Calculable Sparticle Masses with Radiatively Driven Inverted Mass Hierarchy

Supersymmetric models with an inverted mass hierarchy (IMH: multi-TeV first and second generation matter scalars, and sub-TeV third generation scalars) can ameliorate problems arising from flavor changing neutral currents, $CP$ violating phases and electric dipole moments, while at the same time satisfying conditions on naturalness. It has recently been shown that such an IMH can be generated radiatively, making use of infra-red fixed point properties of renormalization group equations given Yukawa coupling unification and suitable $GUT$ scale boundary conditions on soft SUSY breaking masses. In these models, explicit spectra cannot be obtained due to problems implementing radiative electroweak symmetry breaking (REWSB). We show that use of SO(10) $D$-term contributions to scalar masses can allow REWSB to occur, while maintaining much of the desired IMH. A somewhat improved IMH is obtained if splittings are applied only to Higgs scalar masses.Comment: revised to coincide with published versio

LHC Reach for Gauge Mediated Supersymmetry Breaking Models Via Prompt Photon Channels

We evaluate the supersymmetry reach of the Large Hadron Collider within the gauge-mediated low energy supersymmetry breaking framework, assuming that a neutralino is the second lightest sparticle and that it decays promptly into a gravitino which escapes detection. We find that the maximum reach is obtained via a search for inclusive \gamma\gamma+\eslt events coming dominantly from chargino and neutralino production. Assuming an integrated luminosity of 10~$fb^{-1}$, we find that LHC experiments will be able to probe values of the model parameter \Lambda \alt 400 TeV, corresponding to $m_{\tg} \leq 2.8$ TeV. A measure of the model parameter $\Lambda$ may be possible from the photon $p_T$ spectrum.Comment: 10 page Revtex file plus 4 EPS figure

The CERN Masterclasses Hands on Particle Physics event : considerations about its role in science communication through its participants perceptions

Neste trabalho são investigados dois aspectos relacionados à experiência da Universidade Federal do ABC (UFABC) e da Universidade de São Paulo (USP) durante a realização do evento CERN Masterclasses Hands on Particle Physics, que envolveu estudantes tanto de Ensino Médio quanto de cursos de Licenciatura em Física. O primeiro aspecto considerado para este estudo refere-se ao perfil motivacional dos participantes, quais suas expectativas e interesses no evento. O segundo busca identificar, relativamente aos conteúdos conceituais e técnicos tratados no evento, quais os principais ganhos e dificuldades percebidas pelos participantes. A partir destas informações, analisamos o papel do evento como instrumento de comunicação científica. Para isso, tomamos como referencial teórico o modelo contemporâneo de comunicação científica de Burns, O’Connor e Stocklmayer, o qual entende a comunicação científica como um conjunto de etapas visando levar a Literacia Científica. À luz dos resultados encontrados, foi possível constatar que as ações do evento estão produzindo em seus participantes processos conducentes tanto a uma Consciência quanto Compreensão Públicas da Ciência. Estes processos operam de forma estrutural no desenvolvimento de uma cultura científica, a qual constitui-se, ao mesmo tempo, em causa e conseqüência do processo que leva ao ideal de Literacia Científica. Desta perspectiva, eventuais ajustes no desenho e composição das atividades do evento podem ser melhor subsidiadas, assim como questões relativas às contribuições sócio-educativas e culturais proporcionadas por iniciativas dessa natureza.In this work we investigate two aspects of the UFABC and USP experience with the CERN Masterclasses – Hands on Particle Physics event designed to students from high schools and undergraduate teaching courses. At first the motivational aspect to participate in the event was considered. Then, taking into account the content of the activities we search for the main goals and difficulties perceived by the students. From those informations we analysed the role of the event as a scientific communication instrument. For this, we take the contemporary definition of Science Communication proposed by Burns, O’Connor and Stocklmayer. In their view, science communication must be understood as a processes aiming to approach the scientific literacy ideals. Based on our results it is possible to suggest that the event is leading the participants to advance in direction of a Public Awareness and Understanding of Science. These processes allow the development of a scientific culture which, at the same time, works as cause and consequence for the processes engendering the Scientific Literacy ideals. From this perspective, we point out that changes in the event design as well as their contribuitions to socio-educational and cultural issues can be better supported

Analysis of Long-Lived Slepton NLSP in GMSB model at Linear Collider

We performed an analysis on the detection of a long-lived slepton at a linear collider with $\sqrt{s}=500$ GeV. In GMSB models a long-lived NLSP is predicted for large value of the supersymmetry breaking scale $\sqrt{F}$. Furthermore in a large portion of the parameter space this particle is a stau. Such heavy charged particles will leave a track in the tracking volume and hit the muonic detector. In order to disentangle this signal from the muon background, we explore kinematics and particle identification tools: time of flight device, dE/dX and Cerenkov devices. We show that a linear collider will be able to detect long-lived staus with masses up to the kinematical limit of the machine. We also present our estimation of the sensitivity to the stau lifetime.Comment: Minor changes, Ref. 10 fixed. 12 pages, RevTex, 4 eps figure

Estado nutricional pre-gestacional, embarazo planificado, nivel educativo y estrato socioeconómico, como determinantes de aborto en embarazadas de Caracas

Objetivo: El estado nutricional es un aspecto sumamente importante durante procesos que implican crecimiento y desarrollo, como el embarazo. Se ha demostrado que el estado nutricional de la madre antes del embarazo tiene gran impacto en el peso al nacer del niño. El nivel educativo y las condiciones socioeconómicas son determinantes sociales del estado nutricional. Con el objetivo de determinar el riesgo de aborto en embarazadas que presentan algún tipo de malnutrición y están expuestas a inequidades sociales.Material y Método. Se realizó un estudio piloto transversal en 173 embarazadas con edad promedio de primer embarazo de 18,5 años, del Municipio Sucre, Miranda, Venezuela, en un período comprendido entre 2013-2014. Resultados: La distribución por estrato fue la siguiente 66,5% de estrato medio bajo (ESE IV); 28,9% de estratos medio y medio alto (ESE II y III) y 2,9

Viable Supersymmetric Models with an Inverted Scalar Mass Hierarchy at the GUT Scale

Supersymmetric models with an inverted mass hierarchy (IMH: multi-TeV first and second generation matter scalars, and sub-TeV third generation and Higgs scalars) have been proposed to ameliorate phenomenological problems arising from flavor changing neutral currents (FCNCs) and CP violating processes, while satisfying conditions of naturalness. Models with an IMH already in place at the GUT scale have been shown to be constrained in that for many model parameter choices, the top squark squared mass is driven to negative values. We delineate regions of parameter space where viable models with a GUT scale IMH can be generated. We find that larger values of GUT scale first and second generation scalar masses act to suppress third generation scalars, leading to acceptable solutions if GUT scale gaugino masses are large enough. We show examples of viable models and comment on their characteristic features. For example, in these models the gluino mass is bounded from below, and effectively decouples, whilst third generation scalars remain at sub-TeV levels. While possibly fulfilling criteria of naturalness, these models present challenges for detection at future pp and e^+e^- collider experiments.Comment: 16 page REVTEX file with 6 PS figure

Yukawa Unified Supersymmetric SO(10) Model: Cosmology, Rare Decays and Collider Searches

It has recently been pointed out that viable sparticle mass spectra can be generated in Yukawa unified SO(10) supersymmetric grand unified models consistent with radiative breaking of electroweak symmetry. Model solutions are obtained only if $\tan\beta \sim 50$, $\mu <0$ and positive $D$-term contributions to scalar masses from SO(10) gauge symmetry breaking are used. In this paper, we attempt to systematize the parameter space regions where solutions are obtained. We go on to calculate the relic density of neutralinos as a function of parameter space. No regions of the parameter space explored were actually cosmologically excluded, and very reasonable relic densities were found in much of parameter space. Direct neutralino detection rates could exceed 1 event/kg/day for a $^{73}$Ge detector, for low values of GUT scale gaugino mass $m_{1/2}$. We also calculate the branching fraction for $b\to s \gamma$ decays, and find that it is beyond the 95% CL experimental limits in much, but not all, of the parameter space regions explored. However, recent claims have been made that NLO effects can reverse the signs of certain amplitudes in the $b\to s\gamma$ calculation, leading to agreement between theory and experiment in Yukawa unified SUSY models. For the Fermilab Tevatron collider, significant regions of parameter space can be explored via $b\bar{b}A$ and $b\bar{b}H$ searches. There also exist some limited regions of parameter space where a trilepton signal can be seen at TeV33. Finally, there exist significant regions of parameter space where direct detection of bottom squark pair production can be made, especially for large negative values of the GUT parameter $A_0$.Comment: Added comparison to Blazek/Raby results and added Comments on de Boer et al. b->s gamma result

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO