Search for lepton flavour violation at LHCb

AbstractWe report the first searches for lepton flavour violating τ decays at a hadron collider. In particular, a search for the decay τ→μμμ is presented, using data corresponding to an integrated luminosity of 1.0 fb-1 collected at 7 TeV by LHCb in 2011. The upper limit on the branching ratio could be set, B(τ−→μ+μ−μ−)<8.0×10−8 at 90 % confidence level (the inclusion of the charge conjugate process is included).In addition, we report on the search for heavy Majorana neutrinos in lepton number violating B−→π+μ−μ− decay (as well as in its charge conjugate). In this case, the whole LHCb dataset is used (1.0 fb-1 at s=7 TeV and 2 fb-1 at s=8 TeV). No signal is found, and a limit on the branching ratio is set, B(B−→π+μ−μ−)<4×10−9 at 95 % confidence level. This limit is then used to set limits on the coupling between the hypothetical Majorana neutrino and muons

A comparative study of acid and alkaline aluminum extraction valorization procedure for aluminum saline slags

A management process for saline slags, one of the wastes from Secondary Aluminum Production, is proposed. The process begins with a grinding step, followed by washing with water, which removed the fluxing salts but provoking the hydrolysis of AlN, yielding Al(OH)3 and ammonia. Sieving of the solid generated an intermediate and a fine fraction. The first one was rich in metallic aluminum, and can also be returned to the Secondary Aluminum Production. The fine fraction was submitted to a extraction process in acid (HCl or HNO3) or alkaline (NaOH, KOH or CsOH) conditions, under reflux at 90 ºC, obtaining an Al(III) solution that can be used in the synthesis of aluminum-based solids. HCl (1-8 mol/L) and NaOH (1-4 mol/L) were used as reference solutions, HNO3, NaOH and KOH were used under specific conditions; the slag fraction:extraction solution solid:liquid ratio was also varied. The optimum extraction conditions were: extraction time 2 h, solid:liquid ratio 3:10, concentration 3 mol/L for the NaOH medium and 4 mol/L for the HCl medium. More than 30% of the aluminum present in the fraction smaller than 0.4 mm was recovered (the remaining aluminum was present as insoluble phases, corundum and spinel). Acid or basic media can be selected depending on the final use of Al(III) solutions, the basic medium leading to an Al(III) solution with a lower amount of impurities. The hazardousness of the solid obtained after the extraction process was greatly decreased, making possible the use of this solid residue in sectors such as construction.This work was supported by 'Memoria de D. Samuel Solórzano Barruso' Foundation (FS/11-2020). AJ thanks Universidad de Salamanca and Banco Santander for a predoctoral contract. AG is grateful for financial support from the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) through project PID2020-112656RB-C21. AG also thanks Santander Bank for funding via the Research Intensification Program

Aspectos filosóficos del proemio de Parménides

Esta tesis doctoral defiende razonadamente el valor filosófico del proemio del poema de Parménides. La metodología ha consistido en un análisis textual pormenorizado y en el estudio del contexto cultural, político, religioso y social de Parménides. El objetivo general de la tesis es demostrar la utilidad de la colaboración entre filología y filosofía para releer textos seminales del pensamiento antiguo y así ofrecer nuevas interpretaciones, mientras que el objetivo específico es reivindicar el valor filosófico del proemio de Parménides y ponerlo en relación con el resto de su poema. Si bien es normal que en el tiempo de Parménides se atribuya la revelación del pensamiento a una divinidad, en el eleata la revelación se encuentra con el empeño autónomo del pensador. La relación entre divinidad y kouros en Parménides es de colaboración. La diosa invita al kouros a comprobar el contenido de la revelación, a que aprehenda la verdad mediante un juicio argumentado, por lo que ya no hay arbitrariedad divina como en Homero y Hesíodo..

Structural, textural and acidic properties of Cu-, Fe- and Cr-doped Ti-pillared montmorillonites

Montmorillonite has been treated with Ti-based solutions, alone or doped with Cu2 +, Fe3 + or Cr3 + cations, yielding new intercalated solids, which have been calcined at various temperatures to test the stability of the so-formed pillars. The solids calcined at 500 °C were fully characterized by chemical analysis, X-ray diffraction, FT-IR spectroscopy, thermal analyses, nitrogen adsorption and acidity evaluation. The evolution of the specific surface area, porosity and acidic properties is discussed, analysing the effect of pillaring and doping procedures on these propertie

Effect of dopants on the structure of titanium oxide used as a photocatalyst for the removal of emergent contaminants

Photocatalysts composed of titanium dioxide modified with B, F, N and P have been synthesized, characterized and applied to the degradation of caffeine, diclofenac, ibuprofen and salicylic acid. The modified TiO2 samples were prepared by the sol–gel technique starting from titanium(IV) isopropoxide and using H3BO3, NH4F, N(C2H5OH)3 and H3PO4 as precursors of the modifiers, with the content varying between 0 and 5 wt%. Structural characterization was based on nitrogen physisorption at −196 °C, powder X-ray diffraction (PXRD), simultaneous thermogravimetric/differential thermal analysis (TG/DTA) and X-ray photoelectron spectroscopy (XPS). The structural properties of the modified TiO2 solids were significantly different depending on the nature and amount of modifiers and the calcination temperature. TiO2 in the anatase phase was obtained in all cases and was stable upon calcination at 400 °C. The photocatalytic degradation of caffeine, diclofenac, ibuprofen and salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 25 °C. The photocatalytic degradation behavior followed the order: caffeine > diclofenac = ibuprofen > salicylic acid. B-doped TiO2 was the most efficient catalyst in the degradation of these selected emerging contaminants

Implementación del uso de tablets pc para la elaboración de documentos audiovisuales como manuales razonados de uso e interpretación de resultados de técnicas de laboratorio de química inorgánica

Memoria ID12-0083. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2012-2013

Rapid microwave-assisted synthesis of saponites and their use as oxidation catalysts

Saponites containing divalent Mg, Ni, or Fe as octahedral cations and trivalent Al and Fe substituting Si in the tetrahedral sheet were synthesized using microwave radiation. Saponite with a high specific surface area was obtained in all the syntheses, although Fe-Al saponite crystallized was impurified by Fe2O3 and analcime. The catalytic activity of the solids for the epoxidation of (Z)-cyclooctene by hydrogen peroxide was tested, the solids obtained being highly active (conversion up to 8.8%, and 100% selectivity to the epoxide

Measurement of CP violation in B-0 -> D+D- decays

The CP violation observables S and C in the decay channel B-0 -> D+D- are determined from a sample of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 3 fb(-1). The observable S describes CP violation in the interference between mixing and the decay amplitude, and C parametrizes direct CP violation in the decay. The following values are obtained from a flavor-tagged, decay-time-dependent analysis: S = -0.54(-0.16)(+0.17) (stat) +/- 0.05(syst) ,C=0.26(-0.17)(+0.18) (stat) +/- 0.02(syst). These values provide evidence for CP violation at a significance level of 4.0 standard deviations. The phase shift due to higher-order standard model corrections is constrained to a small value of Delta phi = -0.16(-0.21)(+0.19) rad