In their Comment, Grientschnig and Lira derive a Bayesian reference prior for cross section measurements that turns out to be identical to one obtained by L. Demortier, S. Jain, and H. B. Prosper [Phys. Rev. D 82, 034002 (2010)]. Since the new derivation uses a different sequence of compact sets to normalize the reference prior, this result points to a certain robustness of posterior inferences in this approach. However, Grientschnig and Lira make some additional claims about their methodology, which we show to be unwarranted.

A Bayesian reference analysis of a typical scenario of high energy physics has recently been performed [Phys. Rev. D 82, 034002 (2010)]. The reference prior with partial information (and hence also the posterior) were found to depend on the sequence of subsets of the parameter space used for a normalization process. A particular choice of the subsets leading to a proper posterior was advocated. Here it is shown that this choice differs from the natural sequence of subsets in the “original parametrization” of the problem, which has been generally recommended elsewhere. Although this questions the manner in which the commented result was obtained, the result itself is corroborated because the present derivation based on a different argument yields a reference prior of the same functional form.

We analyze how a large value of the leptonic mixing angle ${\theta }_{13}^{\mathrm{MNS}}$ can be generated via charged lepton corrections in unified flavor models, using novel combinations of Clebsch-Gordan factors for obtaining viable quark-lepton mass ratios for the first two families. We discuss how these Clebsch-Gordan factors affect the relations between down-type quark mixing and charged lepton mixing in SU(5) grand unified theories and Pati-Salam unified models and calculate the resulting possible predictions for ${\theta }_{13}^{\mathrm{MNS}}$ for models with ${\theta }_{13}^{\nu }$, ${\theta }_{13}^e\ll {\theta }_{12}^e$. While symmetric mass matrices with zero (1, 1) elements always lead to comparatively small ${\theta }_{13}^{\mathrm{MNS}}\approx 2.8°$, we find novel combinations of Clebsch-Gordan factors for nonsymmetric mass matrices which can yield ${\theta }_{13}^{\mathrm{MNS}}\approx 5.1°$, 6.1°, 7.6°, or 10.1°, as favored by the current experimental hints for large ${\theta }_{13}^{\mathrm{MNS}}$. We discuss applications to classes of models with underlying tribimaximal or bimaximal mixing in the neutrino sector.

The Large Hadron Collider (LHC) is anticipated to provide signals of new physics at the TeV scale, which are likely to involve production of a weakly interacting massive particle dark matter candidate. The International Linear Collider (ILC) is to sort out these signals and lead us to some viable model of the new physics at the TeV scale. In this article, we discuss how the ILC can discriminate new physics models, taking the following three examples: the inert Higgs model, the supersymmetric model, and the littlest Higgs model with $T$-parity. These models predict dark matter particles with different spins, 0, $1/2$, and 1, respectively, and hence comprise representative scenarios. Specifically, we focus on the pair production process, $e^{+}{e}^{-}\to {\chi }^{+}{\chi }^{-}\to {\chi }^0{\chi }^0{W}^{+}{W}^{-}$, where ${\chi }^0$ and ${\chi }^{\pm }$ are the weakly interacting massive particle dark matter and a new charged particle predicted in each of these models. We then evaluate how accurately the properties of these new particles can be determined at the ILC and demonstrate that the ILC is capable of identifying the spin of the new charged particle and discriminating these models.

We discuss the positive indications of a possible dark matter signal in direct detection experiments in terms of a mechanism of interaction between the dark matter particle and the nuclei occurring via the exchange of a light mediator, resulting in a long-range interaction. We analyze the annual modulation results observed by the DAMA and CoGeNT experiments and the observed excess of events of CRESST. In our analysis, we discuss the relevance of uncertainties related to the velocity distribution of galactic dark matter and to the channeling effect in NaI. We find that a long-range force is a viable mechanism, which can provide full agreement between the reconstructed dark matter properties from the various experimental data sets, especially for masses of the light mediator in the 10–30 MeV range and a light dark matter with a mass around 10 GeV. The relevant bounds on the light mediator mass and scattering cross section are then derived, should the annual modulation effects be due to this class of long-range forces.

Dijet anomaly reported by the CDF (Collider Detector at Fermilab) collaboration in 1.96 TeV $p\overline{p}$ collisions is investigated within the standard model by considering effects of parton distribution functions on various processes: $W+\mathrm{\text{dijet}}$, $Z+\mathrm{\text{dijet}}$, $WW$, $ZW$, and top production. Since the anomalous peak exists in the dijet-mass region of 140 GeV with the $p\overline{p}$ center-of-mass energy $\sqrt{s}=1.96\mathrm{TeV}$, a relevant momentum fraction $x$ of partons is roughly 0.1. In this $x$ region, recent HERMES semi-inclusive charged-lepton scattering experiment indicated that the strange-quark distribution could be very different from a conventional one, which has been used for many years, based on opposite-sign dimuon measurements in neutrino deep inelastic scattering. We investigate effects of such variations in the strange-quark distribution $s(x)$ on the anomaly. We find that distributions of $W+\mathrm{\text{dijets}}$ and other process are affected by the strange-quark modifications in wide dijet-mass regions including the 140 GeV one. Since the CDF anomaly was observed in the shoulder region of the dijet-mass distribution, a slight modification of the distribution shape could explain at least partially the CDF excess. Therefore, it is important to consider such effects within the standard model for judging whether the CDF anomaly indicates new physics beyond the standard model. We also show modification effects of the strange-quark distribution in the LHC (Large Hadron Collider) kinematics, where cross sections are sensitive to a smaller-$x$ region of $s(x)$.

The prediction of backgrounds to new-physics signals in topologies with large missing transverse energy and jets is important to new-physics searches at the LHC. Following a CMS study, we investigate theoretical issues in using measurements of $\gamma +2$-jet production to predict the irreducible background to searches for missing energy plus two jets that originates from $Z+2$-jet production where the $Z$ boson decays to neutrinos. We compute ratios of $\gamma +2$-jet to $Z+2$-jet production cross sections and kinematic distributions at next-to-leading order in ${\alpha }_s$, as well as using a parton shower matched to leading-order matrix elements. The former ratios rely on the first next-to-leading-order calculation of $\gamma +2$-jet production at a hadron collider. We find that the ratios obtained in the two approximations are quite similar, making $\gamma +2$-jet production a theoretically reliable estimator for the missing energy plus two jets background. We employ a Frixione-style photon isolation, but we also show that for isolated prompt-photon production at high transverse momentum the difference between this criterion and the standard-cone isolation used by CMS is small.

A complete next-to-leading-order calculation in ${\alpha }_s$ for the $J/\psi$ and ${\psi }^{\prime }$ prompt production at the Tevatron, LHC, and RHIC in nonrelativistic QCD is presented. We argue that the next-to-next-to-leading-order color-singlet contribution may not be so important as to resolve the large discrepancy between theory and experiment in $J/\psi$ large $p_T$ production cross sections. Therefore, a complete next-to-leading-order calculation, including both color-singlet and color-octet contribution, is necessary and essential to give a good description for $J/\psi$ and ${\psi }^{\prime }$ production. We also study the methods to fit the long-distance matrix elements using either two linear combined matrix elements or three matrix elements, and find these two methods can give consistent results. Compared with the measurements at the LHC and RHIC for prompt $J/\psi$ and ${\psi }^{\prime }$ production, our predictions are found to agree with all data. In particular, the recently released large $p_T$ data (up to 60–70 GeV) at the LHC are in good agreement with our predictions. Our results imply that the universality of color-octet matrix elements holds approximately in charmonium hadroproduction, when one uses fixed-order perturbative calculation to describe data (the data in small $p_T$ region are not included). Our work may provide a new test for the universality of color-octet matrix elements, and the color-octet mechanism in general.

We examine the interplay between Higgs mediation of dark-matter annihilation and scattering on one hand and the invisible Higgs decay width on the other, in a generic class of models utilizing the Higgs portal. We find that, while the invisible width of the Higgs to dark matter is now constrained for a minimal singlet scalar dark matter particle by experiments such as XENON100, this conclusion is not robust within more generic examples of Higgs mediation. We present a survey of simple dark matter scenarios with $m_{\mathrm{DM}}<m_h/2$ and Higgs portal mediation, where direct-detection signatures are suppressed, while the Higgs width is still dominated by decays to dark matter.

We consider the scattering of fermions off antifermions with spin $1/2$ and $3/2$. Starting from helicity partial-wave scattering amplitudes, we derive transformations that eliminate all kinematical constraints. Such amplitudes are expected to satisfy partial-wave dispersion relations and therefore provide a suitable basis for data analysis and the construction of effective field theories. Our derivation relies on a decomposition of the various scattering amplitudes into suitable sets of invariant functions.

If general relativity is spontaneously induced, that is if the reciprocal Newton constant serves as a vacuum expectation value, the electrically charged black hole limit is governed by a Davidson-Gurwich phase transition which occurs precisely at the would-have-been outer horizon. The transition profile which connects the exterior Reissner-Nordstrom solution with the novel interior is analytically derived. The inner core is characterized by a vanishing spatial volume and constant surface gravity, and in some respects, resembles a maximally stretched horizon. The Komar mass residing inside any concentric interior sphere is proportional to the surface area of that sphere, and consequently, is non-negative definite and furthermore nonsingular at the origin. The Kruskal structure is recovered, admitting the exact Hawking imaginary time periodicity, but unconventionally, with the conic defect defused at the origin. The corresponding holographic entropy packing locally saturates the ’t Hooft-Susskind-Bousso holographic bound, thus making the core Nature’s ultimate information storage.

Previous studies have demonstrated that gravitational radiation reliably encodes information about the natural emission direction of the source (e.g., the orbital plane). In this paper, we demonstrate that these orientations can be efficiently estimated by the principal axes of $⟨L_{(a}{L}_{b)}⟩$, an average of the action of rotation group generators on the Weyl tensor at asymptotic infinity. Evaluating this average at each time provides the instantaneous emission direction. Further averaging across the entire signal yields an average orientation, closely connected to the angular components of the Fisher matrix. The latter direction is well-suited to data analysis and parameter estimation when the instantaneous emission direction evolves significantly. Finally, in the time domain, the average $⟨L_{(a}{L}_{b)}⟩$ provides fast, invariant diagnostics of waveform quality.

Empirically determining the averaged variations of the orbital parameters of the stars orbiting the Supermassive Black Hole (SBH) hosted by the Galactic center (GC) in Sgr ${\mathrm{A}}^{*}$ is, in principle, a valuable tool to test the General Theory of Relativity (GTR), in regimes far stronger than those tested so far, and certain key predictions of it like the “no-hair” theorems. We analytically work out the long-term variations of all the six osculating Keplerian orbital elements of a test particle orbiting a nonspherical, rotating body with quadrupole moment $Q_2$ and angular momentum $\mathit{S}$ for a generic spatial orientation of its spin axis $\widehat{\mathit{k}}$. This choice is motivated by the fact that, basically, we do not know the position in the sky of the spin axis of the SBH in Sgr ${\mathrm{A}}^{*}$ with sufficient accuracy. We apply our results to S2, which is the closest star discovered so far having an orbital period $P_{\mathrm{b}}=15.98\mathrm{yr}$, and to a hypothetical closer star $X$ with $P_{\mathrm{b}}=0.5\mathrm{yr}$. Our calculations are quite general, not being related to any specific parameterization of $\widehat{\mathit{k}}$, and can be applied also to astrophysical binary systems, stellar planetary systems, and planetary satellite geodesy in which different reference frames, generally not aligned with the primary’s rotational axis, are routinely used.

With a launch planned in March 2013, the ESA Gaia mission will scan the whole sky several times during its operational five years. It will provide highly accurate astrometric observations of celestial bodies (at the sub-milli-arcsecond level) not exclusively beyond the Solar System, since about 250 000 asteroids will be observed. Gaia will thus give us the opportunity of performing various valuable tests of fundamental physics by assessing global parameters from the dynamics of minor planets; in this paper, we evaluated its performance from realistic simulated data and a variance analysis carried out from the observation residuals on a data model linearized with respect to the initial position and velocity of each asteroid and the set of global parameters. Currently, the most relevant fits turn out to be for the PPN parameter $\beta$ (${\sigma }_{\beta }\sim 1.4\times {10}^{-3}$), the temporal variation of the gravitational constant $\dot{G}/G$ (${\sigma }_{\dot{G}/G}\sim 3.2\times {10}^{-12}\mathrm{y}{\mathrm{r}}^{-1}$), the Nordtvedt parameter $\eta$ (${\sigma }_{\eta }\sim 2.4\times {10}^{-3}$) and the $Gm$ of Jupiter (${\sigma }_{G{m}_j}\sim 2.9\times {10}^{-15}{\mathrm{au}}^3{\mathrm{d}}^{-2}$), which show a low level of correlation. The underestimated astrometric precision used in the simulations and the possibility to combine Gaia data with future accurate ground-based observations foreshadow more accurate determinations.

Extensions of the standard model with gauge symmetry $SU(3{)}_c\otimes SU(4{)}_L\otimes U(1{)}_X$ (3-4-1 extensions) where anomaly cancellation takes place between the fermion families (three-family models) predict the existence of two new heavy neutral gauge bosons which transmit flavor changing neutral currents at tree level. In this work, in the context of a three-family 3-4-1 extension which does not contain particles with exotic electric charges, we study the constraints coming from neutral meson mixing on the parameters of the extension associated to tree-level flavor changing neutral current effects. Taking into account experimental measurements of observables related to $K$ and $B$ meson mixing and including new $CP$-violating phases, we study the resulting bounds for angles and phases in the mixing matrix for the down-quark sector, as well as the implications of these bounds for the modifications in the amplitudes of the clean rare decays $K^{+}\to {\pi }^{+}\overline{\nu }\nu$, $K_L\to {\pi }^0\nu \overline{\nu }$, $K_L\to {\pi }^0{l}^{+}{l}^{-}$ ($l=e$, $\mu$) and $B_{d/s}\to {\mu }^{+}{\mu }^{-}$.

We report the first reconstruction in hadron collisions of the suppressed decays $B^{-}\to D(\to K^{+}{\pi }^{-})K^{-}$ and $B^{-}\to D(\to K^{+}{\pi }^{-}){\pi }^{-}$, sensitive to the Cabibbo-Kobayashi-Maskawa phase $\gamma$, using data from $7{\mathrm{fb}}^{-1}$ of integrated luminosity collected by the CDF II detector at the Tevatron collider. We reconstruct a signal for the $B^{-}\to D(\to K^{+}{\pi }^{-})K^{-}$ suppressed mode with a significance of 3.2 standard deviations, and measure the ratios of the suppressed to favored branching fractions $R(K)=[22.0\pm 8.6(\mathrm{stat})\pm 2.6(\mathrm{syst})]\times {10}^{-3}$, $R^{+}(K)=[42.6\pm 13.7(\mathrm{stat})\pm 2.8(\mathrm{syst})]\times {10}^{-3}$, $R^{-}(K)=[3.8\pm 10.3(\mathrm{stat})\pm 2.7(\mathrm{syst})]\times {10}^{-3}$ as well as the direct $CP$-violating asymmetry $A(K)=-0.82\pm 0.44(\mathrm{stat})\pm 0.09(\mathrm{syst})$ of this mode. Corresponding quantities for $B^{-}\to D(\to K^{+}{\pi }^{-}){\pi }^{-}$ decay are also reported.

Fast scramblers process information in characteristic times scaling logarithmically with the entropy, a behavior which has been conjectured for black hole horizons. In this paper we use the AdS/CFT context to argue that causality bounds on information flow only depend on the properties of a single thermal cell, and admit a geometrical interpretation in terms of the optical depth, i.e. the thickness of the Rindler region in the so-called optical metric. The spatial sections of the optical metric are well approximated by constant-curvature hyperboloids. We use this fact to propose an effective kinetic model of scrambling which behaves like a compact hyperbolic billiard, furnishing a classic example of hard chaos. It is suggested that classical chaos at large $N$ is a crucial ingredient in reconciling the notion of fast scrambling with the required saturation of causality.

Neutrino nonstandard interactions (NSI) were investigated earlier in the solar case and were shown to reduce the tensions between the data and the large mixing angle solution predictions. We extend the previous framework to the supernova and evaluate the appearance probabilities for neutrinos and antineutrinos as a function of their energy after leaving the collapsing star with and without NSI. For normal hierarchy the probability for electron neutrinos and antineutrinos at low energy ($E\lesssim 0.8–0.9\mathrm{MeV}$) is substantially increased with respect to the non-NSI case and joins its value for inverse hierarchy which is constant with energy. Also for inverse hierarchy the NSI and non-NSI probabilities are the same for each neutrino and antineutrino species. Although detection in such a low energy range remains at present an experimental challenge, it will become a visible trace of NSI with normal hierarchy if they exist. On the other hand, the neutrino decay probability into an antineutrino and a majoron, an effect previously shown to be induced by dense matter, is, as in the case of the sun, too small to be observed as a direct consequence of NSI.

We study renormalizable Lorentz invariant stable quantum field theories in two space-time dimensions with instantaneous causal structure (causal ordering induced by the light “cone” time ordering). These models provide a candidate UV completion of the two-dimensional ghost condensate. They exhibit a peculiar UV/IR mixing—energies of all excitations become arbitrarily small at high spatial momenta. We discuss several phenomena associated with this mixing. These include the impossibility to reach a thermal equilibrium and metastability of all excitations towards decay into short-wavelength modes resulting in an indefinite turbulent cascade. In spite of the UV/IR mixing in many cases the UV physics can still be decoupled from low-energy phenomena. However, a patient observer in the Lineland is able to produce arbitrarily heavy particles simply by waiting for a long enough time.

In nonrelativistic quantum mechanics and in relativistic quantum field theory, the time coordinate $t$ is a parameter and thus the time-reversal operator $\mathcal{T}$ does not actually reverse the sign of $t$. In contrast, in the five-dimensional approach to relativistic quantum mechanics introduced by Feynman, time $t$ is a quantum-mechanical operator. In this paper it is shown how one can use this five-dimensional approach to extend $\mathcal{T}$ and $\mathcal{P}\mathcal{T}$ symmetry from nonrelativistic to relativistic quantum mechanics and implement time-reversal as an operation that effects $\mathcal{T}t\mathcal{T}=-t$ just as $\mathcal{P}$ effects $\mathcal{P}x\mathcal{P}=-x$, with $\mathcal{P}\mathcal{T}$ thus effecting $\mathcal{P}\mathcal{T}{x}_{\mu }\mathcal{P}\mathcal{T}=-x_{\mu }$. Some illustrative relativistic quantum-mechanical models are constructed whose associated Hamiltonians are non-Hermitian but $\mathcal{P}\mathcal{T}$ symmetric, and it is shown that for each such Hamiltonian the energy eigenvalues are all real.