Imprints of massive inverse seesaw model neutrinos in lepton flavor violating Higgs boson decays

In this paper we consider a Higgs boson with mass and other properties compatible with those of the recently discovered Higgs particle at the LHC, and explore the possibility of new Higgs leptonic decays, beyond the standard model, with the singular feature of being lepton flavor violating (LFV). We study these LFV Higgs decays, $H \to l_k\bar l_m$, within the context of the inverse seesaw model (ISS) and consider the most generic case where three additional pairs of massive right-handed singlet neutrinos are added to the standard model particle content. We require in addition that the input parameters of this ISS model are compatible with the present neutrino data and other constraints, like perturbativity of the neutrino Yukawa couplings. We present a full one-loop computation of the BR($H \to l_k\bar l_m$) rates for the three possible channels, $l_k\bar l_m=\mu \bar \tau,\, e \bar \tau,\, e \bar \mu$, and analyze in full detail the predictions as functions of the various relevant ISS parameters. We study in parallel the correlated one-loop predictions for the radiative decays, $l_m \to l_k \gamma$, within this same ISS context, and require full compatibility of our predictions with the present experimental bounds for the three radiative decays, $\mu \to e \gamma$, $\tau \to \mu \gamma$, and $\tau \to e \gamma$. After exploring the ISS parameter space we conclude on the maximum allowed LFV Higgs decay rates within the ISS.Comment: 29 pages, 13 figures, 1 table, 1 appendix: v4 matches the manuscript published in PR

Exotic μτjj\mu\tau j j events from heavy ISS neutrinos at the LHC

In this letter we study new relevant phenomenological consequences of the right-handed heavy neutrinos with masses at the ${\cal O}(1)$ TeV energy scale, working within the context of the Inverse Seesaw Model that includes three pairs of quasi-degenerate pseudo-Dirac heavy neutrinos. We propose a new exotic signal of these heavy neutrinos at the CERN Large Hadron Collider containing a muon, a tau lepton, and two jets in the final state, which is based on the interesting fact that this model can incorporate large Lepton Flavor Violation for specific choices of the relevant parameters, particularly, the neutrino Yukawa couplings. We will show here that an observable number of $\mu\tau jj$ exotic events, without missing energy, can be produced at this ongoing run of the LHC.Comment: 7 pages, 4 figures. This version v3 matches the manuscript published in Physics Letters

E-hailing and Employment Rights: The Case for an Employment Relationship Between Uber and its Drivers in South Africa

South Africa’s Uber dilemma has forced jurists to answer important questions about the country’s largest black-owned sector: the taxi industry. Since the days of apartheid, taxi drivers have struggled to secure their livelihoods. Lamentably, they have found themselves restricted by a legacy of oppression that, despite significant progress, lingers on. As of late, Uber has exploded onto the transportation market, and labor courts must decide whether Uber drivers fit within a system that never contemplated the emergence of gig economy companies. If future jurists continue to draw inspiration from South Africa’s highly progressive constitution, international agreements, and pro-union culture, it is likely that Uber drivers will soon see the day that a labor court classifies them as employees. Accordingly, a hybrid or new labor classification for drivers is not a viable solution for the Uber dilemma. These classifications give equal weight to corporate interests and disadvantaged workers’ needs, and they fail to recognize the importance of protecting workers from businesses with far more capital and power. Moreover, although Uber claims that its business model has provided drivers with an avenue for entrepreneurship, these success stories ignore most drivers’ realities, which are characterized by long, grueling workdays and unsustainable wages. Hence, it is crucial for jurists to understand that hybrid or new classifications unfairly compromise the rights and needs of historically oppressed groups. Ultimately, the struggle for labor and employment rights in the gig economy does not end here. Not all Uber drivers are vehicle-owners, and some vehicle-owners function as middle-persons between Uber BV and hired drivers. This situation raises questions about the existence of coemployment relationships and whether an employee classification only extends to some Uber drivers. An employee classification also complicates the situation for many foreign nationals who cannot find employment elsewhere. At some point, lawmakers will have to reconsider immigration and naturalization laws that have made it difficult for foreign workers to make a living in South Africa. Finally, there are countless issues related to driver and commuter safety that the State has yet to resolve. Recognizing drivers’ rights as Uber employees, however, is a step in the right direction

E-hailing and Employment Rights: The Case for an Employment Relationship Between Uber and its Drivers in South Africa

South Africa’s Uber dilemma has forced jurists to answer important questions about the country’s largest black-owned sector: the taxi industry. Since the days of apartheid, taxi drivers have struggled to secure their livelihoods. Lamentably, they have found themselves restricted by a legacy of oppression that, despite significant progress, lingers on. As of late, Uber has exploded onto the transportation market, and labor courts must decide whether Uber drivers fit within a system that never contemplated the emergence of gig economy companies. If future jurists continue to draw inspiration from South Africa’s highly progressive constitution, international agreements, and pro-union culture, it is likely that Uber drivers will soon see the day that a labor court classifies them as employees. Accordingly, a hybrid or new labor classification for drivers is not a viable solution for the Uber dilemma. These classifications give equal weight to corporate interests and disadvantaged workers’ needs, and they fail to recognize the importance of protecting workers from businesses with far more capital and power. Moreover, although Uber claims that its business model has provided drivers with an avenue for entrepreneurship, these success stories ignore most drivers’ realities, which are characterized by long, grueling workdays and unsustainable wages. Hence, it is crucial for jurists to understand that hybrid or new classifications unfairly compromise the rights and needs of historically oppressed groups. Ultimately, the struggle for labor and employment rights in the gig economy does not end here. Not all Uber drivers are vehicle-owners, and some vehicle-owners function as middle-persons between Uber BV and hired drivers. This situation raises questions about the existence of coemployment relationships and whether an employee classification only extends to some Uber drivers. An employee classification also complicates the situation for many foreign nationals who cannot find employment elsewhere. At some point, lawmakers will have to reconsider immigration and naturalization laws that have made it difficult for foreign workers to make a living in South Africa. Finally, there are countless issues related to driver and commuter safety that the State has yet to resolve. Recognizing drivers’ rights as Uber employees, however, is a step in the right direction

Charged lepton flavour violation from low scale seesaw neutrinos

In the work presented here, we have studied the impact of right handed neutrinos, which are introduced to account for the evidence of neutrino masses, on charged lepton flavour violating observables. In particular, we have focused on the loop induced decays of the Z boson into two leptons of different flavour. We have performed a numerical study of the rates predicted for these processes within the Inverse Seesaw model, specifically considering scenarios where $\mu -e$ transitions are suppressed. Our conclusion, after comparison with the most relevant experimental constraints, is that branching ratios as large as $10^{-7}$ can be predicted in the $\tau -\mu$ or $\tau -e$ channels, together with heavy neutrinos having masses of the TeV order. Such rates could be accessible at next generation colliders.Comment: 13 pages, 5 figures, 3 tables. Proceedings of the Corfu Summer Institute 2016 "School and Workshops on Elementary Particle Physics and Gravity", 31 August - 23 September 2016, Corfu, Greec

A cluster model with random anisotropy for hysteresis jumps in CeNi1−x_{1-x}Cux_{x} alloys

Some Cerium compounds exhibit hysteresis cycles with sharp macroscopic jumps in the magnetization at very low temperatures. This effect is attributed to the formation of clusters in which the anisotropy competes with the applied magnetic field. Here, we present a simple model where a lattice of ferromagnetically coupled spins is separated in clusters of random sizes and with random anisotropy. Within this model, we obtain hysteresis cycles presenting jumps that behave in a similar way that the experimental ones, and that disappear when increasing the temperature. The results are in good agreement with the hysteresis cycles measured at very low temperatures in CeNi$_{1-x}$Cu$_{x}$ and the comparison with these experimental results allows to discriminate the relative importance of the mechanisms driving the thermal evolution of the cycles.Comment: Accepted in PR

A first checklist of the lichen-forming fungi of the Venezuelan Andes

Basing on an evaluation of the literature and some unpublished collections, 745 taxa of lichen forming-fungi are reported from the Venezuelan Andes, including 10 infraspecific taxa. Of these taxa 37 are new records for Venezuela: Actinoplaca vulgaris (Müll. Arg.) Vezda & Poelt, Asterothyrium decipiens (Rehm) R. Sant., Calopadia foliicola (Fée) Vezda, C. fusca (Müll. Arg.) Vezda, C. phyllogena (Müll. Arg.) Vezda, Chrysothrix chlorina (Ach.) J. R. Laundon, Cystocoleus ebeneus (Dillwyn) Thwaites, Diploschistes scruposus (Schreb.) Norm., Echinoplacaleucotrichoides (Vain.) R. Sant., Fellhanerabouteillei (Desm.) Vezda, F.dominicana (Vain.) Vezda, F. fuscatula (Müll. Arg.) Vezda, F. sublecanorina (Nyl.) Vezda, Gyalectidium filicinum Müll. Arg., Lecidea limosa Ach., Lepraria neglecta Auct., Ochrolechia africana Vain., Peltigera vainioi Gyelnik, Phyllobathelium nigrum R. Sant. & Tibell, Phyllophialealba R. Sant., Polymeridiumalbidum (Müll. Arg.) R. C. Harris, Porina epiphylla (Fée) Fée, Racodium rupestre Pers., Ramalina asahinae W. Culb. & C. Culb., R. calcarata Krog & Swinsc., R. puiggarii Müll Arg., R. rectangularis Nyl., Rhizoplaca melanophthalma (DC.) Leuckert & Poelt, Strigula antillarum (Fée) Müll. Arg., S. platypoda (Müll. Arg.) R. C. Harris, Tapellaria epiphylla (Müll. Arg.) R. Sant., T.nana (Fée) R. Sant., Tephromela aglaea (Sommerf.) Hertel & Rambold, Tricharia vainioi R. Sant., Trichothelium epiphyllum Müll. Arg., T. bipindense F. Schill. and Vezdaea foliicola Sérusiaux. Another 4 species are new records only for the Venezuelan Andes: Dimerellaepiphylla (Müll. Arg.) Malme, Porinaatrocoerulea Müll. Arg., Ramalina peruviana Ach. and Woessia apiahica (Müll. Arg.) Sérus. A list of synonyms used in the consulted literature is added. Four new combinations are proposed: Dictyonema zahlbruckneri (Schiffn.) V. Marcano, Heterodermia tropica (Kurok.) Sipman, Parmelinopsis cleefii (Sipman) V. Marcano & Sipman and Phyllobaeislinearis (De Vries) V. Marcano & Sipman