We investigate the direct determination of expansion history using redshift distortions without plugging into detailed cosmological parameters. The observed spectra in redshift space include a mixture of information: fluctuations of density-density and velocity-velocity spectra, and distance measures of perpendicular and parallel components to the line of sight. Unfortunately it is hard to measure all the components simultaneously without any specific prior assumption. Common prior assumptions include a linear/quasilinear model of redshift distortions or a model for the shape of the power spectra, which eventually breaks down on small scales at later epochs where nonlinear structure formation disturbs coherent growth. The degeneracy breaking, between the effect of cosmic distances and redshift distortions for example, depends on the prior we assume. An alternative approach is to utilize the cosmological principle inscribed in the heart of the Friedmann-Lemaître-Robertson-Walker universe, that is, the specific relation between the angular diameter distance and the Hubble parameter, in this degeneracy breaking. We show that utilizing this Friedmann-Lemaître-Robertson-Walker prior early in the step of distinguishing the distance effect from redshift distortions helps us improve the detectability of power spectra and distance measures with no leaning on a combination of other experiments.

The flux and nuclear composition of ultrahigh energy cosmic rays depend on the cosmic distribution of their sources. Data from cosmic ray observatories are yet inconclusive about their exact location or distribution, but provide a measure for the average local density of these emitters. Due to the discreteness of the emitters, the flux and nuclear composition is expected to show ensemble fluctuations on top of the statistical variations, i.e., “cosmic variance.” This effect is strongest for the most energetic cosmic rays due to the limited propagation distance in the cosmic radiation background and is hence a local phenomenon. For the statistical analysis of cosmic ray emission models, it is important to quantify the possible level of this variance. In this paper we present a completely analytic method that describes the variation of the flux and nuclear composition with respect to the local source density. We highlight that proposed future space-based observatories with exposures of $\mathcal{O}({10}^6{\mathrm{km}}^2\mathrm{sr}\mathrm{yr})$ will attain sensitivity to observe these spectral fluctuations in the cosmic ray energy spectrum at Earth relative to the overall power-law fit.

We investigate the radiative $B_c\to D_{s1}\gamma$ transition in the framework of QCD sum rules. In particular, we calculate the transition form factors responsible for this decay in both weak annihilation and electromagnetic penguin channels using the quark condensate, mixed, and two-gluon condensate diagrams, as well as propagation of the soft quark in the electromagnetic field, as nonperturbative corrections. These form factors are then used to estimate the branching ratios of the channels under consideration. The total branching ratio of the $B_c\to D_{s1}\gamma$ transition is obtained to be of the order of ${10}^{-5}$, and the dominant contribution comes from the weak annihilation channel.

In the scenario of isospin-violating dark matter (IVDM), the dark matter (DM) spin-independent couplings to protons and to neutrons are allowed to be different, which has been considered to relax the tensions between the results of DAMA, CoGeNT and XENON experiments. We explore the allowed values of DM-nucleon couplings favored and excluded by the current experiments under the assumption of IVDM. We find that the recently updated XENON100 result excludes the main part of the overlapping signal region between DAMA and CoGeNT. We also show that the possible tensions between some experiments such as those between DAMA and SIMPLE are unlikely to be affected by isospin-violating interactions. In an effective operator approach, we investigate conservative upper bounds on the DM-quark couplings required by the IVDM scenario from the cosmic ray antiproton fluxes measured recently by BESS-Polar II and PAMELA and that from the relic density. The results show that the relatively large couplings favored by DAMA and CoGeNT are tightly constrained, if the operators contribute to velocity-independent annihilation cross sections. For thermal relic DM, the upper bounds from the relic density can also be stringent.

We discuss anomalous Higgs interactions in the scenario of gauge-Higgs unification. In the scenario Higgs originates from a higher dimensional gauge field and has a physical meaning as an Aharonov-Bohm phase or Wilson loop. As its inevitable consequence, physical observables are expected to be periodic in the Higgs field. In particular, the Yukawa coupling is expected to show some periodic and nonlinear behavior as the function of the Higgs vacuum expectation value (VEV). For a specific choice of the VEV, the Yukawa coupling of the Kaluza-Klein zero mode fermion even vanishes. On the other hand, the Yukawa coupling is originally provided by gauge interaction, which is linear in the Higgs field. We discuss how such two apparent contradictions about the nonlinearity of the Yukawa coupling can be reconciled and at the same time how these two “pictures” give different predictions in the simplest framework of the scenario: $SU(3)$ electroweak model in 5-dimensional flat space-time with orbifolding. The deviation of the Yukawa coupling from the standard model prediction is also calculated for arbitrary VEV. Also discussed is the Higgs interaction with $W^{\pm }$ and $Z^0$. It turns out that in our framework of flat space-time the interaction does not show deviation from the standard model prediction, except for the specific case of the VEV.

We consider the pair production of color triplet spin-$3/2$ quarks and their subsequent decays at the LHC. This particle, if produced, will most likely decay into top quark and gluon, bottom quark and gluon, or a light quark jet and gluon, depending on the quantum number of the spin-$3/2$ particle. This would lead to signals with $t\overline{t}jj$, $b\overline{b}jj$, or $4j$ in the final states. We present a detailed analysis of the signals and backgrounds at $\sqrt{s}=7$, 8, and 14 TeV and show the reach for such particles by solving for observable mass values for the spin-$3/2$ quarks through its decay products.

We investigate an application of twisted boundary conditions for the study of low-energy hadron-hadron interactions with Lüscher’s finite size method. This allows us to calculate the phase shifts for elastic scattering of two hadrons at any small value of the scattering momentum even in a finite volume. We then can extract model-independent information of low-energy scattering parameters, such as the scattering length, the effective range, and the effective volume, from the $S$-wave and $P$-wave scattering phase shifts through the effective range expansion. This approach also enables us to examine the existence of near-threshold and narrow resonance states, whose characteristics are observed in many of newly discovered charmonium-like $XYZ$ mesons. As a simple example, we demonstrate our method for low-energy $J/\psi \mathrm{\text{−}}\varphi$ scatterings to search for $Y(4140)$ resonance using $2+1$ flavor PACS-CS gauge configurations at the lightest pion mass, $m_{\pi }=156\mathrm{MeV}$.

We study multiparticle-state contributions to the QCD two-point functions of the axial-vector and pseudoscalar quark bilinears in a finite spatial volume. For sufficiently small quark masses one expects three-meson states with two additional pions at rest to have the lowest total energy after the ground state. We calculate this three-meson-state contribution using chiral perturbation theory. We find it to be strongly suppressed and too small to be seen in present-day lattice simulations.

The Nambu-Jona-Lasinio model reduced to $2+1$ dimensions has two different path integral formulations: at finite chemical potential one formulation has a severe sign problem similar to that found in QCD, while the other does not. At large $N$, where $N$ is the number of flavors, one can compute the probability distributions of fermion correlators analytically in both formulations. In the former case one finds a broad distribution with small mean; in the latter one finds a heavy tailed positive distribution amenable to the cumulant expansion techniques developed in earlier work. We speculate on the implications of this model for QCD.

We derive a factorization theorem for production of an arbitrary number of color-singlet particles accompanied by a fixed number of jets at the LHC. The jets are defined with the standard anti-$k_T$ algorithm, and the fixed number of jets is obtained by imposing a veto on additional radiation in the final state. The formalism presented here is useful for current Higgs boson analyses using exclusive jet bins, and for other studies using a similar strategy. The derivation uses the soft-collinear effective theory and assumes that the transverse momenta of the hard jets are larger than the veto scale. We resum the large Sudakov logarithms ${\alpha }_s^n{log}^{2n-m}(p_T^J/p_T^{\mathrm{veto}})$ up to the next-to-leading logarithmic accuracy, and present numerical results for Higgs boson production in association with a jet at the LHC. We comment on the experimentally interesting parameter region in which we expect our factorization formula to hold.

We propose to describe the process $p\overline{p}\to {\overline{D}}^0{D}^0$ in a perturbative QCD motivated framework where a double-handbag hard process $ud\overline{u}\overline{d}\to \overline{c}c$ factorizes from transition distribution amplitudes, which are quasiforward hadronic matrix elements of ${\Psi }_q{\Psi }_q{\Psi }_c$ operators, where $q$ denotes light quarks and $c$ denotes the heavy quark. We advocate that the charm-quark mass acts as the large scale allowing this factorization. We calculate this process in the simplified framework of the scalar diquark model and present the expected cross sections for the PANDA experiment at GSI-FAIR.

Data on neutrino oscillation often involve reconstructed neutrino energies while the analysis implies the real neutrino energy. The corrections corresponding to the transformation from real to reconstructed energy are discussed in the case of Cherenkov detectors where multinucleon events appear as quasielastic ones. These corrections show up as a tendency for the events to escape the region of high flux, with a clear preference for the low energy side. This is an effect of the multinucleon component of the quasielastic cross section. We have applied our corrections to the T2K and MiniBooNE data for electron appearance or ${\nu }_{\mu }$ disappearance data. We show that the inclusion of this correction in the analysis is expected to lead to an increase of the best fit oscillation mass parameters, particularly pronounced for the MiniBooNE neutrino data. This inclusion in the analysis of the MiniBooNE neutrino data should improve the compatibility with the existing constraints.

A search for squarks and gluinos in final states containing jets, missing transverse momentum and no high-$p_{\mathrm{T}}$ electrons or muons is presented. The data represent the complete sample recorded in 2011 by the ATLAS experiment in 7 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of $4.7{\mathrm{fb}}^{-1}$. No excess above the Standard Model background expectation is observed. Gluino masses below 860 GeV and squark masses below 1320 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino, for squark or gluino masses below 2 TeV, respectively. Squarks and gluinos with equal masses below 1410 GeV are excluded. In minimal supergravity/constrained minimal supersymmetric Standard Model models with $\tan \beta =10$, $A_0=0$ and $\mu >0$, squarks and gluinos of equal mass are excluded for masses below 1360 GeV. Constraints are also placed on the parameter space of supersymmetric models with compressed spectra. These limits considerably extend the region of supersymmetric parameter space excluded by previous measurements with the ATLAS detector.

We consider Higgs boson pair production at the LHC in the $b\overline{b}{W}^{+}{W}^{-}$ channel, with subsequent decay of the $W^{+}{W}^{-}$ pair into $\ell \nu jj$. Employing jet substructure and event reconstruction techniques, we show that strong evidence for this channel can be found at the 14 TeV LHC with $600{\mathrm{fb}}^{-1}$ of integrated luminosity, thus improving the current reach for the production of Higgs boson pairs. This measurement will allow us to probe the trilinear Higgs boson coupling $\lambda$.

We study the geometry generated by a massless cosmic string. We find that this is given by a Riemann flat spacetime with a conical singularity along the world sheet of the string. The geometry of such a spacetime is completely fixed by the holonomy of a simple loop wrapping the conical singularity. In the case of a massless cosmic string, this holonomy is a null rotation or parabolic Lorentz transformation with a parabolic angle given by the linear energy density of the cosmic string. This description explicitly shows that there is no gravitational shockwave accompanying the massless cosmic string as has been suggested in the past. To illustrate the nonsingular nature of the surrounding geometry, we construct a metric for the massless cosmic string that is smooth everywhere outside the conical singularity.

We present a simple “Wald-like” formula for gravitational energy about a constant-curvature background spacetime. The formula is derived following the Abbott-Deser-Tekin approach for the definition of conserved asymptotic charges in higher-derivative gravity.

We give a precise theoretical description of initially aligned sets of orthogonal gyroscopes which are transported along different paths from some initial point to the same final point in spacetime. These gyroscope systems can be used to synchronize separated observers’ spatial frames by free fall along timelike geodesics. We find that initially aligned gyroscope systems, or spatial frames, lose their synchronization due to the curvature of spacetime and their relative motion. On the basis of our results we propose a simple experiment that enables observers to determine locally whether their spacetime is described by a rotating Kerr or a nonrotating Schwarzschild metric.

We use the canonical Hamiltonian formalism to generalize to spinning point particles the first law of mechanics established for binary systems of nonspinning point masses moving on circular orbits [A. Le Tiec, L. Blanchet, and B. F. Whiting, Phys. Rev. D 85, 064039 (2012)]. We find that the redshift observable of each particle is related in a very simple manner to the canonical Hamiltonian and, more generally, to a class of Fokker-type Hamiltonians. Our results are valid through linear order in the spin of each particle, but hold also for quadratic couplings between the spins of different particles. The knowledge of spin effects in the Hamiltonian allows us to compute spin-orbit terms in the redshift variable through 2.5PN order, for circular orbits and spins aligned or anti-aligned with the orbital angular momentum. To describe extended bodies such as black holes, we supplement the first law for spinning point-particle binaries with some “constitutive relations” that can be used for diagnosis of spin measurements in quasi-equilibrium initial data.

It is often the case that scalar fields are produced in the early Universe in the form of coherent oscillation. These scalar fields may have huge abundances and affect the evolution of the Universe. In particular, if the lifetime is long enough, they may cause cosmological disasters. We revisit the issue of coherent oscillation of the scalar field when it couples with another oscillating scalar field, and find a situation that the abundance, or the amplitude of the oscillation, is significantly reduced by a variant type of the adiabatic suppression mechanism. As a concrete example, it is applied to the saxion, a flat direction in the supersymmetric axion model, and we show that the cosmological saxion problem is solved in a particular setup.

We study the effect that uncertainties in the nuclear spin-dependent structure functions have in the determination of the dark matter (DM) parameters in a direct detection experiment. We show that different nuclear models that describe the spin-dependent structure function of specific target nuclei can lead to variations in the reconstructed values of the DM mass and scattering cross section. We propose a parametrization of the spin structure functions that allows us to treat these uncertainties as variations of three parameters, with a central value and deviation that depend on the specific nucleus. The method is illustrated for germanium and xenon detectors with an exposure of 300 kg yr, assuming a hypothetical detection of DM and studying a series of benchmark points for the DM properties. We find that the effect of these uncertainties can be similar in amplitude to that of astrophysical uncertainties, especially in those cases where the spin-dependent contribution to the elastic scattering cross section is sizable.