Hadron properties in dense medium are treated in a unified way in a skyrmion model constructed with an effective Lagrangian, in which the $\rho$ and $\omega$ vector mesons are introduced as hidden gauge bosons, valid up to $O(p^4)$ terms in chiral expansion including the homogeneous Wess-Zumino terms. All the low energy constants of the Lagrangian—apart from the pion decay constant and the vector meson mass—are fixed by the master formula derived from the relation between the five-dimensional holographic QCD and the four-dimensional hidden local symmetry Lagrangian. This Lagrangian allows one to pin down the density $n_{1/2}$ at which the skyrmions in medium fractionize into half-skyrmions, bringing in a drastic change in the equation of state of dense baryonic matter. We find that the $U(1)$ field that figures in the Chern-Simons term in the five-dimensional holographic QCD action or equivalently the $\omega$ field in the homogeneous Wess-Zumino term in the dimensionally reduced hidden local symmetry action plays a crucial role in the half-skyrmion phase. The importance of the $\omega$ degree of freedom may be connected to what happens in the instanton structure of elementary baryon noticed in holographic QCD. The most striking and intriguing in what is found in the model is that the pion decay constant that smoothly drops with increasing density in the skyrmion phase stops decreasing at $n_{1/2}$ and remains nearly constant in the half-skyrmion phase. In accordance with the large $N_c$ consideration, the baryon mass also stays nonscaling in the half-skyrmion phase. This feature which is reminiscent of the parity-doublet baryon model with a chirally invariant mass $m_0$ is supported by the nuclear effective field theory with the parameters of the Lagrangian scaling modified at the skyrmion–half-skyrmion phase transition. It also matches with one-loop renormalization group analysis based on hidden local symmetry. A link between a nonvanishing $m_0$ and the origin of nucleon mass distinctive from dynamically generated mass is suggested. We briefly discuss the possible consequences of the topology change found in this paper on the forthcoming experiments at the rare isotope beam machines under construction.

In a Comment [S. Hossenfelder Phys. Rev. D 88, 028701 (2013)], Hossenfelder proposes a generalization of the results we reported in [Phys. Rev. D 84, 087702 (2011)] and argues that thermal fluctuations introduce incurable pathologies for the description of macroscopic bodies in the relative-locality framework. We here show that Hossenfelder’s analysis, while raising a very interesting point, is incomplete and leads to incorrect conclusions. Her estimate for the fluctuations did not take into account some contributions from the geometry of momentum space, which must be included at the relevant order of approximation. Using the full expression here derived, one finds that thermal fluctuations are not, in general, large for macroscopic bodies in the relative-locality framework. We find that such corrections can be unexpectedly large only for some choices of momentum-space geometry, and we comment on the possibility of developing a phenomenology suitable for possibly ruling out such geometries of momentum space.

It is explained why the argument by Amelino-Camelia et al. [Phys. Rev. D 84, 087702 (2011)] does not answer the question how to describe multiparticle states in models with a deformed Lorentz symmetry in momentum space.

Recently it has been speculated that the $S$-matrix elements on the world volume of $D_3$-branes should satisfy the Ward identity corresponding to the $S$-duality transformations. For a single brane and in the low energy limit, this indicates that in the Abelian Dirac-Born-Infeld and Chern-Simons actions, the combination of contact terms and tree-level massless poles in an $n$-point function should satisfy the $S$-duality. In this paper, we examine in details the $S$-matrix element of three gauge bosons and one 2-form and the $S$-matrix element of six gauge bosons in favor of the above proposal.

We examine the relationships between three proposals for the six-dimensional (2,0) theory: the discrete light-cone quantization (DLCQ) of Aharony et al. [Adv. Theor. Math. Phys. 1, 148 (1998); Adv. Theor. Math. Phys. 2, 119 (1998)], the deconstruction prescription of Arkani-Hamed et al. [J. High Energy Phys. 01 (2003) 083], and the five-dimensional maximally supersymmetric Yang-Mills proposal of Douglas and Lambert et al. [J. High Energy Phys. 02 (2011) 011; J. High Energy Phys. 01 (2011) 083]. We show that Arkani-Hamed et al. gives a deconstruction of five-dimensional maximally supersymmetric Yang-Mills. The proposal of Aharony et al. uses a subset of the degrees of freedom of five-dimensional Yang-Mills, and we show that compactification of it on a circle of finite radius agrees with the DLCQ arising from the proposal of Douglas and Lambert et al. or from the deconstruction proposal of Arkani-Hamed et al.

We derive dynamical, real time radiation reaction effects from lightfront QED. Combining the Hamiltonian formalism with a plane wave background field, the calculation is performed in the Furry picture for which the background is treated exactly while interactions between quantum fields are treated in perturbation theory as normal. We work to a fixed order in perturbation theory, but no other approximation is made. The literature contains many proposals for the correct classical equation describing a radiating particle; we take the classical limit of our results and identify which equations are consistent with QED.

We study massive real scalar ${\varphi }^4$ theory in the expanding Poincare patch of de Sitter space. We calculate the leading two-loop infrared contribution to the two-point function in this theory. We do that for the massive fields both from the principal and complementary series. As can be expected at this order, light fields from the complementary series show stronger infrared effects than the heavy fields from the principal one. For the principal series, unlike the complementary one, we can derive the kinetic equation from the system of Dyson–Schwinger equation, which allows us to sum up the leading infrared contributions from all loops. We find two peculiar solutions of the kinetic equation. One of them describes the stationary Gibbons–Hawking-type distribution for the density per comoving volume. Another solution shows explosive (square root of the pole in finite proper time) growth of the particle number density per comoving volume. That signals the possibility of the destruction of the expanding Poincaré patch even by the very massive fields. We conclude with the consideration of the infrared divergences in global de Sitter space and in its contracting Poincaré patch.

This work is devoted to analyze the role of the electromagnetic field and a viable $f(R)=R+\delta R^2$ model on the range of dynamical instability. For this purpose, we assume a charged spherically symmetric anisotropic star, which begins collapsing adiabatically under the expansion-free condition. We formulate the dynamical equations using contracted Bianchi identities for the usual, effective dark source and electromagnetic energy-momentum tensor. The perturbation scheme is applied to the metric as well as physical variables. We conclude that the instability range of the observed expansion-free fluid does not depend upon the numerical values of the index $\Gamma$; rather, it relies on the anisotropy of the pressure, radial density profile, electromagnetic field, and $f(R)$ model.

We present a derivation of two-point correlations of general tracers in the peak-background split (PBS) framework by way of a rigorous definition of the PBS argument. Our expressions only depend on connected matter correlators and “renormalized” bias parameters with clear physical interpretation, and are independent of any coarse-graining scale. This result should be contrasted with the naive expression derived from a local bias expansion of the tracer number density with respect to the matter density perturbation ${\delta }_L$ coarse-grained on a scale $R_L$. In the latter case, the predicted tracer correlation function receives contributions of order $⟨{\delta }_L^n⟩$ at each perturbative order $n$, whereas, in our formalism, these are absorbed in the PBS bias parameters at all orders. Further, this approach naturally predicts both a scale-dependent bias $\propto k^2$ such as found for peaks of the density field, and the scale-dependent bias induced by primordial non-Gaussianity in the initial conditions. The only assumption made about the tracers is that their abundance at a given position depends solely on the matter distribution within a finite region around that position.

We propose a model to describe the low energy physics of the partially composite Standard Model, in which the electroweak sector in the Standard Model is weakly coupled to some strong dynamics. The vector resonances in the strong sector are introduced as the effective degrees of freedom, $W^{\prime }$ and $Z^{\prime }$, which mixes with the $W$ and $Z$ bosons through the electroweak symmetry breaking. Through the coupling to the strong sector, the Standard Model Higgs boson becomes partially composite, and its properties are modified. We study the constraints from the electroweak precision data and direct searches of $W^{\prime }$ and $Z^{\prime }$ at the LHC expriments, and discuss the effects on the production/decay properties of the Higgs boson.

Since the discovery of a Higgs boson at the LHC and the measurement of many of its branching ratios, there have been numerous studies exploring the restrictions these results place on the parameter space of two Higgs doublet models. We extend these results to include the full data set and study the expected sensitivity that can be obtained with $300{\mathrm{fb}}^{-1}$ and $3000{\mathrm{fb}}^{-1}$ integrated luminosity. We consider searches for a heavy Standard Model Higgs boson, with a mass ranging from 200 to 400 GeV, and show that the nonobservation of such a Higgs boson can substantially narrow the allowed regions of parameter space in two Higgs doublet models.

We consider that the direct production of a single neutralino in a proton-proton collision at the CERN Large Hadron Collider focusing on the lightest neutralino is possibly a candidate for dark matter and escapes detection. We present a comprehensive investigation of the dependence of total cross sections of the processes $pp(q\overline{q})\to {\tilde{\chi }}_i^0\tilde{\mathrm{g}}$, $pp(q\mathrm{g})\to {\tilde{\chi }}_i^0{\tilde{q}}_{L,R}$, and $pp(q{\overline{q}}^{\prime })\to {\tilde{\chi }}_i^0{\tilde{\chi }}_j^{+}$ at tree level and $pp(\mathrm{gg})\to {\tilde{\chi }}_i^0\tilde{\mathrm{g}}$ at one-loop level, on the center-of-mass energy, on the $M_2\mathrm{\text{−}}\mu$ mass plane, on the squark mass, and on the $\tan \beta$ for the Constrained Minimal Supersymmetric Standard Model and three extremely different scenarios in the Minimal Supersymmetric Standard Model. In particular, the cross section of the process $pp\to {\tilde{\chi }}_2^0{\tilde{\chi }}_1^{+}$ in the gauginolike scenario can reach about 0.6 (1.7) pb at a center-of-mass energy of $\sqrt{s}=7(14)\mathrm{TeV}$. We extract therefrom that our results might lead to new aspects corresponding to experimental explorations, and these dependencies might be used as the bases of experimental research of the single neutralino production at hadron colliders.

We revisit QCD sum rules for the decay constants of heavy-light mesons. In the sum rules for the vector mesons $B_{(s)}^{*}$ and $D_{(s)}^{*}$ we improve the accuracy of OPE, taking into account the $O({\alpha }_s^2)$ terms in the perturbative part and calculating the $O({\alpha }_s)$ corrections to the quark-condensate contribution. With this accuracy, we obtain the ratios of decay constants: $f_{B^{*}}/f_B={1.02}_{-0.03}^{+0.07}$, $f_{D^{*}}/f_D={1.20}_{-0.07}^{+0.10}$. The sum rule predictions for the decay constants of pseudoscalar mesons are updated with the results $f_B=({207}_{-9}^{+17})\mathrm{MeV}$, $f_{B_s}=({242}_{-12}^{+17})\mathrm{MeV}$, $f_D=({201}_{-13}^{+12})\mathrm{MeV}$, $f_{D_s}=({238}_{-23}^{+13})\mathrm{MeV}$. In order to assess the sensitivity of our calculation to the form of the sum rule, we consider alternative versions such as the power moments and Borel sum rules with different weights of the spectral density. We also investigated the heavy-quark limit of the sum rules for vector and pseudoscalar mesons, estimating the violations of the heavy-quark spin and flavor symmetry.

Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.

By assuming that $Y(4260)$ either is a $D_1\overline{D}$ molecular state or has sizeable couplings with $D_0{\overline{D}}^{*}$ and $D_1^{\prime }\overline{D}$, we investigate several decay modes of $Y(4260)$. Under the special kinematic configurations, triangle singularity may occur in the rescattering amplitude, which will significantly change the threshold behavior. Obvious threshold enhancements or narrow cusp structures appear quite naturally without introducing a genuine resonance. We emphasize that the radiative decay modes may be useful for studying $D^{(*)}\overline{D}$ $S$-wave scattering.

We investigate the effects of realistic quark masses and local color neutrality on quark pairing in the three-flavor Polyakov–Nambu–Jona-Lasinio model. While prior studies have indicated the presence of light flavor quark (2SC) or symmetric color-flavor-locked (CFL) pairing at low temperatures, we find that in the absence of a local color neutrality constraint the inclusion of the Polyakov loop gives rise to phases in which all quark colors and flavors pair, but with unequal magnitudes. We study this asymmetric color-flavor-locked (ACFL) phase, which can exist even for equal mass quarks, identifying its location in the phase diagram, the order of the associated phase transitions, and its symmetry breaking pattern, which proves to be the intersection of the symmetry groups of the 2SC and CFL phases. We also investigate the effects of the strange quark mass on this new phase and the QCD phase diagram generally. Finally, we analyze the effect of a local color neutrality constraint on these phases of asymmetric pairing. We observe that for massless quarks the neutrality constraint renders the 2SC phase energetically unfavorable, eliminating it at low temperatures, and giving rise to the previously proposed low temperature critical point, with associated continuity between the hadronic and ACFL phases. For realistic strange quark masses, however, the neutrality constraint shrinks the 2SC region of the phase diagram, but does not eliminate it, at $T=0$.

An appropriately oriented D3-D7-brane system is the holographic dual of relativistic fermions occupying a $2+1$-dimensional defect embedded in a $3+1$-dimensional spacetime. The fermions interact via fields of $\mathcal{N}=4$ Yang-Mills theory in the $3+1$-dimensional bulk. Recently, using internal flux to stabilize the system in the probe $N_7\ll N_3$ limit, a number of solutions which are dual to conformal field theories with fermion content have been found. We use holographic techniques to study perturbations of a particular one of the conformal field theories by relevant operators. Generally, the response of a conformal field theory to such a perturbation grows and becomes nonperturbative at low energy scales. We shall find that a perturbation which switches on a background magnetic field $B$ and fermion mass $m$ induces a renormalization group flow that can be studied perturbatively in the limit of small $m^2/B$. We solve the leading order explicitly. We find that, for one particular value of internal flux, the system exhibits magnetic catalysis, the spontaneous breaking of chiral symmetry enhanced by the presence of the magnetic field. In the process, we derive formulas predicting the Debye screening length of the fermion-antifermion plasma at finite density and the diamagnetic moment of the ground state of the fermion system in the presence of a magnetic field.

We study non-self-dual classical solutions in the ${\mathbb{C}\mathbb{P}}^{N-1}$ model with ${\mathbb{Z}}_N$ twisted boundary conditions on the spatially compactified cylinder. These solutions have finite, and fractional, classical action and topological charge, and are “unstable” in the sense that the corresponding fluctuation operator has negative modes. We propose a physical interpretation of these solutions as saddle point configurations whose contributions to a resurgent semi-classical analysis of the quantum path integral are imaginary nonperturbative terms that must be cancelled by infrared renormalon terms generated in the perturbative sector.

A quantum energy inequality is derived for the massive Ising model, giving a state-independent lower bound on suitable averages of the energy density, the first quantum energy inequality to be established for an interacting quantum field theory with nontrivial $S$-matrix. It is shown that the Ising model has one-particle states with locally negative energy densities and that the energy density operator is not additive with respect to the combination of one-particle states into multiparticle configurations.

We introduce a new background field method for $\mathrm{N}=2$ superspace. (We treat projective hyperspace, but similar remarks apply for the harmonic case.) In analogy to $\mathrm{N}=1$, background gauge fields are in the real representation, so the lowest-dimension potentials are spinor and the usual nonrenormalization theorems are manifest. Another consequence is that the R-coordinates disappear from the effective action.