The comparative analysis of different sets of the parton distribution functions (PDFs), based on the description of the whole sets of experimental data of electromagnetic form factors of the proton and neutron, is made in the framework of the model of $t$ dependence of the generalized parton distributions with minimum free parameters and some extending variants of the model. In some cases, a large difference in the description of electromagnetic form factors of nucleons with using the different sets of PDF are found out. The different variants of the flavor dependence of the up and down quark form factors are presented and discussed. The gravitation form factors, obtained with the different sets of PDF, are also calculated and the anomalous gravimagnetic moment is compared with the equivalence principle. The calculations of the differential cross sections of the real Compton scattering are presented.

In recent years, an increasing number of devices and experiments are shown to be limited by mechanical thermal noise. In particular, subhertz laser frequency stabilization and gravitational wave detectors that are able to measure fluctuations of ${10}^{-18}\mathrm{m}/\sqrt{\mathrm{Hz}}$ or less are being limited by thermal noise in the dielectric coatings deposited on mirrors. In this paper, we present a new measurement of thermal noise in low absorption dielectric coatings deposited on microcantilevers, and we compare it with the results obtained from the mechanical loss measurements. The coating thermal noise is measured on the widest range of frequencies with the highest signal-to-noise ratio ever achieved. In addition, we present a novel technique to deduce the coating mechanical losses from the measurement of the mechanical quality factor which does not rely on the knowledge of the coating and substrate Young’s moduli. The dielectric coatings are deposited by ion beam sputtering. The results presented here give a frequency-independent loss angle of $(4.7\pm 0.2)\times {10}^{-4}$ with a Young’s modulus of 118 GPa for annealed tantala from 10 Hz to 20 kHz. For as-deposited silica, a weak frequency dependence ($\propto f^{-0.025}$) is observed in this frequency range, with a Young’s modulus of 70 GPa and an internal damping of $(6.0\pm 0.3)\times {10}^{-4}$ at 16 kHz, but this value decreases by one order of magnitude after annealing, and the frequency dependence disappears.

We present a formulation of the quantum kinetic equations (QKEs), which govern the evolution of neutrino flavor at high density and temperature. Here, the structure of the QKEs is derived from the ground up, using fundamental neutrino interactions and quantum field theory. We show that the resulting QKEs describe coherent flavor evolution with an effective mass when inelastic scattering is negligible. The QKEs also contain a collision term. This term can reduce to the collision term in the Boltzmann equation when scattering is dominant and the neutrino effective masses and density matrices become diagonal in the interaction basis. We also find that the QKEs include equations of motion for a new dynamical quantity related to neutrino spin. This quantity decouples from the equations of motion for the density matrices at low densities or in isotropic conditions. However, the spin equations of motion allow for the possibility of coherent transformation between neutrinos and antineutrinos at high densities and in the presence of anisotropy. Although the requisite conditions for this exist in the core collapse supernova and compact object merger environments, it is likely that only a self-consistent incorporation of the QKEs in a sufficiently realistic model could establish whether or not significant neutrino-antineutrino conversion occurs.

We establish a new model of coupling between a cosmic dark fluid and electrodynamic systems, based on an analogy with effects of electric and magnetic striction, piezoelectricity and piezomagnetism, and pyroelectricity and pyromagnetism, which appear in classical electrodynamics of continuous media. Extended master equations for electromagnetic and gravitational fields are derived using Lagrange formalism. A cosmological application of the model is considered, and it is shown that a striction-type interaction between the dark energy (the main constituent of the dark fluid) and electrodynamic system provides the universe history to include the so-called unlighted epochs, during which electromagnetic waves cannot propagate and thus cannot scan the universe interior.

A classical nonlocal generalization of Einstein’s theory of gravitation has recently been developed via the introduction of a scalar causal “constitutive” kernel that must ultimately be determined from observational data. It turns out that the nonlocal aspect of gravity in this theory can simulate dark matter; indeed, in the Newtonian regime of nonlocal gravity, we recover the phenomenological Tohline-Kuhn approach to modified gravity. A simple generalization of the Kuhn kernel in the context of nonlocal general relativity leads to a two-parameter modified Newtonian force law that involves an additional repulsive Yukawa-type interaction. We determine the parameters of our nonlocal kernel by comparing the predictions of the theory with observational data regarding the rotation curves of spiral galaxies. The best-fitting stellar mass-to-light ratio turns out to be in agreement with astrophysical models; moreover, our results are consistent with the Tully-Fisher relation for spiral galaxies. Light deflection in nonlocal gravity is consistent with general relativity at solar-system scales, while beyond galactic scales, an enhanced deflection angle is predicted that is compatible with lensing by the effective “dark matter.” Furthermore, we extend our results to the internal dynamics of rich clusters of galaxies and show that the dynamical mass of the cluster obtained from nonlocal gravity is consistent with the measured baryonic mass.

Updated constraints on the dark matter cross section and mass are presented combining cosmic microwave background (CMB) power spectrum measurements from Planck, WMAP9, ACT, and SPT as well as several low-redshift data sets (BAO, HST, and supernovae). For the CMB data sets, we combine WMAP9 temperature and polarization data for $l\le 431$ with Planck temperature data for $432\le l\le 2500$, ACT and SPT data for $l>2500$, and Planck CMB four-point lensing measurements. We allow for redshift-dependent energy deposition from dark matter annihilation by using a “universal" energy absorption curve. We also include an updated treatment of the excitation, heating, and ionization energy fractions and provide an updated deposition efficiency factors ($f_{\text{eff}}$) for 41 different dark matter models. Assuming perfect energy deposition ($f_{\text{eff}}=1$) and a thermal cross section, dark matter masses below 26 GeV are excluded at the $2\sigma$ level. Assuming a more generic efficiency of $f_{\text{eff}}=0.2$, thermal dark matter masses below 5 GeV are disfavored at the $2\sigma$ level. These limits are a factor of $\sim 2$ improvement over those from WMAP9 data alone. These current constraints probe, but do not exclude, dark matter as an explanation for reported anomalous indirect detection observations from AMS-02/PAMELA and the Fermi gamma-ray inner-Galaxy data. They also probe relevant models that would explain anomalous direct detection events from CDMS, CRESST, CoGeNT, and DAMA, as originating from a generic thermal weakly interacting massive particle. Projected constraints from the full Planck release should improve the current limits by another factor of $\sim 2$ but will not definitely probe these signals. The proposed CMB Stage IV experiment will more decisively explore the relevant regions and improve upon the Planck constraints by another factor of $\sim 2$.

We study the nonlinear regime of unified dark energy models, using generalized Chaplygin gas cosmologies as a representative example, and introduce a new parameter characterizing the level of small scale clustering in these scenarios. We show that viable generalized Chaplygin gas cosmologies, consistent with the most recent observational constraints, may be constructed for any value of the generalized Chaplygin gas parameter by considering models with a sufficiently high level of nonlinear clustering.

Using the effective Lagrangian approach, we study the decay behavior of the newly observed $B(5970)$ meson, which is assigned as the $2{}^3{S}_1$ state in the $B$ meson family. A more important prediction is the detailed information of the partial and total decay widths of $B(2{}^1{S}_0)$, $B_s(2{}^1{S}_0)$, and $B_s(2{}^3{S}_1)$ as the spin and strange partners of $B(5970)$, which can be tested in future experimental searches for these missing states.

We compute the dominant term in the expansion in $\rho =1-M_W/m_t$ of the unknown next-to-next-to-leading order nonresonant contributions to the $e^{+}{e}^{-}\to W^{+}{W}^{-}b\overline{b}$ total cross section at energies close to the top-antitop threshold. Our analytic result disagrees with a previous calculation by other authors [A. A. Penin and J. H. Piclum, J. High Energy Phys. 01 (2012) 034]. We show that our determination has the correct infrared structure needed to cancel the divergences proportional to the top width arising in the resonant production of the same final state, and we point to a missing contribution in the computation of Penin and Piclum [J. High Energy Phys. 01 (2012) 034] to explain the discrepancy.

We propose a new strategy to systematically search for new physics processes in particle collisions at the energy frontier. An examination of all possible topologies which give identifiable resonant features in a specific final state leads to a tractable number of “topological models” per final state and gives specific guidance for their discovery. Using one specific final state, $\ell \ell jj$, as an example, we find that the number of possibilities is reasonable and reveals simple, but as-yet-unexplored, topologies which contain significant discovery potential. We propose analysis techniques and estimate the sensitivity for $pp$ collisions with $\sqrt{s}=14\mathrm{TeV}$ and $\mathcal{L}=300{\mathrm{fb}}^{-1}$.

In the wake of the Higgs discovery and over the long haul of the LHC run, one should keep a lookout for kinematic anomalies in the most massive known trio of coupled particles, $t\overline{t}h$. After surveying the scope of prior constraints on chromomagnetic dipole and Higgs-gluon kinetic couplings, we focus on surpluses of boosted-$p_T$ Higgs bosons fomented by these momentum-dependent dimension-six operators in $t\overline{t}h$ final states. We uncover a number of simple, $p_T$-weighted angular variables useful for discriminating Standard Model from dimension-six boosted Higgs distributions, and we make headway by arguing that one of these variables may improve the reach of existing Standard Model top-Higgs searches. The approach we take is model independent because we just consider a set of effective operators that contribute to the same three-body final state.

We discuss the viability of the $\mu –\tau$ interchange symmetry imposed on the neutrino mass matrix in the flavor space. Whereas the exact symmetry is shown to lead to textures of a completely degenerate spectrum, which is incompatible with the neutrino oscillation data, introducing small perturbations into the preceding textures, inserted in a minimal way, leads, however, to four deformed textures representing an approximate $\mu$–$\tau$ symmetry. We motivate the form of these “minimal” textures, which disentangle the effects of the perturbations, and present some concrete realizations assuming exact $\mu –\tau$ at the Lagrangian level but at the expense of adding new symmetries and matter fields. We find that all of these deformed textures are capable of accommodating the experimental data, and in all types of neutrino mass hierarchies, particularly the nonvanishing value for the smallest mixing angle.

The $\mathrm{MINER}\nu \mathrm{A}$ experiment investigates neutrino interactions with nucleons needed for an understanding of electroweak interactions of hadrons. Since nuclear targets are being used, many-body effects may affect the extracted cross sections and the energy reconstruction. The latter is essential for the extraction of neutrino oscillation properties. We investigate the influence of nuclear effects on neutrino interaction cross sections and make predictions for charged current quasielastic (QE) scattering, nucleon knockout, and pion and kaon production on a CH target. The Giessen Boltzmann-Uehling-Uhlenbeck model is used for the description of neutrino-nucleus reactions. Integrated and differential cross sections for inclusive neutrino scattering, QE processes and particle production for the $\mathrm{MINER}\nu \mathrm{A}$ neutrino flux are calculated. The influence of final-state interactions on the identification of these processes is discussed. In particular, energy and $Q^2$ reconstruction for the $\mathrm{MINER}\nu \mathrm{A}$ flux are critically examined. The $Q^2$ dependence of the inclusive cross sections is found to be sensitive to the energy reconstruction. Cutoffs in flux distributions have a large effect. Final-state interactions affect the pion kinetic energy spectra significantly and increase the kaon cross sections by cross feeding from other channels.

Perturbative corrections to the Casimir free energy due to macroscopic roughness of dielectric interfaces are obtained in the framework of an effective low-energy field theory. It describes the interaction of electromagnetic fields with materials whose plasma frequency ${\omega }_p$ determines the low-energy scale. The naïve perturbative expansion of the single-interface scattering matrix in the variance of the profile is sensitive to short-wavelength components of the roughness correlation function. We introduce generalized counterterms that subtract and correct these high-momentum contributions to the loop expansion. To leading order, the counterterms are determined by the phenomenological plasmon model. The latter is found to be consistent with the low-energy description. The proximity force approximation is recovered in the limit of long correlation length and gives the upper limit for the roughness correction to the Casimir force. The renormalized low-energy theory is insensitive to the high-momentum behavior of the roughness correlation function. Predictions at zero temperature of the improved theory are compared with those of the unrenormalized model and with experiment. The Casimir interaction of interfaces with low levels of roughness is found to be well reproduced by that of flat parallel plates with the measured reflection coefficients at a distance that is slightly less than the mean separation of the rough surfaces.

Working in Einstein frame, we introduce, in order to avoid singularities, holonomy corrections to the $f(R)=R+\alpha R^2$ model. We perform a detailed analytical and numerical study when holonomy corrections are taken into account in both Jordan and Einstein frames, obtaining, in Jordan frame, a dynamics which differs qualitatively, at early times, from the one of the original model. More precisely, when holonomy corrections are taken into account, the Universe is not singular, starting at early times in the contracting phase and bouncing to enter the expanding one where, as in the original model, it inflates. This dynamics is completely different from the one obtained in the original $R+\alpha R^2$ model, where the Universe is singular at early times and never bounces. Moreover, we show that these holonomy corrections may lead to better predictions for the inflationary phase as compared with current observations.

In a cosmological first-order phase transition, bubbles of the stable phase nucleate and expand in the supercooled metastable phase. In many cases, the growth of bubbles reaches a stationary state, with bubble walls propagating as detonations or deflagrations. However, these hydrodynamical solutions may be unstable under corrugation of the interface. Such instability may drastically alter some of the cosmological consequences of the phase transition. Here, we study the hydrodynamical stability of deflagration fronts. We improve upon previous studies by making a more careful and detailed analysis. In particular, we take into account the fact that the equation of motion for the phase interface depends separately on the temperature and fluid velocity on each side of the wall. Fluid variables on each side of the wall are similar for weakly first-order phase transitions, but differ significantly for stronger phase transitions. As a consequence, we find that, for large enough supercooling, any subsonic wall velocity becomes unstable. Moreover, as the velocity approaches the speed of sound, perturbations become unstable on all wavelengths. For smaller supercooling and small wall velocities, our results agree with those of previous works. Essentially, perturbations on large wavelengths are unstable, unless the wall velocity is higher than a critical value. We also find a previously unobserved range of marginally unstable wavelengths. We analyze the dynamical relevance of the instabilities, and we estimate the characteristic time and length scales associated with their growth. We discuss the implications for the electroweak phase transition and its cosmological consequences.

Charged lepton flavor violation is reappraised in the context of a supersymmetric seesaw mechanism. It is pointed out that a nontrivial flavor structure of right-handed neutrinos, whose effect has been thus far less studied, can give rise to significant slepton flavor transitions. Under the premise that the neutrino Yukawa couplings are of $\mathcal{O}(1)$, the right-handed neutrino mixing contribution could form a basis of the $\mu \to e\gamma$ amplitude, which by itself might lead to an experimentally accessible rate, given a typical low-energy sparticle spectrum. Emphasis is placed on the crucial role of the recently measured lepton mixing angle ${\theta }_{13}$ as well as the leptonic $CP$-violating phases.

We calculate the scalar form factor of the pion using two dynamical flavors of nonperturbatively $\mathcal{O}(a)$-improved Wilson fermions, including both the connected and the disconnected contribution to the relevant correlation functions. We employ the calculation of all-to-all propagators using stochastic sources and a generalized hopping parameter expansion. From the form factor data at vanishing momentum transfer, $Q^2=0$, and two nonvanishing $Q^2$, we obtain an estimate for the scalar radius $⟨r^2{⟩}_{\mathrm{s}}^{\pi }$ of the pion at one value of the lattice spacing and for five different pion masses. Using chiral perturbation theory at next-to-leading order, we find $⟨r^2{⟩}_{\mathrm{s}}^{\pi }=0.635\pm 0.016{\mathrm{f}\mathrm{m}}^2$ at the physical pion mass (statistical error only). This is in good agreement with the phenomenological estimate from $\pi \pi$-scattering. The inclusion of the disconnected contribution is essential for achieving this level of agreement.

We present lattice-QCD results on the nucleon isovector axial, scalar and tensor charges, the isovector electromagnetic Dirac and Pauli form factors, and the connected parts of the isoscalar charges. The calculations have been done using two ensembles of highly improved staggered quarks lattices generated by the MILC collaboration with $2+1+1$ dynamical flavors at a lattice spacing of 0.12 fm and with light-quark masses corresponding to pions with masses 310 and 220 MeV. We perform a systematic study including excited-state degrees of freedom and examine the dependence of the extracted nucleon matrix elements on source-sink separation. This study demonstrates with high-statistics data that including excited-state contributions and generating data at multiple separations is necessary to remove contamination that would otherwise lead to systematic error. We also determine the renormalization constants of the associated quark bilinear operators in the RI-sMOM scheme and make comparisons of our renormalized results with previous dynamical-lattice calculations.