602 research outputs found
Composite Higgs and leptoquarks from a simple group
We propose a composite grand unified theory to study the anomalies in the
semileptonic decays. We show a simple group containing the custodial and
Standard Model gauge symmetries, that can deliver a set of composite pseudo
Nambu-Goldstone bosons: the Higgs, a colorless SU(2)-fourplet and three
leptoquarks: a triplet and two doublets. We give a description in terms of an
effective theory of resonances. By assuming anarchic partial compositeness of
the Standard Model fermions, we find representations for the composite fermions
that allow to obtain the Higgs Yukawa couplings, as well as leptoquark
interactions explaining the deviations in . We calculate
the one-loop potential, we show that it can trigger electroweak symmetry
breaking and we find a region of the parameter space that can reproduce the
Standard Model spectrum. The model predicts leptoquark masses of order
TeV, corrections to some electroweak observables, with
saturating the current bounds, and a very reach phenomenology at LHC. We also
study the possibility of explaining .Comment: 36 pages, 4 figures, v2: typos corrected, references adde
Model for the singlet-triplet leptoquarks
The deviations of B-meson decays measured in RD(∗)τℓ and RK(∗)μe can be explained by the presence of two scalar leptoquarks, a singlet S1 and a triplet S3, mostly coupled to the third generation. We consider a theory of resonances, as an effective description of a strongly interacting theory, that generates the leptoquarks and the Higgs as Nambu-Goldstone bosons, with the rest of the resonances at a scale of order 10-30 TeV. We assume anarchic partial compositeness for the flavor of the SM fermions. Under this hypothesis, we study whether it is possible to reproduce the deviations in the B decays without being in conflict with flavor and electroweak bounds. We find a tension between RD(∗)τℓ and some flavor observables, dominated by flavor violating τ decays and ΔmBs, that require a tuning of order 10%-25%. We also compute the potential of the scalars showing that leptoquarks with masses O(2-3) TeV can be naturally expected in the model. We discuss briefly the phenomenology of the other resonances.Fil: Da Rold, Leandro. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Lamagna, Federico Agustín. 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; Argentin
A vector leptoquark for the B-physics anomalies from a composite GUT
A vector leptoquark at the TeV scale, mostly coupled to the fermions of the third generation, is the preferred option to explain the hints of lepton flavor universality violation in the decays of B-mesons. It seems interesting to assume that this leptoquark belongs to the same beyond the Standard Model sector that solves the hierarchy problem, since the third generation of fermions play the leading role in the instability of the Higgs potential. We present a composite Grand Unified Theory with resonances at the TeV that contains the required vector leptoquark and develops the Higgs as a pseudo Nambu-Goldstone boson. We show that anarchic partial compositeness of the Standard Model fermions can accommodate the couplings of Left-handed currents required by the B-anomalies, predicting very small couplings to the Right-handed currents without any additional hypothesis. By making use of an effective theory description of the strong dynamics, in terms of weakly coupled resonances, we are able to compute the corrections to B-physics, as well as the one-loop potential for the pseudo Nambu-Goldstone bosons. The theory has a rich phenomenology and a candidate for dark matter.Fil: Da Rold, Leandro. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Lamagna, Federico Agustín. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin
Composite Higgs and leptoquarks from a simple group
We propose a composite grand unified theory to study the anomalies in the semileptonic B decays. We show a simple group containing the custodial and Standard Model gauge symmetries, that can deliver a set of composite pseudo Nambu-Goldstone bosons: the Higgs, a colorless SU(2)L-fourplet and three leptoquarks: a triplet and two doublets. We give a description in terms of an effective theory of resonances. By assuming anarchic partial compositeness of the Standard Model fermions, we find representations for the composite fermions that allow to obtain the Higgs Yukawa couplings, as well as leptoquark interactions explaining the deviations in RK(∗)μe" role="presentation">(∗). We calculate the one-loop potential, we show that it can trigger electroweak symmetry breaking and we find a region of the parameter space that can reproduce the Standard Model spectrum. The model predicts leptoquark masses of order 0.4?1.3 TeV, corrections to some electroweak observables, with ZbLb¯L" role="presentation">⎯⎯⎯ saturating the current bounds, and a very reach phenomenology at LHC. We also study the possibility of explaining RD(∗)τℓ" role="presentation">ℓ(∗).Fil: 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; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Lamagna, Federico Agustín. 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; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentin
Composite Froggatt-Nielsen model of flavor
A natural composite Higgs demands the presence of light resonances at the TeV scale that, in general, are in conflict with bounds from flavor and CP violation. We propose a composite model with a Froggatt-Nielsen mechanism that offers new possibilities for the origin of flavor. We analyze the interplay of partial compositeness and the horizontal U(1) symmetry in achieving the quark masses and mixing angles. We study the contributions to ΔF=2 4-fermion operators, as well as to ΔF=1 and neutron dipole operators. We find scenarios in which the contribution to left-right and right-handed operators involving the first and second generations can be suppressed; in particular, for a region of parameter space it is possible to simultaneously suppress the mixed-chirality contribution to K0-K̄0 mixing by one power of the Cabibbo angle, λC, and the dipole moments by λC2 compared with anarchic partial compositeness, possibly making the resonances accessible at LHC. 4-fermion operators of Bs-meson mixing and left-handed operators are not suppressed.Fil: Da Rold, Leandro. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Lamagna, Federico Agustín. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin
Analysis of Embodied and Situated Systems from an Antireductionist Perspective
The analysis of embodied and situated agents form a dynamical system perspective is often
limited to a geometrical and qualitative description. However, a quantitative analysis is necessary
to achieve a deep understanding of cognitive facts.
The field of embodied cognition is multifaceted, and the first part of this thesis is devoted to exploring
the diverse meanings proposed in the existing literature. This is a preliminary fundamental
step as the creation of synthetic models requires well-founded theoretical and foundational
boundaries for operationalising the concept of embodied and situated cognition in a concrete
neuro-robotic model. By accepting the dynamical system view the agent is conceived as highly
integrated and strictly coupled with the surrounding environment. Therefore the antireductionist
framework is followed during the analysis of such systems, using chaos theory to unveil global
properties and information theory to describe the complex network of interactions among the
heterogeneous sub-components.
In the experimental section, several evolutionary robotics experiments are discussed. This class
of adaptive systems is consistent with the proposed definition of embodied and situated cognition.
In fact, such neuro-robotics platforms autonomously develop a solution to a problem exploiting
the continuous sensorimotor interaction with the environment.
The first experiment is a stress test for chaos theory, a mathematical framework that studies erratic
behaviour in low-dimensional and deterministic dynamical systems. The recorded dataset
consists of the robots’ position in the environment during the execution of the task. Subsequently,
the time series is projected onto a multidimensional phase space in order to study the underlying
dynamic using chaotic numerical descriptors. Finally, such measures are correlated and confronted
with the robots’ behavioural strategy and the performance in novel and unpredictable
environments.
The second experiment explores the possible applications of information-theoretic measures for
the analysis of embodied and situated systems. Data is recorded from perceptual and motor
neurons while robots are executing a wall-following task and pairwise estimations of the mutual
information and the transfer entropy are calculated in order to create an exhaustive map of the
nonlinear interactions among variables. Results show that the set of information-theoretic employed
in this study unveils characteristics of the agent-environemnt interaction and the functional
neural structure.
This work aims at testing the explanatory power and impotence of nonlinear time series analysis
applied to observables recorded from neuro-robotics embodied and situated systems
Male and female robots
A population of male and female robots evolves in an environment in which to remain alive they must eat the food contained in the environment and to reproduce they must mate with a robot of the opposite sex. The only difference between male and female robots is that after mating males can mate again (reproductively) while females have a fixed period during which they are nonreproductive. The results show that males have a greater variance in reproductive success compared to females and they tend to be always very active looking for the ?scarce resource? constituted by reproductive females and eating any food they are able to find while they are looking for reproductive females. Reproductive females are less active than males and they adopt the reproductive strategy of waiting for males to find and mate with them. On the contrary, nonreproductive females are as active as males but they look for food and are not interested in anything else. We also find a number of differences between males and females in their preferences for different types of food and in offspring care if males do not have parental certainty
An embedding technique to determine ττ backgrounds in proton-proton collision data
An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe
Bose-Einstein correlations of charged hadrons in proton-proton collisions at = 13 TeV
Bose-Einstein correlations of charged hadrons are measured over a broad multiplicity range, from a few particles up to about 250 reconstructed charged hadrons in proton-proton collisions at = 13 TeV. The results are based on data collected using the CMS detector at the LHC during runs with a special low-pileup configuration. Three analysis techniques with different degrees of dependence on simulations are used to remove the non-Bose-Einstein background from the correlation functions. All three methods give consistent results. The measured lengths of homogeneity are studied as functions of particle multiplicity as well as average pair transverse momentum and mass. The results are compared with data from both CMS and ATLAS at = 7 TeV, as well as with theoretical predictions.[graphic not available: see fulltext]Bose-Einstein correlations of charged hadrons are measured over a broad multiplicity range, from a few particles up to about 250 reconstructed charged hadrons in proton-proton collisions at 13 TeV. The results are based on data collected using the CMS detector at the LHC during runs with a special low-pileup configuration. Three analysis techniques with different degrees of dependence on simulations are used to remove the non-Bose-Einstein background from the correlation functions. All three methods give consistent results. The measured lengths of homogeneity are studied as functions of particle multiplicity as well as average pair transverse momentum and mass. The results are compared with data from both CMS and ATLAS at 7 TeV, as well as with theoretical predictions
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