Distinguishing models with μ→e\mu \to e observables

Upcoming experiments will improve the reach for the lepton flavour violating (LFV) processes $\mu \to e \gamma$, $\mu \to e \bar{e} e$ and $\mu A \to e A$ by orders of magnitude. We investigate whether this upcoming data could rule out some popular TeV-scale LFV models (the type II seesaw, the inverse seesaw and a scalar leptoquark) using a bottom-up EFT approach involving twelve Wilson coefficients that can in principle all be determined by experimental measurements. In this 12-dimensional coefficient space, each model can only predict points in a specific subspace; for instance, flavour change involving singlet electrons is suppressed in the seesaw models, and the leptoquark induces negligible coefficients for 4-lepton scalar operators. Using the fact that none of these models can populate the whole region accessible to upcoming experiments, we show that $\mu \to e$ experiments have the ability to rule them out.Comment: 14 pages, 7 Figure

Axion quality from the (anti)symmetric of SU(N)

We propose two models where a U(1) Peccei-Quinn global symmetry arises accidentally and is respected up to high-dimensional operators, so that the axion solution to the strong CP problem is successful even in the presence of Planck-suppressed operators. One model is SU$(N)$ gauge interactions with fermions in the fundamental and a scalar in the symmetric. The axion arises from spontaneous symmetry breaking to SO$(N)$, that confines at a lower energy scale. Axion quality in the model needs $N \gtrsim 10$. SO bound states and possibly monopoles provide extra Dark Matter candidates beyond the axion. In the second model the scalar is in the anti-symmetric: SU$(N)$ broken to Sp$(N)$ needs even $N \gtrsim 20$. The cosmological DM abundance, consisting of axions and/or super-heavy relics, can be reproduced if the PQ symmetry is broken before inflation (Boltzmann-suppressed production of super-heavy relics) or after (super-heavy relics in thermal equilibrium get partially diluted by dark glue-ball decays).Comment: 26 pages, 5 figures. v3: extra application mentioned; dilution factor in eq. (27) corrected, qualitative conclusions unchange

Helichrysum microphyllum subsp. tyrrhenicum, Its Root-Associated Microorganisms, and Wood Chips Represent an Integrated Green Technology for the Remediation of Petroleum Hydrocarbon-Contaminated Soils

Phytoremediation and the use of suitable amendments are well-known technologies for the mitigation of petroleum hydrocarbon (PHC) contaminations in terrestrial ecosystems. Our study is aimed at combining these two approaches to maximize their favorable effects. To this purpose, Helichrysum microphyllum subsp. tyrrhenicum, a Mediterranean shrub growing on sandy and semiarid soils, was selected. The weathered PHC-polluted matrix (3.3 ± 0.8 g kg−1 dry weight) from a disused industrial site was employed as the cultivation substrate with (WCAM) or without (UNAM) the addition and mixing of wood chips. Under the greenhouse conditions, the species showed a survival rate higher than 90% in the UNAM while the amendment administration restored the totality of the plant survival. At the end of the greenhouse test (nine months), the treatment with the wood chips significantly increased the moisture, dehydrogenase activity and abundance of the microbial populations of the PHC degraders in the substrate. Cogently, the residual amount of PHCs was significantly lower in the UNAM (3–92% of the initial quantity) than in the WCAM (3–14% of the initial quantity). Moreover, the crown diameter was significantly higher in the WCAM plants. Overall, the results establish the combined technology as a novel approach for landscaping and the bioremediation of sites chronically injured by PHC-weathered contaminations

Anaplasma phagocytophilum, Sardinia, Italy

Anaplasma phagocytophilum (formerly Ehrlichia phagocytophila), a tick-transmitted pathogen that infects several animal species, including humans (involved as accidental "dead-end" hosts), is the causative agent of human granulocytic anaplasmosis (HGA). It is a pathogen of veterinary importance responsible for tickborne fever of ruminants and for granulocytic anaplasmosis of horses and dogs). HGA was first described in the United States in 1994 and is emerging in Europe. Although only 2 human cases have been reported in Italy, serologic and molecular findings have shown A. phagocytophilum infections in dogs and Ixodes ricinus ticks. Incidence, prevalence, and public impact of HGA and horse granulocytic anaplasmosis are, therefore, unknown for this geographic area. From 1992 to 1996, an average rate of 13.4 cases/year/100,000 inhabitants of tick bite–related fever of unknown etiology has been reported on the island of Sardinia, Italy, which is considerably higher than the corresponding national average value of 2.1 cases/year/100,000 inhabitants. Moreover, 117 cases of tick bite–related fever, whose etiology remains obscure, have been reported from 1995 to 2002 in the central west coast area of the island. Local newspapers occasionally report deaths as a result of tick bites, although no HGA-associated deaths have been documented in Europe.This study investigated A. phagocytophilum in Sardinia

Six-month color change and water sorption of 9 new-generation flowable composites in 6 staining solutions

Abstract Color match and water sorption are two factors that affect restorative materials. Discoloration is essential in the lifespan of restorations. The aim of this study was to evaluate color change and water sorption of nine flowable composites at multiple time points over 6 months. 60 samples of each composite were divided into two groups (Color Change and Water Sorption/Solubility). Each Color Change group was divided into six subgroups, which were immersed in distilled water (DW), coffee (CF), Coca-Cola (CC), red wine (RW), tea (TE) and orange juice (OJ). The color was measured at the baseline, 1, 2, 3 and 4 weeks, and 3 and 6 months and color change values (ΔE) were calculated. Each Water Sorption [WS]/Solubility [WL] group was tested according to ISO 4049:2009. The data were evaluated using two-way ANOVA, Fisher’s post-hoc test and Pearson’s correlation test. The composite with the lowest ΔE differed for each solution: Filtek™ Bulk Fill in DW (∆E = 0.73 (0.17–1.759)); Vertise Flow in CF (∆E = 14.75 (7.91–27.41)), in TE (∆E = 7.27 (2.81–24.81)) and OJ (∆E = 3.17 (0.87–9.92)); Tetric EvoFlow® in CC (∆E = 1.27 (0.45–4.02)); and Filtek™ Supreme XTE in RW (∆E = 8.88 (5.23–19.59)). RW caused the most discoloration (∆E = 23.62 (4.93–51.36)). Vertise Flow showed the highest water sorption (WS = 69.10 ± 7.19). The Pearson test showed statistically significant positive correlations between water sorption and solubility and between water sorption and ∆E; the positive solubility-∆E correlation was not statistically significant. The findings suggest that water sorption is one factor associated with the ability of composites to discolor; however, discoloration is a multifactorial problem

Axion from high-quality accidental Peccei-Quinn symmetry

We propose two models where a U(1) Peccei-Quinn (PQ) global symmetry arises accidentally and is respected up to high-dimensional operators, so that the axion solution to the strong CP problem is successful even in the presence of Planck-suppressed operators. One model is SU(N) gauge interactions with fermions in the fundamental and a scalar in the symmetric. The axion arises from spontaneous symmetry breaking to SO(N), that confines at a lower energy scale. Axion quality in the model needs N=>10. SO bound states and possibly monopoles provide extra Dark Matter (DM) candidates beyond the axion. In the second model, the scalar is in the anti-symmetric: SU(N) broken to Sp(N) needs even N=>20. The cosmological DM abundance, consisting of axions and/or super-heavy relics, can be reproduced if the PQ symmetry is broken before inflation (Boltzmann-suppressed production of super-heavy relics) or after (super-heavy relics in thermal equilibrium get partially diluted by dark glue-ball decays)

Théories effectives de la saveur leptonique en physique des particules

Despite its tremendous success, the Standard Model (SM) of particle physics is incomplete, as various observations provide conclusive evidence of physics beyond the Standard Model (BSM). A notable example is the discovery of neutrino masses and oscillations, which clearly indicate that lepton flavour is not a symmetry of nature, thus demanding an extension of the Standard Model. Lepton Flavor Violation (LFV), defined as short-range flavour-changing interactions among the charged leptons, is expected to occur but it is yet to be observed. The new generation of experiments aimed at detecting lepton flavour-changing transitions will provide unprecedented experimental sensitivities and further probe LFV new physics.In this thesis, we assume that LFV physics is heavy and parametrize its effects using the Standard Model Effective Field Theory (SMEFT). LFV interactions are described by higher-dimensional operators constructed out-of-the SM fields, and observables are computed in terms of the operator coefficients.First, we introduce a small power counting parameter à la Wolfenstein to asses whether the state-of-the-art SMEFT calculations, which include the dimension six operators and their one-loop renormalization group equations, are sufficient to have a complete effective description of LFV observables. We find that the upcoming searches of muto e can be sensitive to a few dozen dimension eight operators, and to some effects of two-loop anomalous dimensions, for new physics scales respectively below 20-100 TeV.We build on these results and explore the sensitivity of muto e searches to tauleftrightarrow e(mu) flavour changing interactions. We describe the tauleftrightarrow e(mu) interactions as dimension six operators in the SM EFT, identify pairs of them giving interesting contributions to muto e processes, and obtain the anomalous dimensions mixing those pairs into dimension eight muto e operators. The dimension eight operator renormalization is mostly unknown, and we computed a subset of renormalization group equations for the first time. We show that upcoming muto e experiments could allow to probe parameter space beyond the reach of current and future searches of tauto e(mu) transitions, including Higgs, tau and B meson decays.Malgré son immense succès, le Modèle Standard (SM) de la physique des particules demeure incomplet, car diverses observations fournissent des preuves concluantes d'une physique au-delà du Modèle Standard (BSM). Un exemple notable est la découverte des masses et des oscillations des neutrinos, qui indiquent clairement que la saveur leptonique n'est pas une symétrie de la nature, exigeant ainsi une extension du Modèle Standard. La violation de la saveur leptonique (LFV), définie comme des interactions de changement de saveur à courte portée parmi les leptons chargés, est prévue, mais n'a pas encore été observée. La nouvelle génération d'expériences visant à détecter les transitions de saveur leptonique offrira des sensibilités expérimentales sans précédent et permettra d'explorer plus en profondeur la nouvelle physique associée à la LFV.Dans cette thèse, nous supposons que la physique de la LFV est lourde et paramétrisons ses effets à l'aide de la Théorie Effective des Champs du Modèle Standard (SMEFT). Les interactions de la LFV sont décrites par des opérateurs de dimension supérieure construits à partir des champs du Modèle Standard, permettant le calcul des observables en fonction des coefficients de ces opérateurs.Tout d'abord, nous introduisons un petit paramètre de comptage des puissances à la Wolfenstein pour évaluer si les calculs de pointe de la SMEFT, qui incluent les opérateurs de dimension six et leurs équations de renormalisation à une boucle, sont suffisants pour obtenir une description effective complète des observables de la LFV. Nous constatons que les futures recherches sur muto e peuvent être sensibles à quelques dizaines d'opérateurs de dimension huit et à certains effets de dimensions anormales à deux boucles, pour des échelles de nouvelle physique respectivement inférieures à 20-100 TeV.Nous nous appuyons sur ces résultats et explorons la sensibilité des recherches sur muto e aux interactions de changement de saveur tauleftrightarrow e(mu). Nous décrivons les interactions tauleftrightarrow e(mu) comme des opérateurs de dimension six dans la SMEFT, identifions des paires d'entre eux donnant des contributions intéressantes aux processus muto e, et obtenons les dimensions anormales mélangeant ces paires dans les opérateurs muto e de dimension huit. La renormalisation des opérateurs de dimension huit est en grande partie inconnue, et nous avons calculé un sous-ensemble des équations de groupe de renormalisation de dimension huit pour la première fois. Nous montrons que les futures expériences sur muto e pourraient permettre d'explorer des espaces de paramètres qui échappent aux recherches actuelles et futures des transitions tauto e(mu), y compris les désintégrations du boson de Higgs, du tau et des mésons B

Introduction to Charged Lepton Flavour Violation

Neutrino masses are evidence of lepton flavour violation, but no violation in the interactions among the charged leptons has been observed yet. Many models of Physics Beyond the Standard Model (BSM) predict Charged Lepton Flavour Violation (CLFV) in a wide spectrum of processes with rates in reach of upcoming experiments. The experimental searches that provide the current best limits on the CLFV searches are reviewed, with a particular emphasis on the muon-based experiments that give the most stringent constraints on BSM parameter space. The next generation of muon-based experiments (MEG-II, Mu2e, COMET, Mu3e) aim to reach improvements by many orders of magnitude w.r.t. the current best limits, thanks to several technological advancements. We review popular heavy BSM theories, and we present state-of-the-art calculations of the predicted CLFV branching ratios, focusing on the more sensitive $\mu\to e$ sector

A viable Le−LμL_e-L_\mu model with μ→e\mu\to e violation

We extend the Standard Model gauge group by $U(1)_{L_e-L_\mu}$ and introduce two scalars, a doublet and a singlet, that are charged under this new group and have lepton flavour violating couplings. Since in this model $\mu \to e$ processes can only be mediated by $\mu\to \tau\times \tau\to e$ interactions, bounds from $\mu\to e$ transitions can be avoided while allowing for accessible new physics. We consider a $Z'$ boson with a mass of $M_{Z'}\simeq10~$GeV and a gauge coupling $g'\simeq 10^{-4}$, which is in reach of Belle-II. Neutrino masses and mixing angles can also be accounted for if sterile neutrinos are added to the spectrum

A viable Le−LμL_e-L_\mu model with μ→e\mu\to e violation

We extend the Standard Model gauge group by $U(1)_{L_e-L_\mu}$ and introduce two scalars, a doublet and a singlet, that are charged under this new group and have lepton flavour violating couplings. Since in this model $\mu \to e$ processes can only be mediated by $\mu\to \tau\times \tau\to e$ interactions, bounds from $\mu\to e$ transitions can be avoided while allowing for accessible new physics. We consider a $Z'$ boson with a mass of $M_{Z'}\simeq10~$GeV and a gauge coupling $g'\simeq 10^{-4}$, which is in reach of Belle-II. Neutrino masses and mixing angles can also be accounted for if sterile neutrinos are added to the spectrum