Establishing that a signal of new physics is undoubtedly supersymmetric requires not only the discovery of the supersymmetric partners but also probing their spins and couplings. We show that the sbottom spin can be probed at the CERN Large Hadron Collider using only angular correlations in the reaction $pp\to \tilde{b}{\tilde{b}}^{*}\to b\overline{b}{\mathrm{p̸}}_T$, which allow us to distinguish a universal extra dimensional interpretation with a fermionic heavy bottom quark from supersymmetry with a bosonic bottom squark. We demonstrate that this channel provides a clear indication of the sbottom spin provided the sbottom production rate and branching ratio into $b{\tilde{\chi }}_1^0$ are sufficiently large to have a clear signal above standard model backgrounds.

Encouraged by recent developments in AdS/QCD models for the light quark system, we study heavy quarkonium in the framework of the AdS/QCD models. We calculate the masses of $c\overline{c}$ vector meson states using the AdS/QCD models at zero and at finite temperature. Among the models adopted in this work, we find that the soft-wall model describes the low-lying heavy quark meson states at zero temperature relatively well. At finite temperature, we observe that once the bound state is above $T_c$, its mass will increase with temperature until it dissociates at a temperature of around 494 MeV. It is shown that the dissociation temperature is fixed by the infrared cutoff of the models. The present model serves as a unified nonperturbative model to investigate the properties of bound quarkonium states above $T_c$.

Within the dispersive approach to the amplitude of the rare decay ${\pi }^0\to e^{+}{e}^{-}$ the nontrivial dynamics is contained only in the subtraction constant. We express this constant, in the leading order in $(m_e/\Lambda {)}^2$ perturbative series, in terms of the inverse moment of the pion transition form factor given in symmetric kinematics. By using the CELLO and CLEO data on the pion transition form factor given in asymmetric kinematics, the lower bound of the decay branching ratio is found. The restrictions following from QCD allow us to make a quantitative prediction for the branching $B({\pi }^0\to e^{+}{e}^{-})=(6.2\pm 0.1)·{10}^{-8}$ which is $3\sigma$ below the recent KTeV measurement. We confirm our prediction by using the quark models and phenomenological approaches based on the vector meson dominance. The decays $\eta \to l^{+}{l}^{-}$ are also discussed.

The noteworthy BABAR and Belle evidence for $D^0\mathrm{\text{−}}{\overline{D}}^0$ mixing motivates us to study its impact on $D^0\to K^{*\pm }{K}^{\mp }$ decays and their $CP$-conjugate processes. We show that both the $D^0\mathrm{\text{−}}{\overline{D}}^0$ mixing parameters ($x$ and $y$) and the strong phase difference between ${\overline{D}}^0\to K^{*\pm }{K}^{\mp }$ and $D^0\to K^{*\pm }{K}^{\mp }$ transitions ($\delta$) can be determined or constrained from the time-dependent measurements of these decay modes. On the $\psi (3770)$ and $\psi (4140)$ resonances at a $\tau$-charm factory, it is even possible to determine or constrain $x$, $y$ and $\delta$ from the time-independent measurements of coherent $(D^0{\overline{D}}^0)\to (K^{*\pm }{K}^{\mp })(K^{*\pm }{K}^{\mp })$ decays. If the $CP$-violating phase of $D^0\mathrm{\text{−}}{\overline{D}}^0$ mixing is significant in a scenario beyond the standard model, it can also be extracted from the $K^{*\pm }{K}^{\mp }$ events.

Boson boson scattering and Higgs production in boson boson fusion will be actively investigated at the CERN LHC. We have performed a parton level study of all processes of the type $q_1{q}_2\to q_3{q}_4{q}_5{q}_6{l}^{+}{l}^{-}$ using for the first time a full fledged six fermion Monte Carlo event generator which employs exact matrix elements at $\mathcal{O}({\alpha }_{em}^6)$. We have examined Higgs production in vector boson fusion followed by the decay chain $H\to ZZ\to l^{+}{l}^{-}jj$, including exactly all electroweak irreducible backgrounds. In the high mass region we have compared the case of a relatively light Higgs with the no-Higgs results. The integrated cross section for the latter case is more than twice that in the former for a minimum invariant mass of the $ZV$ pair of about 800 GeV. We find, in a preliminary analysis at parton level, that, summing up the muon and the electron channels, about 25 events are expected in the light Higgs case for $L=100{\mathrm{fb}}^{-1}$.

We present a general procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted by considering two-particle and triple unitarity cuts of the corresponding bubble and triangle integral functions. After choosing a specific parametrization of the cut loop momentum we can uniquely identify the coefficients of the desired integral functions simply by examining the behavior of the cut integrand as the unconstrained parameters of the cut loop momentum approach infinity. In this way we can produce compact forms for scalar integral coefficients. Applications of this method are presented for both QCD and electroweak processes, including an alternative form for the recently computed three-mass triangle coefficient in the six-photon amplitude $A_6(1^{-},2^{+},3^{-},4^{+},5^{-},6^{+})$. The direct nature of this extraction procedure allows for a very straightforward automation of the procedure.

We describe a natural inhomogeneous generalization of high frequency plane gravitational waves. The waves are high frequency waves of the Kundt type whose null propagation direction in space-time has vanishing expansion, twist, and shear but is not covariantly constant. The introduction of a cosmological constant is discussed in some detail and a comparison is made with high frequency gravity waves having wave fronts homeomorphic to 2-spheres.

The measurement of the flavor composition of the neutrino fluxes from astrophysical sources has been proposed as a method to study not only the nature of their emission mechanisms, but also the fundamental neutrino properties. It is however problematic to reconcile these two goals, since a sufficiently accurate understanding of the neutrino fluxes at the source is needed to extract information about the physics of neutrino propagation. In this work we discuss critically the expectations for the flavor composition and energy spectrum from different types of astrophysical sources, and comment on the theoretical uncertainties connected to our limited knowledge of their structure.

In this paper, we derive simple and general perturbative formulas for the flavor flux ratios $R_{\alpha \beta }={\varphi }_{{\nu }_{\alpha }}/{\varphi }_{{\nu }_{\beta }}$ that could be measured at neutrino telescopes. We discuss in detail the role of the uncertainties of the neutrino mixing parameters showing that they have to be seriously taken into account in any realistic discussion about flavor measurements at neutrino telescopes. In addition, we analyze the impact of such uncertainties in telling the standard neutrino oscillation framework from scenarios involving, e.g., neutrino decay and we find that the ratio $R_{e\mu }$ is the most sensitive one to “new physics” effects beyond the standard model. We also compute the more realistic muon-to-shower ratio for a particular configuration of the IceCube experiment, observing that using this experimental quantity a clear separation between standard and nonstandard neutrino physics cannot be obtained.

We discuss in detail a five-dimensional minimal supersymmetric standard model compactified on $S^1/Z_2$ extended by the effective Majorana neutrino mass operator. We study the evolution of neutrino masses and mixings. Masses and angles, in particular, the atmospheric mixing angle ${\theta }_{23}$, can be significantly lowered at high energies with respect to their value at low energy.

We couple a recently established $N=1$ globally supersymmetric self-dual Yang-Mills multiplet in three dimensions to supergravity. This becomes possible due to our previous result on globally supersymmetric formulation based on a compensator multiplet. We further couple the self-dual vector to a supersymmetric $\sigma$-model on the coset $SO(8,n)/SO(8)\times SO(n)$ via minimal couplings for an arbitrary gauged subgroup $H_0\subset SO(8)\times SO(n)$. A corresponding superspace formulation is also presented.

We calculate the self-force acting on a particle with scalar charge moving on a generic geodesic around a Schwarzschild black hole. This calculation requires an accurate computation of the retarded scalar field produced by the moving charge; this is done numerically with the help of a fourth-order convergent finite-difference scheme formulated in the time domain. The calculation also requires a regularization procedure, because the retarded field is singular on the particle’s world line; this is handled mode-by-mode via the mode-sum regularization scheme first introduced by Barack and Ori. This paper presents the numerical method, various numerical tests, and a sample of results for mildly eccentric orbits as well as “zoom-whirl” orbits.

A new model is studied which describes the quantum behavior of transitions through an isotropic quantum cosmological bounce in loop quantum cosmology sourced by a free and massless scalar field. As an exactly solvable model even at the quantum level, it illustrates properties of dynamical coherent states and provides the basis for a systematic perturbation theory of loop quantum gravity. The detailed analysis is remarkably different from what is known for harmonic oscillator coherent states. Results are evaluated with regard to their implications in cosmology, including a demonstration that in general quantum fluctuations before and after the bounce are unrelated. Thus, even within this solvable model the condition of classicality at late times does not imply classicality at early times before the bounce without further assumptions. Nevertheless, the quantum state does evolve deterministically through the bounce.

On a compact space with nontrivial cycles, for sufficiently small values of the radii of the compact dimensions, $\mathrm{SU}(N)$ gauge theories coupled with fermions in the fundamental representation spontaneously break charge conjugation, time reversal, and parity. We show at one loop in perturbation theory that a physical signature for this phenomenon is a nonzero baryonic current wrapping around the compact directions. The persistence of this current beyond the perturbative regime is checked by lattice simulations.

We explore a minimal extension of the standard model with fermionic cold dark matter by introducing a gauge singlet Dirac fermion. The interactions between the dark matter and the standard model matters are described by the nonrenormalizable dimension-5 term. We show that the measured relic abundance of the cold dark matter can be explained in our model and predict the direct detection cross section. The direct search of the dark matter provides severe constraints on the mass and coupling of the minimal fermionic dark matter with respect to the Higgs boson mass.

We report on a new search for two-body baryonic decays of the $B$ meson. Improved sensitivity compared to previous Belle results is obtained from $414{\mathrm{fb}}^{-1}$ of data that corresponds to $449\times {10}^6$ $B\overline{B}$ pairs, which were taken on the ${\rm Y}(4\mathrm{S})$ resonance and collected with the Belle detector at the KEKB $e^{+}{e}^{-}$ collider. No significant signals are observed and we set the 90% confidence level upper limits: $\mathcal{B}(B^0\to p\overline{p})<1.1\times {10}^{-7}$, $\mathcal{B}(B^0\to \Lambda \overline{\Lambda })<3.2\times {10}^{-7}$, and $\mathcal{B}(B^{+}\to p\overline{\Lambda })<3.2\times {10}^{-7}$.