Direct and indirect signals of natural composite Higgs models

We present a comprehensive numerical analysis of a four-dimensional model with the Higgs as a composite pseudo-Nambu-Goldstone boson that features a calculable Higgs potential and protective custodial and flavour symmetries to reduce electroweak fine-tuning. We employ a novel numerical technique that allows us for the first time to study constraints from radiative electroweak symmetry breaking, Higgs physics, electroweak precision tests, flavour physics, and direct LHC bounds on fermion and vector boson resonances in a single framework. We consider four different flavour symmetries in the composite sector, one of which we show to not be viable anymore in view of strong precision constraints. In the other cases, all constraints can be passed with a sub-percent electroweak fine-tuning. The models can explain the excesses recently observed in $WW$, $WZ$, $Wh$ and $\ell^+\ell^-$ resonance searches by ATLAS and CMS and the anomalies in angular observables and branching ratios of rare semi-leptonic $B$ decays observed by LHCb. Solving the $B$ physics anomalies predicts the presence of a dijet or $t\bar t$ resonance around 1 TeV just below the sensitivity of LHC run 1. We discuss the prospects to probe the models at run 2 of the LHC. As a side product, we identify several gaps in the searches for vector-like quarks at hadron colliders, that could be closed by reanalyzing existing LHC data.Comment: 74 pages, 21 figures. v2: references added, discussion in 3.2.6 extende

Violation of lepton flavour universality in composite Higgs models

We investigate whether the $2.6\sigma$ deviation from lepton flavour universality in $B^+\to K^+\ell^+\ell^-$ decays recently observed at the LHCb experiment can be explained in minimal composite Higgs models. We show that a visible departure from universality is indeed possible if left-handed muons have a sizable degree of compositeness. Constraints from $Z$-pole observables are avoided by a custodial protection of the muon coupling. The deficit in the invisible $Z$ width at LEP is explained in the same region of parameters.Comment: 5 pages, 2 figures. v4: discussion of invisible Z width adde

Cache policies for cloud-based systems: To keep or not to keep

In this paper, we study cache policies for cloud-based caching. Cloud-based caching uses cloud storage services such as Amazon S3 as a cache for data items that would have been recomputed otherwise. Cloud-based caching departs from classical caching: cloud resources are potentially infinite and only paid when used, while classical caching relies on a fixed storage capacity and its main monetary cost comes from the initial investment. To deal with this new context, we design and evaluate a new caching policy that minimizes the overall cost of a cloud-based system. The policy takes into account the frequency of consumption of an item and the cloud cost model. We show that this policy is easier to operate, that it scales with the demand and that it outperforms classical policies managing a fixed capacity.Comment: Proceedings of IEEE International Conference on Cloud Computing 2014 (CLOUD 14

Electroweak symmetry breaking and collider signatures in the next-to-minimal composite Higgs model

We conduct a detailed numerical analysis of the composite pseudo-Nambu-Goldstone Higgs model based on the next-to-minimal coset $\text{SO}(6)/\text{SO}(5)\cong\text{SU}(4)/\text{Sp}(4)$, featuring an additional SM singlet scalar in the spectrum, which we allow to mix with the Higgs boson. We identify regions in parameter space compatible with all current experimental constraints, including radiative electroweak symmetry breaking, flavour physics, and direct searches at colliders. We find the additional scalar, with a mass predicted to be below a TeV, to be virtually unconstrained by current LHC data, but potentially in reach of run 2 searches. Promising indirect searches include rare semi-leptonic $B$ decays, CP violation in $B_s$ mixing, and the electric dipole moment of the neutron.Comment: 32 pages + appendices, 9 figures. v2: minor clarifications, matches the JHEP versio

Bs→μ+μ−B_s\to\mu^+\mu^- as current and future probe of new physics

The rare flavour-changing neutral current decay $B_s\to\mu^+\mu^-$ is among the most important indirect probes of new physics at the LHC, as it is strongly suppressed in the Standard Model, very sensitive to new physics effects, and theoretically exceptionally clean. We present a thorough state-of-the-art analysis of the constraints on new physics from present and future measurements of this decay, focusing on scalar operators. We show model-independently and in concrete new physics models, namely the MSSM and two leptoquark scenarios, that a future precise measurement of the mass-eigenstate rate asymmetry in $B_s\to\mu^+\mu^-$ would allow to disentangle new physics scenarios that would be indistinguishable based on measurements of the branching ratio alone. We also highlight the complementarity between $B_s\to\mu^+\mu^-$ and direct searches in both model classes. Our numerics is based on the open source code flavio and is made publicly available.Comment: 25 pages, 8 figures. Plot scripts available at https://github.com/DavidMStraub/paper-bsmumu-ans. v2: numerics updated using published LHCb result, references added. Conclusions unchange

Status of the B→K∗μ+μ−B\to K^*\mu^+\mu^- anomaly after Moriond 2017

Motivated by recent results by the ATLAS and CMS collaborations on the angular distribution of the $B \to K^* \mu^+\mu^-$ decay, we perform a state-of-the-art analysis of rare $B$ meson decays based on the $b \to s \mu \mu$ transition. Using standard estimates of hadronic uncertainties, we confirm the presence of a sizable discrepancy between data and SM predictions. We do not find evidence for a $q^2$ or helicity dependence of the discrepancy. The data can be consistently described by new physics in the form of a four-fermion contact interaction $(\bar s \gamma_\alpha P_L b)(\bar \mu \gamma^\alpha \mu)$. Assuming that the new physics affects decays with muons but not with electrons, we make predictions for a variety of theoretically clean observables sensitive to violation of lepton flavour universality.Comment: 20 pages, 8 figures, 3 tables. v3: numerics updated using v2 of arXiv:1606.04731. Conclusions unchanged. Matches published version. Example script available at https://github.com/DavidMStraub/paper-bkstarmumu-ans

Anatomy of ε′/ε\varepsilon'/\varepsilon beyond the Standard Model

We present for the first time a model-independent anatomy of the ratio $\varepsilon'/\varepsilon$ in the context of the $\Delta S = 1$ effective theory with operators invariant under QCD and QED and in the context of the Standard Model Effective Field Theory (SMEFT) with the operators invariant under the full SM gauge group. Our goal is to identify the new physics scenarios that are probed by this ratio and which could help to explain a possible deviation from the SM that is hinted by the data. To this end we derive a master formula for $\varepsilon'/\varepsilon$, which can be applied to any theory beyond the Standard Model (BSM) in which the Wilson coefficients of all contributing operators have been calculated at the electroweak scale. The relevant hadronic matrix elements of BSM operators are from the Dual QCD approach and the SM ones from lattice QCD. Within SMEFT, the constraints from $K^0$ and $D^0$ mixing as well as electric dipole moments limit significantly potential new physics contributions to $\varepsilon'/\varepsilon$. Correlations of $\varepsilon'/\varepsilon$ with $K\to\pi\nu\bar\nu$ decays are briefly discussed. Building on our EFT analysis and the model-independent constraints, we discuss implications of a possible deviation from the SM in $\varepsilon'/\varepsilon$ for model building, highlighting the role of the new scalar and tensor matrix elements in models with scalar mediators.Comment: 47 pages, 4 figures. v3: signs in tables 6-10 corrected, numerical results and conclusions unchange

What is the Minimum to Trust AI?—A Requirement Analysis for (Generative) AI-based Texts

The generative Artificial Intelligence (genAI) innovation enables new potentials for end-users, affecting youth and the inexperienced. Nevertheless, as an innovative technology, genAI risks generating misinformation that is not recognizable as such. The extraordinary AI outputs can result in increased trustworthiness. An end-user assessment system is necessary to expose the unfounded reliance on erroneous responses. This paper identifies requirements for an assessment system to prevent end-users from overestimating trust in generated texts. Thus we conducted requirements engineering based on a literature review and two international surveys. The results confirmed the requirements which enable human protection, human support, and content veracity in dealing with genAI. Overestimated trust is rooted in miscalibration; clarity about genAI and its provider is essential to solving this phenomenon, and there is a demand for human verifications. Consequently, our findings provide evidence for the significance of future IS research on human-centered genAI trust solutions

Impact of the Sensory and Sympathetic Nervous System on Fracture Healing in Ovariectomized Mice

The peripheral nervous system modulates bone repair under physiological and pathophysiological conditions. Previously, we reported an essential role for sensory neuropeptide substance P (SP) and sympathetic nerve fibers (SNF) for proper fracture healing and bone structure in a murine tibial fracture model. A similar distortion of bone microarchitecture has been described for mice lacking the sensory neuropeptide alpha-calcitonin gene-related peptide (alpha-CGRP). Here, we hypothesize that loss of SP, alpha-CGRP, and SNF modulates inflammatory and pain-related processes and also affects bone regeneration during fracture healing under postmenopausal conditions. Intramedullary fixed femoral fractures were set to 28 days after bilateral ovariectomy (OVX) in female wild type (WT), SP-, alpha-CGRP-deficient, and sympathectomized (SYX) mice. Locomotion, paw withdrawal threshold, fracture callus maturation and numbers of TRAP-, CD4-, CD8-, F4/80-, iNos-, and Arg1-positive cells within the callus were analyzed. Nightly locomotion was reduced in unfractured SP-deficient and SYX mice after fracture. Resistance to pressure was increased for the fractured leg in SP-deficient mice during the later stages of fracture healing, but was decreased in alpha-CGRP-deficient mice. Hypertrophic cartilage area was increased nine days after fracture in SP-deficient mice. Bony callus maturation was delayed in SYX mice during the later healing stages. In addition, the number of CD 4-positive cells was reduced after five days and the number of CD 8-positive cells was additionally reduced after 21 days in SYX mice. The number of Arg1-positive M2 macrophages was higher in alpha-CGRP-deficient mice five days after fracture. The alkaline phosphatase level was increased in SYX mice 16 days after fracture. Absence of alpha-CGRP appears to promote M2 macrophage polarization and reduces the pain threshold, but has no effect on callus tissue maturation. Absence of SP reduces locomotion, increases the pain-threshold, and accelerates hypertrophic callus tissue remodeling. Destruction of SNF reduces locomotion after fracture and influences bony callus tissue remodeling during the later stages of fracture repair, whereas pain-related processes are not affected

Slow cortical potential neurofeedback in attention deficit hyperactivity disorder: is there neurophysiological evidence for specific effects?

This study compared changes in quantitative EEG (QEEG) and CNV (contingent negative variation) of children suffering from ADHD treated by SCP (slow cortical potential) neurofeedback (NF) with the effects of group therapy (GT) to separate specific from non-specific neurophysiological effects of NF. Twenty-six children (age: 11.1±1.15years) diagnosed as having ADHD were assigned to NF (N=14) or GT (N=12) training groups. QEEG measures at rest, CNV and behavioral ratings were acquired before and after the trainings and statistically analyzed. For children with ADHD-combined type in the NF group, treatment effects indicated a tendency toward improvement of selected QEEG markers. We could not find the expected improvement of CNV, but CNV reduction was less pronounced in good NF performers. QEEG changes were associated with some behavioral scales. Analyses of subgroups suggested specific influences of SCP training on brain functions. To conclude, SCP neurofeedback improves only selected attentional brain functions as measurable with QEEG at rest or CNV mapping. Effects of neurofeedback including the advantage of NF over GT seem mediated by both specific and non-specific factor