pinecone/core-2020-05-10-deduplication huggingface dataset:
Resumming double non-global logarithms in the evolution of a jet

We consider the Banfi-Marchesini-Smye (BMS) equation which resums non-global
energy logarithms in the QCD evolution of the energy lost by a pair of jets via
soft radiation at large angles. We identify a new physical regime where,
besides the energy logarithms, one has to also resum (anti)collinear
logarithms. Such a regime occurs when the jets are highly collimated (boosted)
and the relative angles between successive soft gluon emissions are strongly
increasing. These anti-collinear emissions can violate the correct
time-ordering for time-like cascades and result in large radiative corrections
enhanced by double collinear logs, making the BMS evolution unstable beyond
leading order. We isolate the first such a correction in a recent calculation
of the BMS equation to next-to-leading order by Caron-Huot. To overcome this
difficulty, we construct a collinearly-improved version of the leading-order
BMS equation which resums the double collinear logarithms to all orders. Our
construction is inspired by a recent treatment of the Balitsky-Kovchegov (BK)
equation for the high-energy evolution of a space-like wavefunction, where
similar time-ordering issues occur. We show that the conformal mapping relating
the leading-order BMS and BK equations correctly predicts the physical
time-ordering, but it fails to predict the detailed structure of the collinear
improvement.Comment: 44 pages, 9 figure
Cluster integrable systems, q-Painleve equations and their quantization

We discuss the relation between the cluster integrable systems and
$q$-difference Painlev\'e equations. The Newton polygons corresponding to these
integrable systems are all 16 convex polygons with a single interior point. The
Painlev\'e dynamics is interpreted as deautonomization of the discrete flows,
generated by a sequence of the cluster quiver mutations, supplemented by
permutations of quiver vertices.
  We also define quantum $q$-Painlev\'e systems by quantization of the
corresponding cluster variety. We present formal solution of these equations
for the case of pure gauge theory using $q$-deformed conformal blocks or
5-dimensional Nekrasov functions. We propose, that quantum cluster structure of
the Painlev\'e system provides generalization of the isomonodromy/CFT
correspondence for arbitrary central charge.Comment: 28 pages; v2 30 pages references added, misprints corrected; v3 small
  changes, references added, to appear in JHE
GeV-scale hot sterile neutrino oscillations: a numerical solution

The scenario of baryogenesis through GeV-scale sterile neutrino oscillations
is governed by non-linear differential equations for the time evolution of a
sterile neutrino density matrix and Standard Model lepton and baryon
asymmetries. By employing up-to-date rate coefficients and a non-perturbatively
estimated Chern-Simons diffusion rate, we present a numerical solution of this
system, incorporating the full momentum and helicity dependences of the density
matrix. The density matrix deviates significantly from kinetic equilibrium,
with the IR modes equilibrating much faster than the UV modes. For equivalent
input parameters, our final results differ moderately (~50%) from recent
benchmarks in the literature. The possibility of producing an observable baryon
asymmetry is nevertheless confirmed. We illustrate the dependence of the baryon
asymmetry on the sterile neutrino mass splitting and on the CP-violating phase
measurable in active neutrino oscillation experiments.Comment: 26 pages. v2: clarifications and references adde
Soft Factorization in QED from 2D Kac-Moody Symmetry

The soft factorization theorem for 4D abelian gauge theory states that the
$\mathcal{S}$-matrix factorizes into soft and hard parts, with the universal
soft part containing all soft and collinear poles. Similarly, correlation
functions on the sphere in a 2D CFT with a $U(1)$ Kac-Moody current algebra
factorize into current algebra and non-current algebra factors, with the
current algebra factor fully determined by its pole structure. In this paper,
we show that these 4D and 2D factorizations are mathematically the same
phenomena. The soft `tHooft-Wilson lines and soft photons are realized as a
complexified 2D current algebra on the celestial sphere at null infinity. The
current algebra level is determined by the cusp anomalous dimension. The
associated complex $U(1)$ boson lives on a torus whose modular parameter is
$\tau =\frac {2\pi i }{e^2}+\frac{\theta}{ 2 \pi}$. The correlators of this 2D
current algebra fully reproduce the known soft part of the 4D
$\mathcal{S}$-matrix, as well as a conjectured generalization involving
magnetic charges.Comment: 20 page
Extremal Black Holes, Stueckelberg Scalars and Phase Transitions

We calculate the entropy of a static extremal black hole in 4D gravity,
non-linearly coupled to a massive Stueckelberg scalar. We find that the scalar
field does not allow the black hole to be magnetically charged. We also show
that the system can exhibit a phase transition due to electric charge
variations. For spherical and hyperbolic horizons, the critical point exists
only in presence of a cosmological constant, and if the scalar is massive and
non-linearly coupled to electromagnetic field. On one side of the critical
point, two extremal solutions coexist: Reissner-Nordstr\"{o}m (A)dS black hole
and the charged hairy (A)dS black hole, while on the other side of the critical
point the black hole does not have hair. A near-critical analysis reveals that
the hairy black hole has larger entropy, thus giving rise to a zero temperature
phase transition. This is characterized by a discontinuous second derivative of
the entropy with respect to the electric charge at the critical point. The
results obtained here are analytical and based on the entropy function
formalism and the second law of thermodynamics.Comment: 20 pages, no figures; Appendix added, formulas corrected, discussion
  extende
Weight Shifting Operators and Conformal Blocks

We introduce a large class of conformally-covariant differential operators
and a crossing equation that they obey. Together, these tools dramatically
simplify calculations involving operators with spin in conformal field
theories. As an application, we derive a formula for a general conformal block
(with arbitrary internal and external representations) in terms of derivatives
of blocks for external scalars. In particular, our formula gives new
expressions for "seed conformal blocks" in 3d and 4d CFTs. We also find simple
derivations of identities between external-scalar blocks with different
dimensions and internal spins. We comment on additional applications, including
derivation of recursion relations for general conformal blocks, reducing
inversion formulae for spinning operators to inversion formulae for scalars,
and deriving identities between general 6j symbols (Racah-Wigner
coefficients/"crossing kernels") of the conformal group.Comment: 84 page
Jet substructure shedding light on heavy Majorana neutrinos at the LHC

The existence of tiny neutrino masses and flavor mixings can be explained
naturally in various seesaw models, many of which typically having additional
Majorana type SM gauge singlet right handed neutrinos ($N$). If they are at
around the electroweak scale and furnished with sizeable mixings with light
active neutrinos, they can be produced at high energy colliders, such as the
Large Hadron Collider (LHC). A characteristic signature would be same sign
lepton pairs, violating lepton number, together with light jets -- $pp\to
N\ell^{\pm}, \; N\to\ell^{\pm}W^{\mp}, \; W^{\mp}\to jj$. We propose a new
search strategy utilising jet substructure techniques, observing that for a
heavy right handed neutrino mass $M_N$ much above $M_{W^\pm}$, the two jets
coming out of the boosted $W^\pm$ may be interpreted as a single fat-jet ($J$).
Hence, the distinguishing signal topology will be $\ell^{\pm}\ell^{\pm} J$.
Performing a comprehensive study of the different signal regions along with
complete background analysis, in tandem with detector level simulations, we
compute statistical significance limits. We find that heavy neutrinos can be
explored effectively for mass ranges $300$ GeV $\leq M_N \leq 800$ GeV and
different light-heavy neutrino mixing $|V_{\mu N}|^{2}$. At the 13 TeV LHC with
3000 $\mathrm{fb}^{-1}$ integrated luminosity one can competently explore
mixing angles much below present LHC limits, and moreover exceed bounds from
electroweak precision data.Comment: Accepted for publication in JHEP. 25 pages, 8 figures, 1 tabl
Dynamics of Relaxed Inflation

The cosmological relaxation of the electroweak scale has been proposed as a
mechanism to address the hierarchy problem of the Standard Model. A field, the
relaxion, rolls down its potential and, in doing so, scans the squared mass
parameter of the Higgs, relaxing it to a parametrically small value. In this
work, we promote the relaxion to an inflaton. We couple it to Abelian gauge
bosons, thereby introducing the necessary dissipation mechanism which slows
down the field in the last stages. We describe a novel reheating mechanism,
which relies on the gauge-boson production leading to strong electromagnetic
fields, and proceeds via the vacuum production of electron-positron pairs
through the Schwinger effect. We refer to this mechanism as Schwinger
reheating. We discuss the cosmological dynamics of the model and the
phenomenological constraints from CMB and other experiments. We find that a
cutoff close to the Planck scale may be achieved. In its minimal form, the
model does not generate sufficient curvature perturbations and additional
ingredients, such as a curvaton field, are needed.Comment: 39 pages, 3 figures, appendices D and E added, published in JHE
Pinning of longitudinal phonons in holographic spontaneous helices

We consider the spontaneous breaking of translational symmetry and identify
the associated Goldstone mode -- a longitudinal phonon -- in a holographic
model with Bianchi VII helical symmetry. For the first time in holography, we
observe the pinning of this mode after introducing a source for explicit
breaking compatible with the helical symmetry of our setup. We study the
dispersion relation of the resulting pseudo-Goldstone mode, uncovering how its
speed and mass gap depend on the amplitude of the source and temperature. In
addition, we extract the optical conductivity as a function of frequency, which
reveals a metal-insulator transition as a consequence of the pinning.Comment: 24 pages, 14 figures. v2: comments and references added; v3:
  discussions added, slight change of title, version published in JHE
A Complex Fermionic Tensor Model in $d$ Dimensions

In this note, we study a melonic tensor model in $d$ dimensions based on
three-index Dirac fermions with a four-fermion interaction. Summing the melonic
diagrams at strong coupling allows one to define a formal large-$N$ saddle
point in arbitrary $d$ and calculate the spectrum of scalar bilinear singlet
operators. For $d=2-\epsilon$ the theory is an infrared fixed point, which we
find has a purely real spectrum that we determine numerically for arbitrary
$d<2$, and analytically as a power series in $\epsilon$. The theory appears to
be weakly interacting when $\epsilon$ is small, suggesting that fermionic
tensor models in 1-dimension can be studied in an $\epsilon$ expansion. For
$d>2$, the spectrum can still be calculated using the saddle point equations,
which may define a formal large-$N$ ultraviolet fixed point analogous to the
Gross-Neveu model in $d>2$. For $2<d<6$, we find that the spectrum contains at
least one complex scalar eigenvalue (similar to the complex eigenvalue present
in the bosonic tensor model recently studied by Giombi, Klebanov and
Tarnopolsky) which indicates that the theory is unstable. We also find that the
fixed point is weakly-interacting when $d=6$ (or more generally $d=4n+2$) and
has a real spectrum for $6<d<6.14$ which we present as a power series in
$\epsilon$ in $6+\epsilon$ dimensions.Comment: 28 pages, 11 figures; v2: added reference
Supersymmetric $\mathrm{AdS}_3$ supergravity backgrounds and holography

We analyse the conditions for $\mathrm{AdS}_3 \times \mathcal{M}_7$
backgrounds with pure NS-NS flux to be supersymmetric. We find that a necessary
condition is that $\mathcal{M}_7$ is a $\mathrm{U}(1)$-fibration over a
balanced manifold. We subsequently classify all $\mathcal{N}=(2,2)$ solutions
where $\mathcal{M}_7$ satisfies the stronger condition of being a
$\mathrm{U}(1)$-fibration over a Kahler manifold. We compute the BPS spectrum
of all the backgrounds in this classification. We assign a natural dual CFT to
the backgrounds and confirm that the BPS spectra agree, thus providing evidence
in favour of the proposal.Comment: 39 pages; v2: minor corrections and references added; v3: section 2
  shortened, final version as published in JHE
Orthogonal Bases of Invariants in Tensor Models

Representation theory provides a suitable framework to count and classify
invariants in tensor models. We show that there are two natural ways of
counting invariants, one for arbitrary rank of the gauge group and a second,
which is only valid for large N. We construct bases of invariant operators
based on the counting, and compute correlators of their elements. The basis
associated with finite N diagonalizes the two-point function of the theory and
it is analogous to the restricted Schur basis used in matrix models. We comment
on future lines of investigation.Comment: Two overlapping but independent results are merged to a joint work.
  16 pages, 1 tabl
Probing the Dark Sector through Mono-Z Boson Leptonic Decays

Collider search for dark matter production has been performed over the years
based on high pT standard model signatures balanced by large missing transverse
energy. The mono-Z boson production with leptonic decay has a clean signature
with the advantage that the decaying electrons and muons can be precisely
measured. This signature not only enables reconstruction of the Z boson rest
frame, but also makes possible recovery of the underlying production dynamics
through the decaying lepton angular distribution. In this work, we exploit full
information carried by the leptonic Z boson decays to set limits on coupling
strength parameters of the dark sector. We study simplified dark sector models
with scalar, vector, and tensor mediators and observe among them different
signatures in the distribution of angular coefficients.Specifically, we show
that angular coefficients can be used to distinguish different scenarios of the
spin-0 and spin-1 models, including the ones with parity-odd and charge
conjugation parity-odd operators. To maximize the statistical power, we perform
a matrix element method study with a dynamic construction of event likelihood
function. We parametrize the test statistic such that sensitivity from the
matrix element is quantified through a term measuring the shape difference. Our
results show that the shape differences provide significant improvements in the
limits, especially for the scalar mediator models. We also present an example
application of a matrix-element-kinematic-discriminator, an easier approach
that is applicable for experimental data.Comment: 26 pages, 16 figure
Vortex-Strings in N=2 SQCD and Bulk-String Decoupling

We study vortex-strings in four-dimensional N=2 supersymmetric SU(Nc)xU(1)
gauge theories with Nf hypermultiplets in the fundamental representation of
SU(Nc) and general U(1) charges. If Nf>Nc, the vacuum is not gapped and the
low-energy theory contains both the vacuum massless excitations and the string
zero-modes. The question we address in this work is whether the vacuum and the
string moduli decouple at low energies, allowing a description of the
low-energy dynamics in terms of a two-dimensional theory on the string
worldsheet. We find a simple condition controlling the bulk-string coupling: If
there exist two flavors such that the product of their U(1) charge difference
with the magnetic flux carried by the string configuration is not an integer
multiple of 2\pi, the string has zero-modes that decay slower than 1/r, where r
is the radial distance from the string core. These modes are coupled to the
vacuum massless excitations even at low energies. If, however, all such
products are integer multiples of 2\pi, long-range modes of this type do not
exist and the string moduli decouple from the bulk at low energies. This
condition turns out to coincide with the condition of trivial Aharonov-Bohm
phases for the particles in the spectrum. In addition to a derivation of the
bulk-string decoupling criterion using classical analysis of the string
zero-modes, we provide a non-perturbative derivation of the criterion, which
uses supersymmetric localization techniques.Comment: Added reference
Loopholes in $Z^\prime$ searches at the LHC: exploring supersymmetric
  and leptophobic scenarios

Searching for heavy vector bosons $Z^\prime$, predicted in models inspired by
Grand Unification Theories, is among the challenging objectives of the LHC. The
ATLAS and CMS collaborations have looked for $Z^\prime$ bosons assuming that
they can decay only into Standard Model channels, and have set exclusion limits
by investigating dilepton, dijet and to a smaller extent top-antitop final
states. In this work we explore possible loopholes in these $Z^\prime$ searches
by studying supersymmetric as well as leptophobic scenarios. We demonstrate the
existence of realizations in which the $Z^\prime$ boson automatically evades
the typical bounds derived from the analyses of the Drell-Yan invariant-mass
spectrum. Dileptonic final states can in contrast only originate from
supersymmetric $Z^\prime$ decays and are thus accompanied by additional
effects. This feature is analyzed in the context of judiciously chosen
benchmark configurations, for which visible signals could be expected in future
LHC data with a $4\sigma-7\sigma$ significance. Our results should hence
motivate an extension of the current $Z^\prime$ search program to account for
supersymmetric and leptophobic models.Comment: 32 pages, 15 figures. After JHEP revision. Published on 15 February
  201
Pinching parameters for open (super) strings

We present an approach to the parametrization of (super) Schottky space
obtained by sewing together three-punctured discs with strips. Different cubic
ribbon graphs classify distinct sets of pinching parameters; we show how they
are mapped onto each other. The parametrization is particularly well-suited to
describing the region within (super) moduli space where open bosonic or
Neveu-Schwarz string propagators become very long and thin, which dominates the
IR behaviour of string theories. We show how worldsheet objects such as the
Green's function converge to graph theoretic objects such as the Symanzik
polynomials in the $\alpha ' \to 0$ limit, allowing us to see how string theory
reproduces the sum over Feynman graphs. The (super) string measure takes on a
simple and elegant form when expressed in terms of these parameters.Comment: 68 pages, 31 figure
On the Higher Spin Spectrum of Chern-Simons Theory coupled to Fermions
  in the Large Flavour Limit

In this note, we compute the higher spin spectrum of $U(M)_k$ Chern-Simons
theory coupled to $N$ flavours of fundamental fermions, in the limit $N\gg M$
with the 't Hooft coupling $\lambda_M =\frac{N}{k_m}$ held fixed, to order
$M/N$. This theory possesses a slightly broken higher spin symmetry, and may be
of interest from the perspective of higher-spin and non-supersymmetric
holography. We find that anomalous dimensions of the higher spin currents
achieve a finite value at strong coupling $\lambda_M \rightarrow \infty$, which
grows with spin as $\log s$ for large $s$, as expected for gauge theories.Comment: 20 pages, 8 figures, v2: added reference
Unifying Relations for Scattering Amplitudes

We derive new amplitudes relations revealing a hidden unity among
wide-ranging theories in arbitrary spacetime dimensions. Our results rely on a
set of Lorentz invariant differential operators which transmute physical
tree-level scattering amplitudes into new ones. By transmuting the amplitudes
of gravity coupled to a dilaton and two-form, we generate all the amplitudes of
Einstein-Yang-Mills theory, Dirac-Born-Infield theory, special Galileon,
nonlinear sigma model, and biadjoint scalar theory. Transmutation also relates
amplitudes in string theory and its variants. As a corollary, celebrated
aspects of gluon and graviton scattering like color-kinematics duality, the KLT
relations, and the CHY construction are inherited traits of the transmuted
amplitudes. Transmutation recasts the Adler zero as a trivial consequence of
the Weinberg soft theorem and implies new subleading soft theorems for certain
scalar theories.Comment: 26 pages+refs, 1 figure for the unified web of theories, v2 matched
  JHEP versio
Novel String Field Theory with also Negative Energy Constituents/Objects
  gives Veneziano Amplitude

We have proposed a new type of string field theory. The main point of the
present article is to cure some technical troubles: missing two out three terms
in veneziano amplitude. Our novel string field theory, describes a theory with
many strings in terms of "objects",which are not exactly, but close to Charles
Thorn's string bits. The new point is that the objects in terms of which the
universe states are constructed,and which have an essentially 26-momentum
variable called J^{\mu}, can have essentially the energy J^0 be also
negative.We get a long way in deriving in this model the veneziano model and
obtain all the three terms needed for a four point amplitude.This result
strongly indicates that our novel string field theory is indeed string theory.Comment: 58 pages, 35 figure
Measurement of branching fractions of charmless four-body Λb0 and Ξb0 decays

A search for charmless four-body decays of Λb0 and Ξb0 baryons with a proton and three charged mesons (either kaons or pions) in the final state is performed. The data sample used was recorded in 2011 and 2012 with the LHCb experiment and corresponds to an integrated luminosity of 3 fb[superscript −1]. Six decay modes are observed, among which Λ[subscript b][superscript 0]→ pK[superscript −]π[superscript+]π[superscript−], Λ[subscript b][superscript 0]→ pK[superscript −]K[superscript +]K[superscript −], Ξ[subscript b][superscript 0]→ pK[superscript −]π[superscript +]π[superscript −] and Ξ[subscript b][superscript 0]→ pK[superscript −]π[superscript +]K[superscript −] are established for the first time. Their branching fractions (including the ratio of hadronisation fractions in the case of the Ξ[subscript b][superscript 0] baryon) are determined relative to the Λ[subscript b][superscript 0] → Λ c[superscript +]π[superscript −] decay. Keywords: B physics; Branching fraction; Hadron-Hadron scattering (experiments