We analyze the response of the gravitational wave detector to a scalar massive plane gravitational wave. We give the compact form of the response and discuss its angular and frequency characteristics. The derivations are carried out in the conformal and the synchronous gauges, and the equivalence of the two approaches is shown. In a particular example of the massive Brans–Dicke theory, we show as well the equivalence of the two gauges on the level of the solution of the linearized field equation.

Solitons are very effective in transporting energy over great distances and collisions between them can produce high energy density spots of relevance to phase transformations, energy localization and defect formation among others. It is then important to study how energy density accumulation scales in multisoliton collisions. In this study, we demonstrate that the maximal energy density that can be achieved in collision of $N$ slowly moving kinks and antikinks in the integrable sine-Gordon field, remarkably, is proportional to $N^2$, while the total energy of the system is proportional to $N$. This maximal energy density can be achieved only if the difference between the number of colliding kinks and antikinks is minimal, i.e., is equal to 0 for even $N$ and 1 for odd $N$ and if the pattern involves an alternating array of kinks and antikinks. Interestingly, for odd (even) $N$ the maximal energy density appears in the form of potential (kinetic) energy, while kinetic (potential) energy is equal to zero. The results of the present study rely on the analysis of the exact multisoliton solutions for $N=1,2$, and 3 and on the numerical simulation results for $N=4,5,6$, and 7. The effect of weak Hamiltonian and non-Hamiltonian perturbations on the maximal energy density in multikink collisions is also discussed as well as that of the collision relative phase. Based on these results one can speculate that the soliton collisions in the sine-Gordon field can, in principle, controllably produce very high energy density. This can have important consequences for many physical phenomena described by the Klein-Gordon equations.

The first measurement on the antiproton to proton ratio by the AMS-02 collaboration agrees with the expectation from conventional cosmic-ray secondaries in the kinetic energy range $\sim 20–100\mathrm{GeV}$, which can be turned into stringent upper limits on the annihilation cross sections of dark matter (DM) above $\sim 300\mathrm{GeV}$. Using the GALPROP code, we derive the upper limits in various propagation models and DM profiles. We show that in the “conventional” propagation model, for the $q\overline{q}$, $b\overline{b}$, and $W^{+}{W}^{-}$ final states, the constraints could be more stringent than that derived from the recent Ferm-LAT gamma-ray data on the dwarf spheroidal satellite galaxies. Making use of the typical minimal, median, and maximal models obtained from a previous GALPROP-based global fit to the preliminary AMS-02 data, we show that the variation of the upper limits is about a factor of five. The possibility of DM contributions to the low and very high energy $\overline{p}/p$ data is discussed.

We argue that the gauge symmetry which includes $SU(3{)}_L$ as a higher weak-isospin symmetry is manifestly given by $SU(3{)}_C\otimes SU(3{)}_L\otimes U(1{)}_X\otimes U(1{)}_N$, where the last two factors determine the electric charge and $B-L$, respectively. This theory not only provides a consistent unification of the electroweak and $B-L$ interactions, but also gives insights in dark matter, neutrino masses, and inflation. The dark matter belongs to a class of new particles that have wrong $B-L$ numbers, and is stabilized due to a newly realized $W$-parity as residual gauge symmetry. The $B-L$ breaking field is important to define the $W$-parity, seesaw scales, and the inflaton. Furthermore, the number of fermion generations and the electric charge quantization are explained naturally. We also show that the previous 3-3-1 models are only an effective theory, as the $B-L$ charge and the unitarity argument are violated. This work substantially generalizes our recently proposed 3-3-1-1 model.

We present a study of the B spectrum performed in the framework of heavy quark effective theory expanded to next-to-leading order in $1/m_{\mathrm{b}}$ and nonperturbative in the strong coupling. Our analyses have been performed on $N_{\mathrm{f}}=2$ lattice gauge field ensembles corresponding to three different lattice spacings and a wide range of pion masses. We obtain the ${\mathrm{B}}_{\mathrm{s}}$-meson mass and hyperfine splittings of the B- and ${\mathrm{B}}_{\mathrm{s}}$-mesons that are in good agreement with the experimental values and examine the mass difference $m_{{\mathrm{B}}_{\mathrm{s}}}-m_{\mathrm{B}}$ as a further cross-check of our previous estimate of the b-quark mass. We also report on the mass splitting between the first excited state and the ground state in the B and ${\mathrm{B}}_{\mathrm{s}}$ systems.

QCD with 2 flavors of massless color-sextet quarks is studied as a possible walking-Technicolor candidate. We simulate the lattice version of this model at finite temperatures near to the chiral-symmetry restoration transition, to determine whether it is indeed a walking theory (QCD-like with a running coupling which evolves slowly over an appreciable range of length scales) or if it has an infrared fixed point, making it a conformal field theory. The lattice spacing at this transition is decreased towards zero by increasing the number $N_t$ of lattice sites in the temporal direction. Our simulations are performed at $N_t=4,6,8,12$, on lattices with spatial extent much larger than the temporal extent. A range of small fermion masses is chosen to make predictions for the chiral (zero mass) limit. We find that the bare lattice coupling does decrease as the lattice spacing is decreased. However, it decreases more slowly than would be predicted by asymptotic freedom. We discuss whether this means that the coupling is approaching a finite value as lattice $N_t$ is increased—the conformal option, or if the apparent disagreement with the scaling predicted by asymptotic freedom is because the lattice coupling is a poor expansion parameter, and the theory walks. Currently, evidence favors QCD with 2 color-sextet quarks being a conformal field theory. Other potential sources of disagreement with the walking hypothesis are also discussed. We also report an estimate of the position of the deconfinement transition for $N_t=12$, needed for choosing parameters for zero-temperature simulations.

In this paper, low-energy scattering of the $(D^{*}{\overline{D}}^{*}{)}^{\pm }$ meson system is studied within Lüscher’s finite-size formalism using $N_f=2$ twisted-mass gauge field configurations. With three different pion mass values, the $s$-wave threshold scattering parameters—namely the scattering length $a_0$ and the effective range $r_0$—are extracted in the $J^{PC}=1^{+-}$ channel. Our results indicate that, in this particular channel, the interaction between the two vector charmed mesons is weakly repulsive in nature and hence it does not support the possibility of a shallow bound state for the two mesons, at least for the pion mass values being studied. However, these results might suffer from undetermined systematic errors due to low-lying states ignored in this exploratory study. Still, it provides some useful information on the nature of the newly discovered resonance-like structure $Z_c(4025)$ observed in various experiments.

We present and test a new method to compute the hadronic vacuum polarization function in lattice simulations. This can then be used, e.g., to determine the leading hadronic contribution to the anomalous magnetic moment of the muon. The method is based on computing susceptibilities with respect to external electromagnetic plane wave fields and allows for a precision determination of both the connected and the disconnected contributions to the vacuum polarization. We demonstrate that the statistical errors obtained with our method are much smaller than those quoted in previous lattice studies, primarily due to a very effective suppression of the errors of the disconnected terms. These turn out to vanish within small errors, enabling us to quote an upper limit. We also comment on the accuracy of the vacuum polarization function determined from present experimental $R$-ratio data.

We derive the pion mass and the elastic pion-pion scattering amplitude in the QCD $\theta$-vacuum up to next-to-leading order in chiral perturbation theory. Using the modified inverse amplitude method, we study the $\theta$-dependence of the mass and width of the light scalar meson $\sigma (500)$ and the vector meson $\rho (770)$.

We propose a new technique that enables an event-by-event selection of neutrino-hydrogen interactions in multinuclear targets and thereby allows application of hydrogen as targets in experiments with neutrino beams without involving cryogenics or high pressure hydrogen gas. This technique could significantly improve the reconstruction of the neutrino energy spectra. Since it allows a separation between hydrogen and the accompanying nuclei, this technique also enables us to measure nuclear effects in neutrino interactions directly.

We investigate the thermodynamic properties of a novel class of gauge-Yukawa theories that have recently been shown to be completely asymptotically safe, because their short-distance behavior is determined by the presence of an interacting fixed point. Not only do all the coupling constants freeze at a constant and calculable value in the ultraviolet, their values can even be made arbitrarily small for an appropriate choice of the ratio $N_c/N_f$ of fermion colors and flavors in the Veneziano limit. Thus, a perturbative treatment can be justified. We compute the pressure, entropy density, and thermal degrees of freedom of these theories to next-to-next-to-leading order in the coupling constants.

The nonextremal stationary black holes do have “hidden” conformal symmetry in which case the generators form the $SL(2,\mathbb{R})$ group. Here, I explicitly show that the Sultana-Dyer black hole solution also possesses the similar near horizon conformal symmetry. This is the first example of a time dependent case which also exhibits such a feature. Moreover, using the corresponding generators I find the expression of the horizon entropy in the context of Virasoro algebra and the Cardy formula. The result matches with the earlier findings. The present analysis is important since, in reality, the metric is not stationary and, hence, one must look into these realistic situations to obtain more information about our Universe. I expect that the analysis will illuminate certain features of the time dependent situations.

It is known that after Affleck-Dine baryogenesis, spatial inhomogeneities of Affleck-Dine field grow into nontopological solitons called Q-balls. In gauge mediated supersymmetry (SUSY) breaking models, sufficiently large Q-balls with baryon charge are stable while Q-balls with lepton charge can always decay into leptons. For a Q-ball that carries nonzero $B$ and $L$ charges, the difference between the baryonic component and the leptonic component in decay rate may induce nonzero electric charge on the Q-ball. This implies that a charged Q-ball, also called gauged Q-ball, may emerge in our universe. In this paper, we investigate two complex scalar fields, a baryonic scalar field and a leptonic one, in an Abelian gauge theory. We find stable solutions of gauged Q-balls for different baryon and lepton charges. Those solutions show that a Coulomb potential arises and the Q-ball becomes electrically charged as expected. It is energetically favored that some amount of leptonic component decays, but there is an upper bound on its amount due to the Coulomb force. The baryonic decay also becomes possible by virtue of electrical repulsion, but we find that the evolution itself stops before it occurs mainly due to the Schwinger limit, so that the charged Q-balls eventually survive in the universe.

We present a mirror model moving in the quantum vacuum of a massive scalar field and study its motion under infinitely fluctuating quantum vacuum stress. The model is similar to the one in [Q. Wang and W. G. Unruh, Motion of a mirror under infinitely fluctuating quantum vacuum stress Phys. Rev. D 89, 085009 (2014).], but this time there is no divergent effective mass to weaken the effect of divergent vacuum energy density. We show that this kind of weakening is not necessary. The vacuum friction and strong anticorrelation property of the quantum vacuum are enough to confine the mirror’s position fluctuations. This is another example illustrating that while the actual value of the vacuum energy can be physically significant even for a nongravitational system, and that its infinite value makes sense, but that its physical effect can be small despite this infinity.

Three relativistic particles in addition to the photon are detected in the cosmic microwave background (CMB). In the standard model of cosmology, these are interpreted as the three neutrino species. However, at the time of CMB decoupling, neutrinos are not only relativistic but they are also free-streaming. Here we investigate whether the CMB is sensitive to this defining feature of neutrinos, or whether the CMB data allow us to replace neutrinos with a relativistic fluid. We show that free-streaming particles are preferred over a relativistic perfect fluid with $\mathrm{\Delta }{\chi }^2\simeq 21$. We then study the possibility to replace the neutrinos by a viscous fluid and find that also a relativistic viscous fluid with either the standard values $c_{\mathrm{eff}}^2=c_{\mathrm{vis}}^2=1/3$ or best-fit values for $c_{\mathrm{eff}}^2$ and $c_{\mathrm{vis}}^2$ has $\mathrm{\Delta }{\chi }^2\simeq 20$ and thus cannot provide a good fit to present CMB data either.

We study the interplay of natural supersymmetry and a supersymmetric solution to the discrepancy observed in measurements of the muon magnetic moment. The strongest constraints on the parameter space currently come from chargino searches in the trilepton channel and slepton searches in the dilepton channel at the LHC, and vast regions are currently allowed, especially at large $\tan \beta$. With light top squarks in the spectrum, as required from naturalness arguments, the situation changes dramatically; stop-assisted chargino and neutralino production via $\tilde{t}\to b{\tilde{\chi }}_1^{\pm }$ and $\tilde{t}\to t{\tilde{\chi }}_1^0$ are already probing the entire parameter space compatible with the muon magnetic moment at $\tan \beta \sim \mathcal{O}(10)$, while upcoming stop searches will probe most of the parameter space at larger $\tan \beta \sim 40$. Direct Higgsino searches as well as compressed slepton and stop searches are crucial to close out corners of parameter space. We consider one such example: in the presence of light sleptons and charginos as required to obtain appreciable contributions to the muon magnetic moment, compressed stops can dominantly undergo the following decay $\tilde{t}\to b\tilde{\ell }\nu (\tilde{\nu }\ell )\to b\ell \nu {\tilde{\chi }}_1^0$, facilitated by off-shell charginos. We find that the enhanced branching to leptons leads to a $5\sigma$ mass reach (with $3000{\mathrm{fb}}^{-1}$ of data at LHC14) of $m_{\tilde{t}}\sim 350\mathrm{GeV}$, with the mass difference between stops and the lightest neutralino being $\sim 80\mathrm{GeV}$. This will further close out a significant part of the parameter space compatible with naturalness and the muon magnetic moment.

Complete expressions of the $\overline{s}bg$ and $\overline{s}b\gamma$ vertices are derived in the framework of minimal supersymmetric extension of the standard model with local $B-L$ gauge symmetry. With some assumptions on parameters of the model, a numerical analysis of the supersymmetric contributions to the branching ratio and $CP$-asymmetry of $\overline{B}\to X_s\gamma$ is presented.

Taking inspiration from lattice QCD data, we argue that a finite nonperturbative contribution to the quark mass is generated as a consequence of the dynamical phenomenon of spontaneous chiral symmetry breaking, in turn triggered by the explicit breaking of chiral symmetry induced by the critical Wilson term in the action. In pure lattice QCD this mass term cannot be separated from the unavoidably associated linearly divergent contribution. However, if QCD is enlarged to a theory where also a scalar field is present, coupled to an SU(2) doublet of fermions via a Yukawa and a Wilson-like term, then in the phase where the scalar field takes a nonvanishing expectation value, a dynamically generated and “naturally” light fermion mass (numerically unrelated to the expectation value of the scalar field) is conjectured to emerge at a critical value of the Yukawa coupling where the symmetry of the model is maximally enhanced. Masses dynamically generated in this way display a natural hierarchy according to which the stronger is the strongest of the interactions the fermion is subjected to, the larger will be its mass.

We study masses and decay widths of positive and negative parity nucleons using a three-flavor parity doublet model, in which we introduce three representations, $[(\mathbf{3},\overline{\mathbf{3}})\oplus (\overline{\mathbf{3}},\mathbf{3})]$, $[(\mathbf{3},\mathbf{6})\oplus (\mathbf{6},\mathbf{3})]$, and $[(\mathbf{8},\mathbf{1})\oplus (\mathbf{1},\mathbf{8})]$ of the chiral $\mathrm{U}(3{)}_{\mathrm{L}}\times \mathrm{U}(3{)}_{\mathrm{R}}$ symmetry. We find an extended version of the Goldberger-Treiman relation among the mass differences and the coupling constants for pionic transitions. This relation leads to an upper bound for the decay width of $N(1440)\to N(939)+\pi$ independently of the model parameters. We perform the numerical fitting of the model parameters and derive several predictions, which can be tested in future experiments or lattice QCD analysis. Furthermore, when we use the axial coupling of the excited nucleons obtained from lattice QCD analyses as inputs, we find that the ground state nucleon $N(939)$ consists of about 80% of $[(\mathbf{3},\mathbf{6})\oplus (\mathbf{6},\mathbf{3})]$ component, and that the chiral invariant mass of $N(939)$ is roughly 500–800 MeV.

We report on a new topological vortex solution in $\mathrm{U}(1)\times \mathrm{U}(1)$ Maxwell-Chern-Simons theory. The existence of the vortex is envisaged by analytical means, and a numerical solution is obtained by integrating the equations of motion. These vortices have a long-range force because one of the U(1)’s remains unbroken in the infrared, which is guarded by the Coleman-Hill theorem. The sum of the winding numbers of an ensemble of vortices has to vanish; otherwise the system would have a logarithmically divergent energy. In turn, these vortices exhibit classical confinement. We investigate the rich parameter space of the solutions, and show that one recovers the Abrikosov-Nielsen-Olesen, U(1) Maxwell-Chern-Simons, U(1) pure Chern-Simons, and global vortices as various limiting cases. Unlike these limiting cases, the higher winding solutions of our vortices carry noninteger charges under the broken U(1). This is the first vortex solution exhibiting such behavior.