Phenomenology of Non-Abelian Flat Directions in a Minimal Superstring Standard Model

Recently, we presented the first non-Abelian flat directions that produce from a heterotic string model solely the three-generation MSSM states as the massless spectrum in the observable sector of the low energy effective field theory. In this paper we continue to develop the systematic techniques for the analysis of nonrenormalizable superpotential terms and non-Abelian flat direction in realistic string models. Some of our non-Abelian directions were F-flat to all finite orders in the superpotential. We study for the same string model the varying phenomenologies resulting from a large set of such all-order flat directions. We focus on the quark, charged lepton, and Higgs doublet mass matrices resulting for our phenomenologically superior non-Abelian flat direction. We review and apply a string-related method for generating large mass hierarchies between MSSM generations, first discussed in string-derived flipped SU(5) models, when all generational mass terms are of renormalizable or very low non-renormalizable order

Phenomenology of U(1)Lμ−LτU(1)_{L_\mu - L_\tau} charged dark matter at PAMELA/FERMI and colliders

Recent data on $e^+/e^-$ and $\bar{p}$ cosmic rays suggest that dark matter annihilate into the standard model (SM) particles through new leptophilic interaction. In this paper, we consider a standard model extension with the gauged $U(1)_{L_\mu - L_\tau}$ group, with a new Dirac fermion charged under this U(1) as a dark matter. We study the muon $(g-2)_\mu$, thermal relic density of the cold dark matter, and the collider signatures of this model. $Z^{'}$ productions at the Tevatron or the LHC could be easily order of $O(1)-O(10^3)$ fb.Comment: 18 pages, 5 figures; minor change

Baryon number violation, baryogenesis and defects with extra dimensions

In generic models for grand unified theories(GUT), various types of baryon number violating processes are expected when quarks and leptons propagate in the background of GUT strings. On the other hand, in models with large extra dimensions, the baryon number violation in the background of a string is not trivial because it must depend on the mechanism of the proton stabilization. In this paper we argue that cosmic strings in models with extra dimensions can enhance the baryon number violation to a phenomenologically interesting level, if the proton decay is suppressed by the mechanism of localized wavefunctions. We also make some comments on baryogenesis mediated by cosmological defects. We show at least two scenarios will be successful in this direction. One is the scenario of leptogenesis where the required lepton number conversion is mediated by cosmic strings, and the other is the baryogenesis from the decaying cosmological domain wall. Both scenarios are new and have not been discussed in the past.Comment: 20pages, latex2e, comments and references added, to appear in PR

Testing the Nature of Kaluza-Klein Excitations at Future Lepton Colliders

With one extra dimension, current high precision electroweak data constrain the masses of the first Kaluza-Klein excitations of the Standard Model gauge fields to lie above $\simeq 4$ TeV. States with masses not much larger than this should be observable at the LHC. However, even for first excitation masses close to this lower bound, the second set of excitations will be too heavy to be produced thus eliminating the possibility of realizing the cleanest signature for KK scenarios. Previous studies of heavy $Z'$ and $W'$ production in this mass range at the LHC have demonstrated that very little information can be obtained about their couplings to the conventional fermions given the limited available statistics and imply that the LHC cannot distinguish an ordinary $Z'$ from the degenerate pair of the first KK excitations of the $\gamma$ and $Z$. In this paper we discuss the capability of lepton colliders with center of mass energies significantly below the excitation mass to resolve this ambiguity. In addition, we examine how direct measurements obtained on and near the top of the first excitation peak at lepton colliders can confirm these results. For more than one extra dimension we demonstrate that it is likely that the first KK excitation is too massive to be produced at the LHC.Comment: 38 pages, 10 Figs, LaTex, comments adde

Higgs and neutrino sector, EDM and epsilon_K in a spontaneously CP and R-parity breaking supersymmetric model

We construct an extension of the supersymmetric standard model where both CP symmetry and R-parity are spontaneously broken. We study the electroweak symmetry breaking sector of the model and find minima consistent with the experimental bounds on Higgs boson masses. Neutrino masses and mixing angles are generated through both seesaw and bilinear R-parity violation. We show that the hierarchical mass pattern is obtained, and mixings are consistent with measured values. Due to the spontaneous CP and R-parity violation, the neutrino sector is CP violating, and we calculate the corresponding phase. We further restrict the parameter space to agree with the limits on the electric dipole moment of the neutron. Finally, we study the CP violation parameter epsilon_K in the kaon system and show that we obtain results consistent with the experimental value.Comment: 13 pages, 7 figures, submitted to EPJ

Leptophobic Z{prime} from superstring derived models

It was recently suggested that the reported anomalies in R{sub b} and R{sub c} can be interpreted as the effect of a heavy vector boson that couples to quarks and is universally decoupled from leptons. We examine how an extra gauge boson with this property can arise from superstring derived models. In a specific three generation model we show that the U(1){sub B-L} symmetry combines with the horizontal flavor symmetries to form a universal leptophobic U(1) symmetry. In our model there is an enhancement of the color gauge group from twisted sectors. The enhancement occurs after the breaking of the unifying gauge symmetry by ``Wilson lines.`` The leptophobic U(1) symmetry then becomes a generator of the color SU(4) gauge group. We examine how similar symmetries may appear in other string models without the enhancement. We propose that if the current LEP anomalies persist it may be evidence for a certain class of un-unified superstring models. 15 refs., 4 tabs

Long-term evaluation of faecal calprotectin levels in a European cohort of children with cystic fibrosis

Objective: Intestinal inflammation with contradictory data on faecal calprotectin (fCP) levels is documented in patients with cystic fibrosis (CF). The aim of this study was to longitudinally evaluate fCP in a cohort of children with CF and their relationship with clinical variables. Design: Prospective observational study to assess evolution of fCP levels, primary aimed at improving fat absorption. Along 1.5 years of follow-up (November 2016-May 2018) with four study visits pertaining to a pilot study (two of four) and to a clinical trial (two of four), the study outcomes were measured. Setting: Six European CF centres in the context of MyCyFAPP Project. Subjects: Children with CF and pancreatic insufficiency (2-18 years old). Main outcome measurements: fCP levels, pulmonary function (percentage of forced expiratory volume in 1 s (FEV1%)) and coefficient of fat absorption (CFA). Additionally, in the last two visits, gastrointestinal (GI) symptoms were evaluated through the PedsQL-GI Questionnaire. Linear mixed regression models were applied to assess association between fCP and FEV1, CFA and GI symptoms. Results: Twenty-nine children with CF and pancreatic insufficiency were included. fCP levels were inversely associated with total modified specific PedsQL-GI score (p=0.04) and positively associated with diarrhoea (p=0.03), but not with CFA. Along the four study visits, fCP significantly increased (from 62 to 256 μg/g) and pulmonary function decreased (from 97% to 87%), with a significant inverse association between the two study outcomes (p&lt;0.001). Conclusions: In children with CF, fCP levels are inversely associated with pulmonary function and thus the specificity of fCP as a marker of intestinal inflammation in paediatric patients with CF warrants further investigation.</p

Long-term evaluation of faecal calprotectin levels in a European cohort of children with cystic fibrosis

Objective: Intestinal inflammation with contradictory data on faecal calprotectin (fCP) levels is documented in patients with cystic fibrosis (CF). The aim of this study was to longitudinally evaluate fCP in a cohort of children with CF and their relationship with clinical variables. Design: Prospective observational study to assess evolution of fCP levels, primary aimed at improving fat absorption. Along 1.5 years of follow-up (November 2016-May 2018) with four study visits pertaining to a pilot study (two of four) and to a clinical trial (two of four), the study outcomes were measured. Setting: Six European CF centres in the context of MyCyFAPP Project. Subjects: Children with CF and pancreatic insufficiency (2-18 years old). Main outcome measurements: fCP levels, pulmonary function (percentage of forced expiratory volume in 1 s (FEV1%)) and coefficient of fat absorption (CFA). Additionally, in the last two visits, gastrointestinal (GI) symptoms were evaluated through the PedsQL-GI Questionnaire. Linear mixed regression models were applied to assess association between fCP and FEV1, CFA and GI symptoms. Results: Twenty-nine children with CF and pancreatic insufficiency were included. fCP levels were inversely associated with total modified specific PedsQL-GI score (p=0.04) and positively associated with diarrhoea (p=0.03), but not with CFA. Along the four study visits, fCP significantly increased (from 62 to 256 μg/g) and pulmonary function decreased (from 97% to 87%), with a significant inverse association between the two study outcomes (p&lt;0.001). Conclusions: In children with CF, fCP levels are inversely associated with pulmonary function and thus the specificity of fCP as a marker of intestinal inflammation in paediatric patients with CF warrants further investigation.</p

AVIATOR: An open international registry to evaluate medical and surgical outcomes of aortic valve insufficiency and ascending aorta aneurysm

Objectives: Current national registries are lacking detailed pathology-driven analysis and long-term patients outcomes. The Heart Valve Society (HVS) aortic valve (AV) repair research network started the Aortic Valve Insufficiency and ascending aorta Aneurysm InternATiOnal Registry (AVIATOR) to evaluate long-term patient outcomes of AV repair and replacement. The purpose of the current report is to describe the AVIATOR initiative and report in a descriptive manner the patients included.Methods: The AV repair research network includes surgeons, cardiologists, and scientists and established an online database compliant with the guidelines for reporting valve-related events. Prospective inclusion started from January 2013. Adult patients (18 years or older) who were operated on between 1995 and 2017 with complete procedural specification of the type of repair/replacement were selected for descriptive analysis.Results: Currently 58 centers from 17 countries include 4896 patients with 89% AV repair (n = 4379) versus 11% AV replacement (n = 517). AV repair was either isolated (28%), or associated with tubular/partial root replacement (22%) or valve-sparing root replacement (49%) with an in-hospital mortality of 0.5%, 1.7%, and 1.2%, respectively. AV replacement was either isolated (24%), associated with tubular/partial root replacement (17%) or root replacement (59%) with an in-hospital mortality of 1%, 2.6%, and 2.0%, respectively.Conclusions: The multicenter surgical AVIATOR registry, by applying uniform definitions, should provide a solid evidence base to evaluate the place of repair versus replacement on the basis of long-term patient outcomes. Obtaining data completeness and adequate representation of all surgery types remain challenging. Toward the near future AVIATOR-medical will start to study natural history, as will AVIATOR-kids, with a focus on pediatric disease.Thoracic Surger