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Papers by Fernando Valencia Bernardino

Research paper thumbnail of Probing neutrino mass with displaced vertices at the Fermilab Tevatron

Physical Review D, 2005

Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can genera... more Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can generate naturally the observed neutrino mass spectrum as well as mixings. One interesting feature of these scenarios is that the lightest supersymmetric particle (LSP) is unstable, with several of its decay properties predicted in terms of neutrino mixing angles. A smoking gun of this model in colliders is the presence of displaced vertices due to LSP decays in large parts of the parameter space. In this work we focus on the simplest model of this type that comes from minimal supergravity with universal R-parity conserving soft breaking of supersymmetry augmented with bilinear R-parity breaking terms at the electroweak scale (RmSUGRA). We evaluate the potential of the Fermilab Tevatron to probe the RmSUGRA parameters through the analysis of events possessing two displaced vertices stemming from LSP decays. We show that requiring two displaced vertices in the events leads to a reach in m1/2 twice the one in the usual multilepton signals in a large fraction of the parameter space.

Research paper thumbnail of Hepatitis C virus and human immunodeficiency virus coinfection in Spain

Journal of Infection, 2003

Bouare et al found that hepatitis C virus (HCV) infection in Malian women is mainly transmitted t... more Bouare et al found that hepatitis C virus (HCV) infection in Malian women is mainly transmitted through medical procedures with contaminated supplies, and that human immunodeficiency virus (HIV) transmission is predominantly sexual. The results of this study confirm those of a recent case-control study in New York and Oregon which demonstrated that healthcare exposures represent an important source of new HCV infections in United States. HCV seroprevalence was only 0.2% in pregnant, young Malian women, indicating that hygiene improved in healthcare facilities over time. Heterosexual transmission of HCV is exceptional, and can occur, from males to females, in extremely rare occasions in case of vaginal mucosal damage or less rarely through anal intercourse. The Malian study did not show an association between HIV infection and hospitalization, transfusion, tattoo, dental care. Transmission by needle-stick injury occurs in 0.9%-2.2% of exposures from HCV-infected subjects and in 0.1%-0.3% of exposures from HIV-infected individuals. HCV is therefore more transmissible through percutaneous exposure.

Research paper thumbnail of The Hunt for New Physics at the Large Hadron Collider

Nuclear Physics B-proceedings Supplements, 2010

The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics... more The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics in the TeV region and shed light on some of the core unresolved issues of particle physics. These include the nature of electroweak symmetry breaking, the origin of mass, the possible constituent of cold dark matter, new sources of CP violation needed to explain the baryon excess in the universe, the possible existence of extra gauge groups and extra matter, and importantly the path Nature chooses to resolve the hierarchy problem -is it supersymmetry or extra dimensions. Many models of new physics beyond the standard model contain a hidden sector which can be probed at the LHC. Additionally, the LHC will be a top factory and accurate measurements of the properties of the top and its rare decays will provide a window to new physics. Further, the LHC could shed light on the origin of neutralino masses if the new physics associated with their generation lies in the TeV region. Finally, the LHC is also a laboratory to test the hypothesis of TeV scale strings and D brane models. An overview of these possibilities is presented in the spirit that it will serve as a companion to the Technical Design Reports (TDRs) by the particle detector groups ATLAS and CMS to facilitate the test of the new theoretical ideas at the LHC. Which of these ideas stands the test of the LHC data will govern the course of particle physics in the subsequent decades.

Research paper thumbnail of Patrón epidemiológico de la infección por el VIH en 15 hospitales españoles: casos de nuevo diagnóstico incluidos en la cohorte VACH en 2001 y 2002

Enfermedades Infecciosas Y Microbiologia Clinica, 2005

Research paper thumbnail of Characteristics and outcome of HIV infection in gypsies in the Spanish VACH Cohort

Enfermedades Infecciosas Y Microbiologia Clinica, 2010

Research paper thumbnail of LEP sensitivities to spontaneous R-parity violating signals

Research paper thumbnail of Probing bilinear R-parity violating supergravity at the LHC

Journal of High Energy Physics, 2008

We study the collider phenomenology of bilinear R-parity violating supergravity, the simplest eff... more We study the collider phenomenology of bilinear R-parity violating supergravity, the simplest effective model for supersymmetric neutrino masses accounting for the current neutrino oscillation data. At the CERN Large Hadron Collider the center-of-mass energy will be high enough to probe directly these models through the search for the superpartners of the Standard Model (SM) particles. We analyze the impact of R-parity violation on the canonical supersymmetry searches - that is, we examine how the decay of the lightest supersymmetric particle (LSP) via bilinear R-parity violating interactions degrades the average expected missing momentum of the reactions and show how this diminishes the reach in the 'usual' channels for supersymmetry searches. However, the R-parity violating interactions lead to an enhancement of the final states containing isolated same-sign di-leptons and trileptons, compensating the reach loss in the fully inclusive channel. We show how the searches for displaced vertices associated to LSP decay substantially increase the coverage in supergravity parameter space, giving the corresponding reaches for two reference luminosities of 10 and 100 fb$^{-1}$ and compare with those of the R-parity conserving minimal supergravity model.

Research paper thumbnail of Probing neutrino mass with displaced vertices at the Fermilab Tevatron

Physical Review D, 2005

Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can genera... more Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can generate naturally the observed neutrino mass spectrum as well mixings.

Research paper thumbnail of Nortonghost15 guia usuario

Research paper thumbnail of Probing neutrino mass with displaced vertices at the Fermilab Tevatron

Physical Review D, 2005

Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can genera... more Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can generate naturally the observed neutrino mass spectrum as well as mixings. One interesting feature of these scenarios is that the lightest supersymmetric particle (LSP) is unstable, with several of its decay properties predicted in terms of neutrino mixing angles. A smoking gun of this model in colliders is the presence of displaced vertices due to LSP decays in large parts of the parameter space. In this work we focus on the simplest model of this type that comes from minimal supergravity with universal R-parity conserving soft breaking of supersymmetry augmented with bilinear R-parity breaking terms at the electroweak scale (RmSUGRA). We evaluate the potential of the Fermilab Tevatron to probe the RmSUGRA parameters through the analysis of events possessing two displaced vertices stemming from LSP decays. We show that requiring two displaced vertices in the events leads to a reach in m1/2 twice the one in the usual multilepton signals in a large fraction of the parameter space.

Research paper thumbnail of Hepatitis C virus and human immunodeficiency virus coinfection in Spain

Journal of Infection, 2003

Bouare et al found that hepatitis C virus (HCV) infection in Malian women is mainly transmitted t... more Bouare et al found that hepatitis C virus (HCV) infection in Malian women is mainly transmitted through medical procedures with contaminated supplies, and that human immunodeficiency virus (HIV) transmission is predominantly sexual. The results of this study confirm those of a recent case-control study in New York and Oregon which demonstrated that healthcare exposures represent an important source of new HCV infections in United States. HCV seroprevalence was only 0.2% in pregnant, young Malian women, indicating that hygiene improved in healthcare facilities over time. Heterosexual transmission of HCV is exceptional, and can occur, from males to females, in extremely rare occasions in case of vaginal mucosal damage or less rarely through anal intercourse. The Malian study did not show an association between HIV infection and hospitalization, transfusion, tattoo, dental care. Transmission by needle-stick injury occurs in 0.9%-2.2% of exposures from HCV-infected subjects and in 0.1%-0.3% of exposures from HIV-infected individuals. HCV is therefore more transmissible through percutaneous exposure.

Research paper thumbnail of The Hunt for New Physics at the Large Hadron Collider

Nuclear Physics B-proceedings Supplements, 2010

The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics... more The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics in the TeV region and shed light on some of the core unresolved issues of particle physics. These include the nature of electroweak symmetry breaking, the origin of mass, the possible constituent of cold dark matter, new sources of CP violation needed to explain the baryon excess in the universe, the possible existence of extra gauge groups and extra matter, and importantly the path Nature chooses to resolve the hierarchy problem -is it supersymmetry or extra dimensions. Many models of new physics beyond the standard model contain a hidden sector which can be probed at the LHC. Additionally, the LHC will be a top factory and accurate measurements of the properties of the top and its rare decays will provide a window to new physics. Further, the LHC could shed light on the origin of neutralino masses if the new physics associated with their generation lies in the TeV region. Finally, the LHC is also a laboratory to test the hypothesis of TeV scale strings and D brane models. An overview of these possibilities is presented in the spirit that it will serve as a companion to the Technical Design Reports (TDRs) by the particle detector groups ATLAS and CMS to facilitate the test of the new theoretical ideas at the LHC. Which of these ideas stands the test of the LHC data will govern the course of particle physics in the subsequent decades.

Research paper thumbnail of Patrón epidemiológico de la infección por el VIH en 15 hospitales españoles: casos de nuevo diagnóstico incluidos en la cohorte VACH en 2001 y 2002

Enfermedades Infecciosas Y Microbiologia Clinica, 2005

Research paper thumbnail of Characteristics and outcome of HIV infection in gypsies in the Spanish VACH Cohort

Enfermedades Infecciosas Y Microbiologia Clinica, 2010

Research paper thumbnail of LEP sensitivities to spontaneous R-parity violating signals

Research paper thumbnail of Probing bilinear R-parity violating supergravity at the LHC

Journal of High Energy Physics, 2008

We study the collider phenomenology of bilinear R-parity violating supergravity, the simplest eff... more We study the collider phenomenology of bilinear R-parity violating supergravity, the simplest effective model for supersymmetric neutrino masses accounting for the current neutrino oscillation data. At the CERN Large Hadron Collider the center-of-mass energy will be high enough to probe directly these models through the search for the superpartners of the Standard Model (SM) particles. We analyze the impact of R-parity violation on the canonical supersymmetry searches - that is, we examine how the decay of the lightest supersymmetric particle (LSP) via bilinear R-parity violating interactions degrades the average expected missing momentum of the reactions and show how this diminishes the reach in the 'usual' channels for supersymmetry searches. However, the R-parity violating interactions lead to an enhancement of the final states containing isolated same-sign di-leptons and trileptons, compensating the reach loss in the fully inclusive channel. We show how the searches for displaced vertices associated to LSP decay substantially increase the coverage in supergravity parameter space, giving the corresponding reaches for two reference luminosities of 10 and 100 fb$^{-1}$ and compare with those of the R-parity conserving minimal supergravity model.

Research paper thumbnail of Probing neutrino mass with displaced vertices at the Fermilab Tevatron

Physical Review D, 2005

Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can genera... more Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can generate naturally the observed neutrino mass spectrum as well mixings.

Research paper thumbnail of Nortonghost15 guia usuario