Using Machine Learning techniques in phenomenological studies on flavour physics

An updated analysis of New Physics violating Lepton Flavour Universality, by using the Standard Model Effective Field Lagrangian with semileptonic dimension six operators at ¿ = 1 TeV is presented. We perform a global fit, by discussing the relevance of the mixing in the first generation. We use for the first time in this context a Montecarlo analysis to extract the confidence intervals and correlations between observables. Our results show that machine learning, made jointly with the SHAP values, constitute a suitable strategy to use in this kind of analysis

Decoupling of supersymmetric particles

The possibility of a heavy supersymmetric spectrum at the Minimal Supersymmetric Standard Model is considered and the decoupling from the low energy electroweak scale is analyzed in detail. The formal proof of decoupling of supersymmetric particles from low energy physics is stated in terms of the effective action for the particles of the Standard Model that results by integrating out all the sparticles in the limit where their masses are larger than the electroweak scale. The computation of the effective action for the standard electroweak gauge bosons W^{+-}, Z and \gamma is performed by integrating out all the squarks, sleptons, charginos and neutralinos to one-loop. The Higgs sector is not considered in this paper. The large sparticle masses limit is also analyzed in detail. Explicit analytical formulae for the two-point functions of the electroweak gauge bosons to be valid in that limit are presented. Finally, the decoupling of sparticles in the S, T and U parameters is studied analitically. A discussion on how the decoupling takes place in terms of both the physical sparticle masses and the non-physical mass parameters as the \mu-parameter and the soft-breaking parameters is included.Comment: 50 pages, LaTeX + 2 postscript figures. Figures added, some points clarified, one section added, references updated. Accepted to Eur. Phys. J.

Leptonic meson decays into invisible ALP

The theoretical calculation of pseudo–scalar leptonic decay widths into an invisible ALP, M→ℓνℓa, is reviewed. Assuming generic flavor–conserving ALP couplings to SM fermions and a generic ALP mass, ma, the latest experimental results for pseudo–scalar leptonic decays are used to provide updated bounds on the ALP–fermion Lagrangian sector. Constrains on the ALP-quark couplings obtained from these channels are not yet competitive with the ones derived from FCNC processes, like M→Pa decays. These leptonic decays can, however, provide the most stringent model–independent upper bounds on ALP-leptons couplings for ma in the (sub)–GeV range

Higgs boson masses and B-physics constraints in Non-Minimal Flavor Violating SUSY scenarios

Journal of High Energy Physics 2012.5 (2012): 015 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)We present one-loop corrections to the Higgs boson masses in the MSSM with Non-Minimal Flavor Violation. The flavor violation is generated from the hypothesis of general flavor mixing in the squark emass matrices, and these are parametrized by a complete set of δ xY ij (X, Y = L,R; i, j = t,c,u or b, s, d). We calculate the corrections to the Higgs masses in terms of these δ xY ij taking into account all relevant restrictions from B-physics data. This includes constraints from BR(B → X sγ), BR(B s → μ +μ -) and ΔM Bs. After taking into account these constraints we find sizable corrections to the Higgs boson masses, in the case of the lightest MSSM Higgs boson mass exceeding tens of GeV. These corrections are found mainly for the low tan β case. In the case of a Higgs boson mass measurement these corrections might be used to set further constraints on δf YThe work of S.H. was supported in part by CICYT (grant FPA 2007-66387), in part by CICYT (grant FPA 2010-22163-C02-01) and by the Spanish MICINN’s Consolider-Ingenio 2010 Program under grant MultiDark CSD2009-00064. The work of M.H. and M.A.-C. was partially supported by CICYT (grant FPA2009-09017) and the Comunidad de Madrid project HEPHACOS, S2009/ESP-1473. The work of S.P. was supported by a Ramón y Cajal contract from MEC (Spain) (PDRYC-2006-000930) and partially by CICYT (grant FPA2009-09638), the Comunidad de Aragón project DCYT-DGA E24/2 and the Generalitat de Catalunya project 2009SGR502. The work is also supported in part by the European Community’s Marie-Curie Research Training Network under contract MRTNCT-2006-035505 ‘Tools and Precision Calculations for Physics Discoveries at Colliders’ and also by the Spanish Consolider-Ingenio 2010 Programme CPAN (CSD2007-00042

MW and sin^2\theta_eff in Split SUSY: present and future expectations

We analyse the precision electroweak observables MW and sin^2\theta_eff and their correlations in the recently proposed Split SUSY model. We compare the results with the Standard Model and Minimal Supersymmetric Standard Model predictions, and with present and future experimental accuracies. Present experimental accuracies in (MW, sin^2\theta_eff) do not allow constraints to be placed on the Split SUSY parameter space. We find that the shifts in (MW, sin^2\theta_eff) induced by Split SUSY can be larger than the anticipated accuracy of the GigaZ option of the International Linear Collider, and that the most sensitive observable is sin^2\theta_eff. These large shifts are possible also for large chargino masses in scenarios with small tan(\beta) =~ 1.Comment: LaTeX, 13 pages, 4 figures. Comments adde

Prevalence of parasite intestinal infections in a rural community of the Caribbean north of Colombia

Objectives: To estimate the prevalence of protozoan and helminth infections in a rural town of the Caribbean coast of Colombia and to identify potential risk factors. Methods: The study was conducted in Santa Catalina, a town and municipality located in the Bolívar during 2014. Parasitological analyses were done using 0.85% saline solution and lugol staining. A questionnaire was applied to participants in order to identify possible risk factors for parasite infections. Results: Mean age of sample population (N = 685) was 29.8 SD 622.46 and 68% were females. There is no sewage access in this town. Most of them were infected by any protozoan species (80%) or soil-transmitted helminthes (71%). The most common protozoan found was Entamoeba coli (53%) followed by Giardia duodenalis (13%), Blastocistys hominis (4%) and E. histolytica 82%). Ascaris lumbricoides was the most prevalent helminth (63%) followed by Trichuris trichuria (36%), hookworms (2%), Taenia sp (2%) and Hymenolepys nana (2%). Frequency rates of protozoan and helminthic infections were significantly lower in those living in a house build made of bricks (versus wood or "bahereque") or with a floor material distinct from soil/earth. Drinking boiled water was associated only with lower rates of trichuriasis (aOR: 0.59 95%CI: 0.41-0.78), but not ascariasis. Almost half of of subjects (56%) reported to have received deworming treatment in the last year, but this was not associated with having any parasite infection. In a sub-group of 109 with available data, Ascaris infection was associated with lower hemoglobin levels (B=0.75, SE: 0.25, p = 0.003, adjusted by age and gender). Conclusions: The prevalence of protozoan and helminth infections in this town, representative of the rural area of the Caribbean coast of Colombia, is high. Indicators of poverty and lower hygienic conditions are positively associated with parasite infections