Impact of the in-medium modified nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter is studied by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A relativistic mean field model and the quark-meson coupling model are respectively adopted for the in-medium effective nucleon mass and nucleon form factors. We find that the cross sections of neutrino scattering in cold nuclear medium decrease when the in-medium modifications of the nucleon weak and electromagnetic form factors are taken into account. This reduction results in the enhancement of the neutrino mean free path, in particular at the baryon density of around a few times of the normal nuclear matter density. The enhancement of the neutrino mean free path is estimated to be about 10%–40% compared with the values obtained without the medium modifications of the nucleon form factors, and the enhancement is expected to accelerate the cooling of neutron stars.

We report the transverse single-spin asymmetries of $J/\psi$ production at forward and backward rapidity, $1.2<|y|<2.2$, as a function of $J/\psi$ transverse momentum ($p_T$) and Feynman-$x$ ($x_F$). The data analyzed were recorded by the PHENIX experiment at the Relativistic Heavy Ion Collider in 2015 from $p+p$, $p+\mathrm{Al}$, and $p+\mathrm{Au}$ collisions with transversely polarized proton beams at $\sqrt{s_{NN}}=200\mathrm{GeV}$. At this collision energy, single-spin asymmetries for heavy-flavor particle production of $p+p$ collisions provide access to the spin-dependent gluon distribution and higher-twist correlation functions inside the nucleon, such as the gluon Qiu-Sterman and trigluon correlation functions. $\mathrm{Proton}+\mathrm{nucleus}$ collisions offer an excellent opportunity to study nuclear effects on the correlation functions. The data indicate a positive asymmetry at the two-standard-deviation level in the $p+p$ data for $2\mathrm{GeV}/c<p_T<10\mathrm{GeV}/c$ at backward rapidity and negative asymmetries at the two-standard-deviation level in the $p+\mathrm{Au}$ data for $p_T<2\mathrm{GeV}/c$ at both forward and backward rapidity, while in $p+\mathrm{Al}$ collisions the asymmetries are consistent with zero within the range of experimental uncertainties.

We report a measurement of the branching fractions of the decays $B\to D^{(*)}\pi \ell \nu$. The analysis uses $772\times {10}^6$ $B\overline{B}$ pairs produced in $e^{+}{e}^{-}\to \mathrm{\Upsilon }(4S)$ data recorded by the Belle experiment at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The tagging $B$ meson in the decay is fully reconstructed in a hadronic decay mode. On the signal side, we reconstruct the decay $B\to D^{(*)}\pi \ell \nu (\ell =e,\mu )$. The measured branching fractions are $\mathcal{B}(B^{+}\to D^{-}{\pi }^{+}{\ell }^{+}\nu )=[4.55\pm 0.27(\mathrm{stat}.)\pm 0.39(\mathrm{syst}.)]\times {10}^{-3}$, $\mathcal{B}(B^0\to {\overline{D}}^0{\pi }^{-}{\ell }^{+}\nu )=[4.05\pm 0.36(\mathrm{stat}.)\pm 0.41(\mathrm{syst}.)]\times {10}^{-3}$, $\mathcal{B}(B^{+}\to D^{*-}{\pi }^{+}{\ell }^{+}\nu )=[6.03\pm 0.43(\mathrm{stat}.)\pm 0.38(\mathrm{syst}.)]\times {10}^{-3}$, and $\mathcal{B}(B^0\to {\overline{D}}^{*0}{\pi }^{-}{\ell }^{+}\nu )=[6.46\pm 0.53(\mathrm{stat}.)\pm 0.52(\mathrm{syst}.)]\times {10}^{-3}$. These are in good agreement with the current world-average values.

We report a measurement of the flux-integrated cross section for inclusive muon neutrino charged-current interactions on carbon. The double-differential measurements are given as a function of the muon momentum and angle. Relative to our previous publication on this topic, these results have an increased angular acceptance and higher statistics. The data sample presented here corresponds to $5.7\times {10}^{20}$ protons on target. The total flux-integrated cross section is measured to be $(6.950\pm 0.662)\times {10}^{-39}{\mathrm{cm}}^2{\text{nucleon}}^{-1}$ and is consistent with our simulation.

We claim that the physical parameters of the constructed black hole solutions in general relativity (GR) coupled to nonlinear electrodynamics (NED) by Zhong-Ying Fan and Xiaobao Wang in the Paper [Phys. Rev. D 94, 124027 (2016)] are misinterpreted, despite the formalism being correct. We argue that because of these misinterpretations, the derived black hole solutions and the Lagrangian densities presented in that paper are slightly inconsistent. In this comment, we present complete black hole solutions of the given Lagrangian densities which correct the interpretation of the physical parameters of the constructed black hole solutions and lead to the correct treatment and weak field limits of the physical parameters of the constructed solutions.

The subregion holographic complexity of a $3+1$-dimensional Lifshitz spacetime having a scaling symmetry is computed. The change in the holographic complexity between the excited state and the ground state is then obtained. It is found that there is a nontrivial change in holographic complexity at first order in the perturbation of the pure Lifshitz geometry. The difference is next related to the changes in the energy and the entanglement chemical potential of the system. The calculation is carried out for both the values of the dynamical scaling exponent $z$ in the Lifshitz spacetime. The relations have a very similar form to the corresponding relation involving the change in entanglement entropy known to be an analogous relation to the first law of thermodynamics.

Integration-by-parts identities between loop integrals arise from the vanishing integration of total derivatives in dimensional regularization. Generic choices of total derivatives in the Baikov or parametric representations lead to identities which involve dimension shifts. These dimension shifts can be avoided by imposing a certain constraint on the total derivatives. The solutions of this constraint turn out to be a specific type of syzygies which correspond to logarithmic vector fields along the Gram determinant formed of the independent external and loop momenta. We present an explicit generating set of solutions in Baikov representation, valid for any number of loops and external momenta, obtained from the Laplace expansion of the Gram determinant. We provide a rigorous mathematical proof that this set of solutions is complete. This proof relates the logarithmic vector fields in question to ideals of submaximal minors of the Gram matrix and makes use of classical resolutions of such ideals.

One-graviton-loop corrections to the vacuum polarization on a de Sitter background show two interesting infrared effects: a secular enhancement of the photon electric field strength and a long-range running of the Coulomb potential. We show that the first effect derives solely from the “tail” term of the graviton propagator, but that the second effect does not. Our result agrees with the earlier observation that the secular enhancement of massless fermion mode functions derives solely from the tail term. We discuss the implications this has for the important project of generalizing to quantum gravity the Starobinsky technique for summing the series of leading infrared effects from inflationary quantum field theory.

It is known that a massive charged scalar field can trigger a superradiant instability in the background of a Kerr-Newman black hole. In this paper, we present a numerical study of such an instability by using the continued-fraction method. It is shown that for given a black hole, the unstable scalar mode with a specific azimuthal index $m$ only occurs in a finite region in the parameter space of the scalar field. The maximum mass of the scalar cloud is exactly the upper bound of the mass of the unstable modes. We show that due to the electromagnetic interaction between the scalar field and the Kerr-Newman black hole, the growth rate of the instability can be 15.7% larger than that of a scalar field in Kerr spacetime of the same rotation parameter. In addition, we find a maximum value of the growth rate ${\tau }^{-1}=1.788\times {10}^{-7}{M}^{-1}$, which is about 4% larger than that in the Kerr case.

We study general properties of the conformal basis, the space of wave functions in ($d+2$)-dimensional Minkowski space that are primaries of the Lorentz group $SO(1,d+1)$. Scattering amplitudes written in this basis have the same symmetry as $d$-dimensional conformal correlators. We translate the optical theorem, which is a direct consequence of unitarity, into the conformal basis. In the particular case of a tree-level exchange diagram, the optical theorem takes the form of a conformal block decomposition on the principal continuous series, with operator product expansion (OPE) coefficients being the three-point coupling written in the same basis. We further discuss the relation between the massless conformal basis and the bulk point singularity in $\mathrm{AdS}/\mathrm{CFT}$. Some three- and four-point amplitudes in ($2+1$) dimensions are explicitly computed in this basis to demonstrate these results.

Dynamical Chern-Simons gravity has an interesting feature that the parity violating term exists, and the coupling is determined by a dynamical scalar field. When the spacetime has spherical symmetry, the parity violating term vanishes, and then the metric of the Schwarzschild spacetime with vanishing scalar field is an exact solution of dynamical Chern-Simons gravity. The effect of the Chern-Simons coupling appears in the study of perturbation around the Schwarzschild spacetime. Due to the parity violating term, the odd parity metric perturbation and the perturbed scalar field are coupled, and the perturbed field equations take the form of the coupled system of the Schrödinger equations. We prove linear mode stability for a generic massive scalar.

In the theories described by a volume normalized action functional, an arbitrary cosmological constant is eliminated from the physical picture of our Universe, and dynamical alternatives must be responsible for today’s accelerated expansion as well as the conjectured early-time inflation in the Universe. A few well-known such scenarios realized by a single homogeneous scalar field are examined in this new context, and their diverse fates are elucidated. Typical inflationary models are not affected at the level of the background evolution, and also give rise to the scalar perturbations equivalent to those obtained in the standard general relativity; however, the primordial quantum tensor fluctuations are absent in the new framework, irrespective of the inflationary model. As a consequence, our proposal would be ruled out should the primordial tensor modes, or their indirect consequences, be observed experimentally.

Axionlike particles (ALPs) are interesting dark matter candidates from both the theoretical and the experimental perspective. Usually they are motivated as pseudo-Nambu-Goldstone bosons. In this case one of their most important features is that their coupling to other particles is suppressed by a large scale, the vacuum expectation value of the field breaking the symmetry that gives rise to them. This naturally endows them with very weak interactions but also restricts the maximal field value and therefore the regions where sufficient dark matter is produced. In this paper we investigate deviations from this simplest setup, where the potential and interactions are as expected for a pseudo-Nambu-Goldstone boson, but the kinetic term has singularities. This leads to a significantly increased area in parameter space where such particles can be dark matter and can be probed by current and near future experiments. We discuss cosmological limits and in the course of this give a simple derivation of a formula for isocurvature fluctuations in models with general anharmonic potentials. As an application of this formula we give an update of the isocurvature constraints for QCD axion dark matter models, using the most recent results for the QCD topological susceptibility and the newest Planck data.

We present the Eisenhart-lift formalism in which the dynamics of a system that evolves under the influence of a conservative force is equivalent to that of a free system embedded in a curved manifold with one additional generalized coordinate. As an illustrative example in classical mechanics, we apply this formalism to simple harmonic motion. We extend the Eisenhart lift to homogeneous field theories by adding one new field. Unlike an auxiliary field, this field is fully dynamical and is therefore termed fictitious. We show that the Noether symmetries of a theory with a potential are solutions of the Killing equations in the lifted field space. We generalize this approach to field theories in four and higher spacetime dimensions by virtue of a mixed vielbein that links the field space and spacetime. Possible applications of the extended Eisenhart-lift formalism including the gauge hierarchy problem and the initial conditions problem in inflation are briefly discussed.

We show that stringent limits on leptoquarks that couple to first-generation quarks and left-handed electrons or muons can be derived from the spectral shape of the charged-current Drell-Yan process ($pp\to {\ell }^{\pm }\nu$) at run 2 of the LHC. We identify and examine all six leptoquark species that can generate such a monolepton signal, including both scalar and vector leptoquarks, and find cases where the leptoquark exchange interferes constructively, destructively or not at all with the Standard Model signal. When combined with the corresponding leptoquark-mediated neutral-current ($pp\to {\ell }^{+}{\ell }^{-}$) process, we find the most stringent limits obtained to date, outperforming bounds from pair production and atomic parity violation. We show that, with $3000{\mathrm{fb}}^{-1}$ of data, combined measurements of the transverse mass in $pp\to {\ell }^{\pm }\nu$ events and invariant mass in $pp\to {\ell }^{+}{\ell }^{-}$ events can probe masses between 8 and 18 TeV, depending on the species of leptoquark, for electroweak-sized couplings. In light of such robust sensitivities, we strongly encourage the LHC experiments to interpret Drell-Yan (dilepton and monolepton) events in terms of leptoquarks, alongside usual scenarios like $Z^{\prime }$ bosons and contact interactions.

Leptogenesis can successfully explain the matter-antimatter asymmetry via out-of-equilibrium decays of heavy Majorana neutrinos in the early Universe. In this article, we focus on nonresonant thermal leptogenesis and the possibility of lowering its scale. In order to do so, we calculate the lepton asymmetry produced from the decays of one and two heavy Majorana neutrinos using three-flavored density matrix equations in an exhaustive exploration of the model parameter space. We find regions of the parameter space where thermal leptogenesis is viable at intermediate scales, $T\sim {10}^6\mathrm{GeV}$. However, the viability of thermal leptogenesis at such scales requires a certain degree of cancellation between the tree- and one-loop level contribution to the light neutrino mass matrix, and we quantify such fine-tuning.

We compute the Euclidean correlators of the stress tensor in pure $SU(3)$ Yang-Mills theory at finite temperature at zero and finite spatial momenta with lattice simulations. We perform continuum extrapolations using $N_{\tau }=10$, 12, 16, 20 lattices with renormalized anisotropy 2. We use these correlators to estimate the shear viscosity of the gluon plasma in the deconfined phase. For $T=1.5T_c$, we estimate $\eta /s=0.17(2)$ using an ansatz motivated by hydrodynamics.

We compute renormalized vertices of the 125 GeV Higgs boson $h$ with the weak gauge bosons ($hVV$), fermions ($hf\overline{f}$), and itself ($hhh$) in the Georgi-Machacek model at one-loop level. The renormalization is performed based on the on-shell scheme with the use of the $\overline{\mathrm{MS}}$ scheme only for the $hhh$ vertex. We explicitly show the gauge dependence in the counterterms of the scalar mixing parameters in the general $R_{\xi }$ gauge and that the dependence can be removed by using the pinch technique in physical scattering processes. We then discuss the possible allowed deviations in these one-loop corrected Higgs couplings from the standard model predictions by scanning model parameters under the constraints of perturbative unitarity and vacuum stability as well as those from experimental data.

Inspired by holographic Wilsonian renormalization, we consider coarse graining a quantum system divided between short-distance and long-distance degrees of freedom (d.o.f.), coupled via the Hamiltonian. Observations using purely long-distance observables are described by the reduced density matrix that arises from tracing out the short-distance d.o.f. The dynamics of this density matrix is non-Hamiltonian and nonlocal in time, on the order of some short time scale. We describe this dynamics in a model system with a simple hierarchy of energy gaps $\mathrm{\Delta }{E}_{\mathrm{UV}}>\mathrm{\Delta }{E}_{\mathrm{IR}}$, in which the coupling between high- and low-energy d.o.f. is treated to second order in perturbation theory. We then describe the equations of motion under suitable time averaging, reflecting the limited time resolution of actual experiments, and find an expansion of the master equation in powers of $\mathrm{\Delta }{E}_{\mathrm{IR}}/\mathrm{\Delta }{E}_{\mathrm{UV}}$, after the fashion of effective field theory. The failure of the system to be Hamiltonian or even Markovian appears at higher orders in this ratio. We compute the evolution of the density matrix in three specific examples: coupled spins, linearly coupled simple harmonic oscillators, and an interacting scalar quantum field theory. Finally, we argue that the logarithm of the Feynman-Vernon influence functional is the correct analog of the Wilsonian effective action for this problem.

We analyze Feynman diagram calculational issues related to the quantum breaking of supercurrent conservation in a supersymmetric non-Abelian Yang-Mills theory. For the sake of simplicity, we take a zero mass gauge field multiplet interacting with a massless Majorana spin-$1/2$ field in the adjoint representation of $SU(2)$. We shed light on a long-standing controversy regarding the perturbative evaluation of the supercurrent anomaly in connection with gauge and superconformal symmetry in different frameworks. We find that only superconformal symmetry is unambiguously broken using an invariant four dimensional regularization and compare with the triangle AVV anomaly. Subtleties related to momentum routing invariance in the loops of diagrams and Clifford algebra evaluation inside divergent integrals are also discussed in connection with finite and undetermined quantities in Feynman amplitudes.