Search

The Nambu–Jona-Lasino model is modified by the inclusion of a running-coupling that was obtained by a fractal approach to Quantum Chromodynamics. The coupling follows a q -exponential function and, in the context of high energy collisions, explains the origin of the Tsallis non-extensive statistics distributions. The parameter q is completely determined in terms of the number of colours and the number of quark flavours. We study several aspects of the extended model and compare our results to the standard NJL model, where a constant coupling is used in combination with a sharp cutoff to regularize the gap equation. We show that the modified coupling regularizes the model in a smooth cutoff fashion and reproduces the pion mass and decay constant, providing an almost identical Gell-Mann-Oakes-Renner relation as in the standard NJL model. In both models the relation is satisfied in similar cutoff scales. An important novelty of this work is the physical explanation, in terms of the fractal QCD vacuum, for a running coupling that renormalizes the quark condensate. [ABSTRACT FROM AUTHOR]

Some fraction of the diffuse photon background is supposed to be linked to high-energy neutrinos by astrophysical mechanisms of production and electromagnetic cascades. This article presents a simulation study of axion-like particles (ALPs) implications for that component, exploiting transport equations. Alternations of that spectrum due to ALP-photon conversion in the intergalactic magnetic field (IGMF) in the cases of various ALP parameters and mixing regimes at sources are studied. The results indicate considerable influence of IGMF-conversion on the ALP-photon flux even in the case of inverse ALP-photon coupling constant M equal to 1011.5 GeV and some residual effects in the case of M = 10 12 GeV. Furthermore, the scenario shows another aspect of a complex multimessenger interplay between IceCube and Fermi data, to a certain extent relieving the tension between them, the existence of which is commonly interpreted to be a signature of limited transparency of the neutrino sources population. [ABSTRACT FROM AUTHOR]

Markarian 421 is a well-known nearby BL Lac blazar at the redshift z = 0.031. Many previous works were investigated to constrain the axion-photon coupling from its TeV gamma-ray observations, showing the upper limit on the coupling constant g a γ ≲ 2.0 × 10 − 11 Ge V − 1 for the axion mass [ 5.0 × 10 − 10 eV ≲ m a ≲ 5.0 × 10 − 7 eV ]. While in this work, we obtain a more stringent upper limit on the axion-photon coupling from the 1038 days gamma-ray observations of the blazar Markarian 421. The long-term VHE gamma-ray spectra are measured by the collaborations Large Area Telescope on board NASA's Fermi Gamma-ray Space Telescope (Fermi-LAT) and High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory from 2015 June to 2018 July. We show the best-fit spectral energy distributions (SEDs) of Markarian 421 under the null and axion hypotheses. Then we set the axion-photon limit in the { m a , g a γ } plane. The 99% C. L. upper limit set by Markarian 421 is g a γ ≲ 4.0 × 10 − 12 Ge V − 1 for the axion mass [ 1.0 × 10 − 9 eV ≲ m a ≲ 1.0 × 10 − 8 eV ]. It is the most stringent upper limit in this axion mass region. [ABSTRACT FROM AUTHOR]

The zeroth law of black hole mechanics asserts that the stationary black hole has a constant surface gravity on the event horizon. This study investigates the zeroth law within the Einstein-Scalar-Gauss-Bonnet gravity, particularly involving a complex scalar field (ECSGB). Assuming that the Lie derivative of the complex scalar field is proportional to itself other than stationary, and that ECSGB gravity converges to the Einstein's gravity analyticaly as the coupling constant approaches zero, as well as the minimally coupled matter fields satisfy the dominant energy condition, we demonstrate that the surface gravity remains constant over the entire event horizon without reliance on additional symmetries. [ABSTRACT FROM AUTHOR]

We investigate self-gravitating solutions of the Einstein-Skyrme theory coupled to spin-isospin Dirac fermions and consider the dependence of the spectral flow on the effective gravitational coupling constant and on the Yukawa coupling. It is shown that the effects of the backreaction of the fermionic mode may strongly deform the configuration. Depending on the choice of parameters, solutions with positive, negative and zero ADM mass may arise. The occurrence of regular anti-gravitating asymptotically flat solutions with negative ADM mass is caused by the violation of the energy conditions. [ABSTRACT FROM AUTHOR]

We compute the baryonic screening masses of the nucleon and of its negative parity partner in thermal QCD with N f = 3 massless quarks for a wide range of temperatures, from T ∼ 1 GeV up to ∼160 GeV. The computation is performed by Monte Carlo simulations of lattice QCD with O (a) -improved Wilson fermions by exploiting a recently proposed strategy to study non-perturbatively QCD at very high temperature. Very large spatial extensions are considered in order to have negligible finite volume effects. For each temperature we have simulated 3 or 4 values of the lattice spacing, so as to perform the continuum limit extrapolation with confidence at a few permille accuracy. The degeneracy of the positive and negative parity-state screening masses, expected from Ward identities associated to non-singlet axial transformations, provides further evidence for the restoration of chiral symmetry in the high temperature regime of QCD. In the entire range of temperatures explored, the baryonic masses deviate from the free theory result, 3 π T , by 4–8%. The contribution due to the interactions is clearly visible up to the highest temperature considered, and cannot be explained by the expected leading behavior in the QCD coupling constant g over the entire range of temperatures explored. [ABSTRACT FROM AUTHOR]

In this paper, we study the post-inflationary era called reheating stage. For this purpose, we consider a model in which the inflaton is non-minimally coupled to the curvature within the hybrid metric-Palatini approach. Furthermore, to investigate the consistency of our results with the observational data, we relate reheating parameters to those of inflation model. By taking into consideration the Higgs potential V (ϕ) = λ / 4 ϕ 4 ; we derive the necessary quantities needed to obtain the reheating duration and the reheating temperature. Moreover, we plot reheating e-folds and temperature as a function of the spectral index, respectively. We consider three cases depending on the coupling constant ξ. In addition, we use some specific values of the effective equation of state ω , which is presumed to remain relatively constant within the range of − 1 3 ≤ ω < 1 3. We find that for ξ = 10 − 4.1 our results are in agreement with the recent Planck data as the reheating instant is corresponding to the central value of the spectral index and to a maximum temperature required by the scale of baryogenesis models. [ABSTRACT FROM AUTHOR]

We extend the computational framework of [1] to analysis of shear and bulk viscosities in generic strongly coupled holographic Gauss-Bonnet gauge theories. The finite Gauss-Bonnet coupling constant encodes holographic plasma with non-equal central charges c ≠ a at the ultraviolet fixed point. In a simple model we discuss transport coefficients within the causality window − 1 2 ≤ c − a c ≤ 1 2 of the theory. [ABSTRACT FROM AUTHOR]

In this work a non-abelian gauge theory is reformulated in a rotating frame. With this new formalism, the influence of the background rotation on the color deconfinement transition for a pure SU(2) gluon system has been studied. The KvBLL caloron, which is a color neutral and topologically nontrivial solution of Yang-Mills equation at finite temperature, is reexamined under rotation and adopted as the confined vacuum of such a system. With rotation-modified solutions of the caloron's constituent solitons, i.e. dyons, the non-perturbative part of effective potential of the rotating system has been obtained. Combining with the perturbative potential by Gaussian fluctuations, the critical temperature of confinement-deconfinement phase transition is investigated. It is found that neither the rotational semi-classical potential nor Gaussian fluctuations can confine color charges more tightly when the rotation becomes faster. While only a stronger coupling constant is able to make the critical temperature increase with angular velocity, as what indicated in lattice simulations. And it is found a non-monotonic dependence of the critical temperature on the angular velocity is established because of the competition between these two contrary contributions. [ABSTRACT FROM AUTHOR]

We present the limits on photon to axionlike particle (ALP) coupling from the 10-year period observations of the TeV BL Lacertae blazar 1ES 1215+303 (with redshift z = 0.130). The contemporaneous gamma-ray spectra are measured by the collaborations Fermi-LAT and VERITAS with five flux phases from 2008 to 2017, including four low states and one flare. Using these flux phases, we show the spectral energy distributions (SEDs) under the null/ALP hypotheses and set the combined limit on ALP. The 95% C. L. combined limit set by 1ES 1215+303 with the 10-year gamma-ray data is roughly at the photon-ALP coupling constant g a γ ≳ 1.5 × 10 − 11 , GeV − 1 for the ALP mass 5.0 × 10 − 10 eV ≲ m a ≲ 1.0 × 10 − 7 eV. [ABSTRACT FROM AUTHOR]

A general model is proposed for time-varying coupling constants in field theory, assuming the ultraviolet cutoff is a varying entity in the expanding universe. It is assumed that the cutoff depends on the scale factor of the universe and all bare couplings remain constant. This leads to varying renormalized coupling constants that evolve in proportion to the Hubble parameter. The evolution of the standard model constants is discussed. [ABSTRACT FROM AUTHOR]

We construct the effective Hamiltonian for hadronic parity violation in strangeness-nonchanging (Δ S = 0) processes in next-to-leading order (NLO) in QCD, for all isosectors, and at a renormalization scale of 2 GeV , thus extending our earlier leading-order (LO) analysis [1,2]. Hadronic parity violation, studied in the context of the low-energy interactions of nucleons and nuclei, exposes the complex interplay of weak and strong interactions in these systems, and thus supports our extension to NLO. Here we exploit the flavor-blind nature of QCD interactions to construct the needed anomalous dimension matrices from those computed in flavor physics, which we then use to refine our effective Hamiltonian and finally our predicted parity-violating meson-nucleon coupling constants, to find improved agreement with few-body experiments. [ABSTRACT FROM AUTHOR]

We discuss prospects of searching for a dark photon (A ′) which serves as mediator between Standard model (SM) particles and light dark matter (LDM) by using the combined results from the NA64 experiment at the CERN SPS running in high-energy electron (NA64e) and muon (NA64 μ) modes. We discuss the most natural values and upper bounds on the A ′ coupling constant to LDM and show they are lying in the range accessible at NA64. While for the projected 5 × 10 12 electrons on target (EOT) NA64e is able to probe the scalar and Majorana LDM scenarios, the combined NA64e and NA64 μ results with ≃ 10 13 EOT and a few 1013 MOT, respectively, will allow covering significant region in the parameter space of the most interesting LDM models. This makes NA64e and NA64 μ extremely complementary to each other and increases significantly the discovery potential of sub-GeV DM. [ABSTRACT FROM AUTHOR]

Additional Abelian gauge interactions are generic to string compactifications. In heterotic string models, gauge coupling unification of such forces and other gauge interactions is natural due to their common origin. In this letter we study systematically the 1-loop running of the coupling constants in effective vacua emerging from Z 8 heterotic orbifold compactifications that provide the matter spectrum of the MSSM plus some vectorlike exotics, restricting to vacua that yield a non-anomalous U (1) ′ symmetry, gauge coupling unification and the observed values of known gauge couplings. We determine the low-energy value of the U (1) ′ coupling constant for different scales of supersymmetry breakdown. We find that the U (1) ′ coupling constant is quite restricted in string models to lie in the range 0.46–0.7 for low-scale supersymmetry or 0.44–0.6 in other cases. We argue that the phenomenology of these string vacua should be further explored to solve some extant issues, such as the stability of the Higgs vacuum. [ABSTRACT FROM AUTHOR]

This paper explores the possibility of using Maxwell algebra and its generalizations called resonant algebras for the unified description of topological insulators. We offer the natural action construction, which includes the relativistic Wen-Zee and other terms, with adjustable coupling constants. By gauging all available resonant algebras formed by Lorentz, translational and Maxwell generators { J a , P a , Z a } we present six Chern-Simons Lagrangians with various terms content accounting for different aspects of the topological insulators. Additionally, we provide complementary actions for another invariant metric form, which might turn out useful in some generalized (2 + 1) gravity models. [ABSTRACT FROM AUTHOR]

Carroll symmetries arise when the velocity of light is sent to zero (ultra-relativistic limit). In this paper, we present the construction of the three-dimensional Chern-Simons supergravity theory invariant under the so-called AdS Carroll superalgebra, which was obtained in the literature as a contraction of the AdS superalgebra. The action is characterized by two coupling constants. Subsequently, we study its flat limit, obtaining the three-dimensional Chern-Simons supergravity theory invariant under the super-Carroll algebra, which is a contraction of the Poincaré superalgebra. We apply the flat limit at the level of the superalgebra, Chern-Simons action, supersymmetry transformation laws, and field equations. [ABSTRACT FROM AUTHOR]

Compactifying type A N − 1 6d N = (2 , 0) supersymmetric CFT on a product manifold M 4 × Σ 2 = M 3 × S ˜ 1 × S 1 × I either over S 1 or over S ˜ 1 leads to maximally supersymmetric 5d gauge theories on M 4 × I or on M 3 × Σ 2 , respectively. Choosing the radii of S 1 and S ˜ 1 inversely proportional to each other, these 5d gauge theories are dual to one another since their coupling constants e 2 and e ˜ 2 are proportional to those radii respectively. We consider their non-Abelian but non-supersymmetric extensions, i.e. SU(N) Yang–Mills theories on M 4 × I and on M 3 × Σ 2 , where M 4 ⊃ M 3 = R t × T p 2 with time t and a punctured 2-torus, and I ⊂ Σ 2 is an interval. In the first case, shrinking I to a point reduces to Yang–Mills theory or to the Skyrme model on M 4 , depending on the method chosen for the low-energy reduction. In the second case, scaling down the metric on M 3 and employing the adiabatic method, we derive in the infrared limit a non-linear SU(N) sigma model with a baby-Skyrme-type term on Σ 2 , which can be reduced further to A N − 1 Toda theory. [ABSTRACT FROM AUTHOR]

Jet angularities are a class of jet substructure observables where a continuous parameter is introduced in order to interpolate between different classic observables such as the jet mass and jet broadening. We consider jet angularities measured on an inclusive jet sample at the LHC where the soft drop grooming procedure is applied in order to remove soft contaminations from the jets. The soft drop algorithm allows for a precise comparison between theory and data and could be used to extract the QCD strong coupling constant α s from jet substructure data in the future. We develop a framework to realize the resummation of all relevant large logarithms at the next-to-leading logarithmic (NLL) accuracy. To demonstrate that the developed formalism is suitable for the extraction of α s , we extend our calculations to next-to-next-to-leading logarithm (NNLL) for the jet mass case. Overall, we find good agreement between our NLL numerical results and Pythia simulations for LHC kinematics and we observe an improved agreement when the NNLL components are included. In addition, we expect that groomed jet angularities will be a useful handle for studying the modification of jets in heavy-ion collisions. [ABSTRACT FROM AUTHOR]

We extend the adiabatic regularization method by introducing an arbitrary mass scale μ in the construction of the subtraction terms. This allows us to obtain, in a very robust way, the running of the coupling constants by demanding μ -invariance of the effective semiclassical (Maxwell-Einstein) equations. In particular, we get the running of the electric charge of perturbative quantum electrodynamics. Furthermore, the method brings about a renormalization of the cosmological constant and the Newtonian gravitational constant. The running obtained for these dimensionful coupling constants has new relevant (non-logarithmic) contributions, not predicted by dimensional regularization. [ABSTRACT FROM AUTHOR]

Abstract Coupling constants of η and η ′ mesons with nucleons have been calculated using the method of QCD sum rules. Starting from vacuum-to-meson correlation function of interpolating fields of two nucleons, its matrix element with respect to nucleon spinors has been considered. Coupling constants at the physical points have been estimated from extrapolation of results obtained at two other points. Anomalous glue has been found to give substantial contribution to the coupling constants and also accounts for a significant OZI-rule violation. [ABSTRACT FROM AUTHOR]

Abstract In this study, we apply LHC data to constrain the extension of the Standard Model by an anomaly–free U (1) L μ − L τ gauge group; this model contains a new gauge boson (Z ′) and a scalar dark matter particle (ϕ DM). We recast a large number of LHC analyses of multi–lepton final states by the ATLAS and CMS collaborations. We find that for 10 GeV < m Z ′ < 60 GeV the strongest constraint comes from a dedicated Z ′ search in the 4 μ final state by the CMS collaboration; for larger Z ′ masses, searches for final states with three leptons plus missing E T are more sensitive. Searches for final states with two leptons and missing E T , which are sensitive to Z ′ decays into dark matter particles, can only probe regions of parameter space that are excluded by searches in the 3 and 4 lepton channels. The combination of LHC data excludes values of Z ′ mass and coupling constant that can explain the deficit in g μ − 2 for 4 GeV ≤ m Z ′ ≤ 500 GeV. However, for much of this range the LHC bound is weaker than the bound that can be derived from searches for "trident" events in neutrino–nucleus scattering. [ABSTRACT FROM AUTHOR]

Abstract We disclose remarkable features of the scalar–tensor theory with the derivative coupling of the scalar field to the curvature in the Palatini formalism. Using disformal transformations, we show that this theory is free from Ostrogradski ghosts. For a special relation between two coupling constants, it is disformally dual to the Einstein gravity minimally coupled to the scalar, which opens the way to constructing several exact solutions. The disformal transformation degenerates at the boundary of the physical region, near which the desingularization properties are revealed, illustrated by exact solutions: non-singular accelerating cosmology and a static spherically symmetric geon. We also construct the exact pp-waves of this theory propagating at the speed of light. [ABSTRACT FROM AUTHOR]

Abstract A new method used to calculate the neutrino for all major tau hadronic decay event by event at the LHC is presented. It is possible because nowadays better detector description is available. With the neutrino fully reconstructed, matrix element for each event can be calculated, the mass of the Higgs particle can also be calculated event by event with high precision. Based on these, the prospect of measuring the Higgs CP mixing angle with h → τ τ decays at the LHC is analyzed. It is predicted that, with a detailed detector simulation, with 3 ab−1 of data at s = 13 TeV, a significant improvement of the measurement of the CP mixing angle to a precision of 5.2 ∘ can be achieved at the LHC, which outperforms the sensitivity from lepton EDM searches up to date in the hττ coupling. [ABSTRACT FROM AUTHOR]

Abstract We determine the strong coupling constant α s (M Z) from the static QCD potential by matching a lattice result and a theoretical calculation. We use a new theoretical framework based on operator product expansion (OPE), where renormalons are subtracted from the leading Wilson coefficient. We find that our OPE prediction can explain the lattice data at Λ QCD r ≲ 0.8. This allows us to use a larger window in matching, which leads to a more reliable determination. We obtain α s (M Z) = 0.1179 − 0.0014 + 0.0015. [ABSTRACT FROM AUTHOR]

We investigate the ground state entanglement entropy of a massive scalar field nonminimally coupled to spacetime curvature, assuming a static, spherically symmetric background. We first discretize the field Hamiltonian by introducing a lattice of spherical shells and imposing a cutoff in the radial direction. We then study the ground state of the field and quantify deviations from area law due to nonminimal coupling, focusing in particular on Schwarzschild-de Sitter and Hayward spacetimes, also discussing de Sitter spacetime as a limiting case. We show that large positive coupling constants can significantly alter the entropy scaling with respect to the boundary area, in case of coordinate-dependent spacetime curvature. Our outcomes are interpreted in view of black hole entropy production and early universe scenarios. [ABSTRACT FROM AUTHOR]

We investigate the elastic photon-proton and photon-photon scattering in a holographic QCD model, focusing on the Regge regime. Considering contributions of the Pomeron and Reggeon exchange, the total and differential cross sections are calculated. While our model involves several parameters, by virtue of the universality of the Pomeron and Reggeon, for most of them the values determined in the preceding study on the proton-proton and proton-antiproton scattering can be employed. Once the two adjustable parameters, the Pomeron-photon and Reggeon-photon coupling constant, are determined with the experimental data of the total cross sections, predicting the both cross sections in a wide kinematic region, from the GeV to TeV scale, becomes possible. We show that the total cross section data can be well described within the model, and our predictions for the photon-proton differential cross section are consistent with the data. [ABSTRACT FROM AUTHOR]

Axion Like Particles (ALPs) with a sub-keV range mass are searched by using the light-shining-through-a-wall technique. A novel system is developed in which injected X rays are converted and reconverted by the Laue-case conversion within a silicon single crystal with dual blades. The resonant ALPs mass of the conversion is scanned by varying the X-ray injection angle to the crystal. No significant signals are observed, and 90% C. L. upper limits on the ALP-two photon coupling constant are obtained as follows, (1) g a γ γ < 4.2 × 10 − 3 GeV − 1 ( m a < 10 eV ) , (2) g a γ γ < 5.0 × 10 − 3 GeV − 1 ( 46 eV < m a < 1020 eV ) . These are the most stringent laboratory-based constraints on ALPs heavier than 300 eV. [ABSTRACT FROM AUTHOR]

Through gravity/gauge duality, the string breaking and running coupling constant of heavy quark-antiquark pair are investigated in the rotating background. For the meson decay mode Q Q ¯ → Q q ¯ + Q ¯ q , we discuss the string breaking and running coupling in the parallel and transverse case. It is found that the parallel case has a more significant on string breaking and running coupling constant than the transverse case in the confined phase. The string-breaking distance and the maximum value of running coupling will decrease with the increase of angular velocity in the parallel case. Besides, we also investigate the running coupling and screening distance at finite angular velocity in the deconfined phase. It is found that the maximum values of the running coupling and screening distance are decreasing functions of angular velocity. The parallel case has a more significant influence on the running coupling and screening distance than the transverse case in the deconfined phase. [ABSTRACT FROM AUTHOR]

We study vector-tensor theories in which a 4-dimensional vector field A μ is coupled to a vector quantity J μ , which is expressed in terms of A μ and a metric tensor g μ ν. The divergence of J μ is equivalent to a Gauss-Bonnet (GB) term. We show that an interacting Lagrangian of the form f (X) A μ J μ , where f is an arbitrary function of X = − (1 / 2) A μ A μ , belongs to a scheme of beyond generalized Proca theories. For f (X) = α = constant , this interacting Lagrangian reduces to a particular class of generalized Proca theories. We apply the latter coupling to a static and spherically symmetric vacuum configuration by incorporating the Einstein-Hilbert term, Maxwell scalar, and vector mass term ηX (η is a constant). Under an expansion of the small coupling constant α with η ≠ 0 , we derive hairy black hole solutions endowed with nonvanishing temporal and radial vector field profiles. The asymptotic properties of solutions around the horizon and at spatial infinity are different from those of hairy black holes present in scalar-GB theories. We also show that black hole solutions without the vector mass term, i.e., η = 0 , are prone to ghost instability of odd-parity perturbations. [ABSTRACT FROM AUTHOR]

We study the higher-order corrections to structure functions in inclusive deep-inelastic scattering (DIS) in massless perturbative QCD, in the context of the conjectured absence of even- n values of the Riemann zeta-function ζ n , i.e., of powers of π 2 , in Euclidean physical quantities. We provide substantial additional support for this conjecture by demonstrating that it holds, as far as it can be tested by the results of diagram computations, for the physical anomalous dimensions of structure functions at the fourth and fifth order in the strong coupling constant α s . The conjecture is then employed to predict hitherto unknown ζ 4 and ζ 6 contributions to the anomalous dimensions for parton distributions and to the coefficient functions for the longitudinal structure function F L . [ABSTRACT FROM AUTHOR]

Heavy axion-like particles have been introduced in several scenarios beyond the Standard Model and their production should be possible in some astrophysical systems. In this study, we re-examine the possibility that this type of particle can be generated in the accretion disks of gamma-ray bursts (GRB), which are the most powerful events in the universe. If the produced axions decay into photons or e + e − pairs at the correct distances, a fireball is generated. We calculate the structure of transient accretion disks in GRBs (density, temperature and thickness profiles) considering the effect of heavy axion emission as well as the rest of the relevant standard cooling processes. This allows us to obtain the values of the coupling constant g a N such that the axions do not become trapped, and we also compute the heavy axion luminosity emitted from the entire disk. We show that for the couplings within the ranges found, the mechanism for powering GRBs based on heavy axion production and decay is an alternative to the standard picture based on magnetohydrodynamic processes and neutrino–antineutrino annihilation. Alternatively, the mechanism fails if heavy axions are produced in the disk but their decay takes place further away. Still, the decay products (gamma rays or electrons and positrons) should leave observable signatures, which are not observed for different ranges of values of the coupling constants, depending on the mass of the heavy axion. [ABSTRACT FROM AUTHOR]

Using non-extensive statistical mechanics, the Bekenstein–Hawking area law is obtained from microstates of black holes in loop quantum gravity, for arbitrary real positive values of the Barbero–Immirzi parameter ( γ ). The arbitrariness of γ is encoded in the strength of the “bias” created in the horizon microstates through the coupling with the quantum geometric fields exterior to the horizon. An experimental determination of γ will fix this coupling, leaving out the macroscopic area of the black hole to be the only free quantity of the theory. [ABSTRACT FROM AUTHOR]

Combined HERA data on charm production in deep-inelastic scattering have previously been used to determine the charm-quark running mass m c ( m c ) in the MS ‾ renormalisation scheme. Here, the same data are used as a function of the photon virtuality Q 2 to evaluate the charm-quark running mass at different scales to one-loop order, in the context of a next-to-leading order QCD analysis. The scale dependence of the mass is found to be consistent with QCD expectations. [ABSTRACT FROM AUTHOR]

We first examine the scaling argument for a renormalization-group (RG) analysis applied to a system subject to the dimensional reduction in strong magnetic fields, and discuss the fact that a four-Fermi operator of the low-energy excitations is marginal irrespective of the strength of the coupling constant in underlying theories. We then construct a scale-dependent effective four-Fermi interaction as a result of screened photon exchanges at weak coupling, and establish the RG method appropriately including the screening effect, in which the RG evolution from ultraviolet to infrared scales is separated into two stages by the screening-mass scale. Based on a precise agreement between the dynamical mass gaps obtained from the solutions of the RG and Schwinger–Dyson equations, we discuss an equivalence between these two approaches. Focusing on QED and Nambu–Jona-Lasinio model, we clarify how the properties of the interactions manifest themselves in the mass gap, and point out an importance of respecting the intrinsic energy-scale dependences in underlying theories for the determination of the mass gap. These studies are expected to be useful for a diagnosis of the magnetic catalysis in QCD. [ABSTRACT FROM AUTHOR]

We calculate 1-loop radiative corrections to the hZZ and hWW couplings in models with next-to-simplest Higgs sectors satisfying the electroweak ρ parameter equal to 1 at tree level: the real Higgs singlet model, the two-Higgs doublet models, and the Georgi–Machacek model. Under theoretical and current experimental constraints, the three models have different correlations between the deviations in the hZZ and hWW couplings from the standard model predictions. In particular, we find for each model predictions with no overlap with the other two models. [ABSTRACT FROM AUTHOR]

Assuming an existence of the anomalous triple electro-weak bosons interaction being defined by coupling constant λ we calculate its contribution to interactions of the Higgs with pairs of heavy particles. Bearing in mind experimental restrictions − 0.011 < λ < 0.011 we present results for possible effects in processes p p → W + W − H , p p → W + Z H , p p → W − Z H , p p → t ¯ t H , p p → b ¯ b H . Effects could be significant with negative sign of λ in associated heavy quarks t , b pairs production with the Higgs. In calculations we rely on results of the non-perturbative approach to a spontaneous generation of effective interactions, which defines the form-factor of the three-boson anomalous interaction. [ABSTRACT FROM AUTHOR]

This Letter presents a search for new physics manifested as anomalous triple gauge boson couplings in W W and W Z diboson production in proton–proton collisions. The search is performed using events containing a W boson that decays leptonically and a W or Z boson whose decay products are merged into a single reconstructed jet. The data, collected at s = 8 TeV with the CMS detector at the LHC, correspond to an integrated luminosity of 19 fb − 1 . No evidence for anomalous triple gauge couplings is found and the following 95% confidence level limits are set on their values: λ ( [ − 0.011 , 0.011 ] ), Δ κ γ ( [ − 0.044 , 0.063 ] ), and Δ g 1 Z ( [ − 0.0087 , 0.024 ] ). These limits are also translated into their effective field theory equivalents: c W W W / Λ 2 ( [ − 2.7 , 2.7 ] TeV − 2 ), c B / Λ 2 ( [ − 14 , 17 ] TeV − 2 ), and c W / Λ 2 ( [ − 2.0 , 5.7 ] TeV − 2 ). [ABSTRACT FROM AUTHOR]

The exo-Higgs model can accommodate a successful baryogenesis mechanism that closely mirrors electroweak baryogenesis in the Standard Model, but avoids its shortcomings. We extend the exo-Higgs model by the addition of a singlet complex scalar χ . In our model, χ can be a viable asymmetric dark matter (ADM) candidate. We predict the mass of the ADM particle to be m χ ≈ 1.3 GeV . The leptophilic couplings of χ can provide for efficient annihilation of the ADM pairs. We also discuss the LHC signals of our scenario, and in particular the production and decays of exo-leptons which would lead to “lepton pair plus missing energy” final states. Our model typically predicts potentially detectable gravitational waves originating from the assumed strong first order phase transition at a temperature of ∼ TeV. If the model is further extended to include new heavy vector-like fermions, e.g. from an ultraviolet extension, χ couplings could explain the ∼ 3.5 σ muon g − 2 anomaly. [ABSTRACT FROM AUTHOR]

A Regge approach to the reaction processes γ p → π − Δ + + and γ p → π + Δ 0 is presented for the description of existing data up to E γ = 16 GeV . The model consists of the t -channel π ( 139 ) + ρ ( 775 ) + a 2 ( 1320 ) exchanges which are reggeized from the relevant Born amplitude. Discussion is given on the minimal gauge prescription for the π exchange to render convergent the divergence of the u -channel Δ-pole in the former process. A new Lagrangian is constructed for the a 2 N Δ coupling in this work and applied to the process for the first time with the coupling constant deduced from the duality plus vector dominance. It is shown that, while the π exchange dominates over the process, the role of the a 2 exchange is crucial rather than the ρ in reproducing the cross sections for total, differential, and photon polarization asymmetry to agree with data at high energy. [ABSTRACT FROM AUTHOR]

Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6 LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1 ( GeV / c ) 2 < Q 2 < 100 ( GeV / c ) 2 in photon virtuality, 0.004 < x < 0.7 in the Bjorken scaling variable and W > 4 GeV / c 2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A 1 d and the deuteron longitudinal-spin structure function g 1 d are presented in bins of x and Q 2 . Towards lowest accessible values of x , g 1 d decreases and becomes consistent with zero within uncertainties. The presented final g 1 d values together with the recently published final g 1 p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g 1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a 0 , which is identified in the MS ‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a 0 ( Q 2 = 3 ( GeV / c ) 2 ) = 0.32 ± 0.02 stat ± 0.04 syst ± 0.05 evol . Together with the recent results on the proton spin structure function g 1 p , the results on g 1 d constitute the COMPASS legacy on the measurements of g 1 through inclusive spin-dependent deep inelastic scattering. [ABSTRACT FROM AUTHOR]

We investigate the parity-violating pion–nucleon–nucleon coupling constant h π N N 1 , based on the chiral quark-soliton model. We employ an effective weak Hamiltonian that takes into account the next-to-leading order corrections from QCD to the weak interactions at the quark level. Using the gradient expansion, we derive the leading-order effective weak chiral Lagrangian with the low-energy constants determined. The effective weak chiral Lagrangian is incorporated in the chiral quark-soliton model to calculate the parity-violating πNN constant h π N N 1 . We obtain a value of about 10 − 7 at the leading order. The corrections from the next-to-leading order reduce the leading order result by about 20%. [ABSTRACT FROM AUTHOR]

We study the production of primordial magnetic fields in inflationary models in type IIB string theory where the role of the inflaton is played by a Kahler modulus. We consider various possibilities to realise the Standard Model degrees of freedom in this setting and explicitly determine the time dependence of the inflaton coupling to the Maxwell term in the models. Using this we determine the strength and scale dependence of the magnetic fields generated during inflation. The usual “strong coupling problem” for primordial magnetogenesis manifests itself by cycle sizes approaching the string scale; this appears in a certain class of fibre inflation models where the standard model is realised by wrapping D7-branes on cycles in the geometric regime. [ABSTRACT FROM AUTHOR]

In dynamical system describing evolution of universe with the flat Friedmann–Robertson–Walker symmetry filled with barotropic dust matter and non-minimally coupled scalar field with a constant potential function an invariant manifold of the de Sitter state is used to obtain exact solutions of the reduced dynamics. Using observational data coming from distant supernovae type Ia, the Hubble function H ( z ) measurements and information coming from the Alcock–Paczyński test we find cosmological constraints on the non-minimal coupling constant ξ between the scalar curvature and the scalar field. For all investigated models we can exclude negative values of this parameter at the 68 % confidence level. We obtain constraints on the non-minimal coupling constant consistent with condition for conformal coupling of the scalar field in higher dimensional theories of gravity. [ABSTRACT FROM AUTHOR]

We study a consistent deformation of the cubic open bosonic string theory in such a way that the non-planar world sheet diagrams of the perturbative string theory are mapped onto their equivalent planar diagrams of the light-cone string field theory with some length parameters fixed. An explicit evaluation of the cubic string vertex in the zero-slope limit yields the correct relationship between the string coupling constant and the Yang–Mills coupling constant. The deformed cubic open string field theory is shown to produce the non-Abelian Yang–Mills action in the zero-slope limit if it is defined on multiple D-branes. Applying the consistent deformation systematically to multi-string world sheet diagrams, we may be able to calculate scattering amplitudes with an arbitrary number of external open strings. [ABSTRACT FROM AUTHOR]

We evaluate the Λ c Σ c π coupling constant ( G Λ c Σ c π ) and the width of the strong decay Σ c → Λ c π in 2 + 1 flavor lattice QCD on four different ensembles with pion masses ranging from 700 MeV to 300 MeV. We find G Λ c Σ c π = 18.332 ( 1.476 ) s t a t . ( 2.171 ) s y s t . and the decay width Γ ( Σ c → Λ c π ) = 1.65 ( 28 ) s t a t . ( 30 ) s y s t . MeV on the physical quark-mass point, which is in agreement with the recent experimental determination. [ABSTRACT FROM AUTHOR]

We compute Lüscher corrections for a giant magnon in the η -deformed ( AdS 5 × S 5 ) η using the s u ( 2 | 2 ) q -invariant S -matrix at strong coupling and compare with the finite-size effect of the corresponding string state, derived previously. We find that these two results match and confirm that the s u ( 2 | 2 ) q -invariant S -matrix is describing world-sheet excitations of the η -deformed background. [ABSTRACT FROM AUTHOR]

Recent data on the differential angular distribution for the transfer reaction 11 Li( p , d ) 10 Li at E / A = 5.7 MeV in inverse kinematics are analyzed within the DWBA reaction framework, using the overlap functions calculated within a three-body model of 11 Li. The weight of the different 10 Li configurations in the system's ground state is obtained from the structure calculations unambiguously. The effect of the 9 Li spin in the calculated observables is also investigated. We find that, although all the considered models succeed in reproducing the shape of the data, the magnitude is very sensitive to the content of p 1 / 2 wave in the 11 Li ground-state wave function. Among the considered models, the best agreement with the data is obtained when the 11 Li ground state contains a ∼31% of p 1 / 2 wave in the n – 9 Li subsystem. Although this model takes into account explicitly the splitting of the 1 + and 2 + resonances due to the coupling of the p 1 / 2 wave to the 3 / 2 − spin of the core, a similar degree of agreement can be achieved with a model in which the 9 Li spin is ignored, provided that it contains a similar p -wave content. [ABSTRACT FROM AUTHOR]

We calculate the spectrum of gravitational waves originated from strongly first order electroweak phase transition in the extended Higgs model with a real singlet scalar field. In order to calculate the bubble nucleation rate, we perform a two-field analysis and evaluate bounce solutions connecting the true and the false vacua using the one-loop effective potential at finite temperatures. Imposing the Sakharov condition of the departure from thermal equilibrium for baryogenesis, we survey allowed regions of parameters of the model. We then investigate the gravitational waves produced at electroweak bubble collisions in the early Universe, such as the sound wave, the bubble wall collision and the plasma turbulence. We find that the strength at the peak frequency can be large enough to be detected at future space-based gravitational interferometers such as eLISA, DECIGO and BBO. Predicted deviations in the various Higgs boson couplings are also evaluated at the zero temperature, and are shown to be large enough too. Therefore, in this model strongly first order electroweak phase transition can be tested by the combination of the precision study of various Higgs boson couplings at the LHC, the measurement of the triple Higgs boson coupling at future lepton colliders and the shape of the spectrum of gravitational wave detectable at future gravitational interferometers. [ABSTRACT FROM AUTHOR]

We explore the idea that the coupling between matter and spacetime is more complex than the one originally envisioned by Einstein. We propose that such coupling takes the form of a new fundamental tensor in the Einstein field equations. We then show that the introduction of this tensor can account for dark phenomenology in General Relativity, maintaining a weak field limit compatible with standard Newtonian gravitation. The same paradigm can be applied any other theory of gravitation. We show, as an example, that in the context of conformal gravity a generalised coupling is able to solve compatibility issues between the matter and the gravitational sector. [ABSTRACT FROM AUTHOR]

For appropriate choices of the coupling constants, the equations of motion of Lovelock gravities up to order n in the Riemann tensor can be factorized such that the theories admit a single (A)dS vacuum. In this paper we construct two classes of exact rotating metrics in such critical Lovelock gravities of order n in d = 2 n + 1 dimensions. In one class, the n angular momenta in the n orthogonal spatial 2-planes are equal, and hence the metric is of cohomogeneity one. We construct these metrics in a Kerr–Schild form, but they can then be recast in terms of Boyer–Lindquist coordinates. The other class involves metrics with only a single non-vanishing angular momentum. Again we construct them in a Kerr–Schild form, but in this case it does not seem to be possible to recast them in Boyer–Lindquist form. Both classes of solutions have naked curvature singularities, arising because of the over rotation of the configurations. [ABSTRACT FROM AUTHOR]