1,721,011 research outputs found
Slim SUSY
Full text linkhe new SM-like Higgs boson discovered recently at the LHC, with mass mh≃125GeV, as well as the direct LHC bounds on the mass of superpartners, which are entering into the TeV range, suggest that the minimal surviving supersymmetric extension of the SM (MSSM), should be characterized by a heavy SUSY-breaking scale. Several variants of the MSSM have been proposed to account for this result, which vary according to the accepted degree of fine-tuning. We propose an alternative scenario here, Slim SUSY, which contains sfermions with multi-TeV masses and gauginos/higgsinos near the EW scale, but it includes the heavy MSSM Higgs bosons (H0, A0, H±) near the EW scale too. We discuss first the formulation and constraints of the Slim SUSY scenario, and then identify distinctive heavy Higgs signals that could be searched at the LHC, within scenarios with the minimal number of superpartners with masses near the EW scale.Fil: Arganda Carreras, Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Díaz Cruz, J. Lorenzo. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Szynkman, Alejandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentin
Novel Higgsino dark matter signal interpretation at the LHC
Full text linkIn the LHC searches for gluinos it is usually assumed that they decay predominantly into the lightest neutralino plus jets. In this work we perform a proof-of-concept collider analysis of a novel supersymmetric signal in which gluinos decay mostly into jets and the bino-like neutralino (χ 30), which in turn decays into the lightest Higgsino-like neutralino (χ 10), considered the dark matter candidate, together with the SM-like Higgs boson (h). This new physics signal then consists of an LHC final state made up by four light jets, four b-jets, and a large amount of missing transverse energy. We identify tt¯, V+jets (V=W, Z), and tt¯+X (X=W, Z, γ∗, h) productions as the most problematic backgrounds, and develop a search strategy for the high luminosity phase of the LHC, reaching signal significances at the evidence level for a luminosity of 1000 fb-1. The prospects for a luminosity of 3000 fb-1 are even more promising, with discovery-level significances.Fil: Arganda Carreras, Ernesto. Departamento de Fisica Teorica ; Facultad de Ciencias ; Universidad Autonoma de Madrid; . Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Delgado de la Rosa, Juan Antonio. University of Notre Dame; Estados UnidosFil: Morales, Roberto Anibal. Departamento de Fisica Teorica ; Facultad de Ciencias ; Universidad Autonoma de Madrid; . Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Quirós, Mariano. Institut de Física d’Altes Energies; Españ
Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance
Full text linkSince the discovery in 2012 of the Higgs boson at the LHC, as the last missing piece of the Standard Model of particle physics, any hint of new physics has been intensively searched for, with no confirmation to date. There are however slight deviations from the SM that are worth investigating. The CMS collaboration has reported, in a search for heavy resonances decaying in tt¯ with a 13-TeV center-of-mass energy and a luminosity of 35.9 fb−1, deviations from the SM predictions at the 3.5σ level locally (1.9σ after the look-elsewhere effect). In addition, in the ditau final state search performed by the ATLAS collaboration at s = 13 TeV and L = 139 fb−1, deviations from the SM at the 2σ level have been also observed. Interestingly, both slight excesses are compatible with a new pseudoscalar boson with a mass around 400 GeV that couples at least to fermions of the third generation and gluons. Starting from a purely phenomenological perspective, we inspect the possibility that a 400-GeV pseudoscalar can account for these deviations and at the same time satisfy the constraints on the rest of the channels that it gives contributions to and that are analyzed by the ATLAS and CMS experiments. After obtaining the range of effective couplings compatible with all experimental measurements, we study the gauge invariant UV completions that can give rise to this type of pseudoscalar resonance, which can be accommodated in an SO(6)/SO(5) model with consistency at the 1σ level and in a SO(5) × U(1)P × U(1)X/SO(4) × U(1)X at the 2σ level, while exceedingly large quartic couplings would be necessary to account for it in a general two Higgs doublet model.Fil: Arganda Carreras, Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Da Rold, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Díaz, Daniel A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Medina, Anibal Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin
Decays of H0/A0 in supersymmetric scenarios with heavy sfermions
Full text linkThe recent discovery of a new boson at the LHC, which resembles a SM-like Higgs boson with m h =125 GeV, is starting to provide strong guidelines into SUSY model building. For instance, the identification of such a state with the lightest CP-even Higgs boson of the MSSM (h0), requires large values of tan(beta) and/or heavy sfermions. One outcome of this result is the possibility to solve the SUSY flavor and CP problems by decoupling, which points towards some realization of Split-inspired SUSY scenarios, in which scalars are much heavier than gauginos and higgsinos. However, we argue here that the remaining Higgs bosons of the MSSM (H0, A0, H±) do not have to be as heavy as the sfermions, and having them with masses near the EW scale does not pose any conflict with current MSSM constraints. We discuss then some SUSY scenarios with heavy sfermions, from a bottom-up approach, which contain the full Higgs sector, as well as a possible dark matter candidate, with masses near the EW scale, and identify distinctive signals from these scenarios that could be searched at the LHC.Fil: Arganda Carreras, Ernesto. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Diaz-cruz, Lorenzo. Benemerita Universidad Autonoma de Puebla;Fil: Szynkman, Alejandro Andres. Universidad Nacional de la Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin
Imposing exclusion limits on new physics with machine-learned likelihoods
Full text linkMachine-Learned Likelihood (MLL) is a method that, by combining modern machine-learning techniques with likelihood-based inference tests, allows estimating the experimental sensitivity of high-dimensional data sets. Here we extend the MLL method by including the exclusion hypothesis tests and study it first on a toy model of multivariate Gaussian distributions, where the true probability distribution functions are known. We then apply it to a case of interest in the search for new physics at the LHC, in which a ′ boson decays into lepton pairs, comparing the performance of MLL for estimating 95% CL exclusion limits with respect to the prospects reported by ATLAS at 14 TeV with a luminosity of 3 ab−1.Fil: Arganda Carreras, Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Consejo Superior de Investigaciones Científicas; España. Universidad Autónoma de Madrid; EspañaFil: de Los Rios, Martín Emilio. Consejo Superior de Investigaciones Científicas; España. Universidad Autónoma de Madrid; EspañaFil: Perez, Andres Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Sandá Seoane, Rosa María. Consejo Superior de Investigaciones Científicas; España. Universidad Autónoma de Madrid; Españ
Composición de la radiación cósmica de ultra-alta energía a partir de los datos del Observatorio Pierre Auger (Composition of ultra-high energy cosmic radiation from the Pierre Auger Observatory data)
No full textMáster Interuniversitario en Astrofísica. Facultad de Ciencias Físicas. Curso 2010-2011Aunque el descubrimiento de los rayos cósmicos se produjo hace casi cien años, algunas de sus propiedades más importantes, como el origen, mecanismos de producción o composición en masa, son aún un misterio. Actualmente el conocimiento de los rayos cósmicos de baja energía es muy
amplio, pero a energías superiores el desconocimiento es cada vez mayor; especialmente sin resolver están las propiedades de los Rayos Cósmicos Ultra-Energéticos (UHECRs), definidos como aquellos con una energía superior a 10^18 eV. Dado el bajo flujo que tienen estas partículas de tan alta energía, su detección directa es inviable; por ello se procede al estudio de las cascadas que generan al incidir en la atmosfera, llamadas Extensive Air Showers (EAS). Para detectarlas necesitamos una red de
detectores que cubra el mayor área posible, como el Observatorio Pierre Auger, el mayor detector construido para estudiar los UHECRs. Para determinar la composición primaria de los UHECRs se presenta un método basado en el desarrollo longitudinal de las cascadas, lo que nos da información de la dependencia de la masa promedio de los UHECRs en función de la energía. Para ello se usa la asimetría acimutal en la distribución temporal de llegada de las partículas de cascadas no verticales a nivel del suelo registradas en los tanques de agua Cherenkov que componen el Detector de Superficie (SD) del Observatorio Pierre Auger. Validado mediante simulaciones, aplicamos este
método a nuestra base de datos de eventos registrados por el SD con el fin de conocer algo más sobre la composición de los UHECRs provenientes de todo el cielo, así como los provenientes de la vecindad de Cen A, una de las radio-fuentes extragalácticas más extensas y brillantes del cielo. Los resultados muestran indicios de que la masa promedio aumenta con la energía. [ABSTRACT] Despite the discovery of cosmic rays was nearly one hundred years ago, some of their most important properties, such as origin, production mechanism and mass composition, remain still
being a mystery. The knowledge of low energy cosmic rays is currently very wide, but at higher energies our ignorance is increasing; in particular, the properties of Ultra High Energy Cosmic Rays (UHECRs), defined as those with energy above 10^18 eV, are unknown. Given the low
flux of these high energetic particles, direct detection is not possible. Therefore, it is necessary to study the showers they induce in the atmosphere, the so-called Extensive Air Showers (EAS). In order to detect them we need an array of detectors covering the largest area possible, such as the Pierre Auger Observatory, the largest detector constructed to study UHECRs up to day. In order to extract the primary mass composition of UHECRs a method based on the longitudinal development of showers is presented, providing information about the mean mass of UHECRs. The technique is based on the azimuthal asymmetry of the time arrival distribution of particles reaching the ground level, recorded by the water-Cherenkov detectors of the Surface Detector (SD) of the Pierre Auger Observatory.
We apply this method, which was validated using simulations, to the events recorded by the Pierre Auger SD. In order to obtain the primary mass composition of UHECRs events coming from all over the sky, as well as from the vicinity of Cen A, one of the brightest and most extended extragalactic radio-sources in the sky, were analyzed. The results show indication of the increase of the average primary mass as energy rises.Depto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEunpu
Effective lepton flavor violating Hij vertex from right-handed neutrinos within the mass insertion approximation
Full text linkIn this work we present a new computation of the lepton flavor violating Higgs boson decays that are generated radiatively to one-loop from heavy right-handed neutrinos. We work within the context of the inverse seesaw model with three νR and three extra singlets X, but the results could be generalized to other low scale seesaw models. The novelty of our computation is that it uses a completely different method by means of the mass insertion approximation which works with the electroweak interaction states instead of the usual 9 physical neutrino mass eigenstates of the inverse seesaw model. This method also allows us to write the analytical results explicitly in terms of the most relevant model parameters, that are the neutrino Yukawa coupling matrix Yν and the right-handed mass matrix MR, which is very convenient for a phenomenological analysis. This Yν matrix, being generically nondiagonal in flavor space, is the only one responsible for the induced charged lepton flavor violating processes of our interest. We perform the calculation of the decay amplitude up to order O(Yν2+Yν4). We also study numerically the goodness of the mass insertion approximation results. In the last part we present the computation of the relevant one-loop effective vertex Hij for the lepton flavor violating Higgs decay which is derived from a large MR mass expansion of the form factors. We believe that our simple formula found for this effective vertex can be of interest for other researchers who wish to estimate the H→īj rates in a fast way in terms of their own preferred input values for the relevant model parameters Yν and MR.Fil: Arganda Carreras, Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Herrero, M. J.. Universidad Autónoma de Madrid; EspañaFil: Marcano, X.. Universidad Autónoma de Madrid; EspañaFil: Morales, Roberto Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Szynkman, Alejandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
