reference and related comment adde
Homogeneous M2 duals

Motivated by the search for new gravity duals to M2 branes with $N>4$
supersymmetry --- equivalently, M-theory backgrounds with Killing superalgebra
$\mathfrak{osp}(N|4)$ for $N>4$ --- we classify homogeneous M-theory
backgrounds with symmetry Lie algebra $\mathfrak{so}(n) \oplus
\mathfrak{so}(3,2)$ for $n=5,6,7$. We find that there are no new backgrounds
with $n=6,7$ but we do find a number of new (to us) backgrounds with $n=5$. All
backgrounds are metrically products of the form $\operatorname{AdS}_4 \times
P^7$, with $P$ riemannian and homogeneous under the action of
$\operatorname{SO}(5)$, or $S^4 \times Q^7$ with $Q$ lorentzian and homogeneous
under the action of $\operatorname{SO}(3,2)$. At least one of the new
backgrounds is supersymmetric (albeit with only $N=2$) and we show that it can
be constructed from a supersymmetric Freund--Rubin background via a Wick
rotation. Two of the new backgrounds have only been approximated numerically.
(The second version of this paper includes an appendix by Alexander~S.~Haupt,
closing a gap in our original analysis.)Comment: 56 page
AdS perturbations, isometries, selection rules and the Higgs oscillator

Dynamics of small-amplitude perturbations in the global anti-de Sitter (AdS)
spacetime is restricted by selection rules that forbid effective energy
transfer between certain sets of normal modes. The selection rules arise
algebraically because some integrals of products of AdS mode functions vanish.
Here, we reveal the relation of these selection rules to AdS isometries. The
formulation we discover through this systematic approach is both simpler and
stronger than what has been reported previously. In addition to the selection
rule considerations, we develop a number of useful representations for the
global AdS mode functions, with connections to algebraic structures of the
Higgs oscillator, a superintegrable system describing a particle on a sphere in
an inverse cosine-squared potential, where the AdS isometries play the role of
a spectrum-generating algebra.Comment: 24 pages; v4: published version with cosmetic correction
Holomorphic Yukawa Couplings in Heterotic String Theory

We develop techniques, based on differential geometry, to compute holomorphic
Yukawa couplings for heterotic line bundle models on Calabi-Yau manifolds
defined as complete intersections in projective spaces. It is shown explicitly
how these techniques relate to algebraic methods for computing holomorphic
Yukawa couplings. We apply our methods to various examples and evaluate the
holomorphic Yukawa couplings explicitly as functions of the complex structure
moduli. It is shown that the rank of the Yukawa matrix can decrease at specific
loci in complex structure moduli space. In particular, we compute the up Yukawa
coupling and the singlet-Higgs-lepton trilinear coupling in the heterotic
standard model described in arXiv:1404.2767Comment: 53 pages, Latex; typos correcte
Open EFTs, IR Effects and Late-Time Resummations: Systematic Corrections
  in Stochastic Inflation

Though simple inflationary models describe the CMB well, their corrections
are often plagued by infrared effects that obstruct a reliable calculation of
late-time behaviour. We adapt to cosmology tools designed to address similar
issues in other physical systems with the goal of making reliable late-time
inflationary predictions. The main such tool is Open EFTs which reduce in the
inflationary case to Stochastic Inflation plus calculable corrections. We apply
this to a simple inflationary model that is complicated enough to have
dangerous IR behaviour yet simple enough to allow the inference of late-time
behaviour. We find corrections to standard Stochastic Inflationary predictions
for the noise and drift, and we find these corrections ensure the IR finiteness
of both these quantities. The late-time probability distribution, ${\cal
P}(\phi)$, for super-Hubble field fluctuations are obtained as functions of the
noise and drift and so these too are IR finite. We compare our results to other
methods (such as large-$N$ models) and find they agree when these models are
reliable. In all cases we can explore in detail we find IR secular effects
describe the slow accumulation of small perturbations to give a big effect: a
significant distortion of the late-time probability distribution for the field.
But the energy density associated with this is only of order $H^4$ at late
times and so does {\em not} generate a dramatic gravitational back-reaction.Comment: 23 pages plus appendices. v2 corrects typos in several formulae and
  adds several reference