We present a comprehensive black-hole event generator, BlackMax, which simulates the experimental signatures of microscopic and Planckian black-hole production and evolution at the LHC in the context of brane world models with low-scale quantum gravity. The generator is based on phenomenologically realistic models free of serious problems that plague low-scale gravity, thus offering more realistic predictions for hadron-hadron colliders. The generator includes all of the black-hole gray-body factors known to date and incorporates the effects of black-hole rotation, splitting between the fermions, nonzero brane tension, and black-hole recoil due to Hawking radiation (although not all simultaneously). The generator can be interfaced with Herwig and Pythia. The main code can be downloaded from http://www-pnp.physics.ox.ac.uk/~issever/BlackMax/blackmax.html.

In QCD with adjoint fermions, the deconfining transition takes place at a lower temperature than the chiral transition. We study the two transitions by use of the Polyakov loop, the monopole order parameter, and the chiral condensate. The deconfining transition is first order, the chiral is a crossover. The order parameters for confinement are not affected by the chiral transition. We conclude that the degrees of freedom relevant to confinement are different from those describing chiral symmetry.

Motivated by the need to correct the potentially large kinematic errors in approximations used in the standard formulation of perturbative QCD, we reformulate deeply inelastic lepton-proton scattering in terms of gauge-invariant, universal parton correlation functions which depend on all components of parton four-momentum. Currently, different hard QCD processes are described by very different perturbative formalisms, each relying on its own set of kinematical approximations. In this paper we show how to set up formalism that avoids approximations on final-state momenta, and thus has a very general domain of applicability. The use of exact kinematics introduces a number of significant conceptual shifts already at leading order, and tightly constrains the formalism. We show how to define parton correlation functions that generalize the concepts of parton density, fragmentation function, and soft factor. After setting up a general subtraction formalism, we obtain a factorization theorem. To avoid complications with Ward identities, the full derivation is restricted to Abelian gauge theories; even so, the resulting structure is highly suggestive of a similar treatment for non-Abelian gauge theories.

The attractor mechanism implies that the supersymmetric black hole near-horizon solution is defined only in terms of the conserved charges and is therefore independent of asymptotic moduli. Starting only with the near-horizon geometry, Sen’s entropy functional formalism computes the entropy of an extreme black hole by means of a Legendre transformation where the electric fields are defined as conjugated variables to the electric charges. However, traditional Euclidean methods require the knowledge of the full geometry to compute the black hole thermodynamic quantities. We establish the connection between the entropy functional formalism and the standard Euclidean formalism taken at zero-temperature. We find that Sen’s entropy function $f$ (on-shell) matches the zero-temperature limit of the Euclidean action. Moreover, Sen’s near-horizon angular and electric fields agree with the chemical potentials that are defined from the zero-temperature limit of the Euclidean formalism.

We study the cosmological stability of a class of theories with a dynamical preferred frame. For a range of actions, we find cosmological solutions which are compatible with observations of the recent history of the Universe: a matter-dominated era followed by accelerated expansion. We then study the evolution of linear perturbations on these backgrounds and find conditions on the parameters of the theory which allow for the growth of structure sourced by the new degrees of freedom.

Many experiments in the near future will test dark energy through its effects on the linear growth of matter perturbations. It is therefore important to find simple and at the same time general parametrizations of the linear growth rate. We show that a simple fitting formula that generalizes previous expressions reproduces the growth function in models that allow for a growth faster than standard, as for instance in interacting or scalar-tensor models. We use data from galaxy and Lyman-$\alpha$ power spectra to constrain the linear growth rate. We find $\gamma ={0.6}_{-0.3}^{+0.4}$ for the growth rate index and $\eta ={0.0}_{-0.2}^{+0.3}$ for the additional growth parameter we introduce.

With sufficient data, CERN LHC experiments can constrain the smuon-selectron mass splitting through differences in the dielectron and dimuon edges from supersymmetry (SUSY) cascade decays. We study the sensitivity of the LHC to this mass splitting, which within minimal supergravity may be constrained down to $\mathcal{O}({10}^{-4})$ for $30{\mathrm{fb}}^{-1}$ of integrated luminosity. Over substantial regions of SUSY breaking parameter space the fractional edge splitting can be significantly enhanced over the fractional mass splitting. Within models where the selectron and smuon are constrained to be universal at a high scale, edge splittings up to a few percent may be induced by renormalization group effects and may be significantly discriminated from zero. The edge splitting provides important information about high-scale SUSY breaking terms and should be included in any fit of LHC data to high-scale models.

In this work, we compile the necessary and sufficient conditions a theory has to fulfill in order to ensure general lepton flavor conservation, in the spirit of the Glashow-Weinberg criteria for the absence of flavor-changing neutral currents. At tree-level, interactions involving electrically neutral and doubly charged bosons are investigated. We also investigate flavor changes at 1-loop level. In all cases we find that the essential theoretical requirements can be reduced to a few basic conditions on the particle content and the coupling matrices. For 1-loop diagrams, we also investigate how exactly a GIM-suppression can occur that will strongly reduce the rates of lepton flavor violating effects even if they are in principle present in a certain theory. In all chapters, we apply our criteria to several models which can in general induce lepton flavor violation, e.g. $LR$-symmetric models or the minimal supersymmetric standard model (MSSM) In the end we give a summarizing table of the obtained results, thereby demonstrating the applicability of our criteria to a large class of models beyond the standard model.

Even highly improved variants of lattice QCD with staggered fermions show significant violations of taste symmetry at currently accessible lattice spacings. In addition, the “rooting trick” is used in order to simulate with the correct number of light sea quarks, and this makes the lattice theory nonlocal, even though there is good reason to believe that the continuum limit is in the correct universality class. In order to understand scaling violations, it is thus necessary to extend the construction of the Symanzik effective theory to include rooted staggered fermions. We show how this can be done, starting from a generalization of the renormalization-group approach to rooted staggered fermions recently developed by one of us. We then explain how the chiral effective theory follows from the Symanzik action, and show that it leads to “rooted” staggered chiral perturbation theory as the correct chiral theory for QCD with rooted staggered fermions. We thus establish a direct link between the renormalization-group based arguments for the correctness of the continuum limit and the success of rooted staggered chiral perturbation theory in fitting numerical results obtained with the rooting trick. In order to develop our argument, we need to assume the existence of a standard partially-quenched chiral effective theory for any local partially-quenched theory. Other technical, but standard, assumptions are also required.

We construct jet observables for energetic top quarks that can be used to determine a short-distance top quark mass from reconstruction in $e^{+}{e}^{-}$ collisions with accuracy better than ${\Lambda }_{\mathrm{QCD}}$. Using a sequence of effective field theories we connect the production energy, mass, and top width scales, $Q\gg m\gg \Gamma$, for the top jet cross section, and derive a QCD factorization theorem for the top invariant mass spectrum. Our analysis accounts for ${\alpha }_s$ corrections from the production and mass scales, corrections due to constraints in defining invariant masses, nonperturbative corrections from the cross talk between the jets, and ${\alpha }_s$ corrections to the Breit-Wigner line shape. This paper mainly focuses on deriving the factorization theorem for hemisphere invariant mass distributions and other event shapes in $e^{+}{e}^{-}$ collisions applicable at a future linear collider. We show that the invariant mass distribution is not a simple Breit-Wigner function involving the top width. Even at leading order it is shifted and broadened by nonperturbative soft QCD effects. We predict that the invariant mass peak position increases linearly with $Q/m$ due to these nonperturbative effects. They are encoded in terms of a universal soft function that also describes soft effects for massless dijet events. In a future paper we compute ${\alpha }_s$ corrections to the jet invariant mass spectrum, including a summation of large logarithms between the scales $Q$, $m$, and $\Gamma$.

We consider a one parameter family of mass terms for the Skyrme model that disfavors shell-like configurations for multibaryon classical solutions. We argue that a model with such mass terms can provide a better description of nuclei as shell-like configurations are now less stable than in the traditional massive Skyrme model.

Charmed baryon strong decays are studied in a chiral quark model. The data for the decays of ${\Lambda }_c^{+}(2593)$, ${\Lambda }_c^{+}(2625)$, ${\Sigma }_c^{++,+,0}$, and ${\Sigma }_c^{+,0}(2520)$ are accounted for successfully, which allows one to fix the pseudoscalar-meson-quark couplings in an effective chiral Lagrangian. Extending this framework to analyze the strong decays of the newly observed charmed baryons, we classify that ${\Lambda }_c(2880)$ and ${\Lambda }_c(2940)$ as $D$-wave states in the $N=2$ shell; ${\Lambda }_c(2880)$ could be $|{\Lambda }_c{}^{2}D_{\lambda \lambda }{\frac{3}{2}}^{+}⟩$ and ${\Lambda }_c(2940)$ could be $|{\Lambda }_c{}^{2}D_{\lambda \lambda }{\frac{5}{2}}^{+}⟩$. Our calculation also suggests that ${\Lambda }_c(2765)$ is very likely a $\rho$-mode $P$-wave excited state in the $N=1$ shell, and favors a $|{\Lambda }_c{}^{4}P_{\rho }{\frac{1}{2}}^{-}⟩$ configuration. The ${\Sigma }_c(2800)$ favors being a $|{\Sigma }_c{}^{2}P_{\lambda }{\frac{1}{2}}^{-}⟩$ state. But its being $|{\Sigma }_c^{++}{}^{4}P_{\lambda }{\frac{5}{2}}^{-}⟩$ cannot be ruled out.

It has recently been suggested that scalar, Dirac, and Rarita-Schwinger perturbations are related to thermodynamic phase transitions of charged (Reissner-Nordström) black holes. In this Brief Report we show that this result is probably a numerical coincidence, and that the conjectured correspondence does not straightforwardly generalize to other metrics, such as Kerr or Schwarzschild (anti–)de Sitter. Our calculations do not rule out a relation between dynamical and thermodynamical properties of black holes, but they suggest that such a relation is nontrivial.

It has previously been proposed that annihilating dark matter particles with MeV-scale masses could be responsible for the flux of 511 keV photons observed from the region of the Galactic Bulge. The conventional wisdom, however, is that it is very challenging to construct a viable particle physics model containing MeV dark matter. In this paper, we challenge this conclusion by describing a simple and natural supersymmetric model in which the lightest supersymmetric particle naturally has a MeV-scale mass and the other phenomenological properties required to generate the 511 keV emission. In particular, the small ($\sim {10}^{-5}$) effective couplings between dark matter and the standard model fermions required in this scenario naturally lead to radiative corrections that generate MeV-scale masses for both the dark matter candidate and the mediator particle.

We present a diagonalization method for generic matrix valued Hamiltonians based on a formal expansion in power of $\hslash$. Considering $\hslash$ as a running parameter, a differential equation connecting two diagonalization processes for two very close values of $\hslash$ is derived. The integration of this differential equation allows the recursive determination of the series expansion in powers of $\hslash$ for the diagonalized Hamiltonian. This approach results in effective Hamiltonians with Berry-phase corrections of higher order in $\hslash$, and deepens previous works on the semiclassical diagonalization of quantum Hamiltonians, which led notably to the discovery of the intrinsic spin Hall effect. As physical applications we consider spinning massless particles in isotropic inhomogeneous media and show that both the energy and the velocity get quantum corrections of order ${\hslash }^2$. We also derive formally to all orders in $\hslash$ the energy spectrum and the equations of motion of Bloch electrons in an external electric field.

Activities in data analysis and numerical simulation of gravitational waves have to date largely proceeded independently. In this work we study how waveforms obtained from numerical simulations could be effectively used within the data analysis effort to search for gravitational waves from black hole binaries. To this end we analyze the cross-correlation between different numerical waveforms weighted by the detector’s noise. This allow us to propose measures to quantify the accuracy of numerical waveforms for the purpose of data analysis, study how sensitive the analysis is to errors in the waveforms, and propose a way to efficiently encode the waveform’s information for its use as a member of the template bank. We estimate that $\sim 100$ templates (and $\sim 10$ simulations with different mass ratios) are needed to detect waves from nonspinning binary black holes with total masses in the range $100M_{\odot }\le M\le 400M_{\odot }$ using initial LIGO. Of course, many more simulation runs will be needed to confirm that the correct physics is captured in the numerical evolutions. From this perspective, we also discuss sources of systematic errors in numerical waveform extraction and provide order of magnitude estimates for the computational cost of simulations that could be used to estimate the cost of parameter space surveys. Finally, we discuss what information from near-future numerical simulations of compact binary systems would be most useful for enhancing the detectability of such events with contemporary gravitational-wave detectors and emphasize the role of numerical simulations for the interpretation of eventual gravitational-wave observations.

In this paper we investigate how well Planck and Lyman-$\alpha$ forest data will be able to constrain the sum of the neutrino masses, and thus, in conjunction with flavor oscillation experiments, be able to determine the absolute masses of the neutrinos. It seems possible that Planck, together with a Lyman-$\alpha$ survey, will be able to put pressure on an inverted hierarchial model for the neutrino masses. However, even for optimistic assumptions of the precision of future Lyman-$\alpha$ data sets, it will not be possible to confirm a minimal-mass normal hierarchy.

We perform a systematic study of dihedral groups used as flavor symmetry. The key feature here is the fact that we do not allow the dihedral groups to be broken in an arbitrary way, but in all cases some (nontrivial) subgroup has to be preserved. In this way we arrive at only five possible (Dirac) mass matrix structures which can arise, if we require that the matrix has to have a nonvanishing determinant and that at least two of the three generations of left-handed (conjugate) fermions are placed into an irreducible two-dimensional representation of the flavor group. We show that there is no difference between the mass matrix structures for single- and double-valued dihedral groups. Furthermore, we comment on possible forms of Majorana mass matrices. As a first application we find a way to express the Cabibbo angle, i.e. the Cabibbo-Kobayashi-Maskawa matrix element $|V_{us}|$, in terms of group theory quantities only, the group index $n$, the representation index j and the index $m_{u,d}$ of the different preserved subgroups in the up and down quark sector: $|V_{us}|=|\cos (\frac{\pi (m_u-m_d)\mathrm{j}}{n})|$ which is $|\cos (\frac{3\pi }{7})|\approx 0.2225$ for $n=7$, $\mathrm{j}=1$, $m_u=3$ and $m_d=0$. We prove that two successful models which lead to maximal atmospheric mixing and vanishing ${\theta }_{13}$ in the lepton sector are based on the fact that the flavor symmetry is broken in the charged lepton, Dirac neutrino and Majorana neutrino sector down to different preserved subgroups whose mismatch results in the prediction of these mixing angles. This also demonstrates the power of preserved subgroups in connection with the prediction of mixing angles in the quark as well as in the lepton sector.

We study the decays of the lightest supersymmetric particle (LSP) in models with spontaneously broken $R$-parity. We focus on the two cases that the LSP is either a bino or a neutral singlet lepton. We work out the most important phenomenological differences between these two scenarios and discuss also how they might be distinguished from explicit $R$-parity breaking models. In both cases we find that certain ratios of decay branching ratios are correlated with either the solar or the atmospheric (and reactor) neutrino angle. The hypothesis that spontaneous $R$-parity violation is the source of the observed neutrino masses is therefore potentially testable at the LHC.