Usually the effects of isotropic inhomogeneities are not seriously taken into account in the determination of the cosmological parameters because of the Copernican principle whose statement is that we do not live in the privileged domain in the Universe. But the Copernican principle has not been observationally confirmed yet in sufficient accuracy, and there is the possibility that there are non-negligible large-scale isotropic inhomogeneities in our Universe. In this paper, we study the effects of the isotropic inhomogeneities on the determination of the cosmological parameters and show the probability that non-Copernican isotropic inhomogeneities mislead us into believing, for example, the phantom energy of the equation of state, $p=w\rho$ with $w<-1$, even in the case that $w=-1$ is the true value.

We extend our previous work on mapping gravitational-wave backgrounds using techniques borrowed from the analysis of cosmic microwave background data to backgrounds which have non-general-relativity (non-GR) polarisations. Our analysis and results are presented in the context of pulsar timing array observations, but the overarching methods are general, and can be easily applied to LIGO or eLISA observations using appropriately modified response functions. Analytic expressions for the pulsar timing response to gravitational waves with non-GR polarisation are given for each mode of a spin-weighted spherical-harmonic decomposition of the background, which permit the signal to be mapped across the sky to any desired resolution. We also derive the pulsar timing overlap reduction functions for the various non-GR polarisations, finding analytic forms for anisotropic backgrounds with scalar-transverse (“breathing”) and vector-longitudinal polarisations, and a semianalytic form for scalar-longitudinal backgrounds. Our results indicate that pulsar timing observations will be completely insensitive to scalar-transverse mode anisotropies in the polarisation amplitude beyond dipole, and anisotropies in the power beyond quadrupole. Analogous to our previous findings that pulsar timing observations lack sensitivity to tensor-curl modes for a transverse-traceless tensor background, we also find insensitivity to vector-curl modes for a vector-longitudinal background.

Based on SU(3) flavor symmetry, we decompose the decay amplitudes of bottom baryon decays to a pseudoscalar meson and an octet (a decuplet) pentaquark in terms of three (two) invariant amplitudes $T_1$ and $T_{2,3}$ (${\tilde{T}}_1$ and ${\tilde{T}}_2$) corresponding to external $W$-emission and internal $W$-emission diagrams, respectively. For antitriplet bottom baryons ${\mathrm{\Lambda }}_b^0$, ${\mathrm{\Xi }}_b^0$, and ${\mathrm{\Xi }}_b^{-}$, their decays to a decuplet pentaquark proceed only through the internal $W$-emission diagram. Assuming the dominance from the external $W$-emission amplitudes, we present an estimate of the decay rates relative to ${\mathrm{\Lambda }}_b^0\to P_p^{+}{K}^{-}$, where $P_p^{+}$ is the hidden-charm pentaquark with the same light-quark content as the proton. Hence, our numerical results will provide a very useful guideline to the experimental search for pentaquarks in bottom baryon decays. For example, ${\mathrm{\Xi }}_b^0\to P_{{\mathrm{\Sigma }}^{+}}{K}^{-}$, ${\mathrm{\Xi }}_b^{-}\to P_{{\mathrm{\Sigma }}^{-}}{\overline{K}}^0$, ${\mathrm{\Omega }}_b^{-}\to P_{{\mathrm{\Xi }}^{-}}{\overline{K}}^0$, and ${\mathrm{\Omega }}_b^{-}\to P_{{\mathrm{\Xi }}^0}{K}^{-}$ may have rates comparable to that of ${\mathrm{\Lambda }}_b^0\to P_p^{+}{K}^{-}$ and these modes should be given the higher priority in the experimental searches for pentaquarks.

The ATLAS collaboration reported excesses at around 2 TeV in the diboson production decaying into hadronic final states. We consider the possibility of explaining the excesses with extra gauge bosons in two simple non-Abelian extensions of the standard model. One is the so-called $G(221)$ models with a symmetry structure of $SU(2{)}_1\otimes SU(2{)}_2\otimes U(1{)}_X$ and the other is the $G(331)$ models with an extended symmetry of $SU(3{)}_C\otimes SU(3{)}_L\otimes U(1{)}_X$. The $W^{\prime }$ and $Z^{\prime }$ bosons emerge after the electroweak symmetry is spontaneously broken. Two patterns of symmetry breaking in the $G(221)$ models are considered in this work: one is $SU(2{)}_L\otimes SU(2{)}_2\otimes U(1{)}_X\to SU(2{)}_L\otimes U(1{)}_Y$, the other is $SU(2{)}_1\otimes SU(2{)}_2\otimes U(1{)}_Y\to SU(2{)}_L\otimes U(1{)}_Y$. The symmetry breaking of the $G(331)$ model is $SU(3{)}_L\otimes U(1{)}_X\to SU(2{)}_L\otimes U(1{)}_Y$. We perform a global analysis of $W^{\prime }$ and $Z^{\prime }$ phenomenology in ten new physics models, including all the channels of $W^{\prime }/Z^{\prime }$ decay. Our study shows that the leptonic mode and the dijet mode of $W^{\prime }/Z^{\prime }$ decays impose a very stringent bound on the parameter space in several new physics models. Such tight bounds provide a useful guide for building new physics models to address on the diboson anomalies. We also note that the left-right and leptophobic models can explain the $3.4\sigma WZ$ excess if the $2.6\sigma$ deviation in the $W^{+}{W}^{-}$ pair around 2 TeV were confirmed to be a fluctuation of the SM backgrounds.

The proton radius puzzle, the discrepancy between the proton radius measured in muonic hydrogen and electronic hydrogen, has yet to be resolved. There are suggestions that beyond-the-standard-model physics could resolve both this puzzle and the muon anomalous magnetic moment discrepancy. Karshenboim et al. point out that simple, nonrenormalizable, models in this direction involving new vector bosons have serious problems when confronting high energy data. The prime example is radiative corrections to $W\to \mu \nu$ decay which exceed experimental bounds. We show how embedding the model in a larger and arguably renormalizable theory restores gauge invariance of the vector particle interactions and controls the high energy behavior of decay and scattering amplitudes. Thus, beyond-the-standard-model explanations of the proton radius puzzle can still be viable.

The ATLAS experiment has recently observed a $3\sigma$ excess in a channel with a leptonically decaying $Z$, jets, and $E_T^{\text{miss}}$. It is tantalizing to interpret the signal as the first sign of a natural supersymmetric spectrum. We study such a possibility in a minimal model containing light stops and a neutralino lightest supersymmetric particle. The signal is characterized by a novel topology (compared to previous attempts) where the $Z$ is emitted from a colored particle in the first step of a decay chain, namely ${\tilde{t}}_2\to {\tilde{t}}_{1}Z$, which is characteristic of mixed stops. We show that the excess is compatible with a compressed stop spectrum and is not excluded by any other relevant search, finding some regions of parameter space with signal strength within $1\sigma$ of that measured by the ATLAS Collaboration. In addition, we notice that the corresponding CMS search could be prone to background contamination in unexpected topologies of this kind.

Light stops consistent with the Higgs boson mass of $\sim 126\mathrm{GeV}$ are investigated within the framework of minimal supergravity. It is shown that models with light stops which are also consistent with the thermal relic density constraints require stop coannihilation with the neutralino LSP. The analysis shows that the residual set of parameter points with light stops satisfying both the Higgs mass and the relic density constraints lie within a series of thin strips in the $m_0-m_{1/2}$ plane for different values of $A_0/m_0$. Consequently, this region of minimal supergravity parameter space makes a number of very precise predictions. It is found that light stops of mass down to 400 GeV or lower can exist consistent with all constraints. A signal analysis for this class of models at LHC run II is carried out and the dominant signals for their detection identified. Also computed is the minimum integrated luminosity for $5\sigma$ discovery of the models analyzed. If supersymmetry is realized in this manner, the stop masses can be as low as 400 GeV or lower, and the mass gap between the lightest neutralino and lightest stop will be approximately 30–40 GeV. We have optimized the ATLAS signal regions specifically for stop searches in the parameter space and find that a stop with mass $\sim 375\mathrm{GeV}$ can be discovered with as little as $\sim 60{\mathrm{fb}}^{-1}$ of integrated luminosity at run II of the LHC; the integrated luminosity needed for discovery could be further reduced with more efficient signature analyses. The direct detection of dark matter in this class of models is also discussed. It is found that dark matter cross sections lie close to, but above, coherent neutrino scattering and would require multiton detectors such as LZ to see a signal of dark matter for this class of models.

We use the gradient flow for the renormalization of the Polyakov loop in various representations. Using $2+1$ flavor QCD with highly improved staggered quarks and lattices with temporal extents of $N_{\tau }=6$, 8, 10 and 12 we calculate the renormalized Polyakov loop in many representations including fundamental, sextet, adjoint, decuplet, 15-plet, 24-plet and 27-plet. This approach allows for the calculations of the renormalized Polyakov loops over a large temperature range from $T=116\mathrm{MeV}$ up to $T=815\mathrm{MeV}$, with small errors not only for the Polyakov loop in fundamental representation, but also for the Polyakov loops in higher representations. We compare our results with standard renormalization schemes and discuss the Casimir scaling of the Polyakov loops.

We study the cross section for the photoproduction process $\gamma N\to hX$ where the incident photon and nucleon are longitudinally polarized and a hadron $h$ is observed at high transverse momentum. Specifically, we address the “direct” part of the cross section, for which the photon interacts in a pointlike way. For this contribution we perform an all-order resummation of logarithmic threshold corrections generated by soft or collinear gluon emission to next-to-leading logarithmic accuracy. We present phenomenological results relevant for the COMPASS experiment and compare to recent COMPASS data.

We compute the next-to-leading-order QCD corrections to the production of two $Z$-bosons in the annihilation of two gluons at the LHC. Being enhanced by a large gluon flux, these corrections provide a distinct and, potentially, the dominant part of the ${\mathrm{N}}^3\mathrm{LO}$ QCD contributions to $Z$-pair production in proton collisions. The $gg\to ZZ$ annihilation is a loop-induced process that receives the dominant contribution from loops of five light quarks, that are included in our computation in the massless approximation. We find that QCD corrections increase the $gg\to ZZ$ production cross section by $\mathcal{O}(50\%–100\%)$ depending on the values of the renormalization and factorization scales used in the leading-order computation and the collider energy. The large corrections to the $gg\to ZZ$ channel increase the $pp\to ZZ$ cross section by about 6% to 8%, exceeding the estimated theoretical uncertainty of the recent next-to-next-to-leading-order QCD calculation.

The baryon Dirac form factor is computed at one-loop order in large-$N_c$ baryon chiral perturbation theory, where $N_c$ is the number of color charges. Loop graphs with octet and decuplet intermediate states are systematically incorporated into the analysis and the effects of the decuplet-octet mass difference are accounted for. There are large-$N_c$ cancellations between different one-loop graphs as a consequence of the large-$N_c$ spin-flavor symmetry of QCD baryons. As a byproduct, the mean-square charge radius is also computed through a detailed numerical analysis. The predictions of large-$N_c$ baryon chiral perturbation theory are in very good agreement both with the expectations from the $1/N_c$ expansion and with the experimental data.

We study the mixing of the Dirac neutrinos in the residual symmetries approach. The key difference from the Majorana case is that the Dirac mass matrix may have larger symmetries: $G_{\nu }={\mathbf{Z}}_n$ with $n\ge 3$. The symmetry group relations have been generalized to the case of Dirac neutrinos. Using them, we have found all new relations between mixing parameters and corresponding symmetry assignments, which are in agreement with the present data. The viable relations exist only for the charged lepton residual symmetry $G_{\ell }={\mathbf{Z}}_2$. The relations involve elements of the rows of the Pontecorvo-Maki-Nakagawa-Sakata matrix and lead to precise predictions of the 2–3 mixing angle and certain ranges of the $CP$ violation phase. For larger symmetries $G_{\ell }$, an agreement with the data can be achieved if $\sim 10\%$ corrections related to breaking of $G_{\ell }$ and $G_{\nu }$ are included.

“KPipe” is a proposed experiment which will study muon neutrino disappearance for a sensitive test of the $\mathrm{\Delta }{m}^2\sim 1{\mathrm{eV}}^2$ anomalies, possibly indicative of one or more sterile neutrinos. The experiment is to be located at the J-PARC Materials and Life Science Experimental Facility’s spallation neutron source, which represents the world’s most intense source of charged kaon decay-at-rest monoenergetic (236 MeV) muon neutrinos. The detector vessel, designed to measure the charged-current interactions of these neutrinos, will be 3 m in diameter and 120 m long, extending radially at a distance of 32 to 152 m from the source. This design allows a sensitive search for ${\nu }_{\mu }$ disappearance associated with currently favored light sterile neutrino models and features the ability to reconstruct the neutrino oscillation wave within a single, extended detector. The required detector design, technology, and costs are modest. The KPipe measurements will be robust since they depend on a known energy neutrino source with low expected backgrounds. Further, since the measurements rely only on the measured rate of detected events as a function of distance, with no required knowledge of the initial flux and neutrino interaction cross section, the results will be largely free of systematic errors. The experimental sensitivity to oscillations, based on a shape-only analysis of the $L/E$ distribution, will extend an order of magnitude beyond present experimental limits in the relevant high-$\mathrm{\Delta }{m}^2$ parameter space.

We study charged particle production (${\mathrm{p}}_T>0.5\mathrm{GeV}/\mathrm{c}$, $|\eta |<0.8$) in proton-antiproton collisions at total center-of-mass energies $\sqrt{s}=300\mathrm{GeV}$, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of $\eta -\varphi$ space: “toward”, “away”, and “transverse.” The average number and the average scalar ${\mathrm{p}}_T$ sum of charged particles in the transverse region are sensitive to the modeling of the “underlying event.” The transverse region is divided into a MAX and MIN transverse region, which helps separate the “hard component” (initial and final-state radiation) from the “beam-beam remnant” and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event is studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.

Charged pion production via charged-current ${\nu }_{\mu }$ interactions on plastic scintillator (CH) is studied using the MINERvA detector exposed to the NuMI wideband neutrino beam at Fermilab. Events with hadronic invariant mass $W<1.4\mathrm{GeV}$ and $W<1.8\mathrm{GeV}$ are selected in separate analyses: the lower $W$ cut isolates single pion production, which is expected to occur primarily through the $\mathrm{\Delta }(1232)$ resonance, while results from the higher cut include the effects of higher resonances. Cross sections as functions of pion angle and kinetic energy are compared to predictions from theoretical calculations and generator-based models for neutrinos ranging in energy from 1.5–10 GeV. The data are best described by calculations which include significant contributions from pion intranuclear rescattering. These measurements constrain the primary interaction rate and the role of final state interactions in pion production, both of which need to be well understood by neutrino oscillation experiments.

General string-theoretic considerations suggest that four-dimensional large-$N$ gauge theories should have dual descriptions in terms of two-dimensional conformal field theories. However, for nonsupersymmetric confining theories such as pure Yang-Mills theory, a long-standing challenge has been to explicitly show that any such dual descriptions actually exist. In this paper, we consider the large-$N$ limit of four-dimensional pure Yang-Mills theory compactified on a three-sphere in the solvable limit where the sphere radius is small compared to the strong length scale, and demonstrate that the confined-phase spectrum of this gauge theory coincides with the spectrum of an irrational two-dimensional conformal field theory.

We perform a phenomenological study of the scalar sector of two models that generate neutrino mass at the three-loop level and contain viable dark matter candidates. Both models contain a charged singlet scalar and a larger scalar multiplet (triplet or quintuplet). We investigate the effect of the extra scalars on the Higgs mass and analyze the modifications to the triple Higgs coupling. The new scalars can give observable changes to the Higgs decay channel $h\to \gamma \gamma$ and, furthermore, we find that the electroweak phase transition becomes strongly first order in large regions of parameter space.

We make use of a unitarized coupled-channel model to analyze the mass distribution data of final states in production processes of $X(4260)$. By analyzing the analytical structures of the decay amplitudes, we find that the line shape of the $Z_c(3900)$ signal is related to the combined effect of a pair of near-threshold “shadow” poles and the $(D{\overline{D}}^{*}{)}^{\pm }$ thresholds, in which the third-sheet pole might provide a dominant contribution. As all the coupled channels effects are tuning off, the trajectories of these two poles suggest that the $Z_c(3900)$ might originate from the attractive interaction of $(D^{*}{\overline{D}}^{*}{)}^{\pm }$ through a long-distance interaction, e.g., $\pi$-exchange interaction, as a “deuteron-like” state. There is no nearby pole structure corresponding to the $Z_c(4025)$ signal in the $(D^{*}{\overline{D}}^{*}{)}^{\pm }$ mass distribution.