Standard Model Higgs Search Strategy at LEP

The Standard Model Higgs boson has been searched for by the four LEP experiments in the last twelve years. The data collected at LEP in the year 2000 suggest the first observation of a Higgs boson. In this letter, I describe the basic concepts of the Higgs search at LEP, with emphasis in the statistical method used to combine the results from the LEP experiments.Comment: 4 pages, 8 figures, submitted to Moriond QCD 200

Measurement of the Higgs Cross Section and Mass with Linear Colliders

We report on the accuracy of the measurement of the Higgs boson mass and the total cross section of the process e+e- -> ZH that would be achieved in a linear collider operating at a centre-of-mass energy of 350 GeV, assuming an integrated luminosity of 500 (1/fb). For that we have exploited the recoil mass off the Z using its leptonic decays into electron and muon pairs. The Higgs mass is determined with 150 MeV accuracy, the recoil mass resolution is about 1.5 GeV and the cross section is obtained with a statistical error of 3%.Comment: 5 pages, 4 figures, to be published in the Proceedings of the LCWS99 (Sitges, Spain) by World Scientific Publishing Company (Singapore

Determination of the Higgs boson spin with a linear e+e- collider

The energy dependence of the production cross section of a light Higgs boson is studied at threshold and compared to the expectations of several spin assumptions. Cross section measurements at three centre-of-mass energies with an integrated luminosity of 20 fb-1 allow the confirmation of the scalar nature of the Higgs Boson.Comment: 4 pages (Latex), 4 figures (Postscript

Measurement of the Charge Ratio of Cosmic Muons using CMS Data

We have performed the measurement of the cosmic ray muon charge ratio, as a function of the muon momentum, using data collected by the CMS experiment, exploiting the capabilities of the muon barrel drift tube (DT) chambers. The cosmic muon charge ratio is defined as the ratio of the number of positive- to negative-charge muons. Cosmic ray muons result from the interaction of high-energy cosmic-ray particles (mainly protons and nuclei), entering the upper layers of the atmosphere, with air nuclei. Since these collisions favour positive meson production, there is an asymmetry in the charge composition and more positive muons are expected. The data samples were collected at the \textit{Magnet Test and Cosmic Challenge} (MTCC). While the MTCC itself was a crucial milestone in the CMS detector construction, not having physics studies among its primary goals, it provided the first opportunity to obtain physics results and test the full analysis chain using real data in CMS before the LHC startup, together with a complementary check of the detector performance.Comment: Poster at ICHEP08, Philadelphia, USA, July 2008. 4 page

Measurement of the Higgs Boson Mass with a Linear e+e- Collider

The potential of a linear e+e- collider operated at a centre-of-mass energy of 350 GeV is studied for the measurement of the Higgs boson mass. An integrated luminosity of 500 fb-1 is assumed. For Higgs boson masses of 120, 150 and 180 GeV the uncertainty on the Higgs boson mass measurement is estimated to be 40, 65 and 70 MeV, respectively. The effects of beam related systematics, namely a bias in the beam energy measurement, the beam energy spread and the luminosity spectrum due to beamstrahlung, on the precision of the Higgs boson mass measurement are investigated. In order to keep the systematic uncertainty on the Higgs boson mass well below the level of the statistical error, the beam energy measurement must be controlled with a relative precision better than 10-4.Comment: 19 pages, 10 Figure

Determination of the Higgs boson spin with a linear e+e− collider

The energy dependence of the production cross section of a light Higgs boson is studied at threshold and compared to the expectations of several spin assumptions. Cross section measurements at three centre-of-mass energies with an integrated luminosity of 20 fb-1 allow the confirmation of the scalar nature of the Higgs Boson.Facultad de Ciencias Exacta

Comparative Study on Microstructure and Corrosion Resistance of Al-Si Alloy Cast from Sand Mold and Binder Jetting Mold

[EN] This investigation is focused on the corrosion evaluation of an as-cast Al-Si alloy, obtained by two different casting methods: traditional sand casting and three-printing casting, using a binder jetted mold. The experimental results are discussed in terms of chemical composition, microstructure, hardness, and corrosion behavior of two different casting parts. The microstructure and composition of the sample before and after the corrosion tests was analyzed using light microscopy (OM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (DRX). The corrosion of the two processed castings was analyzed using anodic polarization (PA) test and electrochemical impedance spectroscopy (EIS) in an aerated solution of 3.5% by weight NaCl, similar to the seawater environment. After the corrosion process, the samples were analyzed by inductively coupled plasma/optical emission spectrometry (ICP/OES); the composition was used to determine the chloride solution after immersion times. The sample processed by binder jetting mold showed higher corrosion resistance with nobler potentials, lower corrosion densities, higher polarization resistance, and more stable passive layers than the sample processed by sand casting. This improvement of corrosion resistance could be related to the presence of coarse silicon particles, which decrease of cathodic/anodic ratio and the number of micro-galvanic couples, and the lower amount of intermetallic β Al-Fe-Si phase observed in cast alloy solidified in binder jetting mold.SIMinisterio de Ciencia, Innovación y Universidade

Resonant CP Violation in Higgs Radiation at e^+e^- Linear Collider

We study resonant CP violation in the Higgsstrahlung process e^+e^- -> H_{1,2,3} (Z -> e^+e^-, \mu^+\mu^-) and subsequent decays H_{1,2,3} -> b \bar{b}, \tau^-\tau^+, in the MSSM with Higgs-sector CP violation induced by radiative corrections. At a high-energy e^+e^- linear collider, the recoil-mass method enables one to determine the invariant mass of a fermion pair produced by Higgs decays with a precision as good as 1 GeV. Assuming an integrated luminosity of 100/fb, we show that the production lineshape of a coupled system of neutral Higgs bosons decaying into b\bar{b} quarks is sensitive to the CP-violating parameters. When the Higgs bosons decay into \tau^-\tau^+, two CP asymmetries can be defined using the longitudinal and transverse polarizations of the tau leptons. Taking into account the constraints from electric dipole moments, we find that these CP asymmetries can be as large as 80 %, in a tri-mixing scenario where all three neutral Higgs states of the MSSM are nearly degenerate and mix significantly.Comment: 22 pages, 8 figures, to appear in Phys. Rev.