K0S decays at LHCb

K0S decays are a new area of interest for LHCb. Latest results on the K0S → μ+μ− search are reported using data collected by the LHCb experiment at a center-of-mass energy of √s = 7TeV, corresponding to an integrated luminosity of 1 fb−1. The upper limit at 90% CL on the branching ratio of this decay is found to be 9 × 10−9. This limit is 30 times lower than the previous world best. LHCb prospects for other K0S decays and other strange mesons decays are also reported

Pushing the boundaries of the LHCb rare decays program: search for the Λ0b→ Λγ decay

[eng] The main goal of this thesis is to test the Standard Model (SM) of particle physics through the experimental analysis of rare processes, those that are suppressed in the SM. In particular, radiative b and rare strange decays are very sensible to potential contributions from beyond the SM (BSM) physics. The data recorded by LHCb in proton-proton (pp) collisions during the Run 1 (2010-2012) and Run 2 (2015-2018) of the LHC is exploited with this purpose. The LHCb detector is a single-arm forward spectrometer characterised by a precise momentum and impact parameter resolution, a good separation between particles of different species and a very flexible trigger system. A trigger selection dedicated to radiative decays of b-hadrons has been developed for Run 2, based on multivariate techniques exploiting the common features of these decay modes. Two complementary configurations select two- and three-body plus photon candidates, respectively. The results obtained on different Monte-Carlo (MC) signal samples show an improvement with respect to the Run 1 selection of at least 20% in absolute efficiency for all the modes, while for some special cases, as B0 K+π−γ and B+ K∗+γ, larger gains of 70% and 60%, respectively, are achieved. Moreover, the rate is reduced to a half with respect to the Run 1 configuration, which allows to dedicate the remaining budget to exclusive selections for decays with special topologies, expanding even more the reach of the radiative decays physics program. Of special interest among rare strange decays are the K0 f+f−f+f− modes, where f can be either an electron or a muon. As a first milestone towards the study of these channels, the feasibility of observing the topologically similar K0 π+π−e+e− at LHCb has been assessed. Selection efficiencies have been extracted from MC samples, obtaining an expected signal yield in Run 1 conditions of 120+280/ fb−1. No −100 signal peak has been observed in the invariant mass distribution of selected candidates in the 2012 dataset and the possibility of observing this mode with these data has been evaluated with pseudoexperiments, concluding that an observation if feasible using a selection with a separation power similar to that usually achieved by multivariate algorithms. For Run 2, tow complementary trigger selections have been developed to improve its efficiency, reaching an expected yield of 620+290/ fb−1, which guarantees an 0−120 + − + − observation of this mode in Run 2 and allows the first studies of the KS → f f f f modes. In the area of radiative b-decays, the most interesting observable is the polarisation of the emitted photon, which is predicted to be almost 100% left-handed in the SM, while right-handed currents can contribute in BSM models. This observable is accessible through the previously unobserved Λ0 Λγ mode so a search for this decay has been performed using the dataset recorded by LHCb in pp collisions during 2016. Due to its particular topology, a dedicated reconstruction has been developed and used both in the trigger and offline. The candidate selection is based on multivariate methods, which have been trained using MC as a proxy for the signal and data as background. The requirement on the output distribution has been optimised by maximising the probability of achieving an observation of the signal, obtaining a 33% signal efficiency with a 99.8% background rejection. The B0 K∗0γ mode has been used as normalisation channel, which allows to measure the signal branching ratio from the ratio of yields. A simultaneous maximum likelihood fit of the invariant mass distributions has been performed resulting in a Λ0 → Λγ yield of (64 ± 13) events and a measurement of the branching fraction of B(Λ0 → Λγ) = (2.59 ± 0.52 (estad.) ± 0.28 (sist.) ± 0.33 (fΛ0 /fB0 )) × 10−6. The statistical significance of the signal has been evaluated by means of a likelihood profile scan, obtaining a 5.7σ significance, which represents the first observation of the Λ0 → Λγ decay and opens the doors to the study of the photon polarisation in this mode.[cat] En aquesta tesi s’han estudiat modes de desintegració radiatius d’hadrons b i rars de mesons estranys, amb l’objectiu de testejar el Model Estàndard (MS). S’han utilitzat dades enregistrades pel detector LHCb en col lisions protó-protó (pp) durant el Run 1 (2010-2012) i el Run 2 (2015-2018) de l’LHC. LHCb ´es un espectòmetre d’un sol brac¸ caracteritzat per una alta precisió en la reconstrucció del moment i el paràmetre d’impacte respecte del punt d’interacció, una gran capacitat per separar partícules de diferents espècies i un sistema activador (trigger) molt flexiu. Per al Run 2 s’ha desenvolupat una selecció de trigger dedicada a processos radiatius basada en algoritmes multivariats, explotant-ne les característiques comunes. S’ha obtingut un augment absolut en l'eficiència entorn del 20%. Per a casos amb topologia especial, com B0 K+π−γ i B+ K∗+γ, el guany arriba al 70% i 60%, respectivament. Pel que fa als modes rars de desintegració d’hadrons estranys, s’ha avaluat la viabilitat d’observar el canal K0 π+π−e+e− a LHCb. Utilitzant mostres de Monte-Carlo (MC), s’ha obtingut una senyal esperada de 120+280/ fb−1 en condicions del Run 1. En les dades del 2012 no s’ha observat la senyal −100 degut a la presència d’un gran fons i per mitjà de pseudo-experiments s’ha arribat a la conclusió que l’observació és possible utilitzant una selecció multivariada. Per al Run 2 s’han desenvolupat seleccions de trigger millorant la senyal esperada fins a 620+290/ fb−1. −120 0 Finalment, utilitzant les dades del 2016 s’ha realitzat una cerca del mode de desintegració Λb Λγ basada en el desenvolupament d’una reconstrucció especial i d’una selecció multivariada, que aconsegueix una eficiència del 33% rebutjant al mateix temps un 99.8% del fons. El nu´mero d’esdeveniments de senyal s’ha extret d’un ajust simultani de màxima versemblança de la distribució de massa invariant, obtenint-ne (64 ± 13), amb una significació estadística de 5.7σ, que constitueix la primera observació d’aquest mode de desintegració. Utilitzant el canal B0 → K∗0γ com a normalització, s’ha mesurat també la fracció d’embrancament B(Λ0 → Λγ) = (2.59 ± 0.52 (estad.) ± 0.28 (sist.) ± 0.33 (fΛ0 /fB0 )) × 10−6

Programa de educación para la salud: prevención de la obesidad infantil

Introducción: La obesidad infantil es una enfermedad crónica y multifactorial; su prevalencia va en aumento convirtiéndose en uno de los principales problemas de salud pública. La obesidad favorece el desarrollo de otras enfermedades como son la diabetes tipo 2 o enfermedades cardiovasculares. La alimentación inadecuada y la inactividad física son dos de los principales factores de riesgo para desarrollar obesidad, por ello las actividades que fomenten buenos hábitos de alimentación y de ejercicio físico serán esenciales para su prevención. Objetivo: Diseñar un programa de educación para la salud dirigido a prevenir el sobrepeso y la obesidad infantil desde atención primaria en el ámbito escolar. Metodología: Se ha realizado una revisión bibliográfica consultando diferentes bases de datos científicas además de varias revistas de pediatría española y páginas web. Se hizo una lectura crítica de la información obtenida para el posterior desarrollo del programa. Conclusión: Mediante este programa de educación para la salud se ha tratado de mejorar los conocimientos de las familias en el tema de la obesidad infantil y hacer hincapié en su prevención. Los profesionales de enfermería cumplen un papel principal en la educación de la población infantil. El desarrollo de programas de salud por parte de estos profesionales permite promover y fomentar conductas saludables de alimentación y actividad física, incluyendo en ellos no solo a los niños sino a toda la familia. <br /

Glucose-6-phosphate dehydrogenase and transketolase modulate breast cancer cell metabolic reprogramming and correlate with poor patient outcome

The pentose phosphate pathway is a fundamental metabolic pathway that provides cells with ribose and NADPH required for anabolic reactions - synthesis of nucleotides and fatty acids - and maintenance of intracellular redox homeostasis. It plays a key role in tumor metabolic reprogramming and has been reported to be deregulated in different types of tumors. Herein, we silenced the most important enzymes of this pathway - glucose-6-phosphate dehydrogenase (G6PD) and transketolase (TKT) - in the human breast cancer cell line MCF7. We demonstrated that inhibition of G6PD, the oxidative branch-controlling enzyme, reduced proliferation, cell survival and increased oxidative stress. At the metabolic level, silencing of both enzymes reduced ribose synthesis. G6PD silencing in particular, augmented the glycolytic flux, reduced lipid synthesis and increased glutamine uptake, whereas silencing of TKT reduced the glycolytic flux. Importantly, we showed using breast cancer patient datasets that expression of both enzymes is positively correlated and that high expression levels of G6PD and TKT are associated with decreased overall and relapse-free survival. Altogether, our results suggest that this metabolic pathway could be subjected to therapeutic intervention to treat breast tumors and warrant further investigation

Micrometric control of the optics of the human eye: environment or genes?

Purpose: The human eye has typically more optical aberrations than conventional artificial optical systems. While the lower order modes (defocus and astigmatism) are well studied, our purpose is to explore the influence of genes versus the environment on the higher order aberrations of the optical components of the eye. Methods: We have performed a classical twin study in a sample from the Region of Murcia (Spain). Optical aberrations using a Hartmann-Shack sensor (AOnEye Voptica SL, Murcia, Spain) and corneal aberrations (using corneal topography data) were measured in 138 eyes corresponding to 69 twins; 36 monozygotic (MZ) and 33 dizygotic (DZ) pairs (age 55 years, SD 7 years). Intraclass correlation coefficients (ICCs) were used to estimate how strongly aberrations of twins resemble each other, and genetic models were fitted to quantify heritability in the selected phenotypes. Results: Genes had a significant influence in the variance of most of the higher order aberration terms (heritability from 40% to 70%). This genetic influence was observed similarly in both cornea and complete eye aberrations. Additionally, the compensation factor of spherical aberration in the eye (i.e., how much corneal spherical aberration was compensated by internal spherical aberration) was found under genetic influence (heritability of 68%). Conclusions: There is a significant genetic contribution to the variance of aberrations of the eye, not only at macroscopic levels, as in myopia or astigmatism, but also at microscopic levels, where a few micrometers changes in surface topography can produce a large difference in the value of the optical aberrations

Constraints on the unitarity triangle angle γ from Dalitz plot analysis of B0 →dK+π- decays

The first study is presented of CP violation with an amplitude analysis of the Dalitz plot of $B^0 \to D K^+ \pi^-$ decays, with $D \to K^+ \pi^-$, $K^+ K^-$ and $\pi^+ \pi^-$. The analysis is based on a data sample corresponding to $3.0\,{\rm fb}^{-1}$ of $pp$ collisions collected with the LHCb detector. No significant CP violation effect is seen, and constraints are placed on the angle $\gamma$ of the unitarity triangle formed from elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated with the $B^0 \to D K^*(892)^0$ decay are determined for the first time. These measurements can be used to improve the sensitivity to $\gamma$ of existing and future studies of the $B^0 \to D K^*(892)^0$ decay

Strong constraints on the b → sγ photon polarisation from B 0 → K *0 e + e − decays

An angular analysis of the B0 → K∗0 e +e − decay is performed using a data sample corresponding to an integrated luminosity of 9 fb−1 of pp collisions collected with the LHCb experiment. The analysis is conducted in the very low dielectron mass squared (q 2 ) interval between 0.0008 and 0.257 GeV2 , where the rate is dominated by the B0 → K∗0γ transition with a virtual photon. The fraction of longitudinal polarisation of the K∗0 meson, FL, is measured to be FL = (4.4 ± 2.6 ± 1.4)%, where the first uncertainty is statistical and the second systematic. The ARe T observable, which is related to the lepton forward-backward asymmetry, is measured to be ARe T = −0.06 ± 0.08 ± 0.02. The A (2) T and AIm T transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be A (2) T = 0.11 ± 0.10 ± 0.02 and AIm T = 0.02 ± 0.10 ± 0.01. The results are consistent with Standard Model predictions and provide the world's best constraint on the b → sγ photon polarisation

Study of η − η′ mixing from measurement of B (s)0 → J/ψη(′) decay rates

A study of B and B0 s meson decays into J/ψη and J/ψη0 final states is performed using a data set of proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, collected by the LCHb experiment and corresponding to 3.0 fb−1 of integrated luminosity. The decay B0 → J/ψη0 is observed for the first time. The following ratios of branching fractions are measured: B(B0 → J/ψη0 ) B(B0 s → J/ψη0) = (2.28 ± 0.65 (stat) ± 0.10 (syst) ± 0.13 (fs/fd)) × 10−2 , B(B0 → J/ψη) B(B0 s → J/ψη) = (1.85 ± 0.61 (stat) ± 0.09 (syst) ± 0.11 (fs/fd)) × 10−2 , where the third uncertainty is related to the present knowledge of fs/fd, the ratio between the probabilities for a b quark to form a B0 s or a B0 meson. The branching fraction ratios are used to determine the parameters of η−η 0 meson mixing. In addition, the first evidence for the decay B0 s → ψ(2S)η 0 is reported, and the relative branching fraction is measured, B(B0 s → ψ(2S)η 0 ) B(B0 s → J/ψη0) = (38.7 ± 9.0 (stat) ± 1.3 (syst) ± 0.9(B)) × 10−2 , where the third uncertainty is due to the limited knowledge of the branching fractions of J/ψ and ψ(2S) mesons

Observation of charmonium pairs produced exclusively in pp collisions

The CP-violating asymmetry a s sl is studied using semileptonic decays of B0 s and B0 s mesons produced in pp collisions at a centre-of-mass energy of 7 TeV at the LHC, exploiting a data sample corresponding to an integrated luminosity of 1.0 fb−1 . The reconstructed final states are D± s µ ∓, with the D± s particle decaying in the φπ± mode. The D± s µ ∓ yields are summed over B0 s and B0 s initial states, and integrated with respect to decay time. Data-driven methods are used to measure efficiency ratios. We obtain a s sl = (−0.06 ± 0.50 ± 0.36)%, where the first uncertainty is statistical and the second systematic