pinecone/core-2020-05-10-deduplication huggingface dataset:
Gluons and gravitons at one loop from ambitwistor strings

We present new and explicit formulae for the one-loop integrands of
scattering amplitudes in non-supersymmetric gauge theory and gravity, valid for
any number of particles. The results exhibit the colour-kinematics duality in
gauge theory and the double-copy relation to gravity, in a form that was
recently observed in supersymmetric theories. The new formulae are expressed in
a particular representation of the loop integrand, with only one quadratic
propagator, which arises naturally from the framework of the loop-level
scattering equations. The starting point in our work are the expressions based
on the scattering equations that were recently derived from ambitwistor string
theory. We turn these expressions into explicit formulae depending only on the
loop momentum, the external momenta and the external polarisations. These
formulae are valid in any number of spacetime dimensions for pure Yang-Mills
theory (gluon) and its natural double copy, NS-NS gravity (graviton, dilaton,
B-field), and we also present formulae in four spacetime dimensions for pure
gravity (graviton). We perform several tests of our results, such as checking
gauge invariance and directly matching our four-particle formulae to previously
known expressions. While these tests would be elaborate in a Feynman-type
representation of the loop integrand, they become straightforward in the
representation we use.Comment: 36 pages, 5 figures. v2: added references, published versio
When Rational Sections Become Cyclic: Gauge Enhancement in F-theory via
  Mordell--Weil Torsion

We explore novel gauge enhancements from abelian to non-simply-connected
gauge groups in F-theory. To this end we consider complex structure
deformations of elliptic fibrations with a Mordell--Weil group of rank one and
identify the conditions under which the generating section becomes torsional.
For the specific case of Z2 torsion we construct the generic solution to these
conditions and show that the associated F-theory compactification exhibits the
global gauge group [SU(2) x SU(4)]/Z2 x SU(2). The subsolution with gauge group
SU(2)/Z2 x SU(2), for which we provide a global resolution, is related by a
further complex structure deformation to a genus-one fibration with a bisection
whose Jacobian has a Z2 torsional section. While an analysis of the spectrum on
the Jacobian fibration reveals an SU(2)/Z2 x Z2 gauge theory, reproducing this
result from the bisection geometry raises some conceptual puzzles about
F-theory on genus-one fibrations.Comment: 51 page
$R^2$ inflation to probe non-perturbative quantum gravity

It is natural to expect a consistent inflationary model of the very early
Universe to be an effective theory of quantum gravity, at least at energies
much less than the Planck one. For the moment, $R+R^2$, or shortly $R^2$,
inflation is the most successful in accounting for the latest CMB data from the
PLANCK satellite and other experiments. Moreover, recently it was shown to be
ultra-violet (UV) complete via an embedding into an analytic infinite
derivative (AID) non-local gravity. In this paper, we derive a most general
theory of gravity that contributes to perturbed linear equations of motion
around maximally symmetric space-times. We show that such a theory is quadratic
in the Ricci scalar and the Weyl tensor with AID operators along with the
Einstein-Hilbert term and possibly a cosmological constant. We explicitly
demonstrate that introduction of the Ricci tensor squared term is redundant.
Working in this quadratic AID gravity framework without a cosmological term we
prove that for a specified class of space homogeneous space-times, a space of
solutions to the equations of motion is identical to the space of backgrounds
in a local $R^2$ model. We further compute the full second order perturbed
action around any background belonging to that class. We proceed by extracting
the key inflationary parameters of our model such as a spectral index ($n_s$),
a tensor-to-scalar ratio ($r$) and a tensor tilt ($n_t$). It appears that $n_s$
remains the same as in the local $R^2$ inflation in the leading slow-roll
approximation, while $r$ and $n_t$ get modified due to modification of the
tensor power spectrum. This class of models allows for any value of $r<0.07$
with a modified consistency relation which can be fixed by future observations
of primordial $B$-modes of the CMB polarization. This makes the UV complete
$R^2$ gravity a natural target for future CMB probes.Comment: 37 page
Gauge choices and Entanglement Entropy of two dimensional lattice gauge
  fields

In this paper, we explore the question of how different gauge choices in a
gauge theory affect the tensor product structure of the Hilbert space in
configuration space. In particular, we study the Coulomb gauge and observe that
the naive gauge potential degrees of freedom cease to be local operators as
soon as we impose the Dirac brackets. We construct new local set of operators
and compute the entanglement entropy according to this algebra in $2+1$
dimensions. We find that our proposal would lead to an entanglement entropy
that behave very similar to a single scalar degree of freedom if we do not
include further centers, but approaches that of a gauge field if we include
non-trivial centers. We explore also the situation where the gauge field is
Higgsed, and construct a local operator algebra that again requires some
deformation. This should give us some insight into interpreting the
entanglement entropy in generic gauge theories and perhaps also in
gravitational theories.Comment: 38 pages,25 figure
Black holes from large N singlet models

The emergent nature of spacetime geometry and black holes can be directly
probed in simple holographic duals of higher spin gravity and tensionless
string theory. To this end, we study time dependent thermal correlation
functions of gauge invariant observables in suitably chosen free large N gauge
theories. At low temperature and on short time scales the correlation functions
encode propagation through an approximate AdS spacetime while interesting
departures emerge at high temperature and on longer time scales. This includes
the existence of evanescent modes and the exponential decay of time dependent
boundary correlations, both of which are well known indicators of bulk black
holes in AdS/CFT. In addition, a new time scale emerges after which the
correlation functions return to a bulk thermal AdS form up to an overall
temperature dependent normalization. A corresponding length scale was seen in
equal time correlation functions in the same models in our earlier work.Comment: 37 pages, 4 figures, 1 tabl
Search for new phenomena in final states with two opposite-charge,
  same-flavor leptons, jets, and missing transverse momentum in pp collisions
  at $\sqrt{s} = $ 13 TeV

Search results are presented for physics beyond the standard model in final
states with two opposite-charge, same-flavor leptons, jets, and missing
transverse momentum. The data sample corresponds to an integrated luminosity of
35.9 fb$^{-1}$ of proton-proton collisions at $\sqrt{s} = $ 13 TeV collected
with the CMS detector at the LHC in 2016. The analysis uses the invariant mass
of the lepton pair, searching for a kinematic edge or a resonant-like excess
compatible with the Z boson mass. The search for a kinematic edge targets
production of particles sensitive to the strong force, while the resonance
search targets both strongly and electroweakly produced new physics. The
observed yields are consistent with the expectations from the standard model,
and the results are interpreted in the context of simplified models of
supersymmetry. In a gauge mediated supersymmetry breaking (GMSB) model of
gluino pair production with decay chains including Z bosons, gluino masses up
to 1500-1770 GeV are excluded at the 95% confidence level depending on the
lightest neutralino mass. In a model of electroweak chargino-neutralino
production, chargino masses as high as 610 GeV are excluded when the lightest
neutralino is massless. In GMSB models of electroweak neutralino-neutralino
production, neutralino masses up to 500-650 GeV are excluded depending on the
decay mode assumed. Finally, in a model with bottom squark pair production and
decay chains resulting in a kinematic edge in the dilepton invariant mass
distribution, bottom squark masses up to 980-1200 GeV are excluded depending on
the mass of the next-to-lightest neutralino.Comment: Replaced with the published version. Added the journal reference and
  the DOI. All the figures and tables, including additional supplementary
  figures and tables, can be found at
  http://cms-results.web.cern.ch/cms-results/public-results/publications/SUS-16-034/
  (CMS Public Pages
New gravitational solutions via a Riemann-Hilbert approach

We consider the Riemann-Hilbert factorization approach to solving the field
equations of dimensionally reduced gravity theories. First we prove that
functions belonging to a certain class possess a canonical factorization due to
properties of the underlying spectral curve. Then we use this result, together
with appropriate matricial decompositions, to study the canonical factorization
of non-meromorphic monodromy matrices that describe deformations of seed
monodromy matrices associated with known solutions. This results in new
solutions, with unusual features, to the field equations.Comment: 29 pages, 2 figures; v2: reference added, matches published versio
Prompt photon production and photon-jet correlations at the LHC

Next-to-leading order predictions matched to parton showers are compared with
recent ATLAS data on inclusive photon production and CMS data on associated
photon and jet production in pp and pPb collisions at different centre-of-mass
energies of the LHC. We find good agreement and, as expected, considerably
reduced scale uncertainties compared to previous theoretical calculations.
Predictions are made for the ratio of inclusive photons over decay photons
$R_\gamma$, an important quantity to evaluate the significance of additional
photon sources, e.g. thermal radiation from a Quark-Gluon-Plasma, and for
distributions in the parton momentum fraction in lead ions $x_{\rm Pb}^{\rm
obs}$, that could be determined by ALICE, ATLAS, CMS and LHCb in ongoing
analyses of photon+jet production in pPb collisions at $\sqrt{s_{NN}}=5.02$
TeV. These data should have an important impact on the determination of nuclear
effects such as shadowing at low $x$.Comment: 20 pages, 13 figure
Towards Generalized Mirror Symmetry for Twisted Connected Sum $G_2$
  Manifolds

We revisit our construction of mirror symmetries for compactifications of
Type II superstrings on twisted connected sum $G_2$ manifolds. For a given
$G_2$ manifold, we discuss evidence for the existence of mirror symmetries of
two kinds: one is an autoequivalence for a given Type II superstring on a
mirror pair of $G_2$ manifolds, the other is a duality between Type II strings
with different chiralities for another pair of mirror manifolds. We clarify the
role of the B-field in the construction, and check that the corresponding
massless spectra are respected by the generalized mirror maps. We discuss hints
towards a homological version based on BPS spectroscopy. We provide several
novel examples of smooth, as well as singular, mirror $G_2$ backgrounds via
pairs of dual projecting tops. We test our conjectures against a Joyce orbifold
example, where we reproduce, using our geometrical methods, the known mirror
maps that arise from the SCFT worldsheet perspective. Along the way, we discuss
non-Abelian gauge symmetries, and argue for the generation of the
Affleck-Harvey-Witten superpotential in the pure SYM case.Comment: are welcome. 75 pages, 5 figure
Light dark Higgs boson in minimal sub-GeV dark matter scenarios

Minimal scenarios with light (sub-GeV) dark matter whose relic density is
obtained from thermal freeze-out must include new light mediators. In
particular, a very well-motivated case is that of a new "dark" massive vector
gauge boson mediator. The mass term for such mediator is most naturally
obtained by a "dark Higgs mechanism" which leads to the presence of an often
long-lived dark Higgs boson whose mass scale is the same as that of the
mediator. We study the phenomenology and experimental constraints on two
minimal, self-consistent dark sectors that include such a light dark Higgs
boson. In one the dark matter is a pseudo-Dirac fermion, in the other a complex
scalar. We find that the constraints from BBN and CMB are considerably relaxed
in the framework of such minimal dark sectors. We present detection prospects
for the dark Higgs boson in existing and projected proton beam-dump
experiments. We show that future searches at experiments like Xenon1T or LDMX
can probe all the relevant parameter space, complementing the various upcoming
indirect constraints from astrophysical observations.Comment: 32 pages, 10 figures, 4 tables. An error in the estimation of the
  dark matter annihilation rates has been corrected and all figures as well as
  section 3.2 have been accordingly updated. References updated, typos
  corrected, matches version published in JHE
Polarized double-virtual amplitudes for heavy-quark pair production

We present the two-loop virtual amplitudes for heavy-quark pair production in
light quark-antiquark annihilation and gluon fusion channels, including full
spin and color dependence. We use expansions around kinematical limits and
numerical integration to obtain results for the involved master integrals. From
these, we determine the renormalised infrared finite remainders of the
coefficients of amplitude decompositions in terms of color and spin structures.
The remainders are given in form of numerical interpolation grids supported by
expansions around the production threshold and the high energy limit. Finally,
we provide the spin density matrix, which encodes the heavy-quark spin
correlations and is sufficient for phenomenological applications. Our results
are necessary for the derivation of top-quark pair production cross sections in
hadron collisions in the narrow width approximation with
next-to-next-to-leading order accuracy in QCD.Comment: 23 pages, 5 figures, results available in electronic form at
  https://git.rwth-aachen.de/mczakon/PolarizedTTNNLO, references added, matches
  published versio
Novel Jet Observables from Machine Learning

Previous studies have demonstrated the utility and applicability of machine
learning techniques to jet physics. In this paper, we construct new observables
for the discrimination of jets from different originating particles exclusively
from information identified by the machine. The approach we propose is to first
organize information in the jet by resolved phase space and determine the
effective $N$-body phase space at which discrimination power saturates. This
then allows for the construction of a discrimination observable from the
$N$-body phase space coordinates. A general form of this observable can be
expressed with numerous parameters that are chosen so that the observable
maximizes the signal vs.~background likelihood. Here, we illustrate this
technique applied to discrimination of $H\to b\bar b$ decays from massive $g\to
b\bar b$ splittings. We show that for a simple parametrization, we can
construct an observable that has discrimination power comparable to, or better
than, widely-used observables motivated from theory considerations. For the
case of jets on which modified mass-drop tagger grooming is applied, the
observable that the machine learns is essentially the angle of the dominant
gluon emission off of the $b\bar b$ pair.Comment: 13 pages, 10 figures; published, JHEP versio
Algebraic geometry and Bethe ansatz (I) the quotient ring for BAE

In this paper and upcoming ones, we initiate a systematic study of Bethe
ansatz equations for integrable models by modern computational algebraic
geometry. We show that algebraic geometry provides a natural mathematical
language and powerful tools for understanding the structure of solution space
of Bethe ansatz equations. In particular, we find novel efficient methods to
count the number of solutions of Bethe ansatz equations based on Gr\"obner
basis and quotient ring. We also develop analytical approach based on companion
matrix to perform the sum of on-shell quantities over all physical solutions
without solving Bethe ansatz equations explicitly. To demonstrate the power of
our method, we revisit the completeness problem of Bethe ansatz of Heisenberg
spin chain, and calculate the sum rules of OPE coefficients in planar
$\mathcal{N}=4$ super-Yang-Mills theory.Comment: minor update
Free Energy of a Heavy Quark-Antiquark Pair in a Thermal Medium from
  AdS/CFT

We study the free energy of a heavy quark-antiquark pair in a thermal medium
using the AdS/CFT correspondence. We point out that a commonly used
prescription for calculating this quantity leads to a temperature dependence in
conflict with general properties of the free energy. The problem originates
from a particular way of subtracting divergences. We argue that the commonly
used prescription gives rise to the binding energy rather than the free energy.
We consider a different subtraction procedure and show that the resulting free
energy is well-behaved and in qualitative agreement with results from lattice
QCD. The free energy and the binding energy of the quark pair are computed for
N = 4 supersymmetric Yang-Mills theory and several non-conformal theories. We
also calculate the entropy and the internal energy of the pair in these
theories. Using the consistent subtraction, we further study the free energy,
entropy, and internal energy of a single heavy quark in the thermal medium for
various theories. Also here the results are found to be in qualitative
agreement with lattice QCD results.Comment: 47 pages, 14 figures; v2: discussion extended, matches journal
  versio
Instantons from geodesics in AdS moduli spaces

We investigate supergravity instantons in Euclidean $\rm AdS_5\times
S^5/\mathbb{Z}_k$. These solutions are expected to be dual to instantons of
$\mathcal{N}=2$ quiver gauge theories. On the supergravity side the (extremal)
instanton solutions are neatly described by the (lightlike) geodesics on the
AdS moduli space for which we find the explicit expression and compute the
on-shell actions in terms of the quantised charges. The lightlike geodesics
fall into two categories depending on the degree of nilpotency of the Noether
charge matrix carried by the geodesic: For degree 2 the instantons preserve 8
supercharges and for degree 3 they are non-SUSY. We expect that these findings
should apply to more general situations in the sense that there is a map
between geodesics on moduli-spaces of Euclidean AdS vacua and instantons with
holographic counterparts.Comment: 21+7 pages; V2 typos corrected, matches published versio
Radiative corrections to masses and couplings in Universal Extra
  Dimensions

Models with an orbifolded universal extra dimension receive important
loop-induced corrections to the masses and couplings of Kaluza-Klein (KK)
particles. The dominant contributions stem from so-called boundary terms which
violate KK number. Previously, only the parts of these boundary terms
proportional to $\ln(\Lambda R)$ have been computed, where $R$ is the radius of
the extra dimension and $\Lambda$ is cut-off scale. However, for typical values
of $\Lambda R \sim 10 \cdots 50$, the logarithms are not particularly large and
non-logarithmic contributions may be numerically important. In this paper,
these remaining finite terms are computed and their phenomenological impact is
discussed. It is shown that the finite terms have a significant impact on the
KK mass spectrum. Furthermore, one finds new KK-number violating interactions
that do not depend on $\ln(\Lambda R)$ but nevertheless are non-zero. These
lead to new production and decay channels for level-2 KK particles at
colliders.Comment: V2: KK-top (mass and decays) updated, correcting a mistake in the
  literatur
Static Black Hole and Vacuum Energy: Thin Shell and Incompressible Fluid

With the back reaction of the vacuum energy-momentum tensor consistently
taken into account, we study static spherically symmetric black-hole-like
solutions to the semi-classical Einstein equation. The vacuum energy is assumed
to be given by that of 2-dimensional massless scalar fields, as a widely used
model in the literature for black holes. The solutions have no horizon.
Instead, there is a local minimum in the radius. We consider thin shells as
well as incompressible fluid as the matter content of the black-hole-like
geometry. The geometry has several interesting features due to the back
reaction of vacuum energy. In particular, Buchdahl's inequality can be violated
without divergence in pressure, even if the surface is below the Schwarzschild
radius. At the same time, the surface of the star can not be far below the
Schwarzschild radius for a density not much higher than the Planck scale, and
the proper distance from its surface to the origin can be very short even for
very large Schwarzschild radius. The results also imply that, contrary to the
folklore, in principle the Boulware vacuum can be physical for black holes.Comment: 44 pages, 20 figures. v2: 49 pages, minor modifications, references
  adde
Extremal Black Hole Horizons

Using the blackfold effective theory applied to extremal Kerr branes we
provide evidence for the existence of new stationary extremal black hole
solutions in asymptotically flat spacetime with both single and multiple
disconnected horizons. These include extremal doubly-spinning black rings,
black saturns, di-rings and bi-rings in five spacetime dimensions as well as
extremal Myers-Perry black holes and black saturns in dimensions greater than
five. Some of these constructions constitute the first examples of black hole
solutions with extremal disconnected horizons in vacuum Einstein gravity.Comment: v2: 30pp, 12 figures; comments and reference added; comparison
  between approximate and analytic black ring and Myers-Perry solutions added;
  to be published in JHE
Holographic Non-equilibrium Heating

We study the holographic entanglement entropy evolution after a global sharp
quench of thermal state. After the quench, the system comes to equilibrium and
the temperature increases from $T_i$ to $T_f$. Holographic dual of this process
is provided by an injection of a thin shell of matter in the black hole
background. The quantitative characteristics of the evolution depend
substantially on the size of the initial black hole. We show that
characteristic regimes during non-equilibrium heating do not depend on the
initial temperature and are the same as in thermalization. Namely these regimes
are pre-local-equilibration quadratic growth, linear growth and saturation
regimes of the time evolution of the holographic entanglement entropy. We study
the initial temperature dependence of quantitative characteristics of these
regimes and find that the critical exponents do not depend on the temperature,
meanwhile the prefactors are the functions on the temperature.Comment: v1:12 pages, 9 figures; v2:The title and abstract are slightly
  changed, the discussion is enlarged, the pictures are changed to make
  presentation more clear and refs. added , 22 pages, 4 figures; v3: typos
  correcte