We develop an integral form for the bispectrum in general single-field inflation whose domain of validity includes models of inflation where the background evolution is not constrained to be slowly varying everywhere. Our integral form preserves the squeezed-limit consistency relation, allows for fast evaluation of the bispectrum for all triangle configurations expediting the efficient comparison of slow-roll violating models with data, and provides complete and compact slow-roll expressions correct to first order in slow-roll parameters. Motivated by the recent Planck results, we consider as an example a sharp step in the warped-brane tension of Dirac-Born-Infeld inflation and provide analytic solutions for the peak of the resulting bispectrum. For the step in the warp that reproduces the oscillations in the power spectrum favored by the Planck data, the corresponding equilateral bispectrum is both extremely large and highly scale dependent. The bispectrum serves as a means of distinguishing such a model from alternative scenarios that generate otherwise indistinguishable power spectra, such as a step in the potential in canonical single-field inflation.

Motivated by the prohibitive computational cost of producing adiabatic extreme mass-ratio inspirals, we explain how a judicious use of resonant orbits can dramatically expedite both that calculation and the generation of snapshot gravitational waves from geodesic sources. In the course of our argument, we clarify the resolution of a lingering debate on the appropriate adiabatic averaging prescription in favor of torus averaging over time averaging.

We explore what can be said on the effective temperature and sound speed of a statistical ensemble of fluid phonons present at the onset of a conventional inflationary phase. The phonons are the actual normal modes of the gravitating and irrotational fluid that dominates the protoinflationary dynamics. The bounds on the tensor-to-scalar ratio result in a class of novel constraints involving the slow roll parameter, the sound speed of the phonons and the temperature of the plasma prior to the onset of inflation. If the current size of the Hubble radius coincides with the inflationary event horizon redshifted down to the present epoch, the sound speed of the phonons can be assessed from independent measurements of the tensor-to-scalar ratio and of the tensor spectral index.

We discuss recent experimental results from the Relativistic Heavy Ion Collider where the flat transverse momentum dependence of a single-spin asymmetry has been found in the inclusive production of neutral pions. This dependence takes place in a wide region of the transverse momenta up to $p_T=10\mathrm{GeV}/\mathrm{c}$. We emphasize that similar dependence has been predicted in the nonperturbative spin filtering mechanism for the single-spin asymmetries in hadron interactions and present some implications for this mechanism from the new experimental data.

A realistic medium- or long-baseline neutrino experiment may suffer from terrestrial matter effects which are likely to contaminate the genuine $T$-violating asymmetry between ${\nu }_{\alpha }\to {\nu }_{\beta }$ and ${\nu }_{\beta }\to {\nu }_{\alpha }$ oscillations. With the help of the commutators of lepton mass matrices in matter, we show that this kind of contamination is negligible for a variety of experiments provided the neutrino beam energy $E$ and the baseline length $L$ satisfy the condition ${10}^{-7}(L/\mathrm{km}{)}^2(\mathrm{GeV}/E)\ll 1$. The same observation is true for the $CP$-violating term of the asymmetry between ${\nu }_{\alpha }\to {\nu }_{\beta }$ and ${\overline{\nu }}_{\alpha }\to {\overline{\nu }}_{\beta }$ oscillations in matter.

We study via the renormalization group equations at one-loop order the perturbativity and vacuum stability of a two-singlet model of cold dark matter (DM) that consists in extending the Standard Model with two real gauge-singlet scalar fields. We then investigate the regions in the parameter space in which the model is viable. For this, we require the model to reproduce the observed DM relic density abundance, to comply with the measured XENON 100 direct-detection upper bounds, and to be consistent with the renormalization group equation perturbativity and vacuum stability criteria up to 40 TeV. For a small mixing angle $\theta$ between the physical Higgs $h$ and auxiliary field, and DM-$h$ mutual coupling constant ${\lambda }_0^{(4)}$, we find that the auxiliary field mass is confined to the interval 116–138 GeV, while the DM mass is mainly confined to the region above 57 GeV. Increasing $\theta$ enriches the existing viability regions without relocating them, while increasing ${\lambda }_0^{(4)}$ shrinks them with a tiny relocation. We show that the model is consistent with the recent Higgs-boson-like discovery by the ATLAS and CMS experiments, while very light dark matter (masses below 5 GeV) is ruled out by the same experiments.

The “$\mu$ from $\nu$” supersymmetric standard model ($\mu \nu \mathrm{SSM}$) cures the $\mu$ problem and concurrently reproduces measured neutrino data by using a set of usual right-handed neutrino superfields. Recently, the LHC has revealed the first scalar boson which naturally makes it tempting to test $\mu \nu \mathrm{SSM}$ in the light of this new discovery. We show that this new scalar, while decaying to a pair of unstable long-lived neutralinos, can lead to a distinct signal with nonprompt multileptons. With concomitant collider analysis we show that this signal provides an intriguing signature of the model, pronounced with light neutralinos. Evidence of this signal is well envisaged with sophisticated displaced vertex analysis, which deserves experimental attention.

We study a two-Higgs-doublet model augmented by a scalar dark matter particle that provides an excellent fit to the LHC Higgs data and the Fermi-LAT 135 GeV line. The heavy $CP$-even Higgs boson, which predominantly mediates annihilation and scattering, must have a coupling to weak gauge bosons at or below percent level to suppress the continuum gamma-ray spectrum below the limit from the Fermi-LAT data and the antiproton spectrum constrained by the PAMELA data. Discovering or excluding this $CP$-even Higgs boson at the LHC with a mass between 265 and 280 GeV is a crucial test of this scenario.

The search for heavy Higgs bosons is an essential step in the exploration of the Higgs sector and in probing the supersymmetric parameter space. This paper discusses the constraints on the $M_A$ and $\tan \beta$ parameters derived from the bounds on the different decay channels of the neutral $H$ and $A$ bosons accessible at the LHC, in the framework of the phenomenological minimal supersymmetric extension of the standard model. The implications from the present LHC results and the expected sensitivity of the 14 TeV data are discussed in terms of the coverage of the [$M_A-\tan \beta$] plane. New channels becoming important at 13 and 14 TeV for low values of $\tan \beta$ are characterized in terms of their kinematics and the reconstruction strategies. The effect of QCD systematics, SUSY loop effects and decays into pairs of SUSY particles on these constraints are discussed in details.

Based on the Lippmann-Schwinger equation approach, a generalized Lüscher’s formula in $1+1$ dimensions for two particles scattering in both the elastic and coupled-channel cases in moving frames is derived. A two-dimensional coupled-channel scattering lattice model is presented, which represents a two-coupled-channel resonant scattering scalars system. The Monte Carlo simulation is performed on finite lattices and in various moving frames. The two-dimensional generalized Lüscher’s formula is used to extract the scattering amplitudes for the coupled-channel system from the discrete finite-volume spectrum.

We discuss the phase structure and thermodynamics of QCD by means of dynamical chiral effective models. Quark and meson fluctuations are included via the functional renormalization group. We study the influence of confinement in addition to the impact of fluctuations by comparing the results of the chiral models to their Polyakov-loop extended versions. Furthermore, we discuss the mass sensitivity of the phase structure and thermodynamics and find interesting modifications close to the chiral limit.

We isolate the two-step mechanism involving a real intermediate photon from the one-step mechanism involving a virtual photon for the trident process in a constant crossed field. The two-step process is shown to agree with an integration over polarized subprocesses. At low to moderate quantum nonlinearity parameter, the one-step process is found to be suppressed. When the parameter is large, the two decay channels are comparable if the field dimensions are not much greater than the formation length.

The Higgs mass determination from diphoton events at the LHC can be affected by interference between the Higgs resonant and continuum background amplitudes with the same initial and final states. For the leading order gluon fusion process, this shift was previously found to exceed 100 MeV, with some dependence on the diphoton mass resolution and the methods used to extract and fit the peak from data. In this paper, I consider the mass shift for the process $pp\to j\gamma \gamma$ that includes an additional central jet in the final state. For cuts on the transverse momentum of the jet of 25 GeV or more, the diphoton Higgs peak mass shift due to interference is found to be very small, due in part to less interference for the gluon-gluon initiated subprocess, and in part to a cancellation between it and the quark-gluon initiated subprocess.

CoGeNT employs $p$-type point-contact (PPC) germanium detectors to search for weakly interacting massive particles (WIMPs). By virtue of its low-energy threshold and ability to reject surface backgrounds, this type of device allows an emphasis on low-mass dark matter candidates ($m_{\chi }\sim 10\mathrm{GeV}/c^2$). We report on the characteristics of the PPC detector presently taking data at the Soudan Underground Laboratory, elaborating on aspects of shielding, data acquisition, instrumental stability, data analysis, and background estimation. A detailed background model is used to investigate the low-energy excess of events previously reported and to assess the possibility of temporal modulations in the low-energy event rate. Extensive simulations of all presently known backgrounds do not provide a viable background explanation for the excess of low-energy events in the CoGeNT data or the previously observed temporal variation in the event rate. Also reported for the first time is a determination of the surface (slow pulse rise time) event contamination in the data as a function of energy. We conclude that the CoGeNT detector technology is well suited to search for the annual modulation signature expected from dark matter particle interactions in the region of WIMP mass and coupling favored by the DAMA/LIBRA results.

We show that a spin-$1/2$ particle in the gravitational field of a massive body of radius $R$, which slightly exceeds the Schwarzschild radius $r_s$, possesses a dense spectrum of narrow resonances. Their lifetimes and densities tend to infinity in the limit $R\to r_s$. We determine the cross section of the particle capture into these resonances and show that it is equal to the spin-$1/2$ absorption cross section for a Schwarzschild black hole. Thus, black-hole properties may emerge in a nonsingular static metric prior to the formation of a black hole.

The stellar magnetic field configuration and solutions of Maxwell equations in the external background spacetime of a magnetized spherical stars in the Hořava-Lifshitz gravity and in modified $f(R)$ gravity are studied. The star is modeled as a sphere consisting of perfect highly magnetized fluid with infinite conductivity and frozen-in magnetic field. With respect to solutions for magnetic fields found in the Schwarzschild spacetime star in modified gravity theories, enhancing corrections are added to the exterior magnetic field. The energy losses through magnetodipolar radiation of the rotating magnetized compact star within alternative gravity theories is also considered. The question of whether these models can be considered as an alternative theory for general relativity is also discussed through astrophysical application of the obtained magnetodipolar energy loss formula. Finally we analyze the role of general relativistic effect on the decay of a neutron star’s magnetic field in modified theories of gravity.

In this paper, we examine the cosmological viability of a slow-moving Galileon field in a potential. The Lagrangian $\mathcal{L}=-\frac{1}{2}{g}^{\mu \nu }{\pi }_{;\mu }{\pi }_{;\nu }+\frac{G^{\mu \nu }}{2M^2}{\pi }_{;\mu }{\pi }_{;\nu }$ respects the Galileon symmetry in curved spacetime. We carry out detailed investigations of the underlying dynamics of this Lagrangian with an Einstein-Hilbert term and a potential. We demonstrate that the model can give rise to a viable ghost-free late-time acceleration of the universe. Furthermore, we study the cosmological perturbation of the model and see that the model gives different big bang nucleosynthesis constraints at early times. We also carry out the observational analysis of the model and use observational data from growth, type Ia supernovae data, baryon acoustic oscillations, and the cosmic microwave background to constrain the parameters of the theory.

We analyze the phenomenological consequences of assuming that the 125 GeV boson measured at the LHC coincides with one of the two $CP$-even Higgs bosons of an effective minimal supersymmetric extension of the Standard Model at the electroweak scale. We consider the two ensuing scenarios and discuss critically the role of the various experimental data (mainly obtained at colliders and at B factories) which provide actual or potential constraints to supersymmetric properties. Within these scenarios, properties of neutralinos as dark matter particles are analyzed from the point of view of their cosmological abundance and rates for direct and indirect detections.

Starting from the general Horndeski action, we derive the most general effective theory for scalar perturbations around flat space that allows us to screen fifth forces via the Vainshtein mechanism. The effective theory is described by a generalization of the Galileon Lagrangian, which we use to study the stability of spherically symmetric configurations exhibiting the Vainshtein effect. In particular, we discuss the phenomenological consequences of a scalar-tensor coupling that is absent in the standard Galileon Lagrangian. This coupling controls the superluminality and stability of fluctuations inside the Vainshtein radius in a way that depends on the density profile of a matter source. Particularly, we find that the vacuum solution is unstable due to this coupling.

We consider the Randall-Sundrum (RS) setup to be a theory of flavor, as an alternative to Froggatt-Nielsen models instead of as a solution to the hierarchy problem. The RS framework is modified by taking the low-energy brane to be at the grand unified theory (GUT) scale. This also alleviates constraints from flavor physics. Fermion masses and mixing angles are fit at the GUT scale. The ranges of the bulk mass parameters are determined using a ${\chi }^2$ fit taking into consideration the variation in $\mathcal{O}(1)$ parameters. In the hadronic sector, the heavy top quark requires large bulk mass parameters localizing the right-handed top quark close to the IR brane. Two cases of neutrino masses are considered: (a) Planck scale lepton number violation and (b) Dirac neutrino masses. Contrary to the case of weak scale RS models, both these cases give reasonable fits to the data, with the Planck scale lepton number violation fitting slightly better compared to the Dirac case. In the supersymmetric version, the fits are not significantly different except for the variation in $\tan \beta$. If the Higgs superfields and the supersymmetry breaking spurion are localized on the same brane, then the structure of the sfermion masses are determined by the profiles of the zero modes of the hypermultiplets in the bulk. Trilinear terms have the same structure as the Yukawa matrices. The resultant squark spectrum is around $\sim 2–3\mathrm{TeV}$ required by the light Higgs mass to be around 125 GeV and to satisfy the flavor violating constraints.