Randall-Sundrum Corrections to the Width Difference and CP-Violating Phase in Bs0B^0_s-Meson Decays

We study the impact of the Randall-Sundrum setup on the width difference $\Delta\Gamma_s$ and the CP-violating phase $\phi_s$ in the $\bar B_s^0$-$B_s^0$ system. Our calculations are performed in the general framework of an effective theory, based on operator product expansion. The result can thus be used for many new physics models. We find that the correction to the magnitude of the decay amplitude $\Gamma_{12}$ is below 4% for a realistic choice of input parameters. The main modification in the $\Delta\Gamma_s/\beta_s$-plane is caused by a new CP-violating phase in the mixing amplitude, which allows for a better agreement with the experimental results of CDF and D\O from $B_s^0\rightarrow J/\psi\phi\,$ decays. The best-fit value of the CP asymmetry $S_{\psi\phi}$ can be reproduced, while simultaneously the theoretical prediction for the semileptonic CP asymmetry $A_{\rm SL}^s$ can enter the $1\sigma$ range.Comment: 12 pages, 1 table, 3 figures, references added, comments added, minor correction in numerics, conclusions unchanged, accepted for publication in Physical Review

Nonstandard electroconvection in a bent-core oxadiazole material

Electroconvection (EC) phenomena have been investigated in the nematic phase of a bent-core oxadiazole material with negative dielectric anisotropy and a frequency dependent conductivity anisotropy. The formation of longitudinal roll (LR) patterns is one of the predominant features observed in the complete frequency and voltage range studied. At voltages much above the LR threshold, various complex patterns such as the "crisscrossed" pattern, bimodal varicose, and turbulence are observed. Unusually, the nonstandard EC (ns-EC) instability in this material, is observed in a regime in which we measure the dielectric and conductivity anisotropies to be negative and positive respectively. A further significant observation is that the EC displays distinct features in the high and low temperature regimes of the nematic phase, supporting an earlier report that EC patterns could distinguish between regions that have been reported as uniaxial and biaxial nematic phases

High resolution measurements of density structures in the Jovian plasma sheet

A recent effort to digitize the plasma density by using the low frequency cutoff of trapped continuum radiation in the vicinity of the Jovian plasma sheet has revealed the existence of sharply defined density structures in the plasma sheet. These structures typically have a plasma density which is relatively constant but of order 50 percent greater or less than in the surrounding plasma. At the boundaries of these structures, the transitions from low to high density occur on time scales of about ten seconds, which correspond to spatial dimensions on the order of a few ion Larmor radii. The structures themselves last for intervals from less than a minute to more than five minutes, corresponding to size scales from a fraction of a Jovian radius to more than a Jovian radius, depending of the velocity of the structure relative to the spacecraft. In view of the importance of near corotation plasma flows, these structures are likely to be limited in both the longitudinal and radial dimensions and, therefore, could represent flux tubes with greatly varying plasma content. These observations are presented as among the first to directly address the theoretically proposed interchange instability

Z₂ Non-Restoration and Composite Higgs: Singlet-Assisted Baryogenesis w/o Topological Defects

Simple scalar-singlet extensions of the Standard Model with a (spontaneouslybroken) $Z_2$ symmetry allow for a strong first order electroweak phasetransition, as sought in order to realize electroweak baryogenesis. Howeverthey generically also lead to the emergence of phenomenologically problematicdomain walls. Here we present a framework with a real scalar singlet thatfeatures a different thermal history that avoids this problem by neverrestoring the $Z_2$ symmetry in the early universe. This is accomplished byconsidering $D>4$ operators that emerge on general grounds, understanding themodel as the low energy tail of a more complete theory, like for example incomposite Higgs scenarios. Sticking to the latter framework, we present aconcrete $SO(6)/SO(5)$ composite realization of the idea. To this end, weadditionally provide a complete classification of the structure of the Higgspotential (and the Yukawa couplings) in $SO(6)/SO(5)$ models with fermions inthe ${\bf 1, 6, 15}$ or ${\bf 20^\prime}$ of $SO(6)$.<br

Higgs Pair Production: Choosing Benchmarks With Cluster Analysis

New physics theories often depend on a large number of free parameters. The precise values of those parameters in some cases drastically affect the resulting phenomenology of fundamental physics processes, while in others finite variations can leave it basically invariant at the level of detail experimentally accessible. When designing a strategy for the analysis of experimental data in the search for a signal predicted by a new physics model, it appears advantageous to categorize the parameter space describing the model according to the corresponding kinematical features of the final state. A multi-dimensional test statistic can be used to gauge the degree of similarity in the kinematics of different models; a clustering algorithm using that metric may then allow the division of the space into homogeneous regions, each of which can be successfully represented by a benchmark point. Searches targeting those benchmark points are then guaranteed to be sensitive to a large area of the parameter space. In this document we show a practical implementation of the above strategy for the study of non-resonant production of Higgs boson pairs in the context of extensions of the standard model with anomalous couplings of the Higgs bosons. A non-standard value of those couplings may significantly enhance the Higgs pair production cross section, such that the process could be detectable with the data that the Large Hadron Collider will collect in Run 2.Comment: Editorial changes, improvements in figures and changes in the appendi

The Hierarchy Problem and the Top Yukawa: An Alternative to Top Partner Solutions

We discuss the role of the top-quark Yukawa coupling $y_t$ concerning thehierarchy problem and construct an alternative scheme to the conventionalsolutions with top partners. In traditional models, like SUSY or compositeHiggs, top partners cancel the top loop contribution to the Higgs quadraticterm. The lack of evidence for such colored partners however drives thesemodels into more and more fine-tuned regions. Here, an alternative means tomitigate the top loop, allowing for natural electroweak symmetry breaking, ispresented. Emphasizing that we have not measured the top-Higgs interactions athigh scales yet, we envisage scenarios where this interaction is onlyapproaching its sizable strength in the infra-red, but gets strongly suppressedat high scales. We first discuss possible effects via a modification of therunning of the top Yukawa coupling. Then, we turn to models where the topYukawa is generated at one-loop level. Originated from a dimension-sixoperator, it drops when crossing the mass threshold of new degrees of freedom.In either case, the top partners are replaced by some new top-philic particleswith strong interaction. Thus, a very different phenomenology, such as largetop mass running and signals in four top final states, is introduced, whichwill be discussed in detail. With the assistance of this mechanism, thesolution to the hierarchy problem can be pushed to a (well-defined) higherscale, and a final test of naturalness might be deferred to a 100 TeV Collider,like the FCC.<br

The Hierarchy Problem and the Top Yukawa: An Alternative to Top Partner Solutions

We discuss the role of the top-quark Yukawa coupling $y_t$ concerning thehierarchy problem and construct an alternative scheme to the conventionalsolutions with top partners. In traditional models, like SUSY or compositeHiggs, top partners cancel the top loop contribution to the Higgs quadraticterm. The lack of evidence for such colored partners however drives thesemodels into more and more fine-tuned regions. Here, an alternative means tomitigate the top loop, allowing for natural electroweak symmetry breaking, ispresented. Emphasizing that we have not measured the top-Higgs interactions athigh scales yet, we envisage scenarios where this interaction is onlyapproaching its sizable strength in the infra-red, but gets strongly suppressedat high scales. We first discuss possible effects via a modification of therunning of the top Yukawa coupling. Then, we turn to models where the topYukawa is generated at one-loop level. Originated from a dimension-sixoperator, it drops when crossing the mass threshold of new degrees of freedom.In either case, the top partners are replaced by some new top-philic particleswith strong interaction. Thus, a very different phenomenology, such as largetop mass running and signals in four top final states, is introduced, whichwill be discussed in detail. With the assistance of this mechanism, thesolution to the hierarchy problem can be pushed to a (well-defined) higherscale, and a final test of naturalness might be deferred to a 100 TeV Collider,like the FCC.<br