pinecone/core-2020-05-10-deduplication huggingface dataset:
Towards Collisions of Inhomogeneous Shockwaves in AdS

We perform a numerical simulation of the evolution of inhomogeneities with
transverse profile in a collision of gravitational shockwaves in asymptotically
anti-de Sitter spacetime. This constitutes a step closer towards an accurate
holographic description of the thermalization of a strongly coupled plasma,
which can model the dynamics of heavy ion collisions. The results indicate that
the considered inhomogeneities typically become hydrodynamical earlier or at
the same moment when hydrodynamics applies to the background, even though they
decay slowly.Comment: 11 pages, 4 figures; added figure and new results. Mathematica
  notebooks can be found at http://users.physics.uoc.gr/~fernandez/Page5.htm
From topological strings to minimal models

We glue four refined topological vertices to obtain the building block of 5D
$U(2)$ quiver instanton partition functions. We take the 4D limit of the result
to obtain the building block of 4D instanton partition functions which, using
the AGT correspondence, are identified with Virasoro conformal blocks.
  We show that there is a choice of the parameters of the topological vertices
that we start with, as well as the parameters and the intermediate states
involved in the gluing procedure, such that we obtain Virasoro minimal model
conformal blocks.Comment: 23 pages, improved the presentation, added introductory material, et
On the intrinsic bottom content of the nucleon and its impact on heavy new physics at the LHC

Heavy quark parton distribution functions (PDFs) play an important role in several Standard Model and New Physics processes. Most analyses rely on the assumption that the charm and bottom PDFs are generated perturbatively by gluon splitting and do not involve any non-perturbative degrees of freedom. It is clearly necessary to test this hypothesis with suitable QCD processes. Conversely, a non-perturbative, intrinsic heavy quark parton distribution has been predicted in the literature. We demonstrate that to a very good approximation the scale-evolution of the intrinsic heavy quark content of the nucleon is governed by non-singlet evolution equations. This allows us to analyze the intrinsic heavy quark distributions without having to resort to a full-fledged global analysis of parton distribution functions. We exploit this freedom to model intrinsic bottom distributions which are so far missing in the literature in order to estimate the impact of this non-perturbative contribution to the bottom-quark PDF, and on parton-parton luminosities at the LHC. This technique can be applied to the case of intrinsic charm, albeit within the limitations outlined in the following
On the breaking of lepton flavor universality in B decays

In view of recent experimental indications of violations of Lepton Flavor Universality (LFU) in B decays, we analyze constraints and implications of LFU interactions, both using an effective theory approach, and an explicit dynamical model. We show that a simple dynamical model based on a SU(2) L triplet of massive vector bosons, coupled predominantly to third generation fermions (both quarks and leptons), can significantly improve the description of present data. In particular, the model decreases the tension between data and SM predictions concerning: i) the breaking of τ - μ universality in B → D (*) ℓν decays; ii) the breaking of μ - e universality in B → Kℓ + ℓ − decays. Indirectly, the model might also decrease the discrepancy between exclusive and inclusive determinations of | V cb | and | V ub |. The minimal version of the model is in tension with ATLAS and CMS direct searches for the new massive vectors (decaying into τ + τ − pairs), but this tension can be decreased with additional non-standard degrees of freedom. Further pre-dictions of the model both at low- and high-energies, in view of future high-statistics data, are discussed
Horava-Lifshitz Gravity From Dynamical Newton-Cartan Geometry

Recently it has been established that torsional Newton-Cartan (TNC) geometry
is the appropriate geometrical framework to which non-relativistic field
theories couple. We show that when these geometries are made dynamical they
give rise to Horava-Lifshitz (HL) gravity. Projectable HL gravity corresponds
to dynamical Newton-Cartan (NC) geometry without torsion and non-projectable HL
gravity corresponds to dynamical NC geometry with twistless torsion
(hypersurface orthogonal foliation). We build a precise dictionary relating all
fields (including the scalar khronon), their transformations and other
properties in both HL gravity and dynamical TNC geometry. We use TNC invariance
to construct the effective action for dynamical twistless torsional
Newton-Cartan geometries in 2+1 dimensions for dynamical exponent 1<z\le 2 and
demonstrate that this exactly agrees with the most general forms of the HL
actions constructed in the literature. Further, we identify the origin of the
U(1) symmetry observed by Horava and Melby-Thompson as coming from the Bargmann
extension of the local Galilean algebra that acts on the tangent space to TNC
geometries. We argue that TNC geometry, which is manifestly diffeomorphism
covariant, is a natural geometrical framework underlying HL gravity and discuss
some of its implications.Comment: 48 page
Higgs mass determination in supersymmetry

We present the state-of-the-art of the effective field theory computation of the MSSM Higgs mass, improving the existing ones by including extra threshold corrections. We show that, with this approach, the theoretical uncertainty is within 1 GeV in most of the relevant parameter space. We confirm the smaller value of the Higgs mass found in the EFT computations, which implies a slightly heavier SUSY scale. We study the large tan β region, finding that sbottom thresholds might relax the upper bound on the scale of SUSY. We present SusyHD, a fast computer code that computes the Higgs mass and its uncertainty for any SUSY scale, from the TeV to the Planck scale, even in Split SUSY, both in the D R ¯ $$ \overline{\mathrm{DR}} $$ and in the on-shell schemes. Finally, we apply our results to derive bounds on some well motivated SUSY models, in particular we show how the value of the Higgs mass allows to determine the complete spectrum in minimal gauge mediation
NLO Higgs effective field theory and κ-framework

A consistent framework for studying Standard Model deviations is developed. It assumes that New Physics becomes relevant at some scale beyond the present experimental reach and uses the Effective Field Theory approach by adding higher-dimensional operators to the Standard Model Lagrangian and by computing relevant processes at the next-to-leading order, extending the original κ -framework. The generalized κ -framework provides a useful technical tool to decompose amplitudes at NLO accuracy into a sum of well defined gauge-invariant sub components
Layers of deformed instantons in holographic baryonic matter

We discuss homogeneous baryonic matter in the decompactified limit of the
Sakai-Sugimoto model, improving existing approximations based on flat-space
instantons. We allow for an anisotropic deformation of the instantons in the
holographic and spatial directions and for a density-dependent distribution of
arbitrarily many instanton layers in the bulk. Within our approximation, the
baryon onset turns out to be a second-order phase transition, at odds with
nature, and there is no transition to quark matter at high densities, at odds
with expectations from QCD. This changes when we impose certain constraints on
the shape of single instantons, motivated by known features of holographic
baryons in the vacuum. Then, a first-order baryon onset and chiral restoration
at high density are possible, and at sufficiently large densities two instanton
layers are formed dynamically. Our results are a further step towards
describing realistic, strongly interacting matter over a large density regime
within a single model, desirable for studies of compact stars.Comment: 37 pages, 7 figures, v2: two panels added to fig. 5, version to
  appear in JHE
The Vector-like Twin Higgs

We present a version of the twin Higgs mechanism with vector-like top
partners. In this setup all gauge anomalies automatically cancel, even without
twin leptons. The matter content of the most minimal twin sector is therefore
just two twin tops and one twin bottom. The LHC phenomenology, illustrated with
two example models, is dominated by twin glueball decays, possibly in
association with Higgs bosons. We further construct an explicit
four-dimensional UV completion and discuss a variety of UV completions relevant
for both vector-like and fraternal twin Higgs models.Comment: 39 pages; v2 published versio
On the global symmetries of 6D superconformal field theories

We study global symmetry groups of six-dimensional superconformal field
theories (SCFTs). In the Coulomb branch we use field theoretical arguments to
predict an upper bound for the global symmetry of the SCFT. We then analyze
global symmetry groups of F-theory constructions of SCFTs with a
one-dimensional Coulomb branch. While in the vast majority of cases, all of the
global symmetries allowed by our Coulomb branch analysis can be realized in
F-theory, in a handful of cases we find that F-theory models fail to realize
the full symmetry of the theory on the Coulomb branch. In one particularly
mysterious case, F-theory models realize several distinct maximal subgroups of
the predicted group, but not the predicted group itself.Comment: 47 pages; v2: typos corrected, added the case su(6)* to the analysis
  of section 5 and section 6.1. v3: references added, minor changes, published
  versio
3D $\tau_{RR}$-minimization in AdS$_4$ gauged supergravity

In this paper we propose the identification in AdS4 N = 2 gauged supergravity
of the coefficient $\tau_{RR}$ of 3D N = 2 SCFTs. We constraint the structure
of this function in supergravity by combining the results from unitarity,
holography and localization. We show that our conjectured function is minimized
by the exact R-charge, corresponding to a gravitational attractor for the
scalars in the special geometry. We identify this mechanism with the
supergravity dual of the $\tau_{RR}$-minimization. We check this proposal in
the ABJM model, comparing with the expectations from localization and the
AdS/CFT duality. We comment also on some possible relations with the black hole
microstate counting, recently obtained from the application of localization
techniques.Comment: 19 page
Bi-Local Holography in the SYK Model

We discuss large $N$ rules of the Sachdev-Ye-Kitaev model and the bi-local
representation of holography of this theory. This is done by establishing $1/N$
Feynman rules in terms of bi-local propagators and vertices, which can be
evaluated following the recent procedure of Polchinski and Rosenhaus. These
rules can be interpreted as Witten type diagrams of the dual AdS theory, which
we are able to define at IR fixed point and off.Comment: 25 pages, 6 figures; v2: minor corrections, typos corrected and
  references added; v3: typos corrected and references added; v4: improved
  discussion of AdS bulk interpretation; v5: improved discussion of zero mode
  and reference added; v6: improved discussion of zero mode, references added,
  version to appear in JHEP; v7: reference adde
Collider Constraints and Prospects of a Scalar Singlet Extension to
  Higgs Portal Dark Matter

This work considers an extension of the Standard Model (SM) Higgs sector by a
real, scalar singlet field, including applicability to a dark matter (DM) model
with the addition of a Yukawa coupling to a Dirac fermion. The collider
signatures and constraints on the mixed two-Higgs scenario are determined,
including limits from Higgs production signals and exclusion searches, as well
as constraints arising from the Higgs total and invisible widths. As there is
overwhelming Higgs data which is consistent with a SM scenario, the case in
which an additional scalar has evaded detection is further explored in the
context of Higgs precision measurement. The discovery reach and prospective
signatures of the model at a proposed linear collider are investigated, with
particular focus on the Higgs triple coupling, and di-Higgs production
processes.Comment: v2: Added references, revised description in Section 2, and small
  revisions to select figures; v3: Minor typographical corrections, published
  versio
Analytical approximations for matter effects on CP violation in the
  accelerator-based neutrino oscillations with E \lesssim 1 GeV

Given an accelerator-based neutrino experiment with the beam energy E
\lesssim 1 GeV, we expand the probabilities of \nu_\mu \to \nu_e and \overline
{\nu}_\mu \to \overline {\nu}_e oscillations in matter in terms of two small
quantities \Delta_{21}/\Delta_{31} and A/\Delta_{31}, where \Delta_{21} \equiv
m^2_2 - m^2_1 and \Delta_{31} \equiv m^2_3 - m^2_1 are the neutrino
mass-squared differences, and A measures the strength of terrestrial matter
effects. Our analytical approximations are numerically more accurate than those
made by Freund in this energy region, and thus they are particularly applicable
for the study of leptonic CP violation in the low-energy MOMENT, ESS\nuSM and
T2K oscillation experiments. As a by-product, the new analytical approximations
help us to easily understand why the matter-corrected Jarlskog parameter
\widetilde{\cal J} peaks at the resonance energy E_* \simeq 0.14 GeV (or 0.12
GeV) for the normal (or inverted) neutrino mass hierarchy, and how the three
Dirac unitarity triangles are deformed due to the terrestrial matter
contamination. We also affirm that a medium-baseline neutrino oscillation
experiment with the beam energy E lying in the E_* \lesssim E \lesssim 2 E_*
range is capable of exploring leptonic CP violation with little matter-induced
suppression.Comment: 36 pages, 11 figures. A crucial mistake removed, highlights changed,
  and a comparison with Freund's result mad
Dynamics of ${\cal N}=4$ supersymmetric field theories in 2+1 dimensions
  and their gravity dual

In this note we consider ${\cal N}=4$ SYM theories in 2+1 dimensions with
gauge group $U(N)\times U(M)$ and $k$ hypermultiplets charged under the $U(N)$.
When $k > 2(N-M)$, the theory flows to a superconformal fixed point in the IR.
Theories with $k <2(N-M)$, on the other hand, flows to strong coupling. We
explore these theories from the perspective of gravity dual. We find that the
gravity duals of theories with $k < (N-M)$ contain enhancons even in situations
where repulson singularities are absent. We argue that supergravity description
is unreliable in the region near these enhancon points. Instead, we show how to
construct reliable sugra duals to particular points on the Coulomb branch where
the enhancon is screened. We explore how these singularities reappear as one
moves around in Coulomb branch and comment on possible field theory
interpretation of this phenomenon. In analyzing gauge/gravity duality for these
models, we encountered one unexpected surprise, that the condition for the
supergravity solution to be reliable and supersymmetric is somewhat weaker than
the expectation from field theory. We also discuss similar issues for theories
with $k=0$.Comment: 31 pages, 12 figure
Consistency of WIMP Dark Matter as radiative neutrino mass messenger

The scotogenic scenario provides an attractive approach to both Dark Matter
and neutrino mass generation, in which the same symmetry that stabilises Dark
Matter also ensures the radiative seesaw origin of neutrino mass. However the
simplest scenario may suffer from inconsistencies arising from the spontaneous
breaking of the underlying $\mathbb{Z}_2$ symmetry. Here we show that the
singlet-triplet extension of the simplest model naturally avoids this problem
due to the presence of scalar triplets neutral under the $\mathbb{Z}_2$ which
affect the evolution of the couplings in the scalar sector. The scenario offers
good prospects for direct WIMP Dark Matter detection through the nuclear recoil
method.Comment: 16 pages, 7 figure
Green-Schwarz superstring on the lattice

We consider possible discretizations for a gauge-fixed Green-Schwarz action
of Type IIB superstring. We use them for measuring the action, from which we
extract the cusp anomalous dimension of planar $\mathcal{N}=4$ SYM as derived
from AdS/CFT, as well as the mass of the two $AdS$ excitations transverse to
the relevant null cusp classical string solution. We perform lattice
simulations employing a Rational Hybrid Monte Carlo (RHMC) algorithm and two
Wilson-like fermion discretizations, one of which preserves the global $SO(6)$
symmetry of the model. We compare our results with the expected behavior at
various values of $g=\frac{\sqrt{\lambda}}{4\pi}$. For both the observables, we
find a good agreement for large $g$, which is the perturbative regime of the
sigma-model. For smaller values of $g$, the expectation value of the action
exhibits a deviation compatible with the presence of quadratic divergences.
After their non-perturbative subtraction the continuum limit can be taken, and
suggests a qualitative agreement with the non-perturbative expectation from
AdS/CFT. Furthermore, we detect a phase in the fermion determinant, whose
origin we explain, that for very small $g$ leads to a sign problem not
treatable via standard reweigthing. The continuum extrapolations of the
observables in the two different discretizations agree within errors, which is
strongly suggesting that they lead to the same continuum limit. Part of the
results discussed here were presented earlier in arXiv:1601.04670.Comment: 33 pages, 14 figures, 2 Tables. Text overlap with the Conference
  Proceedings where some preliminary results were presented, arXiv:1601.04670v
Non-standard charged Higgs decay at the LHC in Next-to-Minimal
  Supersymmetric Standard Model

We consider next-to-minimal supersymmetric standard model (NMSSM) which has a
gauge singlet superfield. In the scale invariant superpotential we do not have
the mass terms and the whole Lagrangian has an additional $Z_3$ symmetry. This
model can have light scalar and/or pseudoscalar allowed by the recent data from
LHC and the old data from LEP. We investigate the situation where a relatively
light charged Higgs can decay to such singlet-like pseudoscalar and a $W^\pm$
boson giving rise to final state containing $\tau$ and/or $b$-jets and
lepton(s). Such decay evades the recent bounds on charged Higgs from the LHC.
According to our PYTHIA-FastJet based simulation such a scenario can be probed
with early data of 10 fb$^{-1}$ at the LHC center of mass energy of 13 and 14
TeV.Comment: 22 pages, 15 figure
Stealth Supersymmetry Simplified

In Stealth Supersymmetry, bounds on superpartners from direct searches can be
notably weaker than in standard supersymmetric scenarios, due to suppressed
missing energy. We present a set of simplified models of Stealth Supersymmetry
that motivate 13 TeV LHC searches. We focus on simplified models within the
Natural Supersymmetry framework, in which the gluino, stop, and Higgsino are
assumed to be lighter than other superpartners. Our simplified models exhibit
novel decay patterns that differ significantly from topologies of the Minimal
Supersymmetric Standard Model, with and without $R$-parity. We determine limits
on stops and gluinos from searches at the 8 TeV LHC. Existing searches
constitute a powerful probe of Stealth Supersymmetry gluinos with certain
topologies. However, we identify simplified models where the gluino can be
considerably lighter than 1 TeV. Stops are significantly less constrained in
Stealth Supersymmetry than the MSSM, and we have identified novel stop decay
topologies that are completely unconstrained by existing LHC searches.Comment: 14 pages plus appendice
Covariant Action for Type IIB Supergravity

Taking clues from the recent construction of the covariant action for type II
and heterotic string field theories, we construct a manifestly Lorentz
covariant action for type IIB supergravity, and discuss its gauge fixing
maintaining manifest Lorentz invariance. The action contains a
(non-gravitating) free 4-form field besides the usual fields of type IIB
supergravity. This free field, being completely decoupled from the interacting
sector, has no physical consequence.Comment: LaTeX, 33 pages; v2,v3: references added; v4: added new section on
  supersymmetr
Projectors and seed conformal blocks for traceless mixed-symmetry
  tensors

In this paper we derive the projectors to all irreducible SO(d)
representations (traceless mixed-symmetry tensors) that appear in the partial
wave decomposition of a conformal correlator of four stress-tensors in d
dimensions. These projectors are given in a closed form for arbitrary length
$l_1$ of the first row of the Young diagram. The appearance of Gegenbauer
polynomials leads directly to recursion relations in $l_1$ for seed conformal
blocks. Further results include a differential operator that generates the
projectors to traceless mixed-symmetry tensors and the general normalization
constant of the shadow operator.Comment: 49 pages, 1 Mathematica notebook, many figures, v2: add reference
Towards a Theory of Nonassociative Gravity

Violating the strong constraint of double field theory, non-geometric fluxes
were argued to give rise to noncommutative/nonassociative structures. We derive
in a rather pedestrian physicist way a differential geometry on the simplest
nonassociative (phase-)space arising for a constant non-geometric R-flux. This
provides a complementary presentation to the quasi-Hopf representation
categorial one delivered by Barnes, Schenkel, Szabo in
arXiv:1409.6331+1507.02792. As there, the notions of tensors, covariant
derivative, torsion and curvature find a star-generalization. We continue the
construction with the introduction of a star-metric and its star-inverse where,
due to the nonassociativity, we encounter major deviations from the familiar
structure. Comments on the Levi-Civita connection, a star-Einstein-Hilbert
action and the relation to string theory are included, as well.Comment: 38 pages, v2: ref. adde
A Megaxion at 750 GeV as a First Hint of Low Scale String Theory

Low scale string models naturally have axion-like pseudoscalars which couple
directly to gluons and photons (but not $W$s) at tree level. We show how they
typically get tree level masses in the presence of closed string fluxes,
consistent with the axion discrete gauge symmetry, in a way akin of the axion
monodromy of string inflation and relaxion models. We discuss the possibility
that the hints for a resonance at 750 GeV recently reported at ATLAS and CMS
could correspond to such a heavy axion state (megaxion). Adjusting the
production rate and branching ratios suggests the string scale to be of order
$M_s$ ~ $7 - 10^4$ TeV, depending on the compactification geometry. If this
interpretation was correct, one extra $Z'$ gauge boson could be produced before
reaching the string threshold at LHC and future colliders.Comment: 26 pages, 3 figures, 1 Megaxio