pinecone/core-2020-05-10-deduplication huggingface dataset:
Towards parton distribution functions with small-$x$ resummation: HELL
  2.0

In global fits of parton distribution functions (PDFs) a large fraction of
data points, mostly from the HERA collider, lies in a region of $x$ and $Q^2$
that is sensitive to small-$x$ logarithmic enhancements. Thus, the proper
theoretical description of these data requires the inclusion of small-$x$
resummation. In this work we provide all the necessary ingredients to perform a
PDF fit to deep-inelastic scattering (DIS) data which includes small-$x$
resummation in the evolution of PDFs and in the computation of DIS structure
functions. To this purpose, not only we include the resummation of DIS massless
structure functions, but we also consider the production of a massive final
state (e.g. a charm quark), and the consistent resummation of mass collinear
logarithms through the implementation of a variable flavour number scheme at
small $x$. As a result, we perform the small-$x$ resummation of the matching
conditions in PDF evolution at heavy flavour thresholds. The resummed results
are accurate at next-to-leading logarithmic (NLL) accuracy and matched, for the
first time, to next-to-next-to-leading order (NNLO). Furthermore, we improve on
our previous work by considering a novel all-order treatment of running
coupling contributions. These results, which are implemented in a new release
of HELL, version 2.0, will allow to fit PDFs from DIS data at the highest
possible theoretical accuracy, NNLO+NLL, thus providing an important step
forward towards precision determination of PDFs and consequently precision
phenomenology at the LHC and beyond.Comment: 65 pages, 7 figures. Improved structure of the presentation of our
  results, added some extra content, new plots in the results section. JHEP
  versio
Crossing symmetry and Higher spin towers

We consider higher spin operators in weakly coupled gauge conformal field
theories. Crossing symmetry of mixed scalar correlators relates different
higher spin towers and we study the consequences for the spectrum and structure
constants of higher spin operators of different twists. Constraints are
obtained to all loops in perturbation theory. The large spin contributions to
the structure constants can be resummed into a theory-dependent prefactor times
a universal factor, whose structure of poles agrees with the one that would be
obtained from a Witten diagram supergravity computation, although only crossing
symmetry is assumed. Finally, our results provide an all loop expression for
the double null limit of mixed correlators, which is in perfect agreement with
the correlator/Wilson loop correspondence.Comment: 26 page
A tauberian theorem for the conformal bootstrap

For expansions in one-dimensional conformal blocks, we provide a rigorous
link between the asymptotics of the spectral density of exchanged primaries and
the leading singularity in the crossed channel. Our result has a direct
application to systems of SL(2,R)-invariant correlators (also known as 1d
CFTs). It also puts on solid ground a part of the lightcone bootstrap analysis
of the spectrum of operators of high spin and bounded twist in CFTs in d>2. In
addition, a similar argument controls the spectral density asymptotics in large
N gauge theories.Comment: 36pp; v2: refs and comments added, misprints correcte
Asymptotic M5-brane entropy from S-duality

We study M5-branes compactified on $S^1$ from the D0-D4 Witten index in the
Coulomb phase. We first show that the prepotential of this index is S-dual, up
to a simple anomalous part. This is an extension of the well-known S-duality of
the 4d $\mathcal{N}=4$ theory to the 6d $(2,0)$ theory on finite $T^2$. Using
this anomalous S-duality, we find that the asymptotic free energy scales like
$N^3$ when various temperature-like parameters are large. This shows that the
number of 5d Kaluza-Klein fields for light D0-brane bound states is
proportional to $N^3$. We also compute some part of the asymptotic free energy
from 6d chiral anomalies, which precisely agrees with our D0-D4 calculus.Comment: 50 pages, 2 figure
On avoiding Ostrogradski instabilities within Asymptotic Safety

We study the renormalization group flow of gravity coupled to scalar matter
using functional renormalization group techniques. The novel feature is the
inclusion of higher-derivative terms in the scalar propagator. Such terms give
rise to Ostrogradski ghosts which signal an instability of the system and are
therefore dangerous for the consistency of the theory. Since it is expected
that such terms are generated dynamically by the renormalization group flow
they provide a potential threat when constructing a theory of quantum gravity
based on Asymptotic Safety. Our work then establishes the following picture:
upon incorporating higher-derivative terms in the scalar propagator the flow of
the gravity-matter system possesses a fixed point structure suitable for
Asymptotic Safety. This structure includes an interacting renormalization group
fixed point where the Ostrogradski ghosts acquire an infinite mass and decouple
from the system. Tracing the flow towards the infrared it is found that there
is a subset of complete renormalization group trajectories which lead to stable
renormalized propagators. This subset is in one-to-one correspondence to the
complete renormalization group trajectories obtained in computations which do
not track of the higher-derivative terms. Thus our asymptotically safe
gravity-matter systems are not haunted by Ostrogradski ghosts.Comment: 35 pages, 10 figure
Vertex operator algebras of Argyres-Douglas theories from M5-branes

We study aspects of the vertex operator algebra (VOA) corresponding to
Argyres-Douglas (AD) theories engineered using the 6d N=(2, 0) theory of type
$J$ on a punctured sphere. We denote the AD theories as $(J^b[k],Y)$, where
$J^b[k]$ and $Y$ represent an irregular and a regular singularity respectively.
We restrict to the `minimal' case where $J^b[k]$ has no associated mass
parameters, and the theory does not admit any exactly marginal deformations.
The VOA corresponding to the AD theory is conjectured to be the W-algebra
$\mathcal{W}^{k_{2d}}(J,Y)$, where $k_{2d}=-h+ \frac{b}{b+k}$ with $h$ being
the dual Coxeter number of $J$. We verify this conjecture by showing that the
Schur index of the AD theory is identical to the vacuum character of the
corresponding VOA, and the Hall-Littlewood index computes the Hilbert series of
the Higgs branch. We also find that the Schur and Hall-Littlewood index for the
AD theory can be written in a simple closed form for $b=h$. We also test the
conjecture that the associated variety of such VOA is identical to the Higgs
branch. The M5-brane construction of these theories and the corresponding TQFT
structure of the index play a crucial role in our computations.Comment: 35 pages, 1 figure, v2: minor corrections, referenced adde
Generalised Scherk-Schwarz reductions from gauged supergravity

A procedure is described to construct generalised Scherk-Schwarz uplifts of
gauged supergravities. The internal manifold, fluxes, and consistent truncation
Ansatz are all derived from the embedding tensor of the lower-dimensional
theory. We first describe the procedure to construct generalised Leibniz
parallelisable spaces where the vector components of the frame are embedded in
the adjoint representation of the gauge group, as specified by the embedding
tensor. This allows us to recover the generalised Scherk-Schwarz reductions
known in the literature and to prove a no-go result for the uplift of
$\omega$-deformed SO(p,q) gauged maximal supergravities. We then extend the
construction to arbitrary generalised Leibniz parallelisable spaces, which turn
out to be torus fibrations over manifolds in the class above.Comment: 38 pages; v2: fixed minor mistake in sec. 4, paper extended with
  fully general construction (see sec. 3.4), references adde
Phase Transition of Anti-Symmetric Wilson Loops in $\mathcal{N}=4$ SYM

We will argue that the 1/2 BPS Wilson loops in the anti-symmetric
representations in the $\mathcal{N}=4$ super Yang-Mills (SYM) theory exhibit a
phase transition at some critical value of the 't Hooft coupling of order
$N^2$. In the matrix model computation of Wilson loop expectation values, this
phase transition corresponds to the transition between the one-cut phase and
the two-cut phase. It turns out that the one-cut phase is smoothly connected to
the small 't Hooft coupling regime and the $1/N$ corrections of Wilson loops in
this phase can be systematically computed from the topological recursion in the
Gaussian matrix model.Comment: 22 pages; v2: added reference; v3: version to appear in JHE
Anomaly matching on the Higgs branch

We point out that we can almost always determine by the anomaly matching the
full anomaly polynomial of a supersymmetric theory in 2d, 4d or 6d if we assume
that its Higgs branch is the one-instanton moduli space of some group G. This
method not only provides by far the simplest method to compute the central
charges of known theories of this class, e.g. 4d E_{6,7,8} theories of Minahan
and Nemeschansky or the 6d E-string theory, but also gives us new pieces of
information about unknown theories of this class.Comment: 23 page
Excitation basis for (3+1)d topological phases

We consider an exactly solvable model in 3+1 dimensions, based on a finite
group, which is a natural generalization of Kitaev's quantum double model. The
corresponding lattice Hamiltonian yields excitations located at
torus-boundaries. By cutting open the three-torus, we obtain a manifold bounded
by two tori which supports states satisfying a higher-dimensional version of
Ocneanu's tube algebra. This defines an algebraic structure extending the
Drinfel'd double. Its irreducible representations, labeled by two fluxes and
one charge, characterize the torus-excitations. The tensor product of such
representations is introduced in order to construct a basis for (3+1)d gauge
models which relies upon the fusion of the defect excitations. This basis is
defined on manifolds of the form $\Sigma \times \mathbb{S}_1$, with $\Sigma$ a
two-dimensional Riemann surface. As such, our construction is closely related
to dimensional reduction from (3+1)d to (2+1)d topological orders.Comment: 33 pages; v2 references added; v3 minor change
Entanglement and correlations in the continuous multi-scale entanglement
  renormalization ansatz

We investigate the entanglement structure of the continuous multi-scale
entanglement renormalization ansatz (cMERA) [Haegeman et al., Phys. Rev. Lett.,
110, 100402 (2013)] for ground states of quantum field theories (QFTs). The
cMERA, proposed as an extension to QFTs of the lattice MERA, is defined
directly in the continuum but is nevertheless naturally equipped with a
short-distance scale $1/\Lambda$ that acts as a UV regulator for quantum
fluctuations. We consider the simplified setting of Gaussian cMERA for free
QFTs, where explicit calculations can be performed. For relativistic free
massless bosonic and fermionic QFTs in both 1+1 and 2+1 spacetime dimensions,
we show that the cMERA state indeed displays no UV divergences in two-point
correlation functions or entanglement entropy, in sharp contrast with the exact
ground states.Comment: 28 pages, 20 figures, 4 appendices. Improved with referee's comment
About the rapidity and helicity distributions of the W bosons produced
  at LHC

$W$ bosons are produced at LHC from a forward-backward symmetric initial
state. Their decay to a charged lepton and a neutrino has a strong spin
analysing power. The combination of these effects results in characteristic
distributions of the pseudorapidity of the leptons decaying from $W^+$ and
$W^-$ of different helicity. This observation may open the possibility to
measure precisely the $W^+$ and $W^-$ rapidity distributions for the two
transverse polarisation states of $W$ bosons produced at small transverse
momentum.Comment: 8 pages, 5 figure
The fate of small classically stable Q-balls

The smallest classically stable Q-balls are, in fact, generically metastable:
in quantum theory they decay into free particles via collective tunneling. We
derive general semiclassical method to calculate the rate of this process in
the entire kinematical region of Q-ball metastability. Our method uses
Euclidean field-theoretical solutions resembling the Coleman's bounce and
fluctuations around them. As an application of the method, we numerically
compute the decay rate to the leading semiclassical order in a particular
one-field model. We shortly discuss cosmological implications of metastable
Q-balls.Comment: 31 pages, 11 figures; journal versio
A functional perspective on emergent supersymmetry

We investigate the emergence of ${\cal N}=1$ supersymmetry in the long-range
behavior of three-dimensional parity-symmetric Yukawa systems. We discuss a
renormalization approach that manifestly preserves supersymmetry whenever such
symmetry is realized, and use it to prove that supersymmetry-breaking operators
are irrelevant, thus proving that such operators are suppressed in the
infrared. All our findings are illustrated with the aid of the
$\epsilon$-expansion and a functional variant of perturbation theory, but we
provide numerical estimates of critical exponents that are based on the
non-perturbative functional renormalization group.Comment: 28 pages, 2 figures; v2: published version, includes a new appendi
On Universality of Holographic Results for (2+1)-Dimensional CFTs on
  Curved Spacetimes

The behavior of holographic CFTs is constrained by the existence of a bulk
dual geometry. For example, in (2+1)-dimensional holographic CFTs living on a
static spacetime with compact spatial slices, the vacuum energy must be
nonpositive, certain averaged energy densities must be nonpositive, and the
spectrum of scalar operators is bounded from below by the Ricci scalar of the
CFT geometry. Are these results special to holographic CFTs? Here we show that
for perturbations about appropriate backgrounds, they are in fact universal to
all CFTs, as they follow from the universal behavior of two- and three-point
correlators of known operators. In the case of vacuum energy, we extend away
from the perturbative regime and make global statements about its negativity
properties on the space of spatial geometries. Finally, we comment on the
implications for dynamics which are dissipative and driven by such a vacuum
energy and we remark on similar results for the behavior of the Euclidean
partition function on deformations of flat space or the round sphere.Comment: 35+4 pages, 1 figure. v2: corrected discussion of torus to deformed
  flat space; additional comments adde
Spectral Flow in 3D Flat Spacetimes

In this paper we investigate spectral flow symmetry in asymptotically flat
spacetimes both from a gravity as well as a putative dual quantum field theory
perspective. On the gravity side we consider models in Einstein gravity and
supergravity as well as their "reloaded" versions, present suitable boundary
conditions, determine the respective asymptotic symmetry algebras and the
thermal entropy of cosmological solutions in each of these models. On the
quantum field theory side we identify the spectral flow symmetry as
automorphisms of the underlying symmetry algebra of the theory. Using spectral
flow invariance we then determine the thermal entropy of these quantum field
theories and find perfect agreement with the results from the gravity side. In
addition we determine logarithmic corrections to the thermal entropy.Comment: 42 pages; v2: added minor clarifications, matches published versio
On the Large $R$-charge Expansion in ${\mathcal N} = 2$ Superconformal
  Field Theories

In this note we study two point functions of Coulomb branch chiral ring
elements with large $R$-charge, in quantum field theories with ${\mathcal N} =
2$ superconformal symmetry in four spacetime dimensions. Focusing on the case
of one-dimensional Coulomb branch, we use the effective-field-theoretic methods
of arXiv:1706.05743, to estimate the two-point function $${\mathcal Y}_n \equiv
|x-y|^{2n\Delta_{\mathcal O}}\left<({\mathcal O}(x))^n(\bar{\mathcal
O}(y))^n\right>$$ in the limit where the operator insertion On has large total
$R$-charge ${\mathcal J} = n\Delta_{\mathcal O}$. We show that ${\mathcal Y}_n$
has a nontrivial but universal asymptotic expansion at large ${\mathcal J}$, of
the form $${\mathcal Y}_n = {\mathcal J}! \left(\frac{\left| {\mathbf
N}_{\mathcal O}\right|}{2\pi}\right)^{2{\mathcal J}}{\mathcal J}^\alpha
{\tilde{\mathcal Y}}_n$$ where ${\mathcal Y}_n$ approaches a constant as
$n\to\infty$, and ${\mathbf N}_{\mathcal O}$ is an $n$-independent constant
describing on the normalization of the operator relative to the effective
Abelian gauge coupling. The exponent $\alpha$ is a positive number proportional
to the difference between the $a$-anomaly coefficient of the underlying CFT and
that of the effective theory of the Coulomb branch. For Lagrangian SCFT, we
check our predictions against exact results from supersymmetric localization of
Baggio et. al. and Gerchkovitz et. al., and find precise agreement for the
logarithm ${\mathcal B}_n = \log{\mathcal Y}_n$, up to and including order
$\log{\mathcal J}$. We also give predictions for the growth of two-point
functions in all rank-one SCFT in the classification of Argyres et. al. In this
way, we show the large-$R$-charge expansion serves as a bridge from the world
of unbroken superconformal symmetry, OPE data, and bootstraps, to the world of
the low-energy dynamics of the moduli space of vacua.Comment: minor change
Heavy stable charged tracks as signatures of non-thermal dark matter at
  the LHC : a study in some non-supersymmetric scenarios

We consider two theoretical scenarios, each including a $\mathbb{Z}_{2}$-odd
sector and leading to an elementary dark matter candidate. The first one is a
variant of the Type-III seesaw model where one lepton triplet is
$\mathbb{Z}_{2}$-odd, together with a heavy sterile neutrino. It leads to a
fermionic dark matter, together with the charged component of the triplet being
a quasi-stable particle which decays only via a higher-dimensional operator
suppressed by a high scale. The second model consists of an inert scalar
doublet together with a $\mathbb{Z}_{2}$-odd right-handed Majorana neutrino
dark matter. A tiny Yukawa coupling delays the decay of the charged component
of the inert doublet into the dark matter candidate, making the former
long-lived on the scale of collider detectors. The parameter space of each
model has been constrained by big-bang nucleosynthesis constraints, and also by
estimating the contribution to the relic density through freeze-out of the
long-lived charged particle as well the freeze-in production of the dark matter
candidate. We consider two kinds of signals at the Large Hadron Collider for
the first kind of models, namely two charged tracks and single track + MET. For
the second kind, the characteristic signals are opposite as well as same-sign
charged track pairs. We perform a detailed analysis using event selection
criteria consistent with the current experimental programmes. It is found that
the scenario with a lepton triplet can be probed upto 960(1190) GeV with an
integrated luminosity of 300(3000) $fb^{-1}$, while the corresponding numbers
for the inert doublet scenario are 630(800) GeV. Furthermore, the second kind
of signal mentioned in each case allows us to differentiate different dark
matter scenarios from each other.Comment: v2:published in JHEP: Minor changes in text, Appendix added: 26
  pages, 8 figures, 6 table
Penrose limits and spin chains in the GJV/CS-SYM duality

We examine Penrose limits of the duality proposed by Guarino, Jafferis and
Varela between a type IIA massive background of the type of a warped, squashed
$AdS_4\times S^6$, and a 2+1 dimensional IR fixed point of ${\cal N}=8$ super
Yang-Mills deformed by Chern-Simons terms to ${\cal N}=2$ supersymmetry. One
type of Penrose limit for closed strings corresponds to a large charge closed
spin chain, and another, for open strings on giant graviton D-branes,
corresponds to an open spin chain on sub-determinant operators. For the first
limit, we find that like in the ABJM case, there are functions $f_a(\lambda)$
that interpolate between the perturbative and nonperturbative (string) regions
for the magnon energy. For the second, we are unable to match the gravity
result with the expected field theory result, making this model more
interesting than ones with more supersymmetry.Comment: 48 pages, 1 figure; typos corrected, references adde
Relaxation of the Composite Higgs Little Hierarchy

We describe a composite Higgs scenario in which a cosmological relaxation
mechanism naturally gives rise to a hierarchy between the weak scale and the
scale of spontaneous global symmetry breaking. This is achieved through the
scanning of sources of explicit global symmetry breaking by a relaxion field
during an exponentially long period of inflation in the early universe. We
explore this mechanism in detail in a specific composite Higgs scenario with
QCD-like dynamics, based on an ultraviolet $SU(N)_{\textrm{TC}}$ 'technicolor'
confining gauge theory with three Dirac technifermion flavors. We find that we
can successfully generate a hierarchy of scales $\xi \equiv \langle h \rangle^2
/ F_\pi^2 \gtrsim 1.2 \times 10^{-4}$ (i.e., compositeness scales $F_\pi \sim
20$ TeV) without tuning. This evades all current electroweak precision bounds
on our (custodial violating) model. While directly observing the heavy
composite states in this model will be challenging, a future electroweak
precision measurement program can probe most of the natural parameter space for
the model. We also highlight signatures of more general composite Higgs models
in the cosmological relaxation framework, including some implications for
flavor and dark matter.Comment: 59 pages, 5 figures. Published versio
Anomalies involving the space of couplings and the Zamolodchikov metric

The anomaly polynomial of a theory can involve not only curvature two-forms
of the flavor symmetry background but also two-forms on the space of coupling
constants. As an example, we point out that there is a mixed anomaly between
the R-symmetry and the topology of the space of exactly marginal couplings of
class S theories. Using supersymmetry, we translate this anomaly to the
K\"ahler class of the Zamolodchikov metric. We compare the result against a
holographic computation in the large N limit.
  In an appendix, we explain how to obtain the bosonic components in the
supergravity completion of the curvature squared terms using compatibility with
the topological twist.Comment: 14 pages. v3: an author added, who pointed out a serious error in v2,
  resolved it, and even provided a new appendix. The main conclusions are
  unchange
Chiral Higher Spin Theories and Self-Duality

We study recently proposed chiral higher spin theories - cubic theories of
interacting massless higher spin fields in four-dimensional flat space. We show
that they are naturally associated with gauge algebras, which manifest
themselves in several related ways. Firstly, the chiral higher spin equations
of motion can be reformulated as the self-dual Yang-Mills equations with the
associated gauge algebras instead of the usual colour gauge algebra. We also
demonstrate that the chiral higher spin field equations, similarly to the
self-dual Yang-Mills equations, feature an infinite algebra of hidden
symmetries, which ensures their integrability. Secondly, we show that off-shell
amplitudes in chiral higher spin theories satisfy the generalised BCJ relations
with the usual colour structure constants replaced by the structure constants
of higher spin gauge algebras. We also propose generalised double copy
procedures featuring higher spin theory amplitudes. Finally, using the
light-cone deformation procedure we prove that the structure of the Lagrangian
that leads to all these properties is universal and follows from Lorentz
invariance.Comment: 51 page, clarifications adde