Determining the neutrino mass hierarchy and measuring the $CP$-violating phase ${\delta }_{CP}$ are two of the main aims in neutrino physics today. The upcoming T2HK (with small matter effects and high statistics) and DUNE (with large matter effects) experiments have been shown to have excellent sensitivity to ${\delta }_{CP}$ and the neutrino mass hierarchy, respectively. The recent T2HKK proposal aims to improve the hierarchy sensitivity of T2HK by placing one of the two tanks of the HK detector at a site in Korea, to collect data at $\sim 1100\mathrm{km}$ baseline. In light of the fact that DUNE will anyway collect data at $\sim 1300\mathrm{km}$, we explore whether it is advantageous to collect additional long-baseline data as proposed with T2HKK, or to enhance the ${\delta }_{CP}$-precision with the “conventional” T2HK by keeping both detector tanks in Japan. We do this by comparing the physics reach of these two options in conjunction with DUNE. We find that $\mathrm{DUNE}+\mathrm{T}2\mathrm{HKK}$ is better at excluding the wrong hierarchy, reaching $\sqrt{\mathrm{\Delta }{\chi }^2}\gtrsim 13$ irrespective of the true parameters. While $\mathrm{DUNE}+\mathrm{T}2\mathrm{HK}$ can measure ${\delta }_{CP}$ with more precision in some parts of the parameter space, both $\mathrm{DUNE}+\mathrm{T}2\mathrm{HK}$ and $\mathrm{DUNE}+\mathrm{T}2\mathrm{HKK}$ perform equally well near the current best-fit point, giving a ${\delta }_{CP}$ uncertainty of around 15°. The T2HKK setup allows us to correlate and constrain the systematic errors between the two detectors collecting data from the same source, which can increase the sensitivity of the experiment by up to 25%. Such a reduction of the systematic errors is crucial for determining the oscillation parameters with greater significance.

We classify the meson and baryon long lived resonances that may exist if quarks with electric charge $5/3$ and $-4/3$ (in units of $|e|$) predicted by some 3-3-1 models do exist. Some of these exotic resonances have the usual electric charges or $\pm (3,4,5)$, and the lightest ones decaying only into leptons plus known resonances. We propose another heavy $SU(3{)}_H$ global symmetry under which hadrons involving only exotic quarks can be constructed.

The main focus of this work is to test the ideas related to the oblique confinement in a theoretically controllable manner using the “deformed QCD” as a toy model. We explicitly show that the oblique confinement in the weakly coupled gauge theories emerges as a result of condensation of $N$ types of monopoles shifted by the phase $\exp (i\frac{\theta +2\pi m}{N})$ in Bloch type construction. It should be contrasted with the conventional and commonly accepted viewpoint that the confinement at $\theta \ne 0$ is due to the condensation of the electrically charged dyons which indeed normally emerge in the systems with $\theta \ne 0$ as a result of Witten’s effect. We explain the basic reason why the “dyon” mechanism does not materialize—it is because the Witten’s effect holds for a static magnetic monopole treated as an external source. It should be contrasted with our case when $N$-types of monopoles are not static, but rather the dynamical degrees of freedom which fluctuate and themselves determine the ground state of the system.

We use the method of QCD sum rules to study the $D$-wave charmed and bottom baryons of the $SU(3)$ flavor ${\mathbf{6}}_F$ and calculate their masses up to the order $\mathcal{O}(1/m_Q)$ with $m_Q$ the heavy-quark mass. Our results suggest that the ${\mathrm{\Xi }}_c(3123)$ can be well interpreted as a $D$-wave ${\mathrm{\Xi }}_c^{\prime }({\mathbf{6}}_F)$ state, and it probably has a partner state close to it. Our results also suggest that there may exist as many as four $D$-wave ${\mathrm{\Omega }}_c$ states in the energy region 3.3–3.5 GeV, and we propose to search for them in the future LHCb and BelleII experiments.

Results are presented from a search for production of Higgs boson pairs ($HH$) where one boson decays to a pair of $b$ quarks and the other to a $\tau$ lepton pair. This work is based on proton-proton collision data collected by the CMS experiment at $\sqrt{s}=8\mathrm{TeV}$, corresponding to an integrated luminosity of $18.3{\mathrm{fb}}^{-1}$. Resonant and nonresonant modes of $HH$ production have been probed and no significant excess relative to the background-only hypotheses has been found in either mode. Upper limits on cross sections of the two $HH$ production modes have been set. The results have been combined with previously published searches at $\sqrt{s}=8\mathrm{TeV}$, in decay modes to two photons and two $b$ quarks, as well as to four $b$ quarks, which also show no evidence for a signal. Limits from the combination have been set on resonant $HH$ production by an unknown particle $X$ in the mass range $m_X=300\mathrm{GeV}$ to $m_X=1000\mathrm{GeV}$. For resonant production of spin 0 (spin 2) particles, the observed 95% CL upper limit is 1.13 pb (1.09 pb) at $m_X=300\mathrm{GeV}$ and to 21 fb (18 fb) at $m_X=1000\mathrm{GeV}$. For nonresonant $HH$ production, a limit of 43 times the rate predicted by the standard model has been set.

The largest global symmetry that can be made local in the Standard $\mathrm{Model}+3{\nu }_R$ while being compatible with Pati-Salam unification is $SU(3{)}_H\times U(1{)}_{B-L}$. The gauge bosons of this theory would induce flavor effects involving both quarks and leptons, and are a potential candidate to explain the recent reports of lepton universality violation in rare $B$-meson decays. In this paper we characterize these types of models and show how they can accommodate the data and naturally be within reach of direct searches.

Numerical evidence is presented that the Poisson-Israel mass inflation instability at the inner horizon of an accreting, rotating black hole is generically followed by Belinskii-Khalatnikov-Lifshitz oscillatory collapse to a spacelike singularity. The computation involves following all 6 degrees of freedom of the gravitational field. To simplify the problem, the computation takes as initial conditions the conformally separable solutions of Andrew J. S. Hamilton and Gavin Polhemus [Interior structure of rotating black holes. I. Concise derivation, Phys. Rev. D 84, 124055 (2011)] and Andrew J. S. Hamilton [Interior structure of rotating black holes. II. Uncharged black holes, Phys. Rev. D 84, 124056 (2011)] just above the inner horizon of a slowly accreting, rotating black hole and integrates the equations inward along single latitudes.

We study the structure of relativistic stars in $\mathcal{R}+\alpha {\mathcal{R}}^2$ theory using the method of matched asymptotic expansion to handle the higher order derivatives in field equations arising from the higher order curvature term. We find solutions, parametrized by $\alpha$, for uniform density stars. We obtain the mass-radius relations and study the dependence of maximum mass on $\alpha$. We find that $M_{\max }$ is almost linearly proportional to $\alpha$. For each $\alpha$ the maximum mass configuration has the biggest compactness parameter ($\eta =GM/R{c}^2$), and we argue that the general relativistic stellar configuration corresponding to $\alpha =0$ is the least compact among these.

Gravitational waves encode invaluable information about the nature of the relatively unexplored extreme gravity regime, where the gravitational interaction is strong, nonlinear and highly dynamical. Recent gravitational wave observations by advanced LIGO have provided the first glimpses into this regime, allowing for the extraction of new inferences on different aspects of theoretical physics. For example, these detections provide constraints on the mass of the graviton, Lorentz violation in the gravitational sector, the existence of large extra dimensions, the temporal variability of Newton’s gravitational constant, and modified dispersion relations of gravitational waves. Many of these constraints, however, are not yet competitive with constraints obtained, for example, through Solar System observations or binary pulsar observations. In this paper, we study the degree to which theoretical physics inferences drawn from gravitational wave observations will strengthen with detections from future detectors. We consider future ground-based detectors, such as the LIGO-class expansions $\mathrm{A}+$, Voyager, Cosmic Explorer and the Einstein Telescope, as well as space-based detectors, such as various configurations of eLISA and the recently proposed LISA mission. We find that space-based detectors will place constraints on general relativity up to 12 orders of magnitude more stringently than current aLIGO bounds, but these space-based constraints are comparable to those obtained with the ground-based Cosmic Explorer or the Einstein Telescope ($\mathrm{A}+$ and Voyager only lead to modest improvements in constraints). We also generically find that improvements in the instrument sensitivity band at low frequencies lead to large improvements in certain classes of constraints, while sensitivity improvements at high frequencies lead to more modest gains. These results strengthen the case for the development of future detectors, while providing additional information that could be useful in future design decisions.

We construct regular configurations of the Einstein-Yang-Mills theory in various dimensions. The gauge field is of meron-type: it is proportional to a pure gauge (with a suitable parameter $\lambda$ determined by the field equations). The corresponding smooth gauge transformation cannot be deformed continuously to the identity. In the three-dimensional case we consider the inclusion of a Chern-Simons term into the analysis, allowing $\lambda$ to be different from its usual value of $1/2$. In four dimensions, the gravitating meron is a smooth Euclidean wormhole interpolating between different vacua of the theory. In five and higher dimensions smooth meron-like configurations can also be constructed by considering warped products of the three-sphere and lower-dimensional Einstein manifolds. In all cases merons (which on flat spaces would be singular) become regular due to the coupling with general relativity. This effect is named “gravitational catalysis of merons”.

The evolutions of the flat Friedmann-Lemaître-Robertson-Walker universe and its linear perturbations are studied systematically in the dressed metric approach of loop quantum cosmology. When it is dominated by the kinetic energy of the inflaton at the quantum bounce, the evolution of the background can be divided into three different phases prior to the preheating: bouncing, transition and slow-roll inflation. During the bouncing phase, the evolution is independent of not only the initial conditions, but also the inflationary potentials. In particular, the expansion factor can be well described by the same exact solution in all the cases considered. In contrast, in the potential-dominated case such a universality is lost. It is because of this universality that the linear perturbations are also independent of the inflationary models and obtained exactly. During the transition phase, the evolutions of the background and its linear perturbations are found explicitly, and then matched to the ones given in the other two phases. Hence, once the initial conditions are imposed, the linear scalar and tensor perturbations will be uniquely determined. Considering two different sets of initial conditions, one imposed during the contracting phase and the other at the bounce, we calculate the Bogoliubov coefficients and find that the two sets yield the same results and all lead to particle creations at the onset of the inflation. Due to the preinflationary dynamics, the scalar and tensor power spectra become scale dependent. By comparing our results with the Planck 2015 data, we find constraints on the total number of $e$-folds since the bounce, in order to be consistent with current observations.

We compute the 20 lowest frequency radial oscillation modes of strange stars admixed with condensed dark matter. We assume a self-interacting bosonic dark matter, and we model dark matter inside the star as a Bose-Einstein condensate. In this case the equation of state is a polytropic one with index $1+1/n=2$ and a constant $K$ that is computed in terms of the mass of the dark matter particle and the scattering length. Assuming a mass and a scattering length compatible with current observational bounds for self-interacting dark matter, we have integrated numerically first the Tolman-Oppenheimer-Volkoff equations for the hydrostatic equilibrium, and then the equations for the perturbations $\xi =\mathrm{\Delta }r/r$ and $\eta =\mathrm{\Delta }P/P$. For a compact object with certain mass and radius we have considered here three cases, namely no dark matter at all and two different dark matter scenarios. Our results show that (i) the separation between consecutive modes increases with the amount of dark matter, and (ii) the effect is more pronounced for higher order modes. These effects are relevant even for a strange star made of 5% dark matter.

The chiral corrections to the magnetic moments of the spin-$\frac{1}{2}$ doubly charmed baryons are systematically investigated up to next-to-next-to-leading order with heavy baryon chiral perturbation theory. The numerical results are calculated up to next-to-leading order: ${\mu }_{{\mathrm{\Xi }}_{cc}^{++}}=-0.25{\mu }_N$, ${\mu }_{{\mathrm{\Xi }}_{cc}^{+}}=0.85{\mu }_N$, ${\mu }_{{\mathrm{\Omega }}_{cc}^{+}}=0.78{\mu }_N$. We also calculate the magnetic moments of the other doubly heavy baryons, including the doubly bottom baryons ($bbq$) and the doubly heavy baryons containing a light quark, a charm quark, and a bottom quark ($\{bc\}q$ and $[bc]q$): ${\mu }_{{\mathrm{\Xi }}_{bb}^0}=-0.84{\mu }_N$, ${\mu }_{{\mathrm{\Xi }}_{bb}^{-}}=0.26{\mu }_N$, ${\mu }_{{\mathrm{\Omega }}_{bb}^{-}}=0.19{\mu }_N$, ${\mu }_{{\mathrm{\Xi }}_{\{bc\}q}^{+}}=-0.54{\mu }_N$, ${\mu }_{{\mathrm{\Xi }}_{\{bc\}q}^0}=0.56{\mu }_N$, ${\mu }_{{\mathrm{\Omega }}_{\{bc\}q}^0}=0.49{\mu }_N$, ${\mu }_{{\mathrm{\Xi }}_{[bc]q}^{+}}=0.69{\mu }_N$, ${\mu }_{{\mathrm{\Xi }}_{[bc]q}^0}=-0.59{\mu }_N$, ${\mu }_{{\mathrm{\Omega }}_{[bc]q}^0}=0.24{\mu }_N$.

The conservation of lepton flavor and total lepton number are no longer guaranteed in the Standard Model after the discovery of neutrino oscillations. The ${\mu }^{-}+N(A,Z)\to e^{+}+N(A,Z-2)$ conversion in a muonic atom is one of the most promising channels to investigate the lepton number violation processes, and measurement of the ${\mu }^{-}-e^{+}$ conversion is planned in future ${\mu }^{-}-e^{-}$ conversion experiments with a muonic atom in a muon-stopping target. This article discusses experimental strategies to maximize the sensitivity of the ${\mu }^{-}-e^{+}$ conversion experiment by introducing the new requirement of the mass relation of $M(A,Z-2)<M(A,Z-1)$, where $M(A,Z)$ is the mass of the muon-stopping target nucleus, to eliminate the backgrounds from radiative muon capture. The sensitivity of the ${\mu }^{-}-e^{+}$ conversion is expected to be improved by 4 orders of magnitude in forthcoming experiments using a proper target nucleus that satisfies the mass relation. The most promising isotopes found are ${}^{40}\mathrm{Ca}$ and ${}^{32}\mathrm{S}$.

We study an economical model of weakly interacting massive particle dark matter (DM) which has spin $3/2$ and interacts with the 125 GeV Higgs boson via effective scalar and pseudoscalar operators. We apply constraints on the model from the relic density data, LHC measurements of the Higgs boson, and direct and indirect searches for DM, taking into account the effective nature of the DM-Higgs couplings. We show that this DM is currently viable in most of the mass region from about 58 GeV to 2.3 TeV and will be probed more stringently by ongoing and upcoming experiments. Nevertheless, the presence of the DM-Higgs pseudoscalar coupling could make parts of the model parameter space elusive from future tests. We find that important aspects of this scenario are quite similar to those of its more popular spin-$1/2$ counterpart.

We propose to introduce general messenger-matter interactions in the deflected anomaly mediated supersymmetry (SUSY) breaking (AMSB) scenario to explain the $g_{\mu }-2$ anomaly. Scenarios with complete or incomplete grand unified theory (GUT) multiplet messengers are discussed, respectively. The introduction of incomplete GUT mulitiplets can be advantageous in various aspects. We found that the $g_{\mu }-2$ anomaly can be solved in both scenarios under current constraints including the gluino mass bounds, while the scenarios with incomplete GUT representation messengers are more favored by the $g_{\mu }-2$ data. We also found that the gluino is upper bounded by about 2.5 TeV (2.0 TeV) in scenario A and 3.0 TeV (2.7 TeV) in scenario B if the generalized deflected AMSB scenarios are used to fully account for the $g_{\mu }-2$ anomaly at $3\sigma$ ($2\sigma$) level. Such a gluino should be accessible in the future LHC searches. Dark matter (DM) constraints, including DM relic density and direct detection bounds, favor scenario B with incomplete GUT multiplets. Much of the allowed parameter space for scenario B could be covered by the future DM direct detection experiments.

We present first evidence for the Landau level structure of Dirac eigenmodes in full QCD for nonzero background magnetic fields, based on first principles lattice simulations using staggered quarks. Our approach involves the identification of the lowest Landau level modes in two dimensions, where topological arguments ensure a clear separation of these modes from energetically higher states, and an expansion of the full four-dimensional modes in the basis of these two-dimensional states. We evaluate various fermionic observables including the quark condensate and the spin polarization in this basis to find how much the lowest Landau level contributes to them. The results allow for a deeper insight into the dynamics of quarks and gluons in background magnetic fields and may be directly compared to low-energy models of QCD employing the lowest Landau level approximation.

Based on gauge-gravity duality, by using holographic entanglement entropy, we have done a phenomenological study to probe the confinement-deconfinement phase transition in the holographic model resembling quantum chromodynamics with two massless flavors and three colors. Our outcomes are in perfect agreement with the expected results, qualitatively and quantitatively. We find out that the (holographic) entanglement entropy is a reliable order parameter for probing the phase transition.

A notion of localization of information within quantum subsystems plays a key role in describing the physics of quantum systems, and in particular is a prerequisite for discussing important concepts such as entanglement and information transfer. While subsystems can be readily defined for finite quantum systems and in local quantum field theory, a corresponding definition for gravitational systems is significantly complicated by the apparent nonlocality arising due to gauge invariance, enforced by the constraints. A related question is whether “soft hair” encodes otherwise localized information, and the question of such localization also remains an important puzzle for proposals that gravity emerges from another structure such as a boundary field theory as in AdS/CFT. This paper describes different approaches to defining local subsystem structure, and shows that at least classically, perturbative gravity has localized subsystems based on a split structure, generalizing the split property of quantum field theory. This, and related arguments for QED, give simple explanations that in these theories there is localized information that is independent of fields outside a region, in particular so that there is no role for “soft hair” in encoding such information. Additional subtleties appear in quantum gravity. We argue that localized information exists in perturbative quantum gravity in the presence of global symmetries, but that nonperturbative dynamics is likely tied to a modification of such structure.

We show how masses for singlet fermions can be generated by interactions with a D-particle model of space-time foam inspired by brane theory. It has been shown previously by one of the authors (N. E. M.) that such interactions may generate dynamically small masses for charged fermions via the recoils of D-particle defects interacting with photons. In this work we consider the direct interactions of D-particle with uncharged singlet fermions such as right-handed neutrinos. Quantum fluctuations of the lattice of D-particles have massless vector (spin-one) excitations that are analogues of phonons. These mediate forces with the singlet fermions, generating large dynamical masses that may be communicated to light neutrinos via the seesaw mechanism.