Additional sources of $CP$ violation in the MSSM may affect $B$-meson mixings and decays, even in scenarios with minimal flavor violation (MFV). We formulate the maximally $CP$-violating and minimally flavor-violating (MCPMFV) variant of the MSSM, which has 19 parameters, including 6 phases that violate $CP$. We then develop a manifestly flavor-covariant effective Lagrangian formalism for calculating Higgs-mediated flavor-changing-neutral-current (FCNC) observables in the MSSM at large $\tan \beta$, and analyze within the MCPMFV framework FCNC and other processes involving $B$ mesons. We include a new class of dominant subleading contributions due to nondecoupling effects of the third-generation quarks. We present illustrative numerical results that include effects of the $CP$-odd MCPMFV parameters on Higgs and sparticle masses, the $B_s$ and $B_d$ mass differences, and on the decays $B_s\to {\mu }^{+}{\mu }^{-}$, $B_u\to \tau \nu$, and $b\to s\gamma$. We use these results to derive illustrative constraints on the MCPMFV parameters imposed by D0, CDF, Belle, and BABAR measurements of $B$ mesons, demonstrating how a potentially observable contribution to the $CP$ asymmetry in the $b\to s\gamma$ decay may arise in the MSSM with MCPMFV.

We determine the light quark masses from lattice QCD simulations incorporating the electromagnetic interaction of valence quarks, using the splittings of charged and neutral pseudoscalar meson masses as inputs. The meson masses are calculated on lattice QCD configurations generated by the RBC Collaboration for two flavors of dynamical domain-wall fermions, which are combined with QED configurations generated via quenched noncompact lattice QED. The electromagnetic part of the pion mass splitting is found to be $m_{{\pi }^{+}}-m_{{\pi }^0}=4.12(21)\mathrm{MeV}$, where only the statistical error is quoted, and similarly for the kaon, 1.443(55) MeV. Our results for the light quark masses are $m_u^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=3.02(27)(19)\mathrm{MeV}$, $m_d^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=5.49(20)(34)\mathrm{MeV}$, and $m_s^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=119.5(56)(74)\mathrm{MeV}$, where the first error is statistical and the second reflects the uncertainty in our nonperturbative renormalization procedure. By averaging over $\pm e$ to cancel $\mathcal{O}(e)$ noise exactly on each combined gauge field configuration, we are able to work at physical $\alpha =1/137$ and obtain very small statistical errors. In our calculation, several sources of systematic error remain, including finite volume, nonzero lattice spacing, chiral extrapolation, quenched QED, and quenched strange quark, which may be more significant than the errors quoted above. We discuss these systematic errors and how to reduce or eliminate them.

The infrared behavior of gluon and ghost propagators in Yang-Mills theories is of central importance for understanding quark and gluon confinement in QCD. While simulations of pure $SU(3)$ gauge theory correspond to the physical case in the limit of infinite quark mass, the $SU(2)$ case (i.e. pure two-color QCD) is usually employed as a simplification, in the hope that qualitative features be the same as for the $SU(3)$ case. Here we carry out the first comparative study of lattice (Landau) propagators for these two gauge groups. Our data were especially produced with equivalent lattice parameters in order to allow a careful comparison of the two cases. We find very good agreement between $SU(2)$ and $SU(3)$ propagators, showing that in the IR limit the equivalence of the two cases is quantitative, at least down to about 1 GeV. Our results suggest that the infrared behavior of these propagators is independent of the gauge group $SU(N_c)$, as predicted by Schwinger-Dyson equations.

A recently proposed theory of modified gravity with an explicit anomalous coupling of the Ricci curvature to matter is discussed, and an inequality is derived which expresses a necessary and sufficient condition to avoid the notorious Dolgov-Kawasaki instability.

We review recent analytic and numerical results concerning the confinement scenario in Coulomb gauge. We then consider a local, renormalizable, BRST(Becchi-Rouet-Stora-Tyutin)-invariant action for QCD in Coulomb gauge that contains auxiliary bose and fermi ghost fields and sources. When the auxiliary fields are integrated out, one obtains the standard Coulomb gauge action with a cutoff at the Gribov horizon. We use the local formulation to calculate the leading correction to the Stefan-Boltzmann equation of state at high temperature due to the cutoff at the Gribov horizon. It is of order $g^6$, which is precisely the order at which the infrared divergence found by Lindé divergence first occurs. No such divergence arises in the present calculation because the propagator of would-be physical gluons is suppressed in the infrared due to the proximity of the Gribov horizon in infrared directions.

Based on the nonrelativistic QCD factorization formalism, we calculate the bottomonium ground state ${\eta }_b$, inclusive charm decays at the leading order in the strong coupling constant ${\alpha }_s$, and quarkonium internal relative velocity $v$. The inclusive charm pair production in ${\eta }_b$ decay is mainly realized through the ${\eta }_b\to c\overline{c}g$ process, where the charm and anticharm quarks then dominantly hadronize into charmed hadrons. The momentum distributions of the final states are presented. In this work, we also calculate the $J/\psi$ inclusive production rate in the ${\eta }_b$ decays, where the color-octet contribution is found to be very important. We expect this study may shed some light on finding ${\eta }_b$ or knowing more about its nature.

Time-dependent soliton solutions are explicitly derived in a five-dimensional theory endowed with one (warped) extra dimension. Some of the obtained geometries, everywhere well defined and technically regular, smoothly interpolate between two five-dimensional anti-de Sitter space-times for a fixed value of the conformal time coordinate. Time-dependent solutions containing both topological and nontopological sectors are also obtained. Supplementary degrees of freedom can be also included and, in this case, the resulting multisoliton solutions may describe time-dependent kink-antikink systems.

We point out a generic inconsistency of the coupling of ordinary gravity as described by general relativity with matter invariant only under unimodular diffeomorphisms, and some previously studied exceptions are pointed out. The most general Lagrangian invariant under unimodular diffeomorphism up to dimension-five operators is determined, and consistency with existing observations is studied in some cases.

We consider the self-energy and the self-force for an electrically charged particle at rest in the wormhole space-time. We develop a general approach to finding the self-force and apply it to the two specific profiles of the wormhole throat with singular and with smooth curvature. The self-force for these two profiles is found in manifest form; it turns out to be an attractive force. We also find an expression for the self-force in the case of arbitrary symmetric throat profile. Far from the throat the self-force is always attractive.

We study the critical collapse of a massless scalar field with angular momentum in spherical symmetry. In order to mimic the effects of angular momentum we perform a sum of the stress-energy tensors for all the scalar fields with the same eigenvalue $l$ of the angular momentum operator and calculate the equations of motion for the radial part of these scalar fields. We have found that the critical solutions for different values of $l$ are discretely self-similar (as in the original $l=0$ case). The value of the discrete, self-similar period, ${\Delta }_l$, decreases as $l$ increases in such a way that the critical solution appears to become periodic in the limit. The mass-scaling exponent, ${\gamma }_l$, also decreases with $l$.

In a previous paper we formulated a set of necessary conditions for the spherically symmetric weakly charged dust to avoid big bang/big crunch, shell crossing, and permanent central singularities. However, we did not discuss the properties of the energy density, some of which are surprising and seem not to have been known up to now. A singularity of infinite energy density does exist—it is a point singularity situated on the worldline of the center of symmetry. The condition that no mass shell collapses to $R=0$ if it had $R>0$ initially thus turns out to be still insufficient for avoiding a singularity. Moreover, at the singularity the energy density $ϵ$ is direction dependent: $ϵ\to -\infty$ when we approach the singular point along a $t=\mathrm{const}$ hypersurface and $ϵ\to +\infty$ when we approach that point along the center of symmetry. The appearance of negative-energy-density regions turns out to be inevitable. We discuss various aspects of this property of our configuration. We also show that a permanently pulsating configuration, with the period of pulsation independent of mass, is possible only if there exists a permanent central singularity.

Modified Newtonian dynamics (MOND) is a possible way to explain the flat galaxy rotation curves without invoking the existence of dark matter. It is, however, quite difficult to predict such a phenomenology in a consistent field theory, free of instabilities and admitting a well-posed Cauchy problem. We examine critically various proposals of the literature, and underline their successes and failures both from the experimental and the field-theoretical viewpoints. We exhibit new difficulties in both cases, and point out the hidden fine-tuning of some models. On the other hand, we show that several published no-go theorems are based on hypotheses which may be unnecessary, so that the space of possible models is a priori larger. We examine a new route to reproduce the MOND physics, in which the field equations are particularly simple outside matter. However, the analysis of the field equations within matter (a crucial point which is often forgotten in the literature) exhibits a deadly problem, namely, that they do not remain always hyperbolic. Incidentally, we prove that the same theoretical framework provides a stable and well-posed model able to reproduce the Pioneer anomaly without spoiling any of the precision tests of general relativity. Our conclusion is that all MOND-like models proposed in the literature, including the new ones examined in this paper, present serious difficulties: Not only they are unnaturally fine-tuned, but they also fail to reproduce some experimental facts or are unstable or inconsistent as field theories. However, some frameworks, notably the tensor-vector-scalar one of Bekenstein and Sanders, seem more promising than others, and our discussion underlines in which directions one should try to improve them.

In the indirect detection of dark matter through its annihilation products, the signals depend on the square of the dark matter density, making precise knowledge of the distribution of dark matter in the Universe critical for robust predictions. Many studies have focused on regions where the dark matter density is greatest, e.g., the galactic center, as well as on the cosmic signal arising from all halos in the Universe. We focus on the signal arising from the whole Milky Way halo; this is less sensitive to uncertainties in the dark matter distribution, and especially for flatter profiles, this halo signal is larger than the cosmic signal. We illustrate this by considering a dark matter model in which the principal annihilation products are neutrinos. Since neutrinos are the least detectable standard model particles, a limit on their flux conservatively bounds the dark matter total self-annihilation cross section from above. By using the Milky Way halo signal, we show that previous constraints using the cosmic signal can be improved on by 1–2 orders of magnitude; dedicated experimental analyses should be able to improve both by an additional 1–2 orders of magnitude.

We obtain cosmological solutions in higher derivative theories of gravity in the presence of an imperfect fluid and a time varying cosmological parameter ($\Lambda$). We explore both power-law and exponential expansion of the universe considering an imperfect fluid described by the Eckart, truncated, and full causal theories proposed by Israel and Stewart. We discuss the physical and geometrical features of the models in the presence of a known time varying $\Lambda$. The interesting feature of the models is that they admit accelerating universes in some specific cases. The evolution of the temperature of the universe in the framework of the full causal theory is also determined.

Astrophysical $\gamma$-ray sources come in a variety of sizes and magnetizations. We deduce general conditions under which $\gamma$-ray spectra from such sources would be significantly affected by axion-photon mixing. We show that, depending on strength and coherence of the magnetic field, axion couplings down to $\sim ({10}^{13}\mathrm{GeV}{)}^{-1}$ can give rise to significant axion-photon conversions in the environment of accreting massive black holes. Resonances can occur between the axion mass term and the plasma frequency term as well as between the plasma frequency term and the vacuum Cotton-Mouton shift. Both resonances and nonresonant transitions could induce detectable features or even strong suppressions in finite energy intervals of $\gamma$-ray spectra from active galactic nuclei. Such effects can occur at keV to TeV energies for couplings that are currently allowed by all experimental constraints.

We discuss the time dependence and future of the cosmic microwave background (CMB) in the context of the standard cosmological model, in which we are now entering a state of endless accelerated expansion. The mean temperature will simply decrease until it reaches the effective temperature of the de Sitter vacuum, while the dipole will oscillate as the sun orbits the Galaxy. However, the higher CMB multipoles have a richer phenomenology. The CMB anisotropy power spectrum will for the most part simply project to smaller scales, as the comoving distance to last scattering increases, and we derive a scaling relation that describes this behavior. However, there will also be a dramatic increase in the integrated Sachs-Wolfe contribution at low multipoles. We also discuss the effects of tensor modes and optical depth due to Thomson scattering. We introduce a correlation function relating the sky maps at two times and the closely related power spectrum of the difference map. We compute the evolution both analytically and numerically, and present simulated future sky maps.

We analyze the possibility of delensing cosmic microwave background (CMB) polarization maps using foreground weak lensing (WL) information. We build an estimator of the CMB lensing potential out of optimally combined projected-potential estimators to different source redshift bins. Our estimator is most sensitive to the redshift depth of the WL survey, less so to the shape noise level. Estimators built using galaxy surveys like the Large Synoptic Survey Telescope and the Supernova Acceleration Probe recover up to 80%–90% of the potential fluctuations power at $l\le 100$ but only $\approx 10\%–20\%$ of the small-angular-scale power ($l\le 1000$). This translates into a 30%–50% reduction in the lensing $B$-mode power. We illustrate the potential advantages of a 21 cm survey by considering a fiducial WL survey for which we take the redshift depth $z_{\max }$ and the effective angular concentration of sources $\overline{n}$ as free parameters. For a noise level of $1\mu \mathrm{K}\mathrm{arcmin}$ in the polarization map itself, as projected for a CMBPol experiment, and a beam with ${\theta }_{\mathrm{FWHM}}=10\mathrm{arcmin}$, we find that going to $z_{\max }=20$ at $\overline{n}=100\mathrm{galaxies}/{\mathrm{arcmin}}^2$ yields a delensing performance similar to that of a quadratic lensing potential estimator applied to small-scale CMB maps: the lensing $B$-mode contamination is reduced by almost an order of magnitude. In this case, there is also a reduction by a factor of $\approx 4$ in the detectability threshold of the tensor $B$-mode power. At this CMB noise level, the $B$-mode detection threshold is only $3\times$ lower even for perfect delensing, so there is little gain from sources with $z_{\max }>20$. The delensing gains are lost if the CMB beam exceeds $\sim 20\mathrm{arcmin}$. The delensing gains and useful $z_{\max }$ depend acutely on the CMB map noise level, but beam sizes below 10 arcmin do not help. Delensing via foreground sources does not require arc-minute-resolution CMB observations, a substantial practical advantage over the use of CMB observables for delensing.

The masses of positive parity $(70,0^{+})$ and $(70,2^{+})$ nonstrange and strange baryons are calculated in the relativistic quark model. The relativistic three-quark equations of the $(70,L^{+})$ multiplets are found in the framework of the dispersion relation technique. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitude are obtained. The calculated mass values of the $(70,L^{+})$ multiplets are in good agreement with the experimental ones.

We study the evolution of heavy quarkonium states with temperature in a quark-gluon plasma (QGP) by evaluating the in-medium $Q\mathrm{\text{−}}\overline{Q}$ $T$-matrix within a reduced Bethe-Salpeter equation in both $S$- and $P$-wave channels. The underlying interaction kernel is extracted from recent finite-temperature QCD lattice calculations of the singlet free energy of a $Q\mathrm{\text{−}}\overline{Q}$ pair. The bound states are found to gradually move above the $Q\mathrm{\text{−}}\overline{Q}$ threshold after which they rapidly dissolve in the hot system. The $T$-matrix approach is particularly suited to investigate these mechanisms as it provides a unified treatment of bound and scattering states including threshold effects and the transition to the (perturbative) continuum. We apply the $T$-matrix to calculate $Q\mathrm{\text{−}}\overline{Q}$ spectral functions as well as pertinent Euclidean-time correlation functions which are compared to results from lattice QCD. A detailed analysis reveals large sensitivities to the interplay of bound and scattering states, to temperature-dependent threshold energies, and to the reconstructed correlator used for normalization. We furthermore investigate the impact of finite-width effects on the single-quark propagators in the QGP as estimated from recent applications of heavy-quark rescattering to RHIC data.

A simple string model inspired by the strong-coupling regime of quantum chromodynamics is used as a potential for studying the spectrum of multiquark systems with two quarks and two antiquarks, with a careful treatment of the four-body problem. It is found that the ground state is stable, lying below the threshold for dissociation into two isolated mesons.