Jay Velasquez | Ninguna - Academia.edu (original) (raw)

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Manu Reyes

Universidad de Ciencias Aplicadas y Ambientales

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Papers by Jay Velasquez

Physics Letters B, 2012

A measurement of the multi-strange Ξ − and Ω − baryons and their antiparticles by the ALICE exper... more A measurement of the multi-strange Ξ − and Ω − baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for proton-proton collisions at centre of mass energy of 7 TeV. The transverse momentum (p t ) distributions were studied at mid-rapidity (|y| < 0.5) in the range of 0.6 < p t < 8.5 GeV/c for Ξ − and Ξ + baryons, and in the range of 0.8 < p t < 5 GeV/c for Ω − and Ω + . Baryons and anti-baryons were measured as separate particles and we find that the baryon to antibaryon ratio of both particle species is consistent with unity over the entire range of the measurement. The statistical precision of the current LHC data has allowed us to measure a difference between the mean p t of Ξ − (Ξ + ) and Ω − (Ω + ). Particle yields, mean p t , and the spectra in the intermediate p t range are not well described by the PYTHIA Perugia 2011 tune Monte Carlo event generator, which has been tuned to reproduce the early LHC data. The discrepancy is largest for Ω − (Ω + ). This PYTHIA tune approaches the p t spectra of Ξ − and Ξ + baryons below p t < 0.85 GeV/c and describes the Ξ − and Ξ + spectra above p t > 6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Ω − +Ω + )/ (Ξ − +Ξ + ) as a function of transverse mass.

The production cross section of electrons from semileptonic decays of beauty hadrons was measured... more The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y| < 0.8) in the transverse momentum range 1 < p T < 8 GeV/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy √ s = 7 TeV using an integrated luminosity of 2.2 nb −1 . Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark-antiquark pairs. * See Appendix A for the list of collaboration members Electrons from beauty hadron decays in pp collisions at √ s = 7 TeV 1

The p T -differential inclusive production cross section of the prompt charm-strange meson D + s ... more The p T -differential inclusive production cross section of the prompt charm-strange meson D + s in the rapidity range |y| < 0.5 was measured in proton-proton collisions at √ s = 7 TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of 2.98×10 8 events collected with a minimum-bias trigger. The corresponding integrated luminosity is L int = 4.8 nb −1 . Reconstructing the decay D + s → φ π + , with φ → K − K + , and its charge conjugate, about 480 D ± s mesons were counted, after selection cuts, in the transverse momentum range 2 < p T < 12 GeV/c. The results are compared with the prediction of a model based on perturbative QCD. The ratios of the cross sections of four D meson species (namely D 0 , D + , D * + and D + s ) were determined both as a function of p T and integrated over p T after extrapolating to full p T range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in e + e − , ep and pp interactions at various centre-of-mass energies.

Higher Education Research & Development, 2012

It can sometimes be difficult to engage students in ‘real life experiences’ within the classroom.... more It can sometimes be difficult to engage students in ‘real life experiences’ within the classroom. In one Bachelor of Social Work program, the development of a Social Work Studio (the Studio) has provided students with opportunities to engage in simulated social work practice in a safe and supportive environment. This article reports on a small exploratory study of students' responses to a survey that sought their views and reactions to the development of this Studio initiative. Findings were analysed from a sociocultural perspective. They indicate that students' responses to the development of the Studio reflect their emerging constructions of the cultural world of social work.

A QUIEN PUEDA INTERESARLE Yo LAURA ANDREA VELASQUEZ BUITRAGO con C.C. 43.979.167 de Medellin doy ... more A QUIEN PUEDA INTERESARLE Yo LAURA ANDREA VELASQUEZ BUITRAGO con C.C. 43.979.167 de Medellin doy fe de que conozco a ANA MARIA BUITRAGO de muchos años y doy parte de que es una gran persona. Muchas gracias. _____________________________________ LAURA ANDREA VELASQUEZ BUITRAGO CC. 43979167

Physics Letters B, 2012

A measurement of the multi-strange Ξ − and Ω − baryons and their antiparticles by the ALICE exper... more A measurement of the multi-strange Ξ − and Ω − baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for proton-proton collisions at centre of mass energy of 7 TeV. The transverse momentum (p t ) distributions were studied at mid-rapidity (|y| < 0.5) in the range of 0.6 < p t < 8.5 GeV/c for Ξ − and Ξ + baryons, and in the range of 0.8 < p t < 5 GeV/c for Ω − and Ω + . Baryons and anti-baryons were measured as separate particles and we find that the baryon to antibaryon ratio of both particle species is consistent with unity over the entire range of the measurement. The statistical precision of the current LHC data has allowed us to measure a difference between the mean p t of Ξ − (Ξ + ) and Ω − (Ω + ). Particle yields, mean p t , and the spectra in the intermediate p t range are not well described by the PYTHIA Perugia 2011 tune Monte Carlo event generator, which has been tuned to reproduce the early LHC data. The discrepancy is largest for Ω − (Ω + ). This PYTHIA tune approaches the p t spectra of Ξ − and Ξ + baryons below p t < 0.85 GeV/c and describes the Ξ − and Ξ + spectra above p t > 6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Ω − +Ω + )/ (Ξ − +Ξ + ) as a function of transverse mass.

The production cross section of electrons from semileptonic decays of beauty hadrons was measured... more The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y| < 0.8) in the transverse momentum range 1 < p T < 8 GeV/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy √ s = 7 TeV using an integrated luminosity of 2.2 nb −1 . Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark-antiquark pairs. * See Appendix A for the list of collaboration members Electrons from beauty hadron decays in pp collisions at √ s = 7 TeV 1

The p T -differential inclusive production cross section of the prompt charm-strange meson D + s ... more The p T -differential inclusive production cross section of the prompt charm-strange meson D + s in the rapidity range |y| < 0.5 was measured in proton-proton collisions at √ s = 7 TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of 2.98×10 8 events collected with a minimum-bias trigger. The corresponding integrated luminosity is L int = 4.8 nb −1 . Reconstructing the decay D + s → φ π + , with φ → K − K + , and its charge conjugate, about 480 D ± s mesons were counted, after selection cuts, in the transverse momentum range 2 < p T < 12 GeV/c. The results are compared with the prediction of a model based on perturbative QCD. The ratios of the cross sections of four D meson species (namely D 0 , D + , D * + and D + s ) were determined both as a function of p T and integrated over p T after extrapolating to full p T range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in e + e − , ep and pp interactions at various centre-of-mass energies.

Higher Education Research & Development, 2012

It can sometimes be difficult to engage students in ‘real life experiences’ within the classroom.... more It can sometimes be difficult to engage students in ‘real life experiences’ within the classroom. In one Bachelor of Social Work program, the development of a Social Work Studio (the Studio) has provided students with opportunities to engage in simulated social work practice in a safe and supportive environment. This article reports on a small exploratory study of students' responses to a survey that sought their views and reactions to the development of this Studio initiative. Findings were analysed from a sociocultural perspective. They indicate that students' responses to the development of the Studio reflect their emerging constructions of the cultural world of social work.

A QUIEN PUEDA INTERESARLE Yo LAURA ANDREA VELASQUEZ BUITRAGO con C.C. 43.979.167 de Medellin doy ... more A QUIEN PUEDA INTERESARLE Yo LAURA ANDREA VELASQUEZ BUITRAGO con C.C. 43.979.167 de Medellin doy fe de que conozco a ANA MARIA BUITRAGO de muchos años y doy parte de que es una gran persona. Muchas gracias. _____________________________________ LAURA ANDREA VELASQUEZ BUITRAGO CC. 43979167

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