pinecone/core-2020-05-10-deduplication huggingface dataset:
Measuring c-quark polarization in W+c samples at ATLAS and CMS

The process $pp \to W^-c$ produces polarized charm quarks. The polarization
is expected to be partly retained in $\Lambda_c$ baryons when those form in the
$c$-quark hadronization. We argue that it will likely be possible for ATLAS and
CMS to measure the $\Lambda_c$ polarization in the $W$+$c$ samples in Run 2 of
the LHC. This can become the first measurement ever of a longitudinal
polarization of charm quarks. Its results will provide a unique input to the
understanding of polarization transfer in fragmentation. They will also allow
applying the same measurement technique to other (e.g., new physics) samples of
charm quarks in which the polarization is a priori unknown. The proposed
analysis is similar to the ATLAS and CMS measurements of the $W$+$c$ cross
section in the 7 TeV run that used reconstructed $D$-meson decays for charm
tagging.Comment: 18 pages, 3 figures; v2: minor improvements; published versio
Subleading soft photons and large gauge transformations

Lysov, Pasterski and Strominger have shown how Low's subleading soft photon
theorem can be understood as Ward identities of new symmetries of massless QED.
In this paper we offer a different perspective and show that there exists a
class of large $U(1)$ gauge transformations such that (i) the associated
(electric and magnetic) charges can be computed from first principles (ii)
their Ward identities are equivalent to Low's theorem. Our framework paves the
way to analyze the sub-subleading theorem in gravity in terms of Ward
identities associated to large diffeomorphisms.Comment: 17 page
Towards Critical Physics in 2+1d with U(2N)-Invariant Fermions

Interacting theories of N relativistic fermion flavors in reducible spinor
representations in 2+1 spacetime dimensions are formulated on a lattice using
domain wall fermions (DWF), for which a U(2N) global symmetry is recovered in
the limit that the wall separation $L_s$ is made large. The Gross-Neveu (GN)
model is studied in the large-N limit and an exponential acceleration of
convergence to the large-$L_s$ limit is demonstrated if the usual
parity-invariant mass $m\bar\psi\psi$ is replaced by the U(2N)-equivalent
$im_3\bar\psi\gamma_3\psi$. The GN model and two lattice variants of the
Thirring model are simulated for N = 2 using a hybrid Monte Carlo algorithm,
and studies made of the symmetry-breaking bilinear condensate and its
associated susceptibility, the axial Ward identity, and the mass spectrum of
both fermion and meson excitations. Comparisons are made with existing results
obtained using staggered fermions. For the GN model a symmetry-breaking phase
transition is observed, the Ward identity is recovered, and the spectrum found
to be consistent with large-N expectations. There appears to be no obstruction
to the study of critical UV fixed-point physics using DWF. For the Thirring
model the Ward identity is not recovered, the spectroscopy measurements are
inconclusive, and no symmetry breaking is observed all the way up to the
effective strong coupling limit. This is consistent with a critical Thirring
flavor number $N_c<2$, contradicting earlier staggered fermion results.Comment: 31 pages, 15 figure
Infinitesimal moduli of G2 holonomy manifolds with instanton bundles

We describe the infinitesimal moduli space of pairs $(Y, V)$ where $Y$ is a
manifold with $G_2$ holonomy, and $V$ is a vector bundle on $Y$ with an
instanton connection. These structures arise in connection to the moduli space
of heterotic string compactifications on compact and non-compact seven
dimensional spaces, e.g. domain walls. Employing the canonical $G_2$ cohomology
developed by Reyes-Carri\'on and Fern\'andez and Ugarte, we show that the
moduli space decomposes into the sum of the bundle moduli
$H^1_{\check{d}_A}(Y,\mathrm{End}(V))$ plus the moduli of the $G_2$ structure
preserving the instanton condition. The latter piece is contained in
$H^1_{\check{d}_\theta}(Y,TY)$, and is given by the kernel of a map
${\cal\check F}$ which generalises the concept of the Atiyah map for
holomorphic bundles on complex manifolds to the case at hand. In fact, the map
${\cal\check F}$ is given in terms of the curvature of the bundle and maps
$H^1_{\check{d}_\theta}(Y,TY)$ into $H^2_{\check{d}_A}(Y,\mathrm{End}(V))$, and
moreover can be used to define a cohomology on an extension bundle of $TY$ by
$\mathrm{End}(V)$. We comment further on the resemblance with the holomorphic
Atiyah algebroid and connect the story to physics, in particular to heterotic
compactifications on $(Y,V)$ when $\alpha'=0$.Comment: 51 pages, minor corrections, references adde
Dual QED3 at "NF = 1/2" is an interacting CFT in the infrared

We study the fate of weakly coupled dual QED3 in the infrared, that is, a
single two-component Dirac fermion coupled to an emergent U(1) gauge field, but
without Chern-Simons term. This theory has recently been proposed as a dual
description of 2D surfaces of certain topological insulators. Using the
renormalization group, we find that the interplay of gauge fluctuations with
generated interactions in the four-fermi sector stabilizes an interacting
conformal field theory (CFT) with finite four-fermi coupling in the infrared.
The emergence of this CFT is due to cancellations in the $\beta$-function of
the four-fermi coupling special to "NF = 1/2". We also quantify how a possible
"strong" Dirac fermion duality between a free Dirac cone and dual QED3 would
constrain the universal constants of the topological current correlator of the
latter.Comment: 21 pages, 8 figures; v2 minor typos fixe
Flavor physics induced by light $Z'$ from SO(10) GUT

In this paper, we investigate predictions of the SO(10) Grand Unified Theory
(GUT), where an extra U(1)$^\prime$ gauge symmetry remains up to the
supersymmetry (SUSY) breaking scale. The minimal setup of SO(10) GUT unifies
quarks and leptons into a ${\bf 16}$-representational field in each
generations. The setup, however, suffers from the realization of the realistic
Yukawa couplings at the electroweak scale. In order to solve this problem, we
introduce ${\bf 10}$-representational matter fields, and then the two kinds of
matter fields mix with each other at the SUSY breaking scale, where the extra
U(1)$^\prime$ gauge symmetry breaks down radiatively. One crucial prediction is
that the Standard Model quarks and leptons are given by the linear combinations
of the fields with two different U(1)$^\prime$ charges. The mixing also depends
on the flavor. Consequently, the U(1)$^\prime$ interaction becomes flavor
violating, and the flavor physics is the smoking-gun signal of our GUT model.
The flavor violating $Z'$ couplings are related to the fermion masses and the
CKM matrix, so that we can derive some explicit predictions in flavor physics.
We especially discuss $K$-$\overline{K}$ mixing, $B_{(s)}$-$\overline{B_{(s)}}$
mixing, and the (semi)leptonic decays of $K$ and $B$ in our model. We also
study the flavor violating $\mu$ and $\tau$ decays and discuss the correlations
among the physical observables in this SO(10) GUT framework.Comment: 30 pages, 20 figures, v2 : texts are improved, comments and
  references are adde
Chiral observables and S-duality in N = 2* U(N) gauge theories

We study N = 2* theories with gauge group U(N) and use equivariant
localization to calculate the quantum expectation values of the simplest chiral
ring elements. These are expressed as an expansion in the mass of the adjoint
hypermultiplet, with coefficients given by quasi-modular forms of the S-duality
group. Under the action of this group, we construct combinations of chiral ring
elements that transform as modular forms of definite weight. As an independent
check, we confirm these results by comparing the spectral curves of the
associated Hitchin system and the elliptic Calogero-Moser system. We also
propose an exact and compact expression for the 1-instanton contribution to the
expectation value of the chiral ring elements.Comment: 37 page
A consistent model for leptogenesis, dark matter and the IceCube signal

We discuss a left-right symmetric extension of the Standard Model in which
the three additional right-handed neutrinos play a central role in explaining
the baryon asymmetry of the Universe, the dark matter abundance and the ultra
energetic signal detected by the IceCube experiment. The energy spectrum and
neutrino flux measured by IceCube are ascribed to the decays of the lightest
right-handed neutrino $N_1$, thus fixing its mass and lifetime, while the
production of $N_1$ in the primordial thermal bath occurs via a freeze-in
mechanism driven by the additional $SU(2)_R$ interactions. The constraints
imposed by IceCube and the dark matter abundance allow nonetheless the heavier
right-handed neutrinos to realize a standard type-I seesaw leptogenesis, with
the $B-L$ asymmetry dominantly produced by the next-to-lightest neutrino $N_2$.
Further consequences and predictions of the model are that: the $N_1$
production implies a specific power-law relation between the reheating
temperature of the Universe and the vacuum expectation value of the $SU(2)_R$
triplet; leptogenesis imposes a lower bound on the reheating temperature of the
Universe at $7\times10^9\,\mbox{GeV}$. Additionally, the model requires a
vanishing absolute neutrino mass scale $m_1\simeq0$.Comment: 19 pages, 4 figures. Constraints from cosmic-ray antiprotons and
  gamma rays added, with hadrophobic assignment of the matter multiplets to
  satisfy bounds. References added. Matches version published in JHE
Massless and Massive Higher Spins from Anti-de Sitter Space Waveguide

Higgs mechanism to massive higher-spin gauge fields is an outstanding open
problem. We investigate this issue in the context of Kaluza-Klein
compactification. Starting from a free massless higher-spin field in
$(d+2)$-dimensional anti-de Sitter space and compactifying over a finite
angular wedge, we obtain an infinite tower of heavy, light and massless
higher-spin fields in $(d+1)$-dimensional anti-de Sitter space. All massive
higher-spin fields are described gauge invariantly in terms of St\"ueckelberg
fields. The spectrum depends on the boundary conditions imposed at both ends of
the wedges. We obseved that higher-derivative boundary condition is inevitable
for spin greater than three. For some higher-derivative boundary conditions,
equivalently, spectrum-dependent boundary conditions, we get a non-unitary
representation of partially-massless higher-spin fields of varying depth. We
present intuitive picture which higher-derivative boundary conditions yield
non-unitary system in terms of boundary action. We argue that isotropic
Lifshitz interfaces in $O(N)$ Heisenberg magnet or $O(N)$ Gross-Neveu model
provides the holographic dual conformal field theory and propose experimental
test of (inverse) Higgs mechanism for massive and partially massless
higher-spin fields.Comment: v1. 62 pages, 7 figures, v2. 68 pages, 8 figures, published versio
Next-to-leading order unitarity fits in Two-Higgs-Doublet models with
  soft $\mathbb{Z}_2$ breaking

We fit the next-to-leading order unitarity conditions to the
Two-Higgs-Doublet model with a softly broken $\mathbb{Z}_2$ symmetry. In doing
so, we alleviate the existing uncertainty on how to treat higher order
corrections to quartic couplings of its Higgs potential. A simplified approach
to implementing the next-to-leading order unitarity conditions is presented.
These new bounds are then combined with all other relevant constraints,
including the complete set of LHC Run I data. The upper $95\%$ bounds we find
are $4.2$ on the absolute values of the quartic couplings, and $235$ GeV ($100$
GeV) for the mass degeneracies between the heavy Higgs particles in the type I
(type II) scenario. In type II, we exclude an unbroken $\mathbb{Z}_2$ symmetry
with a probability of $95\%$. All fits are performed using the open-source code
HEPfit.Comment: 33 pages, 13 figures, 5 tables. Comments are welcom
Non-associativity in non-geometric string and M-theory backgrounds, the
  algebra of octonions, and missing momentum modes

We propose a non-associative phase space algebra for M-theory backgrounds
with locally non-geometric fluxes based on the non-associative algebra of
octonions. Our proposal is based on the observation that the non-associative
algebra of the non-geometric R-flux background in string theory can be obtained
by a proper contraction of the simple Malcev algebra generated by imaginary
octonions. Furthermore, by studying a toy model of a four-dimensional locally
non-geometric M-theory background which is dual to a twisted torus, we show
that the non-geometric background is "missing" a momentum mode. The resulting
seven-dimensional phase space can thus be naturally identified with the
imaginary octonions. This allows us to interpret the full uncontracted algebra
of imaginary octonions as the uplift of the string theory R-flux algebra to
M-theory, with the contraction parameter playing the role of the string
coupling constant $g_s$.Comment: 27 page
Deriving covariant holographic entanglement

We provide a gravitational argument in favour of the covariant holographic
entanglement entropy proposal. In general time-dependent states, the proposal
asserts that the entanglement entropy of a region in the boundary field theory
is given by a quarter of the area of a bulk extremal surface in Planck units.
The main element of our discussion is an implementation of an appropriate
Schwinger-Keldysh contour to obtain the reduced density matrix (and its powers)
of a given region, as is relevant for the replica construction. We map this
contour into the bulk gravitational theory, and argue that the saddle point
solutions of these replica geometries lead to a consistent prescription for
computing the field theory Renyi entropies. In the limiting case where the
replica index is taken to unity, a local analysis suffices to show that these
saddles lead to the extremal surfaces of interest. We also comment on various
properties of holographic entanglement that follow from this construction.Comment: 39 pages. 9 figure
Fundamental partial compositeness

We construct renormalizable Standard Model extensions, valid up to the Planck
scale, that give a composite Higgs from a new fundamental strong force acting
on fermions and scalars. Yukawa interactions of these particles with Standard
Model fermions realize the partial compositeness scenario. Under certain
assumptions on the dynamics of the scalars, successful models exist because
gauge quantum numbers of Standard Model fermions admit a minimal enough 'square
root'. Furthermore, right-handed SM fermions have an SU(2)$_R$-like structure,
yielding a custodially-protected composite Higgs. Baryon and lepton numbers
arise accidentally. Standard Model fermions acquire mass at tree level, while
the Higgs potential and flavor violations are generated by quantum corrections.
We further discuss accidental symmetries and other dynamical features stemming
from the new strongly interacting scalars. If the same phenomenology can be
obtained from models without our elementary scalars, they would reappear as
composite states.Comment: 36 pages, 3 figures, 5 tables. v2: final published version, expanded
  discussion about neutrino masses, dark matter and flavou
Closure of the Operator Product Expansion in the Non-Unitary Bootstrap

We use the numerical conformal bootstrap in two dimensions to search for
finite, closed sub-algebras of the operator product expansion (OPE), without
assuming unitarity. We find the minimal models as special cases, as well as
additional lines of solutions that can be understood in the Coulomb gas
formalism. All the solutions we find that contain the vacuum in the operator
algebra are cases where the external operators of the bootstrap equation are
degenerate operators, and we argue that this follows analytically from the
expressions in arXiv:1202.4698 for the crossing matrices of Virasoro conformal
blocks. Our numerical analysis is a special case of the "Gliozzi" bootstrap
method, and provides a simpler setting in which to study technical challenges
with the method.
  In the supplementary material, we provide a Mathematica notebook that
automates the calculation of the crossing matrices and OPE coefficients for
degenerate operators using the formulae of Dotsenko and Fateev.Comment: 11 figures, 24+19 page
On Butterfly effect in Higher Derivative Gravities

We study butterfly effect in $D$-dimensional gravitational theories
containing terms quadratic in Ricci scalar and Ricci tensor. One observes that
due to higher order derivatives in the corresponding equations of motion there
are two butterfly velocities. The velocities are determined by the dimension of
operators whose sources are provided by the metric. The three dimensional TMG
model is also studied where we get two butterfly velocities at generic point of
the moduli space of parameters. At critical point two velocities coincide.Comment: 16 pages, references adde
On the null origin of the ambitwistor string

In this paper we present the null string origin of the ambitwistor string.
Classically, the null string is the tensionless limit of string theory, and so
too is the Ambitwistor string. Both have as constraint algebra the Galilean
Conformal Algebra in two dimensions. But something interesting happens in the
quantum theory since there is an ambiguity in quantizing the null string. We
show that, given a particular choice of quantization scheme and a particular
gauge, the null string coincides with the ambitwistor string both classically
and quantum mechanically. We also show that the same holds for the spinning
versions of the null string and Ambitwistor string. With these results we
clarify the relationship between the Ambitwistor string, the null string, the
usual string and the Hohm-Siegel-Zwiebach theory.Comment: 22 pages, 1 figur
Notes on Relevant, Irrelevant, Marginal and Extremal Double Trace
  Perturbations

Double trace deformations, that is products of two local operators, define
perturbations of conformal field theories that can be studied exactly in the
large-N limit. Even when the double trace deformation is irrelevant in the
infrared, it is believed to flow to an ultraviolet fixed point. In this note we
define the Kallen-Lehmann representation of the two-point function of a local
operator O in a theory perturbed by the square of such operator. We use such
representation to discover potential pathologies at intermediate points in the
flow that may prevent to reach the UV fixed point. We apply the method to an
"extremal" deformation that naively would flow to a UV fixed point where the
operator O would saturate the unitarity bound. We find that the UV fixed point
is not conformal and that the deformed two-point function propagates unphysical
modes. We interpret the result as showing that the flow to the UV fixed point
does not exist. This resolves a potential puzzle in the holographic
interpretation of the deformation.Comment: 20 pages. Accepted by JHEP, extended discussion in Summary, added
  references and fixed minor typo
Doubled strings, negative strings and null waves

We revisit the fundamental string (F1) solution in the doubled formalism. We
show that the wave-like solution of double field theory (DFT) corresponding to
the F1/pp-wave duality pair is more properly a solution of the DFT action
coupled to a doubled sigma model action. The doubled string configuration which
sources the pp-wave can be thought of as static gauge with the string oriented
in a dual direction. We also discuss the DFT solution corresponding to a
vibrating string, carrying both winding and momentum. We further show that the
solution dual to the F1 in both time and space can be viewed as a "negative
string" solution. Negative branes are closely connected to certain exotic
string theories which involve unusual signatures for both spacetime and brane
worldvolumes. In order to better understand this from the doubled point of
view, we construct a variant of DFT suitable for describing theories in which
the fundamental string has a Euclidean worldsheet, for which T-dualities appear
to change the spacetime signature.Comment: 37 pages including 2 appendices, v2: version to appear in JHEP (typos
  fixed, some minor comments added
Holographic Renormalization of Einstein-Maxwell-Dilaton Theories

We generalize the boundary value problem with a mixed boundary condition that
involves the gauge and scalar fields in the context of Einstein-Maxwell-Dilaton
theories. In particular, the expectation value of the dual scalar operator can
be a function of the expectation value of the current operator. The properties
are prevalent in a fixed charge ensemble because the conserved charge is shared
by both fields through the dilaton coupling, which is also responsible for
non-Fermi liquid properties. We study the on-shell action and the stress energy
tensor to note practical importances of the boundary value problem. In the
presence of the scalar fields, physical quantities are not fully fixed due to
the finite boundary terms that manifest in the massless scalar or the scalar
with mass saturating the Breitenlohner-Freedman bound.Comment: 39+1 pages. Improved discussions, typos fixed and references adde
VEV of Baxter's Q-operator in N=2 gauge theory and the BPZ differential
  equation

In this short notes using AGT correspondence we express simplest fully
degenerate primary fields of Toda field theory in terms an analogue of Baxter's
$Q$-operator naturally emerging in ${\cal N}=2$ gauge theory side. This
quantity can be considered as a generating function of simple trace chiral
operators constructed from the scalars of the ${\cal N}=2$ vector multiplets.
In the special case of Liouville theory, exploring the second order
differential equation satisfied by conformal blocks including a degenerate at
the second level primary field (BPZ equation) we derive a mixed
difference-differential relation for $Q$-operator. Thus we generalize the
$T$-$Q$ difference equation known in Nekrasov-Shatashvili limit of the
$\Omega$-background to the generic case.Comment: 10 pages, 2 figure
Extended Supersymmetric BMS$_3$ algebras and Their Free Field
  Realisations

We study $N=(2,4,8)$ supersymmetric extensions of the three dimensional BMS
algebra (BMS$_3$) with most generic possible central extensions. We find that
$N$-extended supersymmetric BMS$_3$ algebras can be derived by a suitable
contraction of two copies of the extended superconformal algebras. Extended
algebras from all the consistent contractions are obtained by scaling
left-moving and right-moving supersymmetry generators symmetrically, while
Virasoro and R-symmetry generators are scaled asymmetrically. On the way, we
find that the BMS/GCA correspondence does not in general hold for
supersymmetric systems. Using the $\beta$-$\gamma$ and the ${\mathfrak
b}$-${\mathfrak c}$ systems, we construct free field realisations of all the
extended super-BMS$_3$ algebras.Comment: 25 pages, 1 tabl
The Lauricella Functions and Exact String Scattering Amplitudes

We discover that the 26D open bosonic string scattering amplitudes (SSA) of
three tachyons and one arbitrary string state can be expressed in terms of the
D-type Lauricella functions with associated SL(K+3,C) symmetry. As a result,
SSA and symmetries or relations among SSA of different string states at various
limits calculated previously can be rederived. These include the linear
relations first conjectured by Gross [1-3] and later corrected and proved in
[4-9] in the hard scattering limit, the recurrence relations in the Regge
scattering limit with associated SL(5,C) symmetry [19-21] and the extended
recurrence relations in the nonrelativistic scattering limit with associated
SL(4,C) symmetry [24] discovered recently. Finally, as an application, we
calculate a new recurrence relation of SSA which is valid for all energies.Comment: 20 pages, no figure, extended form of arXiv:1603.0039