pinecone/core-2020-05-10-deduplication huggingface dataset:
Measurement of the tt¯ production cross section in the dilepton channel in pp collisions at s√ = 8 TeV

The top-antitop quark ( tt¯ ) production cross section is measured in proton-proton collisions at s√ = 8 TeV with the CMS experiment at the LHC, using a data sample corresponding to an integrated luminosity of 5.3 fb−1. The measurement is performed by analysing events with a pair of electrons or muons, or one electron and one muon, and at least two jets, one of which is identified as originating from hadronisation of a bottom quark. The measured cross section is 239 ± 2 (stat.) ± 11 (syst.) ± 6 (lum.) pb, for an assumed top-quark mass of 172.5 GeV, in agreement with the prediction of the standard model
A simple harmonic universe

We explore simple but novel bouncing solutions of general relativity that avoid singularities. These solutions require curvature k  = +1, and are supported by a negative cosmological term and matter with −1  < w <  −1 / 3. In the case of moderate bounces (where the ratio of the maximal scale factor a + to the minimal scale factor a − is $ \mathcal{O}(1) $ ), the solutions are shown to be classically stable and cycle through an infinite set of bounces. For more extreme cases with large a + /a − , the solutions can still oscillate many times before classical instabilities take them out of the regime of validity of our approximations. In this regime, quantum particle production also leads eventually to a departure from the realm of validity of semiclassical general relativity, likely yielding a singular crunch. We briefly discuss possible applications of these models to realistic cosmology
Statistical issues in the parton distribution analysis of the Tevatron jet data

We analyse a tension between the D0 and CDF inclusive jet data and the perturbative QCD calculations, which are based on the ABKM09 and ABM11 parton distribution functions (PDFs) within the nuisance parameter framework. Particular attention is paid on the uncertainties in the nuisance parameters due to the data fluctuations and the PDF errors. We show that with account of these uncertainties the nuisance parameters corresponding to the luminosity uncertainties in the D0 and the CDF data sets take the values $ r_{\mathrm{norm}}^{{\mathrm{D}0}} $ = 4 . 1 ± 1 . 3 and $ r_{\mathrm{norm}}^{\mathrm{CDF}} $ = 5 . 4 ± 1 . 7, respectively, while dropping luminosity uncertainty leads to variation of the PDFs well within uncertainties. A statistical bias of the estimator based on the nuisance parameters is also discussed
Supersymmetric Lifshitz-like backgrounds from N=4 SYM with heavy quark
  density

We examine a class of gravity backgrounds obtained by considering the
backreaction of a spatially uniform density of mutually BPS Wilson lines or
heavy quarks in N=4 SUSY Yang-Mills theory. The configurations preserve eight
supercharges and an SO(5) subgroup of the SO(6) R-symmetry. They are obtained
by considering the 1/4-BPS geometries associated to smeared string/D3-brane
(F1-D3) intersections. We argue that for the (partially) localized
intersection, the geometry exhibits a flow from AdS_5 x S^5 in the UV to a
novel IR scaling solution displaying anisotropic Lifshitz-like scaling with
dynamical critical exponent z=7, hyperscaling violation and a logarithmic
running dilaton. We also obtain a two-parameter family of smeared 1/4-BPS
solutions on the Coulomb branch of N=4 SYM exhibiting Lifshitz scaling and
hyperscaling violation. For a certain parametric range these yield IR
geometries which are conformal to AdS_2 x R^3, and which have been argued to be
relevant for fermionic physics.Comment: 24 pages, 2 figures, references added, version published in JHEP,
  Feb. 201
A topological Chern-Simons sigma model and new invariants of three-manifolds

We construct a topological Chern-Simons sigma model on a Riemannian threemanifold M with gauge group G whose hyperkähler target space X is equipped with a G -action. Via a perturbative computation of its partition function, we obtain new topological invariants of M that define new weight systems which are characterized by both Lie algebra structure and hyperkähler geometry. In canonically quantizing the sigma model, we find that the partition function on certain M can be expressed in terms of Chern-Simons knot invariants of M and the intersection number of certain G -equivariant cycles in the moduli space of G -covariant maps from M to X . We also construct supersymmetric Wilson loop operators, and via a perturbative computation of their expectation value, we obtain new knot invariants of M that define new knot weight systems which are also characterized by both Lie algebra structure and hyperkähler geometry
Two-loop corrections to the muon magnetic moment from fermion/sfermion loops in the MSSM: detailed results

Recently, first results were presented for two-loop corrections to the muon ( g −2) from fermion/sfermion loops in the MSSM. These corrections were shown to be generally large and even logarithmically enhanced for heavy sfermions. Here, full details of the calculation and analytical results are presented. Also, a very compact formula is provided which can be easily implemented and serves as a good approximation of the full result as a function of the fourteen most important input parameters. Finally, a thorough discussion of the numerical behaviour of the fermion/sfermion-loop corrections to ( g −2) μ is given. The discussion includes the case of very heavy SUSY masses as well as experimentally allowed scenarios with very light SUSY masses
Study of $J/\psi$ production and cold nuclear matter effects in $p$Pb collisions at $\sqrt{s_{NN}}=5 \mathrm{TeV}$

The production of $J/\psi$ mesons with rapidity $1.5<y<4.0$ or $-5.0<y<-2.5$ and transverse momentum $p_\mathrm{T} < 14 \mathrm{GeV}/c$ is studied with the LHCb detector in proton-lead collisions at a nucleon-nucleon centre-of-mass energy $\sqrt{s_{NN}}=5 \mathrm{TeV}$. The analysis is based on a data sample corresponding to an integrated luminosity of about $1.6 \mathrm{nb}^{-1}$. For the first time the nuclear modification factor and forward-backward production ratio are determined separately for prompt $J/\psi$ mesons and $J/\psi$ from $b$-hadron decays. Clear suppression of prompt $J/\psi$ production with respect to proton-proton collisions at large rapidity is observed, while the production of $J/\psi$ from $b$-hadron decays is less suppressed. These results show good agreement with available theoretical predictions. The measurement shows that cold nuclear matter effects are important for interpretations of the related quark-gluon plasma signatures in heavy-ion collisions
Resolving Lifshitz horizons

Via the AdS/CFT correspondence, ground states of field theories at finite charge density are mapped to extremal black brane solutions. Studies of simple gravity + matter systems in this context have uncovered wide new classes of extremal geometries. The Lifshitz metrics characterising field theories with non-trivial dynamical critical exponent z  ≠ 1 emerge as one common endpoint in doped holographic toy models. However, the Lifshitz horizon exhibits mildly singular behaviour - while curvature invariants are finite, there are diverging tidal forces. Here we show that in some of the simplest contexts where Lifshitz metrics emerge, Einstein-Maxwell-dilaton theories, toy models of generic corrections can lead (presumably as one possibility among many) to a replacement of the Lifshitz metric, in the deep infrared, by a re-emergent AdS 2  ×  R 2 geometry. Thus, at least in these cases, the Lifshitz scaling characterises the physics over a wide range of energy scales, but the mild singularity is cured by quantum or stringy effects
The BFKL equation, Mueller-Navelet jets and single-valued harmonic
  polylogarithms

We introduce a generating function for the coefficients of the leading
logarithmic BFKL Green's function in transverse-momentum space, order by order
in alpha_s, in terms of single-valued harmonic polylogarithms. As an
application, we exhibit fully analytic azimuthal-angle and transverse-momentum
distributions for Mueller-Navelet jet cross sections at each order in alpha_s.
We also provide a generating function for the total cross section valid to any
number of loops.Comment: 28 pages, 2 figures. v2: added one table, various explanatory
  remarks, and corrected typo
Conformal symmetry limit of QED and QCD and identities between perturbative contributions to deep-inelastic scattering sum rules

Conformal symmetry-based relations between concrete perturbative QED and QCD approximations for the Bjorken , the Ellis-Jaffe sum rules of polarized lepton- nucleon deep-inelastic scattering (DIS), the Gross-Llewellyn Smith sum rules of neutrino-nucleon DIS, and for the Adler functions of axial-vector and vector channels are derived. They result from the application of the operator product expansion to three triangle Green functions, constructed from the non-singlet axial-vector, and two vector currents, the singlet axial-vector and two non-singlet vector currents and the non-singlet axial-vector, vector and singlet vector currents in the limit, when the conformal symmetry of the gauge models with fermions is considered unbroken. We specify the perturbative conditions for this symmetry to be valid in the case of the U(1) and SU( N c ) models. The all-order perturbative identity following from the conformal invariant limit between the concrete contributions to the Bjorken, the Ellis-Jaffe and the Gross-Llewellyn Smith sum rules is proved. The analytical and numerical O ( α 4 ) and $ O\left( {\alpha_s^2} \right) $ conformal symmetry based approximations for these sum rules and for the Adler function of the non-singlet vector currents are summarized. Possible theoretical applications of the results presented are discussed
N=2 higher-derivative couplings from strings

We consider the Calabi-Yau reduction of the Type IIA eight derivative
one-loop stringy corrections focusing on the couplings of the four dimensional
gravity multiplet with vector multiplets and a tensor multiplet containing the
NS two-form. We obtain a variety of higher derivative invariants generalising
the one-loop topological string coupling, $F_1$, controlled by the lowest order
Kahler potential and two new non-topological quantities built out of the
Calabi-Yau Riemann curvature.Comment: 43 page
On supersymmetric Chern-Simons-type theories in five dimensions

We present a closed-form expression for the supersymmetric non-Abelian
Chern-Simons action in conventional five-dimensional N=1 superspace. Our
construction makes use of the superform formalism to generate supersymmetric
invariants. Similar ideas are applied to construct supersymmetric actions for
off-shell supermultiplets with an intrinsic central charge. In particular, the
large tensor multiplet is described in superspace for the first time.Comment: 26 pages; V2: comments added and typos corrected, published versio
Exact Partition Functions on RP2 and Orientifolds

We consider gauged linear sigma models (GLSM) on $\mathbb{RP}^2$, obtained
from a parity projection of $S^2$. The theories admit squashing deformation,
much like GLSM on $S^2$, which allows us to interpret the partition function as
the overlap amplitude between the vacuum state and crosscap states. From these,
we extract the central charge of Orientifold planes, and observe that the Gamma
class makes a prominent appearance as in the recent D-brane counterpart. We
also repeat the computation for the mirror Landau-Ginzburg theory, which
naturally brings out the $\theta$-dependence as a relative sign between two
holonomy sectors on $\mathbb{RP}^2$. We also show how our results are
consistent with known topological properties of D-brane and Orientifold plane
world-volumes, and discuss what part of the wrapped D-brane/Orientifold central
charge should be attributed to the quantum volumes.Comment: 55 pages, 1 figure, published version: discussions on role of theta
  angle and on r-charge dependent normalization calrified; typos corrected; one
  reference adde
Complete QED NLO contributions to the reaction e + e − → μ + μ − γ and their implementation in the event generator PHOKHARA

KLOE and Babar have an observed discrepancy of 2% to 5% in the invariant pion pair production cross section. These measurements are based on approximate NLO μ + μ − γ cross section predictions of the Monte Carlo event generator PHOKHARA7.0. In this article, the complete NLO radiative corrections to μ + μ − γ production are calculated and implemented in the Monte Carlo event generator PHOKHARA9.0. Numerical reliability is guaranteed by two independent approaches to the real and the virtual corrections. The novel features include the contribution of pentagon diagrams in the virtual corrections, which form a gauge-invariant set when combined with their box diagram partners. They may contribute to certain distributions at the percent level. Also the real emission was complemented with two-photon final state emission contributions not included in the generator PHOKHARA7.0. We demonstrate that the numerical influence reaches, for realistic charge-averaged experimental setups, not more than 0.1% at KLOE and 0.3% at BaBar energies. As a result, we exclude the approximations in earlier versions of PHOKHARA as origin of the observed experimental discrepancy
Double field theory on group manifolds

A new version of double field theory (DFT) is derived for the exactly solvable background of an in general left-right asymmetric WZW model in the large level limit. This generalizes the original DFT that was derived via expanding closed string field theory on a torus up to cubic order. The action and gauge transformations are derived for fluctuations around the generalized group manifold background up to cubic order, revealing the appearance of a generalized Lie derivative and a corresponding C-bracket upon invoking a new version of the strong constraint. In all these quantities a background dependent covariant derivative appears reducing to the partial derivative for a toroidal background. This approach sheds some new light on the conceptual status of DFT, its background (in-)dependence and the up-lift of non-geometric Scherk-Schwarz reductions
A cluster bootstrap for two-loop MHV amplitudes

We apply a bootstrap procedure to two-loop MHV amplitudes in planar N = 4 $$ \mathcal{N}=4 $$ super-Yang-Mills theory. We argue that the mathematically most complicated part (the Λ 2 B 2 coproduct component) of the n -particle amplitude is uniquely determined by a simple cluster algebra property together with a few physical constraints (dihedral symmetry, analytic structure, supersymmetry, and well-defined collinear limits). We present a concise, closed-form expression which manifests these properties for all n
Vector meson spectral function and dilepton production rate in a hot and dense medium within an effective QCD approach

The properties of the vector meson current-current correlation function and its spectral representation are investigated in details with and without isoscalar-vector interaction within the framework of effective QCD approach, namely Nambu-Jona-Lasinio (NJL) model and its Polyakov Loop extended version (PNJL), at finite temperature and finite density. The influence of the isoscalar-vector interaction on the vector meson correlator is obtained using the ring resummation known as the Random Phase Approximation (RPA). The spectral as well as the correlation function in PNJL model show that the vector meson retains its bound property up to a moderate value of temperature above the phase transition. Using the vector meson spectral function we, for the first time, obtained the dilepton production rate from a hot and dense medium within the framework of PNJL model that takes into account the nonperturbative effect through the Polyakov Loop fields. The dilepton production rate in PNJL model is enhanced compared to NJL and Born rate in the deconfined phase due to the suppression of color degrees of freedom at moderate temperature. The presence of isoscalar-vector interaction further enhances the dileption rate over the Born rate in the low mass region. Further, we also have computed the Euclidean correlation function in vector channel and the conserved density fluctuation associated with temporal correlation function appropriate for a hot and dense medium. The dilepton rate and the Euclidean correlator are also compared with available lattice data and those quantities in PNJL model are found to agree well in certain domain
SU(2)-colored (A)dS black holes in conformal gravity

We consider four-dimensional conformal gravity coupled to the U(1) Maxwell and SU(2) Yang-Mills fields. We study the structure of general black hole solutions carrying five independent parameters: the mass, the electric U(1) and magnetic SU(2) charges, the massive spin-2 charge and the thermodynamical pressure associated with the cosmological constant, which is an integration constant in conformal gravity. We derive the thermodynamical first law of the black holes. We obtain some exact solutions including an extremal black hole with vanishing mass and entropy, but with non-trivial SU(2) Yang-Mills charges. We derive the remainder of the first law for this special solution. We also reexamine the colored black holes and derive their first law in Einstein-Yang-Mills gravity with or without a cosmological constant
Prospects for dark matter searches in the pMSSM

We investigate the prospects for detection of neutralino dark matter in the 19-parameter phenomenological MSSM (pMSSM). We explore very wide ranges of the pMSSM parameters but pay particular attention to the higgsino-like neutralino at the ∼ 1 TeV scale, which has been shown to be a well motivated solution in many constrained supersymmetric models, as well as to a wino-dominated solution with the mass in the range of 2–3 TeV. After summarising the present bounds on the parameter space from direct and indirect detection experiments, we focus on prospects for detection of the Cherenkov Telescope Array (CTA). To this end, we derive a realistic assessment of the sensitivity of CTA to photon fluxes from dark matter annihilation by means of a binned likelihood analysis for the Einasto and Navarro-Frenk-White halo profiles. We use the most up to date instrument response functions and background simulation model provided by the CTA Collaboration. We find that, with 500 hours of observation, under the Einasto profile CTA is bound to exclude at the 95% C.L. almost all of the ∼ 1 TeV higgsino region of the pMSSM, effectively closing the window for heavy supersymmetric dark matter in many realistic models. CTA will be able to probe the vast majority of cases corresponding to a spin-independent scattering cross section below the reach of 1-tonne underground detector searches for dark matter, in fact even well below the irreducible neutrino background for direct detection. On the other hand, many points lying beyond the sensitivity of CTA will be within the reach of 1-tonne detectors, and some within collider reach. Altogether, CTA will provide a highly sensitive way of searching for dark matter that will be partially overlapping and partially complementary with 1-tonne detector and collider searches, thus being instrumental to effectively explore the nearly full parameter space of the pMSSM
Nonlocal probes of thermalization in holographic quenches with spectral methods

We describe the application of pseudo-spectral methods to problems of holographic thermal quenches of relevant couplings in strongly coupled gauge theories. We focus on quenches of a fermionic mass term in a strongly coupled N = 4 $$ \mathcal{N}=4 $$ supersymmetric Yang-Mills plasma, and the subsequent equilibration of the system. From the dual gravitational perspective, we study gravitational collapse of a massive scalar field in asymptotically anti-de-Sitter geometry with a prescribed boundary condition for its non-normalizable mode. Access to the full background geometry of the gravitational collapse allows for the study of nonlocal probes of the thermalization process. We discuss the evolution of the apparent and the event horizons, the two-point correlation functions of operators of large conformal dimensions, and the evolution of the entanglement entropy of the system. We compare the thermalization process from the viewpoint of local (the one-point) correlation functions and these nonlocal probes, finding that the thermalization time as measured by the probes is length dependent, and can exceed that of the one-point function. We further discuss how the different energy scales of the problem contribute to its thermalization
Localised anti-branes in non-compact throats at zero and finite T

We investigate the 3-form singularities that are typical to anti-brane solutions in supergravity and check whether they can be cloaked by a finite temperature horizon. For anti-D3-branes in the Klebanov-Strassler background, this was already shown numerically to be impossible when the branes are partially smeared. In this paper, we present analytic arguments that also localised branes remain with singular 3-form fluxes at both zero and finite temperature. These results may have important, possibly fatal, consequences for constructions of meta-stable de Sitter vacua through uplifting
Supersymmetry of AdS and flat IIB backgrounds

We present a systematic description of all warped AdS n × w M 10− n and ℝ n − 1 , 1 × w M 10 − n $$ {\mathbb{R}}^{n-1,1}{\times}_w{M}^{10-n} $$ IIB backgrounds and identify the a priori number of supersymmetries N preserved by these solutions. In particular, we find that the AdS n backgrounds preserve N = 2 n 2 k $$ N={2}^{\left[\frac{n}{2}\right]}k $$ for n ≤ 4 and N = 2 n 2 + 1 k $$ N={2}^{\left[\frac{n}{2}\right]+1}k $$ for 4 < n ≤ 6 supersymmetries and for k ∈ ℕ + $$ k\in {\mathbb{N}}_{+} $$ suitably restricted. In addition under some assumptions required for the applicability of the maximum principle, we demonstrate that the Killing spinors of AdS n backgrounds can be identified with the zero modes of Dirac-like operators on M 10− n establishing a new class of Lichnerowicz type theorems. Furthermore, we adapt some of these results to ℝ n − 1 , 1 × w M 10 − n $$ {\mathbb{R}}^{n-1,1}{\times}_w{M}^{10-n} $$ backgrounds with fluxes by taking the AdS radius to infinity. We find that these backgrounds preserve N = 2 n 2 k $$ N={2}^{\left[\frac{n}{2}\right]}k $$ for 2 < n ≤ 4 and N = 2 n + 1 2 k $$ N={2}^{\left[\frac{n+1}{2}\right]}k $$ for 4 < n ≤ 7 supersymmetries. We also demonstrate that the Killing spinors of AdS n × w M 10− n do not factorize into Killing spinors on AdS n and Killing spinors on M 10− n
Space-like D p branes: accelerating cosmologies versus conformally de Sitter space-time

We consider the space-like D p brane solutions of type II string theories having isometries ISO( p + 1) × SO(8 − p, 1). These are asymptotically flat solutions or in other words, the metrics become flat at the time scale τ ≫ τ 0 . On the other hand, when τ ∼ τ 0 , we get ( p + 1) + 1 dimensional flat FLRW metrics upon compactification on a (8 − p ) dimensional hyperbolic space with time dependent radii. We show that the resultant ( p + 1) + 1 dimensional metrics describe transient accelerating cosmologies for all p from 1 to 6, i.e., from (2+1) to (7+1) space-time dimensions. We show how the accelerating phase changes with the interplay of the various parameters characterizing the solutions in (3 + 1) dimensions. Finally, for τ ≪ τ 0 , after compactification on (8 − p ) dimensional hyperbolic space, the resultant metrics are shown to take the form of ( p + 1) + 1 dimensional de Sitter spaces upto a conformal transformation. Cosmologies here are decelerating, but, only in a particular conformal frame we get eternal acceleration