We use distribution amplitudes of the light $\Sigma$ baryon and the most general form of the interpolating current for heavy ${\Sigma }_b$ baryon to investigate the semileptonic ${\Sigma }_b\to \Sigma l^{+}{l}^{-}$ transition in light cone QCD sum rules. We calculate all 12 form factors responsible for this transition and use them to evaluate the branching ratio of the considered channel. The order of branching fraction shows that this channel can be detected at LHC.

The phase structure of two-flavor QCD is investigated at real isospin and imaginary quark chemical potentials by using the Polyakov-loop extended Nambu–Jona-Lasinio model. In the region, parity symmetry is spontaneously broken by the pion-superfluidity phase transition, whereas charge-conjugation symmetry is spontaneously violated by the Roberge-Weiss transition. The chiral (deconfinement) crossover at zero isospin and quark chemical potentials is a remnant of the parity (charge-conjugation) violation. The interplay between the parity and charge-conjugation violations are analyzed, and it is investigated how the interplay is related to the correlation between the chiral and deconfinement crossovers at zero isospin and quark chemical potentials.

We propose the minimal (least) version of the supersymmetric standard model which can solve the hierarchy problem in the same way as the so-called minimal supersymmetric standard model and presents solutions to some of its problems. Supersymmetry is broken in a secluded sector and mediated to the observable sector by messengers of a gauge group $G$ under which the first two generations transform. The group $G$ spontaneously breaks (almost) supersymmetrically at a scale at most a few orders of magnitude below the scale of gauge messengers $M_{*}\sim {10}^{15}\mathrm{GeV}$. By gauge mediation, sfermions of the first two generations acquire supersymmetry breaking masses $\widehat{m}\sim 10\mathrm{TeV}$. Supersymmetry breaking is also mediated by gravity which generates masses for all sfermions, Higgsinos, and gauginos at the TeV scale and can provide appropriate values to the $\mu$ and $B_{\mu }$ parameters by $D$-term effective operators. If gravity mediation is minimal flavor violating there is no supersymmetric flavor problem. In the presence of $R$-parity dark matter can be the lightest neutralino, as in the minimal supersymmetric standard model, and the LHC model phenomenology is characterized by the fact that only third-generation squarks and sleptons are present.

The status of light $I=0$, $J^{PC}=2^{++}$, and $0^{++}$ mesons is discussed, particularly the separation of $n\overline{n}$ and $s\overline{s}$ states. They fall into a simple scheme except for $f_2(1810)$. A case is made that this has been confused with the $f_0(1790)$. It should be possible to check this with existing or forthcoming data.

In grand unified theories with gauge groups larger than $SU(5)$, the multiplets that contain the known quarks and leptons also contain fermions that are singlets under the standard model gauge group. Some of these could be the dark matter of the Universe. Grand unified theories can also have accidental $U(1)$ global symmetries (analogous to $B-L$ in minimal $SU(5)$) that can stabilize dark matter. These ideas are illustrated in an $SU(6)$ model.

We report a measurement of the inclusive semileptonic branching fraction of the $B_s$ meson using data collected with the BABAR detector in the center-of-mass energy region above the ${\rm Y}(4S)$ resonance. We use the inclusive yield of $\varphi$ mesons and the $\varphi$ yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of $B_s$ mesons relative to all $B$ mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the $B_s$ meson is determined to be $\mathcal{B}(B_s\to \ell \nu X)={9.5}_{-2.0}^{+2.5}(\mathrm{stat}{)}_{-1.9}^{+1.1}(\mathrm{syst})\%$, where $\ell$ indicates the average of $e$ and $\mu$.

We study the effect of the quadratic field strength correction to the usual Maxwell field on the holographic dual models in the backgrounds of AdS black hole and AdS soliton. We find that in the black hole background, the higher correction to the Maxwell field makes the condensation harder to form and changes the expected relation in the gap frequency. This effect is similar to that caused by the curvature correction. However, in the soliton background we find that, unlike the curvature effect correction, the correction to the Maxwell field does not influence the holographic superconductor and insulator phase transition.

We recalculate the first analytic correction beyond proximity force approximation for a sphere in front of a plane for a scalar field and for the electromagnetic field. We use the method of Bordag and Nikolaev [J. Phys. A 41, 164002 (2008)]. We confirm their result for Dirichlet boundary conditions whereas we find a different one for Robin, Neumann and conductor boundary conditions. The difference can be traced back to a sign error. As a result, the corrections depend on the Robin parameter. Agreement is found with a very recent method of derivative expansion.

We investigate finite temperature effects in O’Raifeartaigh models with global symmetries which exhibit supersymmetry breaking at a metastable vacuum accompanied by $U(1{)}_R$ breaking. The pseudomoduli field is stabilized at one-loop order at zero temperature within some coupling parameter region. We analyze the behavior of the parameter space according to nonzero temperatures and find that the parameter region which allows $U(1{)}_R$ breaking is considerably extended at sufficiently low temperature, even though it shrinks down at high temperature as expected. We also discuss the thermal history of the metastable supersymmetry breaking vacuum.

We demonstrate that the integrated gravitational wave signal of type Ia supernovae (SNe Ia) in the single-degenerate channel out to cosmological distances gives rise to a continuous background to spaceborne gravitational wave detectors, including the Big Bang Observer and Deci-Hertz Interferometer Gravitational wave Observatory planned missions. This gravitational wave background from SNe Ia acts as a noise background in the frequency range 0.1–10 Hz, which heretofore was thought to be relatively free from astrophysical sources apart from neutron-star and white-dwarf binaries, and therefore a key window in which to study primordial gravitational waves generated by inflation. While inflationary energy scales of $\gtrsim {10}^{16}\mathrm{GeV}$ yield inflationary gravitational wave backgrounds in excess of our range of predicted backgrounds, for lower energy scales of $\sim {10}^{15}\mathrm{GeV}$, the inflationary gravitational wave background becomes comparable to the noise background from SNe Ia.

We study the possibility of extracting model independent information about the dynamics of the Universe by using cosmography. We intend to explore it systematically, to learn about its limitations and its real possibilities. Here we are sticking to the series expansion approach on which cosmography is based. We apply it to different data sets: Supernovae type Ia (SNeIa), Hubble parameter extracted from differential galaxy ages, gamma ray bursts, and the baryon acoustic oscillations data. We go beyond past results in the literature extending the series expansion up to the fourth order in the scale factor, which implies the analysis of the deceleration $q_0$, the jerk $j_0$, and the snap $s_0$. We use the Markov chain Monte Carlo method (MCMC) to analyze the data statistically. We also try to relate direct results from cosmography to dark energy (DE) dynamical models parametrized by the Chevallier-Polarski-Linder model, extracting clues about the matter content and the dark energy parameters. The main results are: (a) even if relying on a mathematical approximate assumption such as the scale factor series expansion in terms of time, cosmography can be extremely useful in assessing dynamical properties of the Universe; (b) the deceleration parameter clearly confirms the present acceleration phase; (c) the MCMC method can help giving narrower constraints in parameter estimation, in particular for higher order cosmographic parameters (the jerk and the snap), with respect to the literature; and (d) both the estimation of the jerk and the DE parameters reflect the possibility of a deviation from the $\Lambda \mathrm{CDM}$ cosmological model.

We introduce a new kludge scheme to model the dynamics of generic extreme mass-ratio inspirals (stellar compact objects spiraling into a spinning supermassive black hole) and to produce the gravitational waveforms that describe the gravitational-wave emission of these systems. This scheme combines tools from different techniques in General Relativity: It uses amultipolar, post-Minkowskian expansion for the far-zone metric perturbation (which provides the gravitational waveforms, here taken up to mass hexadecapole and current octopole order) and for the local prescription of the self-force (since we are lacking a general prescription for it); a post-Newtonian expansion for the computation of the multipole moments in terms of the trajectories; and a BH perturbation theory expansion when treating the trajectories as a sequence of self-adjusting Kerr geodesics. The orbital evolution is thus equivalent to solving the geodesic equations with time-dependent orbital elements, as dictated by the multipolar post-Minkowskian radiation-reaction prescription. To complete the scheme, both the orbital evolution and wave generation require to map the Boyer-Lindquist coordinates of the orbits to the harmonic coordinates in which the different multipolar post-Minkowskian quantities have been derived, a mapping that we provide explicitly in this paper. This new kludge scheme is thus a combination of approximations that can be used to model generic inspirals of systems with extreme mass ratios to systems with more moderate mass ratios, and hence can provide valuable information for future space-based gravitational-wave observatories like the Laser Interferometer Space Antenna and even for advanced ground detectors. Finally, due to the local character in time of our multipolar post-Minkowskian self-force, this scheme can be used to perform studies of the possible appearance of transient resonances in generic inspirals.

The causal entropic principle aims to predict the unexpectedly small value of the cosmological constant $\Lambda$ using a weighting by entropy increase on causal diamonds. The original work assumed a purely isotropic and homogeneous cosmology. But even the level of inhomogeneity observed in our universe forces reconsideration of certain arguments about entropy production. In particular, we must consider an ensemble of causal diamonds associated with each background cosmology and we can no longer immediately discard entropy production in the far future of the universe. Depending on our choices for a probability measure and our treatment of black hole evaporation, the prediction for $\Lambda$ may be left intact or dramatically altered.

Time delays in strong gravitational lensing systems possess significant complementarity with distance measurements to determine the dark energy equation of state, as well as the matter density and Hubble constant. Time delays are most useful when observations permit detailed lens modeling and variability studies, requiring high resolution imaging, long time monitoring, and rapid cadence. We quantify the constraints possible between a sample of 150 such time delay lenses and a near term supernova program, such as might become available from an Antarctic telescope such as the KDUST and the Dark Energy Survey. Adding time delay data to supernovae plus cosmic microwave background information can improve the dark energy figure of merit by almost a factor 5 and determine the matter density ${\Omega }_m$ to 0.004, the Hubble constant $h$ to 0.7%, and the dark energy equation of state time variation $w_a$ to 0.26, systematics permitting.

We investigate the $Q$-ball decay in the gauge-mediated supersymmetry breaking. $Q$ balls decay mainly into nucleons, and partially into gravitinos, while they are kinematically forbidden to decay into sparticles which would be cosmologically harmful. This is achieved by the $Q$-ball charge small enough to be unstable for the decay and large enough to be protected kinematically from an unwanted decay channel. We can then have right amounts of the baryon asymmetry and the dark matter of the universe, evading any astrophysical and cosmological observational constraints such as the big bang nucleosynthesis, which has not been treated properly in the literatures.

We study the hybrid inflationary potential in a regime where the defect field is light, and more than 60 e-folds of accelerated expansion occur after the symmetry-breaking transition. Using analytic and numerical techniques, we then identify parameter values within this regime for which the statistics of the primordial curvature perturbation are significantly non-Gaussian. Focusing on this range of parameters, we provide a specific example which leads to an observationally consistent power spectrum, and a level of non-Gaussianity within current WMAP bounds and in reach of the Planck satellite. An interesting feature of this example is that the initial conditions at horizon crossing appear quite natural.

The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an $E^{-2}$ differential energy spectrum the limit on the single-flavor neutrino is $E^2\mathrm{d}N/\mathrm{d}E<1.74\times {10}^{-7}\mathrm{GeVc}{\mathrm{m}}^{-2}{\mathrm{s}}^{-1}\mathrm{s}{\mathrm{r}}^{-1}$ at 90% C.L. in the energy range $1\times {10}^{17}\mathrm{eV}<E<1\times {10}^{20}\mathrm{eV}$.

We discuss radiation reaction effects on charges propagating in ultraintense laser fields. Our analysis is based on an analytic solution of the Landau-Lifshitz equation. We suggest quantifying radiation reaction in terms of a symmetry breaking parameter associated with the violation of null translation invariance in the direction opposite to the laser beam. As the Landau-Lifshitz equation is nonlinear, the energy transfer within the pulse is rather sensitive to initial conditions. This is elucidated by comparing colliding and fixed target modes in electron laser collisions.

Using the QCD sum rules we test if the charmonium-like structure $Y(4260)$, observed in the $J/\psi \pi \pi$ invariant mass spectrum, can be described as a exotic state, with a $J/\psi f_0(980)$ molecular current with $J^{PC}=1^{--}$. By exotic we mean a more complex structure than the simple quark-antiquark state and not exotic $J^{PC}$ quantum numbers. We consider the contributions of condensates up to dimension six and we work at leading order in ${\alpha }_s$. We keep terms which are linear in the strange quark mass $m_s$. The mass obtained for such state is $m_Y=(4.67\pm 0.09)\mathrm{GeV}$, when the vector and scalar mesons are in color singlet configurations. We conclude that the proposed current can better describe the $Y(4660)$ state that could be interpreted as a $\Psi (2S)f_0(980)$ molecular state. We also use different $J^{PC}=1^{--}$ currents to study the recently observed $Y_b(10890)$ state. Our findings indicate that the $Y_b(10890)$ can be well described by a scalar-vector tetraquark current.