We study a gauged $B-L$ extension of the standard model where the new fermions with fractional $B-L$ charges that play the role of keeping the model anomaly free can also explain the origin of the neutrino mass at one loop level as well as dark matter. We discuss two different versions of the model to realize fermion and scalar dark matter, both of which guarantee the dark matter stability by a remnant discrete symmetry to which $U(1{)}_{B-L}$ gauge symmetry gets spontaneously broken down to. Apart from giving rise to the observed neutrino mass and dark matter abundance, the model also has tantalizing signatures at a variety of experiments operating at cosmic, intensity, and energy frontiers, particularly direct and indirect detection experiments of dark matter, rare decay experiments looking for charged lepton flavor violation as well as collider experiments. The model also predicts vanishing lightest neutrino mass that can be tested at experiments sensitive to the absolute neutrino mass scale.

We incorporate a clockwork mechanism into the standard model flavor sector and show that the observed pattern of fermion masses and mixing can be obtained without any unnaturally small or large parameter in the fundamental theory. By introducing $N_f$ pairs of vectorlike fermions, as clockwork gears, for each generation of the standard model fermions and setting up a characteristic clockwork potential, it is shown that the intergenerational mass hierarchies are determined by $N_f$. For a given type of fermions, strong or mild hierarchy in the masses and mixing parameters can be obtained by taking the large or small value of $N_f$. The mechanism is shown to lead to a generalized version of the Froggatt-Nielsen mechanism as an effective description.

We explore the intermediate dark matter mass regime of the inert Higgs doublet model, approximately between 400 and 550 GeV, which is allowed by latest constraints from direct and indirect detection experiments, but the thermal relic abundance remains suppressed. We extend the model by three copies of right-handed neutrinos, odd under the built-in $Z_2$ symmetry of the model. This discrete $Z_2$ symmetry of the model allows these right-handed neutrinos to couple to the usual lepton doublets through the inert Higgs doublet allowing the possibility of radiative neutrino mass in the scotogenic fashion. Apart from generating nonzero neutrino mass, such an extension can also revive the intermediate dark matter mass regime. The late decay of the lightest right-handed neutrino to dark matter makes it possible for the usual thermally underabundant dark matter in this intermediate mass regime to satisfy the correct relic abundance limit. The revival of this wide intermediate mass range can have relevance not only for direct and indirect search experiments but also for neutrino experiments as the long lifetime of the lightest right-handed neutrino also results in almost vanishing lightest neutrino mass.

Using a quark-diquark model of baryons and by working in the framework of perturbative quantum chromodynamics we present, for the first time, the next-to-leading-order (NLO) corrections to the fragmentation process of a heavy quark into a ground state triply heavy baryon. For a complete analysis, we also study the effect of nonperturbative dynamic of baryon bound state on the extracted fragmentation functions considering a typical wave function which is different from the Dirac-delta function that was applied in all previous works. Our results show that the NLO corrections are significant, while the effect of the baryonic wave function is of minor importance.

The mass and the lifetime of a gluon are evaluated from first principles at a finite temperature across the deconfinement transition of pure SU(3) Yang-Mills theory, by a direct calculation of the pole of the propagator in the complex plane, using the finite temperature extension of a massive expansion in the Landau gauge. Even at $T=0$, the quasigluon lifetime is finite, and the gluon is canceled from the asymptotic states, yielding a microscopic proof of confinement from first principles. Above the transition, the damping rate is a linear increasing function of temperature as predicted by standard perturbation theory.

The entanglement entropy (EE) of gauge theories in three spacetime dimensions is analyzed using manifestly gauge-invariant variables defined directly in the continuum. Specifically, we focus on the Maxwell, Maxwell-Chern-Simons (MCS), and non-Abelian Yang-Mills theories. Special attention is paid to the analysis of edge modes and their contribution to EE. The contact term is derived without invoking the replica method and its physical origin is traced to the phase space volume measure for the edge modes. The topological contribution to the EE for the MCS case is calculated. For all the Abelian cases, the EE presented in this paper agrees with known results in the literature. The EE for the non-Abelian theory is computed in a gauge-invariant Gaussian approximation, which incorporates the dynamically generated mass gap. A formulation of the contact term for the non-Abelian case is also presented.

Using covariant methods, we construct and explore the Wetterich equation for a nonminimal coupling $F(\varphi )R$ of a quantized scalar field to the Ricci scalar of a prescribed curved space. This includes the often considered nonminimal coupling $\xi {\varphi }^{2}R$ as a special case. We consider the truncations without and with scale- and field-dependent wave-function renormalization in dimensions between four and two. Thereby the main emphasis is on analytic and numerical solutions of the fixed point equations and the behavior in the vicinity of the corresponding fixed points. We determine the nonminimal coupling in the symmetric and spontaneously broken phases with vanishing and nonvanishing average fields, respectively. Using functional perturbative renormalization group methods, we discuss the leading universal contributions to the RG flow below the upper critical dimension $d=4$.

The cosmic microwave background (CMB) temperature anisotropies exhibit a large-scale dipolar power asymmetry. To determine whether this is due to a real, physical modulation or is simply a large statistical fluctuation requires the measurement of new modes. Here we forecast how well CMB polarization data from Planck and future experiments will be able to confirm or constrain physical models for modulation. Fitting several such models to the Planck temperature data allows us to provide predictions for polarization asymmetry. While for some models and parameters Planck polarization will decrease error bars on the modulation amplitude by only a small percentage, we show, importantly, that cosmic-variance-limited (and in some cases even Planck) polarization data can decrease the errors by considerably better than the expectation of $\sqrt{2}$ based on simple $\ell$-space arguments. We project that if the primordial fluctuations are truly modulated (with parameters as indicated by Planck temperature data) then Planck will be able to make a $2\sigma$ detection of the modulation model with 20%–75% probability, increasing to 45%–99% when cosmic-variance-limited polarization is considered. We stress that these results are quite model dependent. Cosmic variance in temperature is important: combining statistically isotropic polarization with temperature data will spuriously increase the significance of the temperature signal with 30% probability for Planck.

We compute the tensor and scalar spectral index $n_t$, $n_s$, the tensor-to-scalar ratio $r$, and the consistency relation $n_t/r$ in the general monomial multifield slow-roll inflation models with potentials $V\sim {\sum }_i{\lambda }_i{|{\varphi }_i|}^{p_i}$. The general models give a novel relation that $n_t$, $n_s$ and $n_t/r$ are all proportional to the logarithm of the number of fields $N_f$ when $N_f$ is getting extremely large with the order of magnitude around $\mathcal{O}({10}^{40})$. An upper bound $N_f\lesssim N_{*}{e}^{Z{N}_{*}}$ is given by requiring the slow variation parameter small enough where $N_{*}$ is the $e$-folding number and $Z$ is a function of distributions of ${\lambda }_i$ and $p_i$. Besides, $n_t/r$ differs from the single-field result $-1/8$ with substantial probability except for a few very special cases. Finally, we derive theoretical bounds $r>2/N_{*}$ ($r\gtrsim 0.03$) and for $n_t$, which can be tested by observation in the near future.

The evolution of the luminosity distance in a contracting universe is studied. It is shown that for quite a lot of natural dynamical evolutions, its behavior is far from trivial and its value can even decrease with an increasing time interval between events. The consequences are investigated and it is underlined that this could both put stringent consistency conditions on bouncing models and open a new observational window on “pre-big bang” physics using standard gravitational waves.

We perform three-dimensional simulations of structure formation in the early Universe, when boosting the primordial power spectrum on $\sim \mathrm{kpc}$ scales. We demonstrate that our simulations are capable of producing power-law profiles close to the steep $\rho \propto r^{-9/4}$ halo profiles that are commonly assumed to be a good approximation to ultracompact minihalos (UCMHs). However, we show that for more realistic initial conditions in which halos are neither perfectly symmetric nor isolated the steep power-law profile is disrupted, and we find that the Navarro-Frenk-White profile is a better fit to most halos. In the presence of background fluctuations, even extreme, nearly spherical initial conditions do not remain exceptional. Nonetheless, boosting the amplitude of initial fluctuations causes all structures to form earlier and thus at larger densities. With a sufficiently large amplitude of fluctuations, we find that values for the concentration of typical halos in our simulations can become very large. However, despite the signal coming from dark matter annihilation inside the cores of these halos being enhanced, it is still orders of magnitude smaller compared to the usually assumed UCMH profile. The upper bound on the primordial power spectrum from the nonobservation of UCMHs should therefore be reevaluated.

We describe in detail the analysis procedure used to derive the first limits from the Haloscope at Yale Sensitive to Axion CDM (HAYSTAC), a microwave cavity search for cold dark matter (CDM) axions with masses above $20\mu \mathrm{eV}$. We have introduced several significant innovations to the axion search analysis pioneered by the Axion Dark Matter eXperiment (ADMX), including optimal filtering of the individual power spectra that constitute the axion search data set and a consistent maximum likelihood procedure for combining and rebinning these spectra. These innovations enable us to obtain the axion-photon coupling $|g_{\gamma }|$ excluded at any desired confidence level directly from the statistics of the combined data.

In the framework of the one-boson-exchange model, we explore whether the intermediate- and short-range forces from $\sigma /\omega$ exchange can be strong enough to bind heavy molecular states. ${\mathrm{\Lambda }}_{c}D(\overline{D})$ and ${\mathrm{\Lambda }}_c{\mathrm{\Lambda }}_c({\overline{\mathrm{\Lambda }}}_c)$ systems have been studied and compared. We find that the force from $\sigma$ exchange is attractive and dominant, whereas the $\omega$-exchange force is not. As a consequence, the S-wave ${\mathrm{\Lambda }}_{c}D$, ${\mathrm{\Lambda }}_c{\mathrm{\Lambda }}_c$, and ${\mathrm{\Lambda }}_c{\overline{\mathrm{\Lambda }}}_c$ can be possible molecular candidates. We further indicate that a one hadron-hadron system with more light quarks $(u,d)$ can be easier to form than a bound state. As a by-product, by studying the heavy-quark mass dependence for the ${\mathrm{\Lambda }}_{c}D(\overline{D})$-like and ${\mathrm{\Lambda }}_c{\mathrm{\Lambda }}_c({\overline{\mathrm{\Lambda }}}_c)$-like systems, we find that the charm/bottom sector can easily accommodate molecular states. Finally, the ${\mathrm{\Lambda }}_{c}N(\overline{N})$ and ${\mathrm{\Lambda }}_{b}N(\overline{N})$ systems are investigated. Our results indicate that they are also likely to form bound states. By including one-$\pi$-exchange forces, providing additional attraction when coupled channels are included, we expect many molecular states in heavy-quark sectors.

In this paper we study ATLAS results on underlying event in $pp$ collisions at $\sqrt{s}=0.9$, 7 and 13 TeV. We show that the center-of-mass energy dependences of the charged-particle production sensitive to the underlying event (“transverse” region) and to the hardest partonic interaction (“towards” and “away” regions) in $pp$ collisions can be both understood in terms of the change of the inclusive average multiplicity. Within uncertainties, the corresponding particle production as a function of the leading charged particle shows no significant $\sqrt{s}$-dependence for the three regions once they are scaled according to the relative change in multiplicity. The scaling properties reported here are well reproduced by pythia 8.212 tune Monash 2013 and suggest an universality of the underlying event in hadronic interactions at high $\sqrt{s}$. Based on the simulations, we observed that the same scaling properties are also present in the average number of multipartonic interactions as a function of the leading charged particle. Moreover, the multiplicity distributions associated to the underlying event exhibit a Koba-Nielsen-Olesen scaling.

We study radiative neutrino pair emission in a deexcitation process of atoms taking into account the coherence effect in a macroscopic target system. In the course of preparing the coherent initial state to enhance the rate, a spatial phase factor is imprinted on the macroscopic target. It is shown that this initial spatial phase changes the kinematics of the radiative neutrino pair emission. We investigate effects of the initial spatial phase in the photon spectrum of the process. It turns out that the initial spatial phase provides us with significant improvements in exploring neutrino physics, such as the Dirac-Majorana distinction and the cosmic neutrino background.

Using a sample of $448.1\times {10}^6\psi (3686)$ events collected with the BESIII detector in 2009 and 2012, we study the decays ${\chi }_{c0,2}\to {\eta }^{\prime }{\eta }^{\prime }$ and $\eta {\eta }^{\prime }$. The decays ${\chi }_{c2}\to {\eta }^{\prime }{\eta }^{\prime }$, ${\chi }_{c0}\to \eta {\eta }^{\prime }$ and ${\chi }_{c2}\to \eta {\eta }^{\prime }$ are observed for the first time with statistical significances of $9.6\sigma$, $13.4\sigma$ and $7.5\sigma$, respectively. The branching fractions are determined to be $\mathcal{B}({\chi }_{c0}\to {\eta }^{\prime }{\eta }^{\prime })=(2.19\pm 0.03\pm 0.14)\times {10}^{-3}$, $\mathcal{B}({\chi }_{c2}\to {\eta }^{\prime }{\eta }^{\prime })=(4.76\pm 0.56\pm 0.38)\times {10}^{-5}$, $\mathcal{B}({\chi }_{c0}\to \eta {\eta }^{\prime })=(8.92\pm 0.84\pm 0.65)\times {10}^{-5}$ and $\mathcal{B}({\chi }_{c2}\to \eta {\eta }^{\prime })=(2.27\pm 0.43\pm 0.25)\times {10}^{-5}$, where the first uncertainties are statistical and the second are systematic. The precision for the measurement of $\mathcal{B}({\chi }_{c0}\to {\eta }^{\prime }{\eta }^{\prime })$ is significantly improved compared to previous measurements. Based on the measured branching fractions, the role played by the doubly and singly Okubo-Zweig-Iizuka disconnected transition amplitudes for ${\chi }_{c0,2}$ decays into pseudoscalar meson pairs can be clarified.

We investigate properties of self-gravitating isorotating Skyrmions in the generalized Einstein-Skyrme model with higher-derivative terms in the matter field sector. These stationary solutions are axially symmetric, regular, and asymptotically flat. We provide a detailed account of the branch structure of the spinning solutions in the topological sector of degree one. We show that additional branches of solutions appear, as the angular frequency increases above some critical value, these “cloudy” configurations can be considered as a bound system of the spinning Skyrmions and “pion” excitations in the topologically trivial sector. Considering the critical behavior of the isorotating solitons in the general Einstein-Skyrme model, we point out that there is no isospinning regular solutions in the reduced self-dual ${\mathcal{L}}_6+{\mathcal{L}}_0$ submodel for any nonzero value of the angular frequency.

Inspired by the interpretation of the cosmological constant from the boundary gauge theory, we here treat it as the number of colors $N$ and its conjugate quantity as the associated chemical potential $\mu$ in the black hole side. Then the thermodynamics and the chemical potential for a five-dimensional charged AdS black hole are studied. It is found that there exists a small-large black hole phase transition of van der Waals type. The critical phenomena are investigated in the $N^2\text{−}\mu$ chart. The result implies that the phase transition can occur for large number of colors $N$, while is forbidden for small number. This to some extent implies that the interaction of the system increases with the number. In particular, in the reduced parameter space, all the thermodynamic quantities can be rescaled with the black hole charge such that these reduced quantities are charge-independent. Then we obtain the coexistence curve and the phase diagram. The latent heat is also numerically calculated. Moreover, the heat capacity and the thermodynamic scalar are studied. The result indicates that the information of the first-order black hole phase transition is encoded in the heat capacity and scalar. However, the phase transition point cannot be directly calculated with them. Nevertheless, the critical point linked to a second-order phase transition can be determined by either the heat capacity or the scalar. In addition, we calculate the critical exponents of the heat capacity and the scalar for the saturated small and large black holes near the critical point.