Baryon chiral perturbation theory combined with the $1/N_c$ expansion is implemented for three flavors. Baryon masses, vector charges and axial vector couplings are studied to one-loop and organized according to the $\xi$-expansion, in which the $1/N_c$ and the low-energy power countings are linked according to $1/N_c=\mathcal{O}(\xi )=\mathcal{O}(p)$. The renormalization to $\mathcal{O}({\xi }^3)$ necessary for the mentioned observables is provided, along with applications to the baryon masses and axial couplings as obtained in lattice QCD calculations.

We derive analytical results for unintegrated color dipole gluon distribution function at small transverse momentum. By Fourier transforming the $S$-matrix for large dipoles we derive the results in the form of a series of Bells polynomials. Interestingly, when resumming the series in leading log accuracy, the results showing up striking similarity with the Sudakov form factor with role play of coupling is being done by a constant that stems from the saddle point condition along the saturation line.

We describe supersymmetric A-branes and B-branes in open $\mathcal{N}=(2,2)$ dynamically gauged nonlinear sigma models (GNLSM), placing emphasis on toric manifold target spaces. For a subset of toric manifolds, these equivariant branes have a mirror description as branes in gauged Landau-Ginzburg models with neutral matter. We then study correlation functions in the topological A-twisted version of the GNLSM and identify their values with open Hamiltonian Gromov-Witten invariants. Supersymmetry breaking can occur in the A-twisted GNLSM due to nonperturbative open symplectic vortices, and we canonically Becchi-Rouet-Stora-Tyutin quantize the mirror theory to analyze this phenomenon.

The membrane paradigm approach adopts a timelike surface, stretched out off the null event horizon, to study several important black hole properties. We use this powerful tool to give a direct derivation of the black hole mass formula in the static and stationary cases without and with electric field. Since here the membrane is a self-gravitating material system, we go beyond the usual applicability on test particles and test fields of the paradigm.

We perform adiabatic regularization of power spectrum in nonminimally coupled general single-field inflation with varying speed of sound. The subtraction is performed within the framework of earlier study by Urakawa and Starobinsky dealing with the canonical inflation. Inspired by Fakir and Unruh’s model on nonminimally coupled chaotic inflation, we find upon imposing near scale-invariant condition, that the subtraction term exponentially decays with the number of $e$-folds. As in the result for the canonical inflation, the regularized power spectrum tends to the “bare” power spectrum as the Universe expands during (and even after) inflation. This work justifies the use of the “bare” power spectrum in standard calculation in the most general context of slow-roll single-field inflation involving nonminimal coupling and varying speed of sound.

We investigate gravitational redshifts (signals of gravitational potential) in measurements of the redshifts of cosmological objects, i.e., central and satellite galaxies in clusters of galaxies, intracluster gas, as well as galaxies associated with voids by developing simple theoretical models. In the analysis with satellite galaxies in clusters, we develop a very simple analytic model for satellite galaxies virialized in halos, which enables us to evaluate the signals depending on the properties of the halo occupation distribution of galaxies. We obtain results consistent with recent previous results, though our results are restricted to the satellite galaxies inside the virial radius. In the analysis of intracluster gas, we develop a simple analytic model including the effect of random motions of gases, which are assumed to generate nonthermal pressure. We demonstrate a possible contribution of the random motions of gases to gravitational potential measurements. We also investigate a possible signature of the gravitational potential in measurements of galaxies associated with voids by utilizing a simple analytic model. We show that the second-order Hubble term, which appears in the expansion of the scale factor around the center of a void, may make a significant contribution depending on the way the galaxy samples are analyzed. The studies on the possible signals of gravitational potential for intracluster gases and voids are performed for the first time.

We reexamine interactions between the dark sectors of cosmology, with a focus on robust constraints that can be obtained using only mildly nonlinear scales. While it is well known that couplings between dark matter and dark energy can be constrained to the percent level when including the full range of scales probed by future optical surveys, calibrating matter power spectrum emulators to all possible choices of potentials and couplings requires many computationally expensive n-body simulations. Here we show that lensing and clustering of galaxies in combination with the cosmic microwave background (CMB) are capable of probing the dark sector coupling to the few percent level for a given class of models, using only linear and quasilinear Fourier modes. These scales can, in principle, be described by semianalytical techniques such as the effective field theory of large-scale structure.

We explore the homogeneous background dynamics and the evolution of generated perturbations of cosmological inflation that is driven by multiple scalar fields interacting with a perfect fluid. Then we apply the method to warm inflation driven by two scalar fields and a radiation fluid, and present general results about the evolution of the inflaton and radiation. After decomposing the perturbations into adiabatic and entropy modes, we give the equation of motion of adiabatic and entropy perturbations on large scales. Then, we give numerical results of background and perturbation equations in a concrete model (the dissipative coefficient $\mathrm{\Gamma }\propto H$). At last, we use the most recent observational data to constrain our models and give the observationally allowed regions of parameters. This work is a natural extension of warm inflation to multifield cases.

Recent direct measurements of Galactic cosmic ray spectra by balloon/space-borne detectors reveal spectral hardenings of all major nucleus species at rigidities of a few hundred GV. The all-sky diffuse $\gamma$-ray emissions measured by the Fermi Large Area Telescope also show spatial variations of the intensities and spectral indices of cosmic rays. These new observations challenge the traditional simple acceleration and/or propagation scenario of Galactic cosmic rays. In this work, we propose a spatially dependent diffusion scenario to explain all these phenomena. The diffusion coefficient is assumed to be anticorrelated with the source distribution, which is a natural expectation from the charged particle transportation in a turbulent magnetic field. The spatially dependent diffusion model also gives a lower level of anisotropies of cosmic rays, which are consistent with observations by underground muons and air shower experiments. The spectral variations of cosmic rays across the Galaxy can be properly reproduced by this model.

Sub-GeV halo dark matter that enters the Sun can potentially scatter off hot solar nuclei and be ejected much faster than its incoming velocity. We derive an expression for the rate and velocity distribution of these reflected particles, taking into account the Sun’s temperature and opacity. We further demonstrate that future direct-detection experiments could use these energetic reflected particles to probe light dark matter in parameter space that cannot be accessed via ordinary halo dark matter.

The study of the anisotropy of the arrival directions is an essential tool to investigate the origin and propagation of cosmic rays primaries. A pentagon array has been designed to collect data around the knee region of cosmic ray spectrum. The experimental results of this array obtained from October 2016 to October 2017. During this period, more than $5.3\times {10}^5$ extensive air shower events at energies in the decade below 1 PeV has been accumulated by this array at Sharif University of Technology in Tehran ($35°43^{\prime }\mathrm{N}$, $51°20^{\prime }\mathrm{E}$, 1200m $\mathrm{a}.\mathrm{s}.\mathrm{l}=890\mathrm{g}{\mathrm{cm}}^{-2}$). In analyzing the data set, we have used appropriate techniques of analysis and considered environmental effects. We report the analysis of the sidereal anisotropy of Galactic cosmic rays (GCRs). In this analysis, in addition to the Compton- Getting effect due to the motion of the earth in the Galaxy, an anisotropy has been observed which is due to a unidirectional anisotropy of cosmic ray flow along the Galactic arms.

Twistor string models have been known for more than a decade now but have come back under the spotlight recently with the advent of the scattering equation formalism which has greatly generalized the scope of these models. A striking ubiquitous feature of these models has always been that, contrary to usual string theory, they do not admit vibrational modes and thus describe only conventional field theory. In this paper we report on the surprising discovery of a whole new sector of one of these theories which we call “twisted strings,” when spacetime has compact directions. We find that the spectrum is enhanced from a finite number of states to an infinite number of interacting higher spin massive states. We describe both bosonic and world sheet supersymmetric models, their spectra and scattering amplitudes. These models have distinctive features of both string and field theory, for example they are invariant under stringy T-duality but have the high energy behavior typical of field theory. Therefore they describe a new kind of field theories in target space, sitting on their own halfway between string and field theory.

Applications of machine learning tools to problems of physical interest are often criticized for producing sensitivity at the expense of transparency. To address this concern, we explore a data planing procedure for identifying combinations of variables—aided by physical intuition—that can discriminate signal from background. Weights are introduced to smooth away the features in a given variable(s). New networks are then trained on this modified data. Observed decreases in sensitivity diagnose the variable’s discriminating power. Planing also allows the investigation of the linear versus nonlinear nature of the boundaries between signal and background. We demonstrate the efficacy of this approach using a toy example, followed by an application to an idealized heavy resonance scenario at the Large Hadron Collider. By unpacking the information being utilized by these algorithms, this method puts in context what it means for a machine to learn.

We consider the possibility of neutron-antineutron ($n-\overline{n}$) conversion, in which the change of a neutron into an antineutron is mediated by an external source, as can occur in a scattering process. We develop the connections between $n-\overline{n}$ conversion and $n-\overline{n}$ oscillation, in which a neutron spontaneously transforms into an antineutron, noting that if $n-\overline{n}$ oscillation occurs in a theory with baryon number minus lepton number (B-L) violation, then $n-\overline{n}$ conversion can occur also. We show how an experimental limit on $n-\overline{n}$ conversion could connect concretely to a limit on $n-\overline{n}$ oscillation, and vice versa, using effective field theory techniques and baryon matrix elements computed in the MIT bag model.

We discuss spontaneous supersymmetry (SUSY) breaking in a model with an anomalous $U(1{)}_A$ symmetry. In this model, the size of the each term in the superpotential is controlled by the $U(1{)}_A$ charge assignment and SUSY is spontaneously broken via the Fayet-Iliopoulos of $U(1{)}_A$ at the metastable vacuum. In the global SUSY analysis, the gaugino masses become much smaller than the sfermion masses, because an approximate $R$ symmetry appears at the SUSY breaking vacuum. In this paper, we show that gaugino masses can be as large as gravitino mass, taking the supergravity effect into consideration. This is because the $R$ symmetry is not imposed so that the constant term in the superpotential, which is irrelevant to the global SUSY analysis, largely contributes to the soft SUSY breaking terms in the supergravity. As the mediation mechanism, we introduce the contributions of the field not charged under $U(1{)}_A$ and the moduli field to cancel the anomaly of $U(1{)}_A$. We comment on the application of our SUSY breaking scenario to the grand unified theory.

We suggest that the exclusive $\mathrm{Higgs}+\text{light}$ (or b)-jet production at the LHC, $pp\to h+j(j_b)$, is a rather sensitive probe of the light-quarks Yukawa couplings and of other forms of new physics (NP) in the Higgs-gluon $hgg$ and quark-gluon $qqg$ interactions. We study the Higgs $p_T$-distribution in $pp\to h+j(j_b)\to \gamma \gamma +j(j_b)$, i.e., in $h+j(j_b)$ production followed by the Higgs decay $h\to \gamma \gamma$, employing the ($p_T$-dependent) signal strength formalism to probe various types of NP which are relevant to these processes and which we parametrize either as scaled Standard Model (SM) couplings (the kappa-framework) and/or through new higher dimensional effective operators (the SMEFT framework). We find that the exclusive $h+j(j_b)$ production at the 13 TeV LHC is sensitive to various NP scenarios, with typical scales ranging from a few TeV to $\mathcal{O}(10)\mathrm{TeV}$, depending on the flavor, chirality and Lorentz structure of the underlying physics.

We examine the possibility of dynamical supersymmetry breaking in two-dimensional $\mathcal{N}=(2,2)$ supersymmetric Yang-Mills theory. The theory is discretized on a Euclidean spacetime lattice using a supersymmetric lattice action. We compute the vacuum energy of the theory at finite temperature and take the zero-temperature limit. Supersymmetry will be spontaneously broken in this theory if the measured ground-state energy is nonzero. By performing simulations on a range of lattices up to $96\times 96$ we are able to perform a careful extrapolation to the continuum limit for a wide range of temperatures. Subsequent extrapolations to the zero-temperature limit yield an upper bound on the ground-state energy density. We find the energy density to be statistically consistent with zero in agreement with the absence of dynamical supersymmetry breaking in this theory.

Lattice QCD calculations including the effects of one or more nondegenerate sea quark flavors are conventionally performed using the rational hybrid Monte Carlo (RHMC) algorithm, which computes the square root of the determinant of ${\mathcal{D}}^{†}\mathcal{D}$, where $\mathcal{D}$ is the Dirac operator. The special case of two degenerate quark flavors with the same mass is described directly by the determinant of ${\mathcal{D}}^{†}\mathcal{D}$—in particular, no square root is necessary—enabling a variety of algorithmic developments, which have driven down the cost of simulating the light (up and down) quarks in the isospin-symmetric limit of equal masses. As a result, the relative cost of single quark flavors—such as the strange or charm—computed with RHMC has become more expensive. This problem is even more severe in the context of our measurements of the $\mathrm{\Delta }I=1/2$ $K\to \pi \pi$ matrix elements on lattice ensembles with $G$-parity boundary conditions, since $G$-parity is associated with a doubling of the number of quark flavors described by $\mathcal{D}$, and thus RHMC is needed for the isospin-symmetric light quarks as well. In this paper we report on our implementation of the exact one flavor algorithm (EOFA) introduced by the TWQCD Collaboration for simulations including single flavors of domain wall quarks. We have developed a new preconditioner for the EOFA Dirac equation, which both reduces the cost of solving the Dirac equation and allows us to reuse the bulk of our existing high-performance code. Coupling these improvements with careful tuning of our integrator, the time per accepted trajectory in the production of our $2+1$ flavor $G$-parity ensembles with physical pion and kaon masses has been decreased by a factor of 4.2.

We report a measurement of the cross section for $K_S^0$ pair production in single-tag two-photon collisions, ${\gamma }^{*}\gamma \to K_S^0{K}_S^0$, for $Q^2$ up to $30{\mathrm{GeV}}^2$, where $Q^2$ is the negative of the invariant mass squared of the tagged photon. The measurement covers the kinematic range $1.0\mathrm{GeV}<W<2.6\mathrm{GeV}$ and $|\cos {\theta }^{*}|<1.0$ for the total energy and kaon scattering angle, respectively, in the ${\gamma }^{*}\gamma$ center-of-mass system. These results are based on a data sample of $759{\mathrm{fb}}^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. For the first time, the transition form factor of the $f_2^{\prime }(1525)$ meson is measured separately for the helicity-0, -1, and -2 components and also compared with theoretical calculations. We have derived the cross section for the process for $W<2.6\mathrm{GeV}$ from 121 signal candidate events. Finally, the ${\gamma }^{*}\gamma$ partial decay widths of the ${\chi }_{c0}$ and ${\chi }_{c2}$ mesons are measured as a function of $Q^2$ based on 10 candidate events in total.

We study a single-channel Kondo effect using a recently developed [1–4] holographic large-$N$ technique. In order to obtain resistivity of this model, we introduce a probe field. The gravity dual of a localized fermionic impurity in $1+1$-dimensional host matter is constructed by embedding a localized two-dimensional Anti-de Sitter (${\mathrm{AdS}}_2$)-brane in the bulk of three-dimensional ${\mathrm{AdS}}_3$. This helps us construct an impurity charge density which acts as a source to the bulk equation of motion of the probe gauge field. The functional form of the charge density is obtained independently by solving the equations of motion for the fields confined to the ${\mathrm{AdS}}_2$-brane. The asymptotic solution of the probe field is dictated by the impurity charge density, which in turn affects the current-current correlation functions and hence the resistivity. Our choice of parameters tunes the near-boundary impurity current to be marginal, resulting in a $\log T$ behavior in the UV resistivity, as is expected for the Kondo problem. The resistivity at the IR fixed point turns out to be zero, signaling a complete screening of the impurity.