22 research outputs found
Composite Charge 8/3 Resonances at the LHC
In composite Higgs models with partial compositeness, the small value of the
observed Higgs mass implies the existence of light fermionic resonances, the
top partners, whose quantum numbers are determined by the symmetry (and
symmetry breaking) structure of the theory. Here we study light top partners
with electric charge 8/3, which are predicted, for instance, in some of the
most natural composite Higgs realizations. We recast data from two same sign
lepton searches and from searches for microscopic blackholes into a bound on
its mass, M8/3 > 940 GeV. Furthermore, we compare potential reach of these
searches with a specifically designed search for three same-sign lepton, both
at 8 and 14 TeV. We provide a simplified model, suitable for collider analysis.Comment: Minor comments are added to match published versio
Probing light top partners with CP violation
We investigate CP-violating effects induced by light top partners in
composite Higgs theories. We find that sizable contributions to the dipole
moments of the light SM quarks and leptons are generically generated at the
two-loop level through Barr-Zee-type diagrams. The present constraints on the
electron and neutron electric dipole moments translate into bounds on top
partner masses of order few TeV and are competitive with the reach of LHC
direct searches. Interestingly, we find that CP-violation effects are sensitive
to the same operators that control top partner single production. Near-future
improvements in the determination of the electron dipole moment will extend the
reach on top partner masses beyond the 5 - 10 TeV range.Comment: 31 pages, 10 figures; v2: typos corrected, matches published versio
A global view on the Higgs self-coupling
The Higgs self-coupling is notoriously intangible at the LHC. It was recently
proposed to probe the trilinear Higgs interaction through its radiative
corrections to single-Higgs processes. This approach however requires to
disentangle these effects from those associated to deviations of other
Higgs-couplings to fermions and gauge bosons. We show that a global fit
exploiting only single-Higgs inclusive data suffers from degeneracies that
prevent one from extracting robust bounds on each individual coupling. We show
how the inclusion of double-Higgs production via gluon fusion, and the use of
differential measurements in the associated single-Higgs production channels
WH, ZH and ttH, can help to overcome the deficiencies of a global
Higgs-couplings fit. In particular, we bound the variations of the Higgs
trilinear self-coupling relative to its SM value to the interval [0.1, 2.3] at
68% confidence level at the high-luminosity LHC, and we discuss the robustness
of our results against various assumptions on the experimental uncertainties
and the underlying new physics dynamics. We also study how to obtain a
parametrically enhanced deviation of the Higgs self-couplings and we estimate
how large this deviation can be in a self-consistent effective field theory
framework.Comment: 41 pages, 6 figures; v2: comments and references added, minor typos
corrected, matches published versio
A global view on the Higgs self-coupling at lepton colliders
We perform a global effective-field-theory analysis to assess the precision on the determination of the Higgs trilinear self-coupling at future lepton colliders. Two main scenarios are considered, depending on whether the center-of-mass energy of the colliders is sufficient or not to access Higgs pair production processes. Low-energy machines allow for ∼ 40% precision on the extraction of the Higgs trilinear coupling through the exploitation of next-to-leading-order effects in single Higgs measurements, provided that runs at both 240/250 GeV and 350 GeV are available with luminosities in the few attobarns range. A global fit, including possible deviations in other SM couplings, is essential in this case to obtain a robust determination of the Higgs self-coupling. High-energy machines can easily achieve a ∼ 20% precision through Higgs pair production processes. In this case, the impact of additional coupling modifications is milder, although not completely negligible
Near real-time monitoring of cassava cultivation area
Remote sensing technologies and deep learning/machine learning approaches play valuable roles in crop inventory, yield estimation, cultivated area estimation, and crop status monitoring. Satellite-based remote sensing has led to increased spatial and temporal resolution, leading to a better quality of land-cover mapping (greater precision, and detail in the number of land cover classes). In this work, we propose to use a long short-term memory neural network (LSTM), an advanced technical model adapted from artificial neural networks (ANN) to estimate cassava cultivation area in southern Laos. LSTM is a modified version of a Recurrent Neural Network (RNN) that uses internal memory to store the information received prior to a given time. This property of LSTMs makes them advantageous for time series regression. We employ Landsat-7/8 and Sentinel-2 time-series datasets and crop phenology information to identify and classify cassava fields using multi-sources remote sensing time-series in a highly fragmented landscape. The results indicate an overall accuracy of > 89% for cassava and > 84% for all-class (barren, bush/grassland, cassava, coffee, forest, seasonal, and water) validating the feasibility of the proposed method. This study demonstrates the
potential of LSTM approaches for crop classification using multi-temporal, multi-sources remote sensing time series
Terra-i+ webtool: Simplifying agroforestry sustainability monitoring
In an ever-evolving landscape of regulations and commitments to net-zero emission commodity chains, Terra-i+ offers a satellite-based solution for agroforestry supply chain sustainability management. At its core, Terra-i+ functions as an integrated platform to access critical information about the sustainability status of coffee supply chains. With Terra-i+, stakeholders gain access to essential metrics and insights, empowering them to make informed decisions that drive adoption of sustainable practices
Probing beyond the Standard Model physics using effective field theory
Ara que el LHC ha proporcionat 120 fb-1 de dades, l'evidència d'una diferència d'energia entre el model estàndard (SM) i la nova física ha augmentat. Això fa que la teoria de camps efectiva (EFT) sigui un mètode versàtil per restringir la nova física amb una dependència mínima del model. En aquesta tesi, basada en el meu treball realitzat durant la meva candidatura a doctorat [1-4], fem ús de la tècnica EFT en diversos estudis. Comencem per estudiar l'extracció de acoblament trilineal del Higgs en els col·lisionadors actuals i futurs de leptons, utilitzant correccions de següent ordre en la producció de Higgs i producció de Higgs doble. Els nostres anàlisis minimitzen la dependència del model gràcies a l'ús de l'EFT. Argumentem que per restringir les diferents possibles desviacions al Model Estàndard, un ajust global amb la inclusió de tants observables com sigui possible és necessari. Hem trobat que la inclusió del trilineal en els processos únics d'Higgs tindrà un efecte marginal a LHC aconseguint una precisió d'ordre ú. La situació és diferent els futurs col·lisionadors de leptons, on l'alta precisió i la diferent energia de centre de masses poden donar el 50% de precisió. A continuació, ampliem l'EFT afegint un singlet escalar per estudiar les propietats del CP de la partícula que podria haver estat amagada després de l'infame excés de di-fotons a 750 GeV. Definim les asimetries sensibles al CP, tant en els canals de fusió de vectors com gluons, i estudiem el seu poder de diferenciar entre el CP imparell o fins i tot les hipòtesis. Finalment, ens movem de l'EFT i considerem un model simplificat de Higgs compost per comparar les mesures a baixa energia procedents
de la mesura del dipol elèctric (EDM) de neutrons i electrons, amb les cerques al LHC. La teoria de camps efectiva no està completament absent, ja que calculem les correccions de dos loops al EDM de quarks i leptons lleugers que coincideixen amb el nostre model simplificat per als operadors de dimensions superiors i obtenim límits per al nostre model.
A continuació, adaptem les cerques de l'LHC i comparem els límits actuals i futurs
Hem trobat que el límit actual és competitiu amb el que proveeix la cerca directa de LHC, que és d'uns quants TeV. La futura actualització de l'experiment que permetrà mesurar el moment dipolar d'electrons ha de portar els límits al rang de 5-10 TeV.Now the LHC has provided 120 fb−1 of data, the evidence for an energy gap between the
Standard Model (SM) and new physics has grown strong. This makes effective field the-
ory (EFT) a versatile method to constrain new physics with minimal model dependence.
In this thesis, based on work done during my PhD candidature [1–4], we make use of
EFT techniques in a variety of studies. We start by exploring the prospect of extracting
the Higgs trilinear self-coupling at current hadron and future lepton colliders, using both
higher order corrections to the single-Higgs process and di-Higgs production. Our anal-
ysis minimizes model dependence thanks to the use of EFT. We argue that in order to
constrain the different possible deviations to the Standard Model, a global fit with the
inclusion of as many observables as possible is needed. We found that the inclusion of
the trilinear correction in single-Higgs processes has a marginal effect at the LHC and
will give a bound on the trilinear of order one. The situation is different at lepton col-
liders, where the high precision and different running energies can give bound of order
50%. We then extend our EFT by adding a scalar singlet to study the CP properties of
the particle which could have been behind the infamous 750 GeV di-photon excess. We
define the CP sensitive asymmetries, in both the vector and gluon fusion channels, and
study their power to differentiate between the CP odd or even hypotheses. Finally, we
move somewhat away from EFT, and use a simplified model to compare the constraints
on composite Higgs models coming from low energy neutron and electron electric dipole
moment (EDM) measurements and LHC searches. Effective field theory is not completely
absent, since we compute the two loop corrections of the light quarks and leptons EDM to
match our simplified model to the higher dimensional operators of a low energy effective
Lagrangian, and obtain bounds for our model. We then recast LHC searches and compare
the present and future bounds. We found that the current bounds are competitive with the
one coming from the LHC direct search and are of order a few TeV. The future upgrade
of the experiment measuring the electron dipole moment should bring the bounds to the
5-10 TeV range