A bilinear $R$-parity violating supersymmetric model is a viable model which can explain the smallness of neutrino masses and the mixing pattern in the lepton sector. In this model, there is a common set of parameters which determines the neutralino and chargino masses, and also determines the neutrino masses and the anomalous magnetic moment of muon, $(g-2{)}_{\mu }$. From the experimental data on neutrino masses and mixing angles, and also from the fact that the experimentally measured value of $(g-2{)}_{\mu }$ differs from the corresponding standard model value by $3\sigma$, we have analyzed some constraints on these model parameters. Constraints on these model parameters are obtained for some values of supersymmetry breaking soft parameters. These constraints can set upper and lower bounds on the chargino masses of this model.

We compute the NLO QCD corrections to the pair production of $W$-bosons in association with two jets at the Tevatron and the LHC. This process is an important background to heavy Higgs-boson production in association with two jets, either in gluon or weak boson fusion. We consider leptonic decays of $W$-bosons and include all the spin correlations exactly. For natural choices of the renormalization scale, the NLO QCD corrections to $pp(\overline{p})\to W^{+}{W}^{-}jj$ are moderate but different for various values of the center-of-mass collision energy at the LHC and the Tevatron, emphasizing the need to compute them explicitly.

The purpose of this work is to study vector meson-octet baryon interactions with the aim to find dynamical generation of resonances in such systems. For this, we consider $s$-, $t$-, $u$-channel diagrams along with a contact interaction originating from the hidden local symmetry Lagrangian. We find the contribution from all these sources, except the $s$ channel, to be important. The amplitudes obtained by solving coupled channel Bethe-Salpeter equations for systems with total strangeness zero, show the generation of one isospin $3/2$, spin $1/2$ resonance and three isospin $1/2$ resonances: two with spin $3/2$ and one with spin $1/2$. We identify these resonances with $\Delta (1900)S_{31}$, $N^{*}(2080)D_{13}$, $N^{*}(1700)D_{13}$, and $N^{*}(2090)S_{11}$, respectively.

We derive a two-parameter formula for the electromagnetic form factors of the nucleon described as an instanton by “integrating out” all Kaluza-Klein modes other than the lowest mesons from the infinite tower of vector mesons in holographic QCD while preserving hidden local symmetry for the resultant vector fields. With only two parameters, the proton Sachs form factors can be fit surprisingly well to the available experimental data for momentum transfers $Q^2\lesssim 0.5{\mathrm{GeV}}^2$ with ${\chi }^2/\mathrm{dof}\lesssim 2$. We interpret this agreement as indicating the importance of an infinite tower in the soliton structure of the nucleon. The prediction of the Sakai-Sugimoto holographic dual model is checked against the fit values to assess its accuracy in describing the proton structure. We find that the structure of the core of roughly $1/3$ in the proton size indicated in experiments and commonly associated with an intrinsic quark-gluon structure in QCD is hidden in the infinite tower in the holographic model.

The effective approach to quantum dynamics allows a reformulation of the Dirac quantization procedure for constrained systems in terms of an infinite-dimensional constrained system of classical type. For semiclassical approximations, the quantum constrained system can be truncated to finite size and solved by the reduced phase space or gauge-fixing methods. In particular, the classical feasibility of local internal times is directly generalized to quantum systems, overcoming the main difficulties associated with the general problem of time in the semiclassical realm. The key features of local internal times and the procedure of patching global solutions using overlapping intervals of local internal times are described and illustrated by two quantum mechanical examples. Relational evolution in a given choice of internal time is most conveniently described and interpreted in a corresponding choice of gauge at the effective level and changing the internal clock is, therefore, essentially achieved by a gauge transformation. This article complements the conceptual discussion in [M. Bojowald, P. A. Höhn, and A. Tsobanjan, Classical Quantum Gravity 28, 035006 (2011).].

A free massive scalar field in inhomogeneous random media is investigated. The coefficients of the Klein-Gordon equation are taken to be random functions of the spatial coordinates. The case of a disordered medium modeled by centered stationary and Gaussian processes is analyzed. After performing the averages over the random functions, we obtain the two-point and the four-point Green’s functions of the model up to one loop. The disordered scalar quantum field theory becomes qualitatively similar to a $\lambda {\phi }^4$ self-interacting theory with a frequency-dependent coupling.

Understanding possible electromagnetic signatures of merging and collapsing compact objects is important for identifying possible sources of the LIGO signal. Electromagnetic emission can be produced as a precursor to the merger, as a prompt emission during the collapse of a neutron star and at the spin-down stage of the resulting Kerr-Newman black hole. For the neutron star–neutron star mergers, the precursor power scales as $L\approx B_{\mathrm{NS}}^{2}G{M}_{\mathrm{NS}}{R}_{\mathrm{NS}}^8/(R_{\mathrm{orb}}^{7}c)$, while for the neutron star–black hole mergers, it is $(GM/(c^2{R}_{\mathrm{NS}}){)}^2$ times smaller. We demonstrate that the time evolution of the axisymmetric force-free magnetic fields can be expressed in terms of the hyperbolic Grad-Shafranov equation, and we formulate the generalization of Ferraro’s law of isorotation to time-dependent angular velocity. We find an exact nonlinear time-dependent Michel-type (split-monopole) structure of magnetospheres driven by spinning and collapsing neutron stars in Schwarzschild geometry. Based on this solution, we argue that the collapse of a neutron star into a black hole happens smoothly, without the natural formation of current sheets or other dissipative structures on the open field lines; thus, it does not allow the magnetic field to become disconnected from the star and escape to infinity. Therefore, as long as an isolated Kerr black hole can produce plasma and currents, it does not lose its open magnetic field lines. Its magnetospheric structure evolves towards a split monopole, and the black hole spins down electromagnetically (the closed field lines get absorbed by the hole). The “no-hair theorem,” which assumes that the outside medium is a vacuum, is not applicable in this case: highly conducting plasma introduces a topological constraint forbidding the disconnection of the magnetic field lines from the black hole. Eventually, a single random large scale spontaneous reconnection event will lead to magnetic field release, shutting down the electromagnetic black hole engine forever. Overall, the electromagnetic power in all the above cases is expected to be relatively small. We also discuss the nature of short gamma-ray bursts and suggest that if the magnetic field is amplified to $\sim {10}^{14}\mathrm{G}$ during the merger or the core collapse, the similarity of the early afterglow properties of long and short gamma-ray bursts can be related to the fact that in both cases a spinning black hole can retain a magnetic field for a sufficiently long time to extract a large fraction of its rotational energy and produce high energy emission via the internal dissipation in the wind.

Based on the work of Chen, Lü, and Pope, we derive expressions for the $D\ge 6$ dimensional metric for Kerr-anti-de Sitter black holes with two independent rotation parameters and all others set equal to zero: $a_1\ne 0$, $a_2\ne 0$, $a_3=a_4=\cdots =0$. The Klein-Gordon equation is then explicitly separated on this background. For $D\ge 6$ this separation results in a radial equation coupled to two generalized spheroidal angular equations. We then develop a full numerical approach that utilizes the asymptotic iteration method to find radial quasinormal modes of doubly rotating flat Myers-Perry black holes for slow rotations. We also develop perturbative expansions for the angular quantum numbers in powers of the rotation parameters up to second order.

In the framework of the power-counting renormalizable theory of gravitation, recently proposed by Hořava, we study the limit $\lambda \to \infty$, which is arguably the most natural candidate for the ultraviolet fixed point of the renormalization group flow. In the projectable version with a dynamical critical exponent $z=3$, we analyze the Friedmann-Robertson-Walker background driven by the so-called “dark matter as integration constant” and perturbations around it. We show that amplitudes of quantum fluctuations for both scalar and tensor gravitons remain finite in the limit and that the theory is weakly coupled under a certain condition.

Three-dimensional gravity in anti-de Sitter space is considered, including torsion. The derivation of the central charges of the algebra that generates the asymptotic isometry group of the theory is reviewed, and a special point of the theory, at which one of the central charges vanishes, is compared with the chiral point of topologically massive gravity. This special point corresponds to a singular point in the Chern-Simons theory, where one of the two coupling constants of the $SL(2,\mathbb{R})$ actions vanishes. A prescription to approach this point in the space of parameters is discussed, and the canonical structure of the theory is analyzed.

We consider how Higgs inflation can be observationally distinguished from variants based on gauge singlet scalar extensions of the standard model, in particular, where the inflaton is a nonminimally coupled gauge singlet scalar ($S$-inflation). We show that radiative corrections generally cause the spectral index $n$ to decrease relative to the classical value as the Higgs mass is increased if the Higgs boson is the inflaton, whereas $n$ increases with increasing Higgs mass if the inflaton is a gauge singlet scalar. The accuracy to which $n$ can be calculated in these models depends on how precisely the reheating temperature can be determined. The number of Einstein frame e-foldings $\tilde{N}$ is similar in both models, with $\tilde{N}\approx 58–61$ for singlet inflation compared with $\tilde{N}\approx 57–60$ for Higgs inflation. This allows the spectral index to be calculated to an accuracy $\Delta n=\pm 0.001$. Provided the Higgs mass is above $\approx 135\mathrm{GeV}$, a combination of a Higgs mass measurement and a precise determination of $n$ will enable Higgs inflation and $S$-inflation to be distinguished.

We show that the hybrid inflation is naturally realized in the framework of a supersymmetric axion model, which is consistent with the WMAP observation if the Peccei-Quinn symmetry-breaking scale is around ${10}^{15}\mathrm{GeV}$. By solving the post-inflationary scalar dynamics, it is found that the scalar partner of the axion, saxion, oscillates with large amplitude and its decay produces a huge entropy and dilutes the axion. As a result, the axion coherent oscillation can be the dominant component of the dark matter in the Universe. Cosmological gravitino and axino problems are solved.

We study the minisuperspace quantization of spatially homogeneous (Bianchi) cosmological universes sourced by a Dirac-spinor field. The quantization of the homogeneous spinor leads to a finite-dimensional fermionic Hilbert space and, thereby, to a multicomponent Wheeler-DeWitt equation whose main features are (i) the presence of spin-dependent Morse-type potentials and (ii) the appearance of a $q$-number squared-mass term, which is of order $\mathcal{O}({\hslash }^2)$ and which is affected by ordering ambiguities. We give the exact quantum solution of the Bianchi type-II system (which contains both scattering states and bound states) and discuss the main qualitative features of the quantum dynamics of the (classically chaotic) Bianchi type-IX system. We compare the exact quantum dynamics of fermionic cosmological billiards to previous works that described the spinor field as being either classical or Grassmann-valued.

Effects of a uniform (electro-)magnetic background field are investigated in the two-flavor nonlocal Polyakov-loop extended Nambu–Jona-Lasinio (PNJL) model. Temperature dependences of the chiral order parameter and the Polyakov loop are investigated under the magnetic field. In the nonlocal PNJL model with four-dimensional momentum dependent distribution function, pseudocritical temperatures of the chiral and deconfinement transitions are coincident to each other even if the magnetic field is strong. This means that we can check the reliability of the distribution function under the strong magnetic field by comparing with lattice QCD data, particularly from the viewpoint of the entanglement between the chiral and deconfinement transitions.

We present results on the lower moments of the nucleon generalized parton distributions within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Our simulations are performed on lattices with three different values of the lattice spacings, namely, $a=0.089\mathrm{fm}$, $a=0.070\mathrm{fm}$, and $a=0.056\mathrm{fm}$, allowing the investigation of cutoff effects. The volume dependence is examined using simulations on two lattices of spatial length $L=2.1\mathrm{fm}$ and $L=2.8\mathrm{fm}$. The simulations span pion masses in the range of 260 to 470 MeV. Our results are renormalized nonperturbatively, and the values are given in the $\overline{\mathrm{MS}}$ scheme at a scale $\mu =2\mathrm{GeV}$. They are chirally extrapolated to the physical point in order to compare with the experiment. The consequences of these results on the spin carried by the quarks in the nucleon are investigated.

We present a parameter-free Wilson-type lattice Dirac operator with an 81-point stencil for the covariant derivative and the Laplacian, which attempts to minimize the breaking of rotational symmetry near the boundary of the Brillouin zone. The usefulness of this “Brillouin operator” in practical applications is explored by studying the scaling of pseudoscalar decay constants in quenched QCD, with rather good results in the physical charm region. We also investigate the suitability of this operator as a kernel to the overlap procedure. Here, the resulting overlap operator is found to be cheaper to construct and significantly better localized than the variety with the standard Wilson kernel.

Motivated by the persistence of a large measured top quark forward-backward asymmetry at the Tevatron, we examine a model of non-Abelian flavor gauge symmetry. The exchange of the gauge bosons in the $t$-channel can give a large $A_{\mathrm{FB}}^t$ due to the forward Rutherford scattering peak. We address generic constraints on non-Abelian $t$-channel physics models including flavor diagonal resonances and potentially dangerous contributions to inclusive top pair cross sections. We caution on the general difficulty of comparing theoretical predictions for top quark signals to the existing experimental results due to potentially important acceptance effects. The first signature at the Large Hadron Collider can be a large inclusive top pair cross section, or like-sign dilepton events, although the latter signal is much smaller than in Abelian models. Deviations of the invariant mass distributions at the LHC will also be promising signatures. A more direct consistency check of the Tevatron asymmetry through the LHC asymmetry is more likely to be relevant at a later stage.

We study $O({\alpha }_s{v}^2)$ corrections to decays of ${}^{1}S_0$ heavy quarkonium into light hadrons and two photons within the framework of nonrelativistic QCD and find these $O({\alpha }_s{v}^2)$ corrections to have significant contributions especially for the decay into light hadrons. With these new results, experimental measurements of the hadronic width and the $\gamma \gamma$ width of ${\eta }_c$ can be described more consistently. By fitting experimental data, we find the long-distance matrix elements of ${\eta }_c$ to be $|{\mathcal{R}}_{{\eta }_c}(0){|}^2={0.834}_{-0.197}^{+0.281}{\mathrm{GeV}}^3$ and $⟨{\mathit{v}}^2{⟩}_{{\eta }_c}={0.232}_{-0.098}^{+0.121}$. Moreover, ${\eta }_c(2S)$ is also discussed and the $\gamma \gamma$ decay width is predicted to be ${3.34}_{-2.10}^{+2.06}\mathrm{KeV}$.

The standard assumption is that all three neutrino mass states are either Dirac or Majorana. However, it was recently suggested by Allaverdi, Dutta, and one of the authors (R.N.M.) that mixed, or bimodal, flavor neutrino scenarios are conceivable and are consistent with all known observations (these were called “schizophrenic” in the ADM paper). In that case each individual mass eigenstate can be either Dirac or Majorana, so that the flavor eigenstates are “large” admixtures of both. An example of this “bimodal” situation is to consider one mass state as a Dirac particle (with a sterile partner), while the other two are of Majorana type. Since only Majorana particles contribute to neutrinoless double beta decay, the usual dependence of this observable on the neutrino mass is modified within this scenario. We study this in detail and, in particular, generalize the idea for all possible bimodal combinations. Inevitably, radiative corrections will induce a pseudo-Dirac nature to the Dirac states at the one-loop level, and the effects of the pseudo-Dirac mass splitting will show up in the flavor ratios of neutrinos from distant cosmological sources. Comparison of the effective mass in neutrinoless double beta decay as well as flavor ratios at neutrino telescopes, for different pseudo-Dirac cases and with their usual phenomenology, can distinguish the different bimodal possibilities.

Recent results from the SNO, Super-Kamiokande, and Borexino experiments do not show the expected upturn of the energy spectrum of events (the ratio $R\equiv N_{\mathrm{obs}}/N_{\mathrm{SSM}}$) at low energies. At the same time, cosmological observations testify for the possible existence of additional relativistic degrees of freedom in the early Universe: $\Delta N_{\mathrm{eff}}=1–2$. These facts strengthen the case of a very light sterile neutrino, ${\nu }_s$, with $\Delta m_{01}^2\sim (0.7–2)\times {10}^{-5}{\mathrm{eV}}^2$, which mixes weakly with the active neutrinos. The ${\nu }_s$ mixing in the mass eigenstate ${\nu }_1$ characterized by ${sin}^{2}2\alpha \sim {10}^{-3}$ can explain an absence of the upturn. The mixing of ${\nu }_s$ in the eigenstate ${\nu }_3$ with ${sin}^2\beta \sim 0.1$ leads to production of ${\nu }_s$ via oscillations in the Universe and to additional contribution $\Delta N_{\mathrm{eff}}\approx 0.7–1$ before the big bang nucleosynthesis and later. Such a mixing can be tested in forthcoming experiments with the atmospheric neutrinos, as well as in future accelerator long baseline experiments. It has substantial impact on conversion of the supernova neutrinos.