We analyze the velocity dispersion for eight of the Milky Way dwarf spheroidal satellites in the context of finite temperature scalar field dark matter. In this model the finite temperature allows the scalar field to be in configurations that possess excited states, a feature that has proved to be necessary in order to explain the asymptotic rotational velocities found in low surface brightness (LSB) galaxies. In this work we show that excited states are not only important in large galaxies but also have visible effects in dwarf spheroidals. Additionally, we stress that contrary to previous works where the scalar field dark matter halos are consider to be purely Bose-Einstein condensates, the inclusion of excited states in these halo configurations provides a consistent framework capable of describing LSB and dwarf galaxies of different sizes without arriving to contradictions within the scalar field dark matter model. Using this new framework we find that the addition of excited states accounts very well for the raise in the velocity dispersion in Milky Way dwarf spheroidal galaxies improving the fit compared to the one obtained assuming all the dark matter to be in the form of a Bose-Einstein condensate.

In view of its physical importance in predicting the order of chiral phase transitions in QCD and frustrated spin systems, we perform the conformal bootstrap program of [$O(n)\times O(2)$]-symmetric conformal field theories in $d=3$ dimensions with a special focus on $n=3$ and 4. The existence of renormalization group fixed points with these symmetries has been controversial over the years, but our conformal bootstrap program provides nonperturbative evidence. In both the $n=3$ and 4 cases, we find singular behaviors in the bounds of scaling dimensions of operators in two different sectors, which we claim correspond to chiral and collinear fixed points, respectively. In contrast to the cases with larger values of $n$, we find no evidence for the antichiral fixed point. Our results indicate the possibility that the chiral phase transitions in QCD and frustrated spin systems are continuous with the critical exponents that we predict from the conformal bootstrap program.

We investigate the chiral phase structure of the Gross-Neveu model on a 2D lattice by using the Borici-Creutz fermion action. We present a strong coupling analysis of the Gross-Neveu model and perform a hybrid Monte Carlo simulation of the model with Borici-Creutz fermions. Both analytic and lattice results show a second-order chiral phase transition.

We calculate the $\mathcal{O}({\alpha }_s^3)$ short-distance, QCD collinear-factorized coefficient functions for all partonic channels that include the production of a heavy quark pair at short distances. This provides the first power correction to the collinear-factorized inclusive hadronic production of heavy quarkonia at large transverse momentum, $p_T$, including the full leading-order perturbative contributions to the production of heavy quark pairs in all color and spin states employed in NRQCD treatments of this process. We discuss the role of the first power correction in the production rates and the polarizations of heavy quarkonia in high-energy hadronic collisions. The consistency of QCD collinear factorization and nonrelativistic QCD factorization applied to heavy quarkonium production is also discussed.

Short-pulse effects are investigated for the nonlinear Breit-Wheeler process, i.e. the production of an electron-positron pair induced by a gamma photon inside an intense plane-wave laser pulse. To obtain the total pair-creation probability we verify (to leading-order) the cutting rule for the polarization operator in the realm of strong-field QED by an explicit calculation. Using a double-integral representation for the leading-order contribution to the polarization operator, compact expressions for the total pair-creation probability inside an arbitrary plane-wave background field are derived. Correspondingly, the photon wave function including leading-order radiative corrections in the laser field is obtained via the Schwinger-Dyson equation in the quasistatic approximation. Moreover, the influence of the carrier-envelope phase and of the laser pulse shape on the total pair-creation probability in a linearly polarized laser pulse is investigated, and the validity of the (local) constant-crossed field approximation analyzed. It is shown that with presently available technology pair-creation probabilities of the order of ten percent could be reached for a single gamma photon.

Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the LHC are reported. Data were collected in proton-proton collisions at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of $20.3{\mathrm{fb}}^{-1}$. The observed data are well described by the expected Standard Model backgrounds. The expected (observed) upper limit on the fiducial cross section for the production of events with a photon and large missing transverse momentum is 6.1 (5.3) fb at 95% confidence level. Exclusion limits are presented on models of new phenomena with large extra spatial dimensions, supersymmetric quarks, and direct pair production of dark-matter candidates.

Motivated by the parametrized post-Einsteinian (ppE) scheme devised by Yunes and Pretorius, which introduces corrections to the post-Newtonian coefficients of the frequency domain gravitational waveform in order to emulate alternative theories of gravity, we compute analytical time domain waveforms that, after a numerical Fourier transform, aim to represent (phase corrected only) ppE waveforms. In this formalism, alternative theories manifest themselves via corrections to the phase and frequency, as predicted by general relativity (GR), at different post-Newtonian (PN) orders. To present a generic test of alternative theories of gravity, we assume that the coupling constant of each alternative theory is manifestly positive, allowing corrections to the GR waveforms to be either positive or negative. By exploring the capabilities of massive black hole binary GR waveforms in the detection and parameter estimation of corrected time domain ppE signals, using the current eLISA configuration (as presented for the European Space Agency Cosmic Vision L3 mission), we demonstrate that for corrections arising at higher than 1PN order in phase and frequency GR waveforms are sufficient for both detecting and estimating the parameters of alternative theory signals. However, for theories introducing corrections at the 0 and 0.5PN orders, GR waveforms are not capable of covering the entire parameter space, requiring the use of non-GR waveforms for detection and parameter estimation.

The late-time cosmological dynamics of disformal gravity are investigated using dynamical systems methods. It is shown that in the general case there are no stable attractors that screen fifth forces locally and simultaneously describe a dark energy dominated universe. Viable scenarios have late-time properties that are independent of the disformal parameters and are identical to the equivalent conformal quintessence model. Our analysis reveals that configurations where the Jordan frame metric becomes singular are only reached in the infinite future, thus explaining the natural pathology resistance observed numerically by several previous works. The viability of models where this can happen is discussed in terms of both the cosmological dynamics and local phenomena. We identify a special parameter tuning such that there is a new fixed point that can match the presently observed dark energy density and equation of state. This model is unviable when the scalar couples to the visible sector but may provide a good candidate model for theories where only dark matter is disformally coupled.

Symmetries play a crucial role in physics and, in particular, the Noether symmetries are a useful tool both to select models motivated at a fundamental level, and to find exact solutions for specific Lagrangians. In this work, we apply Noether point symmetries to metric-Palatini hybrid gravity in order to select the $f(\mathcal{R})$ functional form and to find analytical solutions for the field equations and for the related Wheeler-DeWitt (WDW) equation. It is important to stress that hybrid gravity implies two definitions of curvature scalar: $R$ for standard metric gravity and $\mathcal{R}$ for further degrees of freedom related to the Palatini formalism. We use conformal transformations in order to find out integrable $f(\mathcal{R})$ models. In this context, we explore two conformal transformations of the forms $d\tau =N(a)dt$ and $d\tau =N(\varphi )dt$. For the former, we found two cases of $f(\mathcal{R})$ functions where the field equations admit Noether symmetries. In the second case, the Lagrangian reduces to a Brans-Dicke-like theory with a general coupling function. For each case, it is possible to transform the field equations by using normal coordinates to simplify the dynamical system and to obtain exact solutions. Furthermore, we perform quantization and derive the WDW equation for the minisuperspace model. The Lie point symmetries for the WDW equation are determined and used to find invariant solutions. In particular, hybrid gravity introduces a further term in cosmic dynamics whose interpretation is related to the signature of an auxiliary scalar field. Solutions are compared with $\mathrm{\Lambda }\mathrm{CDM}$.

The simplest possible classical model leading to a cosmological bounce is examined in the light of the non-Gaussianities it can generate. Concentrating solely on the transition between contraction and expansion, and assuming initially purely Gaussian perturbations at the end of the contracting phase, we find that the bounce acts as a source such that the resulting value for the post-bounce $f_{\mathrm{NL}}$ may largely exceed all current limits, to the point of potentially casting doubts on the validity of the perturbative expansion. We conjecture that if one can assume that the non-Gaussianity production depends only on the bouncing behavior of the scale factor and not on the specifics of the model examined, then many realistic models in which a nonsingular classical bounce takes place could exhibit a generic non-Gaussianity excess problem that would need to be addressed for each case.

We relate the observed hemispherical anisotropy in the cosmic microwave radiation data to an inhomogeneous power spectrum model. The hemispherical anisotropy can be parametrized in terms of the dipole modulation model. This model leads to correlations between spherical harmonic coefficients corresponding to multipoles, $l$ and $l+1$. We extract the $l$ dependence of the dipole modulation amplitude, $A$, by making a fit to the WMAP and PLANCK CMBR data. We propose an inhomogeneous power spectrum model and show that it also leads to correlations between multipoles, $l$ and $l+1$. The model parameters are determined by making a fit to the data. The spectral index of the inhomogeneous power spectrum is found to be consistent with zero.

Inflationary attractors predict the spectral index and tensor-to-scalar ratio to take specific values that are consistent with Planck. An example is the universal attractor for models with a generalized nonminimal coupling, leading to Starobinsky inflation. In this paper we demonstrate that it also predicts a specific relation between the amplitude of the power spectrum and the number of $e$-folds. The length and height of the inflationary plateau are related via the nonminimal coupling: in a wide variety of examples, the observed power normalization leads to at least 55 flat $e$-foldings. Prior to this phase, the inflationary predictions vary and can account for the observational indications of power loss at large angular scales.

The photothermal transfer function from absorbed power incident on a dielectric mirror to the effective mirror position is calculated using the coating design as input. The effect is found to change in amplitude and sign for frequencies corresponding to diffusion length comparable to the coating thickness. Transfer functions are calculated for the $Ti$-doped ${\mathrm{Ta}}_2{\mathrm{O}}_5:{\mathrm{SiO}}_2$ coating used in Advanced LIGO and for a crystalline ${\mathrm{Al}}_{\mathrm{x}}{\mathrm{Ga}}_{1-\mathrm{x}}\mathrm{As}$ coating. The shape of the transfer function at high frequencies is shown to be a sensitive indicator of the effective absorption depth, providing a potentially powerful tool to distinguish coating-internal absorption from surface contamination related absorption. The sign change of the photothermal effect could also be useful to stabilize radiation pressure-based optomechanical systems. High frequency corrections to the previously published thermo-optic noise estimates are also provided. Finally, estimating the quality of the thermo-optic noise cancellation occurring in fine-tuned ${\mathrm{Al}}_{\mathrm{x}}{\mathrm{Ga}}_{1-\mathrm{x}}\mathrm{As}$ coatings requires the detailed heat flow analysis done in this paper.

Many dark energy (DE) models have been proposed, in recent years, to explain the acceleration of the expansion of the Universe. It seems necessary to differentiate the various DE models in order to check the viability of each model. The statefinder diagnostic is a useful method to accomplish this. In this paper, we investigate the statefinder diagnosis parameters for the holographic dark energy (HDE) model in two cosmological setups. First, we study the statefinder diagnosis for HDE in the context of a flat Friedmann-Robertson-Walker Universe in Einstein gravity. Then, we extend our study to the Dvali-Gabadadze-Porrati braneworld framework. For the system’s IR cutoff we choose the Hubble radius and the Granda-Oliveros cutoff inspired by the Ricci scalar curvature. We plot the evolution of statefinder parameters $\{r,s\}$ in terms of the redshift parameter $z$. We also compare the results with those obtained for statefinder diagnosis parameters of other DE models, in particular the $\mathrm{\Lambda }\mathrm{CDM}$ model.

Comparatively few searches have been performed for violations of local Lorentz invariance in the pure-gravity sector. We show that tests of short-range gravity are sensitive to a broad class of unconstrained and novel signals that depend on the experimental geometry and on sidereal time.

A radion in a scenario with a warped extra dimension can be lighter than the Higgs boson, even if the Kaluza-Klein excitation modes of the graviton turn out to be in the multi-TeV region. The discovery of such a light radion would be a gateway to new physics. We show how the two-photon mode of decay can enable us to probe a radion in the mass range 60–110 GeV. We take into account the diphoton background, including fragmentation effects, and include cuts designed to suppress the background to the maximum possible extent. Our conclusion is that, with an integrated luminosity of $3000{\mathrm{fb}}^{-1}$ or less, the next run of the Large Hadron Collider should be able to detect a radion in this mass range, with a significance of 5 standard deviations or more.

We discuss within the framework of effective four–fermion scalar interaction the phenomenology of a weakly interacting massive particle (WIMP) Dirac dark matter candidate which is exothermic (i.e., is metastable and interacts with nuclear targets down-scattering to a lower-mass state) and Ge-phobic (i.e., whose couplings to quarks violate isospin symmetry leading to a suppression of its cross section off Germanium targets). We discuss the specific example of the CDMS–II Silicon three-candidate effect showing that a region of the parameter space of the model exists where WIMP scatterings can explain the excess in compliance with other experimental constraints, while at the same time the dark matter particle can have a thermal relic density compatible with observation. In this scenario the metastable state $\chi$ and the lowest-mass one ${\chi }^{\prime }$ have approximately the same density in the present Universe and in our Galaxy, but direct detection experiments are only sensitive to the down-scatters of $\chi$ to ${\chi }^{\prime }$. We include a discussion of the recently calculated next-to-leading order corrections to dark matter–nucleus scattering, showing that their impact on the phenomenology is typically small, but can become sizable in the same parameter space where the thermal relic density is compatible to observation.

We investigate the critical endpoint of finite temperature phase transition of $N_f=3$ QCD at zero chemical potential. We employ the renormalization-group improved Iwasaki gauge action and nonperturbatively $O(a)$-improved Wilson-clover fermion action. The critical endpoint is determined by using the intersection point of kurtosis for the temporal size $N_t=4$, 6, 8. Spatial sizes of $N_l=6–16$ ($N_t=4$), 10–24 ($N_t=6$), and 12–24 ($N_t=8$) are employed. We find that $N_t=4$ is out of the scaling region. Using results for $N_t=6$ and 8 and making linear extrapolations in $1/N_t^2$, we obtain $\sqrt{t_0}{T}_{\mathrm{E}}=0.0988(14)(9)$, $\sqrt{t_0}{m}_{\mathrm{PS},\mathrm{E}}=0.2274(52)(108)$, and $m_{\mathrm{PS},\mathrm{E}}/T_{\mathrm{E}}=2.302(62)(13)$, where the first error is statistical error, the second error is systematic error, and $m_{\mathrm{PS}}$ is the pseudoscalar meson mass. If one uses $1/\sqrt{t_0}=1.347(30)\mathrm{GeV}$, as reported by Borsanyi et al., one finds $T_{\mathrm{E}}=133(2)(1)(3)\mathrm{MeV}$, $m_{\mathrm{PS},\mathrm{E}}=306(7)(14)(7)\mathrm{MeV}$, and $m_{\mathrm{PS},\mathrm{E}}/m_{\mathrm{PS}}^{\text{phys},\text{sym}}=0.745(17)(35)(17)$, where the third error comes from the error of $\sqrt{t_0}$ and $m_{\mathrm{PS}}^{\text{phys},\text{sym}}=\sqrt{(m_{\pi }^2+2m_K^2)/3}$. Our current estimation of $\sqrt{t_0}{m}_{\mathrm{PS},\mathrm{E}}$ in the continuum limit is about 25% smaller than the SU(3) symmetric point.