pinecone/core-2020-05-10-deduplication huggingface dataset:
Conformal algebra: R-matrix and star-triangle relation

The main purpose of this paper is the construction of the R-operator which
acts in the tensor product of two infinite-dimensional representations of the
conformal algebra and solves Yang-Baxter equation. We build the R-operator as a
product of more elementary operators S_1, S_2 and S_3. Operators S_1 and S_3
are identified with intertwining operators of two irreducible representations
of the conformal algebra and the operator S_2 is obtained from the intertwining
operators S_1 and S_3 by a certain duality transformation. There are
star-triangle relations for the basic building blocks S_1, S_2 and S_3 which
produce all other relations for the general R-operators. In the case of the
conformal algebra of n-dimensional Euclidean space we construct the R-operator
for the scalar (spin part is equal to zero) representations and prove that the
star-triangle relation is a well known star-triangle relation for propagators
of scalar fields. In the special case of the conformal algebra of the
4-dimensional Euclidean space, the R-operator is obtained for more general
class of infinite-dimensional (differential) representations with nontrivial
spin parts. As a result, for the case of the 4-dimensional Euclidean space, we
generalize the scalar star-triangle relation to the most general star-triangle
relation for the propagators of particles with arbitrary spins.Comment: Added references and corrected typo
Towards the fast scrambling conjecture

Many proposed quantum mechanical models of black holes include highly non-local interactions. The time required for thermalization to occur in such models should reflect the relaxation times associated with classical black holes in general relativity. Moreover, the time required for a particularly strong form of thermalization to occur, sometimes known as scrambling, determines the time scale on which black holes should start to release information. It has been conjectured that black holes scramble in a time logarithmic in their entropy, and that no system in nature can scramble faster. In this article, we address the conjecture from two directions. First, we exhibit two examples of systems that do indeed scramble in logarithmic time: Brownian quantum circuits and the antiferromagnetic Ising model on a sparse random graph. Unfortunately, both fail to be truly ideal fast scramblers for reasons we discuss. Second, we use Lieb-Robinson techniques to prove a logarithmic lower bound on the scrambling time of systems with finite norm terms in their Hamiltonian. The bound holds in spite of any nonlocal structure in the Hamiltonian, which might permit every degree of freedom to interact directly with every other one.CIFARNSERCCanada Research Chairs programONR/N0001480811249United States NS
Randall-Sundrum model with a small curvature and dimuon production at
  the LHC

The $p_{\perp}$-distributions for the dimuon production at the LHC are
calculated in the Randall-Sundrum scenario with a small curvature $\kappa$. The
$pp$ collisions at 7 TeV and 14 TeV are considered. The widths of massive
graviton excitations are taken into account. It is found that the LHC discovery
limit on 5-dimensional gravity scale $M_5$ is equal to 5.5 TeV for $\sqrt{s} =
7$ TeV and integrated luminositiy 5 fb$^{-1}$. For $\sqrt{s} = 14$ TeV and
integrated luminosities 30 fb$^{-1}$ and 100 fb$^{-1}$, the search limits in
the dimuon events are 12.0 TeV and 14.6 TeV, respectively. Contrary to the
standard RS model, these limits are independent of $\kappa$, provided $\kappa
\ll M_5$.Comment: 18 pages, 7 figures, journal versio
QCD matrix elements + parton showers : the NLO case.\ud

We present a process-independent technique to consistently combine next-to-leading order parton-level calculations of varying jet multiplicity and parton showers. Double counting is avoided by means of a modified truncated shower scheme. This method preserves both the fixed-order accuracy of the parton-level result and the logarithmic accuracy of the parton shower. We discuss the renormalisation and factorisation scale dependence of the approach and present results from an automated implementation in the SHERPA event generator using the test case of W -boson production at the Large Hadron Collider. We observe a dramatic reduction of theoretical uncertainties compared to existing methods which underlines the predictive power of our novel technique
LHC Coverage of RPV MSSM with Light Stops

We examine the sensitivity of recent LHC searches to signatures of
supersymmetry with R-parity violation (RPV). Motivated by naturalness of the
Higgs potential, which would favor light third-generation squarks, and the
stringent LHC bounds on spectra in which the gluino or first and second
generation squarks are light, we focus on scenarios dominated by the pair
production of light stops. We consider the various possible direct and cascade
decays of the stop that involve the trilinear RPV operators. We find that in
many cases, the existing searches exclude stops in the natural mass range and
beyond. However, typically there is little or no sensitivity to cases dominated
by UDD operators or LQD operators involving taus. We propose several ideas for
searches which could address the existing gaps in experimental coverage of
these signals.Comment: 41 pages, 12 figures; v2: included new searches (see footnote 10),
  minor corrections and improvement
Same-sign Tops: A Powerful Diagnostic Test for Models of New Physics

We study the connection between the same sign top (SST) and the top quark
forward-backward asymmetry $A^t_{FB}$. We find that a large class of new
physics models that have been proposed to account for the $A^t_{FB}$ lead to
SST quark production rate much larger than the observed rate at the LHC and
consequently are severely constrained or ruled out. Our model independent,
general, operator analysis shows that none of the tree-level flavor-changing
operators are able to explain $A^t_{FB}$ and simultaneously remain consistent
with the same-sign top-quark production constraints from the LHC data.Comment: 19 LaTeX pages, 3 Tables and 4 png Figures, accepted version for
  publication in JHE
On holographic thermalization and gravitational collapse of tachyonic
  scalar fields

In this paper we study the thermalization of a spatially homogeneous system
in a strongly coupled CFT. The non-equilibrium initial state is created by
switching on a relevant perturbation in the CFT vacuum during Delta t >= t >=
-Delta t. Via AdS/CFT, the thermalization process corresponds to the
gravitational collapse of a tachyonic scalar field (m^2 = -3) in the Poincare
patch of AdS_5. In the limit Delta t < 0.02/T, the thermalization time t_T is
found to be quantitatively the same as that of a non-equilibrium state created
by a marginal perturbation discussed in Ref. [5]. In the case Delta t >= 1/T,
we also obtain double-collapse solutions but with a non-equilibrium
intermediate state at t = 0. In all the cases our results show that the system
thermalizes in a typical time t_T ~ O(1)/T. Besides, a conserved energy-moment
current in the bulk is found, which helps understand the qualitative difference
of the collapse process in the Poincare patch from that in global AdS[9, 10].Comment: 24 pages, 13 figures, minor modifications, references added, final
  version to appear in JHE
Near-Extremal Vanishing Horizon AdS5 Black Holes and Their CFT Duals

We consider families of charged rotating asymptotically AdS5 Extremal black
holes with Vanishing Horizon (EVH black holes) whose near horizon geometries
develop locally AdS3 throats. Using the AdS3/CFT2 duality, we propose an
EVH/CFT2 correspondence to describe the near-horizon low energy IR dynamics of
near-EVH black holes involving a specific large N limit of the 4d N = 4 SYM. We
give a map between the UV and IR near-EVH excitations, showing that the UV
first law of thermodynamics reduces to the IR first law satisfied by the near
horizon BTZ black holes in this near-EVH limit. We also discuss the connection
between our EVH/CFT proposal and the Kerr/CFT correspondence in the cases where
the two overlap.Comment: 36 pages, 3 figures, updated to published versio
Multi-Superthreads and Supersheets

We obtain new BPS solutions of six-dimensional, N = 1 supergravity coupled to
a tensor multiplet. These solutions are sourced by multiple "superthreads"
carrying D1-D5-P charges and two magnetic dipole charges. These new solutions
are sourced by multiple threads with independent and arbitrary shapes and
include new shape-shape interaction terms. Because the individual superthreads
can be given independent profiles, the new solutions can be smeared together
into continuous "supersheets," described by arbitrary functions of two
variables. The supersheet solutions have singularities like those of the
three-charge, two dipole-charge generalized supertube in five dimensions and we
show how such five-dimensional solutions emerge from a very simple choice of
profiles. The new solutions obtained here also represent an important step in
finding superstrata, which are expected to play a role in the description of
black-hole microstates, due to their ability to store a large amount of entropy
in their two-dimensional profile.Comment: 17 pages, 2 figure
Pre-Equilibrium Radial Flow from Central Shock-Wave Collisions in AdS5

Using gauge/gravity duality, central ultrarelativistic nucleus-nucleus
collisions are modelled as collisions of shock waves in five-dimensional
asymptotic AdS space. For early times after the collision, it is possible to
analytically match the metric from the past to the future light-cone. This
allows extraction of the pre-equilibrium energy-momentum tensor of the strongly
coupled, large N gauge theory. For central collisions, this allows qualitative
statements concerning the build-up of radial flow at mid-rapidity in AA and pA
collisions. We find that the early-time radial flow buildup is identical to
that expected from ideal hydrodynamics with an entropy density proportional to
the square root of the product of the matter densities in the individual
"nuclei".Comment: 13 page
Tensor modes on the string theory landscape

We attempt an estimate for the distribution of the tensor mode fraction $r$
over the landscape of vacua in string theory. The dynamics of eternal inflation
and quantum tunneling lead to a kind of democracy on the landscape, providing
no bias towards large-field or small-field inflation regardless of the class of
measure. The tensor mode fraction then follows the number frequency
distributions of inflationary mechanisms of string theory over the landscape.
We show that an estimate of the relative number frequencies for small-field vs
large-field inflation, while unattainable on the whole landscape, may be within
reach as a regional answer for warped Calabi-Yau flux compactifications of type
IIB string theory.Comment: LaTeX, 1+55 pages, 4 figures, v2: citations added, extended and more
  precise discussion of the vacuum count ratios in the 'landscape Drake
  equation' in section 4.4, 4.5 and in the conclusion
Simple metastable de Sitter vacua in N=2 gauged supergravity

We construct a simple class of N=2 gauged supergravity theories that admit
metastable de Sitter vacua, generalizing the recent work done in the context of
rigid supersymmetry. The setup involves one hypermultiplet and one vector
multiplet spanning suitably curved quaternionic-Kahler and special-Kahler
geometries, with an Abelian gauging based on a single triholomorphic isometry,
but neither Fayet-Iliopoulos terms nor non-Abelian gauge symmetries. We
construct the most general model of this type and show that in such a situation
the possibility of achieving metastable supersymmetry breaking vacua crucially
depends on the value of the cosmological constant V relative to the gravitino
mass squared m_{3/2}^2 in Planck units. In particular, focusing on de Sitter
vacua with positive V, we show that metastability is only possible when V >=
2.17 m_{3/2}^2. We also derive an upper bound on the lightest scalar mass in
this kind of model relative to the gravitino mass m_{3/2} as a function of the
cosmological constant V, and discuss its physical implications.Comment: 26 pages, 2 figures; v2 minor corrections, some additional comments
  and one reference adde
Enhanced supersymmetry from vanishing Euler number

We argue that compactifications on Calabi-Yau threefolds with vanishing Euler
number yield effective four dimensional theories exhibiting (spontaneously
broken) N=4 supersymmetry. To this end, we derive the low-energy effective
action for general SU(2) structure manifolds in type IIA string theory and show
its consistency with gauged N=4 supergravity. Focusing on the special case of
Calabi-Yau manifolds with vanishing Euler number, we explain the absence of
perturbative corrections at the two-derivative level. In addition, we
conjecture that all non-perturbative corrections are governed and constrained
by the couplings of N=4 massive gravitino multiplets.Comment: 49 page
The imaginary part of the gravity action and black hole entropy

As observed recently in arXiv:1212.2922, the action of General Relativity
(GR) in finite spacetime regions has an imaginary part that resembles the
Bekenstein entropy. In this paper, we expand on that argument, with attention
to different causal types of boundaries. This property of the GR action may
open a new approach to the puzzles of gravitational entropy. In particular, the
imaginary action can be evaluated for non-stationary finite regions, where the
notion of entropy is not fully understood. As a first step in constructing the
precise relationship between the imaginary action and entropy, we focus on
stationary black hole spacetimes. There, we identify a class of bounded regions
for which the action's imaginary part precisely equals the black hole entropy.
As a powerful test on the validity of the approach, we also calculate the
imaginary action for Lovelock gravity. The result is related to the
corresponding entropy formula in the same way as in GR.Comment: 37 pages, 8 figures; v2: sign error corrected; v3: refined the
  treatment of Lovelock gravity, added section 3 with expanded discussion,
  added reference
Inspecting the Higgs for New Weakly Interacting Particles

We explore new physics scenarios which are optimally probed through precision
Higgs measurements rather than direct collider searches. Such theories consist
of additional electroweak charged or singlet states which couple directly to or
mix with the Higgs boson; particles of this kind may be weakly constrained by
direct limits due to their meager production rates and soft decay products. We
present a simplified framework which characterizes the effects of these states
on Higgs physics by way of tree level mixing (with neutral scalars) and loop
level modifications (from electrically charged states), all expressed in terms
of three mixing angles and three loop parameters, respectively. The theory
parameters are constrained and in some cases even fixed by ratios of Higgs
production and decay rates. Our setup is simpler than a general effective
operator analysis, in that we discard parameters irrelevant to Higgs
observables while retaining complex correlations among measurements that arise
due to the underlying mixing and radiative effects. We show that certain
correlated observations are forbidden, e.g. a depleted ratio of Higgs
production from gluon fusion versus vector boson fusion together with a
depleted ratio of Higgs decays to bb versus WW. Moreover, we study the strong
correlation between the Higgs decay rate to gamma gamma and WW and how it can
be violated in the presence of additional electrically charged particles. Our
formalism maps straightforwardly onto a variety of new physics models, such as
the NMSSM. We show, for example, that with a Higgsino of mass > 100 GeV and a
singlet-Higgs coupling of lambda=0.7, the photon signal strength can deviate
from the vector signal strength by up to ~ 40-60% while depleting the vector
signal strength by only 5-15% relative to the Standard Model.Comment: 30 pages, 12 figure
SuGra on G2 Structure Backgrounds that Asymptote to AdS4 and Holographic
  Duals of Confining 2+1d Gauge Theories with N=1 SUSY

In this work the solution generated by performing a U-duality on a
deformation of the Maldacena-Nastase solution is studied. This is a solution of
type-IIA with a metric that is asymptotically AdS4 and supports a G2 structure.
It is believed to be dual to a 2+1d, N=1 gauge theory similar to the baryonic
branch of Klebanov-Strassler with an additional intermediate scale. An improved
radial coordinate is used allowing the derivation of UV series solutions to the
BPS equation that persist to all orders. A study of the properties of the dual
field theory is performed which includes an operator analysis, Wilson loops and
a proposal for gauge couplings. The gauge theory dual appears to be a confining
Chern-Simons quiver with gauge couplings that become constant at high energies.Comment: 23 pages + appendices. 4 figures. v2: Typos corrected, discussions on
  the profile and gauge couplings expanded. Version to appear in JHE
The Same-Sign Dilepton Signature of RPV/MFV SUSY

The lack of observation of superpartners at the Large Hadron Collider so far
has led to a renewed interest in supersymmetric models with R-parity violation
(RPV). In particular, imposing the Minimal Flavor Violation (MFV) hypothesis on
a general RPV model leads to a realistic and predictive framework. Naturalness
suggests that stops and gluinos should appear at or below the TeV mass scale.
We consider a simplified model with these two particles and MFV couplings. The
model predicts a significant rate of events with same-sign dileptons and
b-jets. We re-analyze a recent CMS search in this channel and show that the
current lower bound on the gluino mass is about 800 GeV at 95% confidence
level, with only a weak dependence on the stop mass as long as the gluino can
decay to an on-shell top-stop pair. We also discuss how this search can be
further optimized for the RPV/MFV scenario, using the fact that MFV stop decays
often result in jets with large invariant mass. With the proposed improvements,
we estimate that gluino masses of up to about 1.4 TeV can be probed at the 14
TeV LHC with a 100 fb^-1 data set.Comment: 18 pages, 6 figures; v2: References adde
Singularities in Hyperscaling Violating Spacetimes

We examine spacetimes which generalize Lifshitz scaling to allow hyperscaling
violation invariance (i.e. a constant conformal transformation) for the types
of singularities frequently found in the Lifshitz case. We find that most of
these spacetimes suffer either from a traditional naked curvature singularity
or a null curvature singularity robust against stringy higher derivative
corrections. We do find a one-parameter family that evades these issues but
this family requires exotic matter, in particular involving a negative energy
density that may not be interpreted as due to a cosmological constant.Comment: 18 pages, 2 figures; v2: added reference
A String Theory Explanation for Quantum Chaos in the Hadronic Spectrum

In the 1950's Wigner and collaborators provided an explanation for the
spectrum of hadronic excitations in terms of Random Matrix Theory. In the
1980's it was understood that some hadronic spectral properties were generic to
systems whose classical limit is chaotic. We use string theory to demonstrate
explicitly how, under very general conditions, recent holographic models of
strong interactions have a spectrum compatible with Wigner's conjecture.Comment: 11 pages, 9 figures. v2: References added, expanded comments on the
  role of minisuperspac
BFKL Pomeron calculus: solution to equations for nucleus-nucleus
  scattering in the saturation domain

In this paper we solve the equation for nucleus-nucleus scattering in the
BFKL Pomeron calculus, suggested by Braun. We find these solutions analytically
at high energies as well as numerically in the entire region of energies inside
the saturation region. The semi-classical approximation is used to select out
the infinite set of the parasite solutions. The nucleus-nucleus cross sections
at high energy are estimated and compared with the Glauber-Gribov approach. It
turns out that the exact formula gives the estimates that are very close to the
ones based on Glauber-Gribov formula which is important for the practical
applicationsComment: 20 pp, 27 figures in eps file
Quark and Gluon Jet Substructure

Distinguishing quark-initiated jets from gluon-initiated jets has the potential to significantly improve the reach of many beyond-the-standard model searches at the Large Hadron Collider and to provide additional tests of QCD. To explore whether quark and gluon jets could possibly be distinguished on an event-by-event basis, we perform a comprehensive simulation-based study. We explore a variety of motivated and unmotivated variables with a semi-automated multivariate approach. General conclusions are that at 50% quark jet acceptance efficiency, around 80%-90% of gluon jets can be rejected. Some benefit is gained by combining variables. Different event generators are compared, as are the effects of using only charged tracks to avoid pileup. Additional information, including interactive distributions of most variables and their cut efficiencies, can be found at http://jets.physics.harvard.edu/qvg.Physic
New Patterns of Natural R-Parity Violation with Supersymmetric Gauged
  Flavor

We point out that supersymmetric gauged flavor models provide a realization
of R-parity violation (RPV) that is natural in the sense that it does not lead
to catastrophic proton decay for natural values of parameters in the theory.
Within specific realizations of the idea, the relative strengths of the $\Delta
B=1$ $u^c d^c d^c$ type RPV operators can be predicted. In particular, we
present examples of gauged flavor models where RPV couplings depend on quark
masses as $(m_{u_i} m_{d_j} m_{d_k} / m_t^3)^n$ where $n=1$ or $n= 1/2$. Some
phenomenological implications of these models are discussed.Comment: 17 pages, 2 figures, 4 table
Winding branes and persistent currents

A D5 brane winding around a stack of D3 branes can be used as a model of
persistent current in a thin superconducting ring, with the number N of D3s
corresponding to the number of transverse channels in the ring. We consider, in
the large N limit, existence and properties of a gapped superconducting state
with a uniform winding number density q. We find that there is a gapped
classical solution for any q, no matter how large, but when q is larger than a
certain q_m the state is unstable with respect to decay by phase slips. We
argue that this decay produces strings via a version of the Hanany-Witten
effect (in a non-transverse, non-supersymmetric arrangement of branes). This
parallels the requirement of quasiparticle production in a clean
(disorder-free) wire in field theory of superconductivity.Comment: 19 pages, 3 figures; published in JHE
Colour-Kinematics Duality for One-Loop Rational Amplitudes

Colour-kinematics duality is the conjecture of a group theory-like structure
for the kinematic dependence of scattering amplitudes in gauge theory and
gravity. This structure has been verified at tree level in various ways, but
similar progress has been lacking at loop level, where the power of the duality
would be most significant. Here we explore colour-kinematics duality at one
loop using the self-dual sector as a starting point. The duality is shown to
exist in pure Yang-Mills theory for two infinite classes of amplitudes:
amplitudes with any number of particles either all of the same helicity or with
one particle helicity opposite the rest. We provide a simple Lagrangian-based
argument in favour of the double copy relation between gauge theory and gravity
amplitudes in these classes, and provide some explicit examples. We further
discuss aspects of the duality which persist after integration, leading to
relations among partial amplitudes. Finally, we describe form factors in the
self-dual theory at tree level which also satisfy the duality.Comment: 36 pages, 5 figures; v2: published versio