8,218 research outputs found
Volatility Transmission between the stock and Currency Markets in Emerging Asia: the Impact of the Global Financial Crisis
This paper examines volatility spillovers between the stock and currency markets of ten Asian economies in the period 2003 to 2014. To carry out this analysis, a multivariate asymmetric GARCH model is used. In general, our results present evidence of bidirectional volatility spillovers between both markets, independently of the individual country’s level of development. Additionally, our findings show that the global financial crisis has had mixed effects on the volatility transmission patterns. Overall, our results suggest that exchange rate policies and investment decisions should not be implemented without first taking into consideration the links between the stock and currency markets
Differential branching fraction and angular analysis of the decay B-0 -> K*(0)mu(+)mu(-)
The angular distribution and differential branching fraction of the decay B-0 -> K*(0)mu(+)mu(-) are studied using a data sample, collected by the LHCb experiment in pp collisions at root s = 7 TeV, corresponding to an integrated luminosity of 1.0 fb(-1). Several angular observables are measured in bins of the dimuon invariant mass squared, q(2). A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q(0)(2) = 4.9 +/- 0.9 GeV2/c(4), where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions
Differential branching fraction and angular analysis of the decay B-0 -> K*(0)mu(+)mu(-)
The angular distribution and differential branching fraction of the decay B-0 -> K*(0)mu(+)mu(-) are studied using a data sample, collected by the LHCb experiment in pp collisions at root s = 7 TeV, corresponding to an integrated luminosity of 1.0 fb(-1). Several angular observables are measured in bins of the dimuon invariant mass squared, q(2). A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q(0)(2) = 4.9 +/- 0.9 GeV2/c(4), where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions.We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3 and Region Auvergne (France); BMBF, DFG, HGF and MPG (Germany); SFI (Ireland); INFN (Italy); FOM and NWO (The Netherlands); SCSR (Poland); MEN/IFA (Romania); MinES, Rosatom, RFBR and NRC "Kurchatov Institute" (Russia); MinECo, XuntaGal and GENCAT (Spain); SNSF and SER (Switzerland); NAS Ukraine (Ukraine); STFC (United Kingdom); NSF (USA). We also acknowledge the support received from the ERC under FP7. The Tier1 computing centres are supported by IN2P3 (France), KIT and BMBF (Germany), INFN (Italy), NWO and SURF (The Netherlands), PIC (Spain), GridPP (United Kingdom). We are thankful for the computing resources put at our disposal by Yandex LLC (Russia), as well as to the communities behind the multiple open source software packages that we depend on.Peer reviewe
Photon polarization in Bs0→φγ decays at the LHCb experiment
El Modelo Estándar (SM) es la descripción mas precisa de las interacciones entre partÃculas fundamentales que existe hasta la fecha. Experimentalmente se han realizado observaciones que coinciden con sus predicciones hasta la precisión disponible. Sin embargo, el SM presenta carencias para describir fenómenos conocidos como son la jerarquÃa de masas de las distintas familias de partÃculas elementales o la bariogénesis. Para solventarlas existe una plétora de distintas hipótesis formalizadas en modelos teóricos, como pueden ser la supersimetrÃa (SUSY) u otros. Estos modelos incluyen nuevos componentes cuya observación marcarÃa el camino a seguir en la experimentación en fÃsica de partÃculas.
Es a través de la medición de los observables relativos a procesos con loops que se puede sondear la posibilidad de modelos mas allá del SM. El trabajo de investigación se realiza en este contexto, en concreto en el estudio de la desintegración radiativa Bs0 → φγ.
El enfoque de este análisis es obtener una medida de la polarización del fotón emitido en el canal Bs0 → φγ a través de una medida precisa de la vida media del mesón madre Bs0. Dicha polarización es predominantemente levógira en el SM. La ventaja de trabajar con mesones Bs0 sobre utilizar mesones B0 se hace evidente cuando se compara la diferencia de anchuras de sus autoestados de masa.
El análisis se basa en un método que no discrimina entre los mesones Bs0 y sus antipartÃculas. En este modo se puede escribir la tasa de desintegración en función de un parámetro AΔ que contiene la información de la proporción de fotones levógiros y dextrógiros emitidos. Se utiliza el canal B0→K*γ como control, dada la similitud entre la cinemática de ambos modos con el objetivo de reducir errores sistemáticos y otros asociados a la función de aceptancia temporal; de vital importancia para el análisis, ya que el parámetro AΔ es especialmente sensible a la parametrización. El cociente de la distribución de desintegraciones en el tiempo de ambos canales es ajustado a la forma funcional esperada, dejando libre el parámetro de interés AΔ.
Durante 2011 y 2012, el experimento LHCb colecciono 3 fb^-1 de datos a energÃas de dentro de masas de 7 y 8 TeV, respectivamente. Estos datos son usados en el análisis tras un proceso de selección, para el cual se ha participado en el diseño y mantenimiento de los algoritmos de selección de LHCb conocidos como stripping. Tras la selección, se realiza un ajuste a las distribuciones de masa tanto del canal de señal como el de control para identificar las fuentes de fondo remanentes en cada uno y poder sustraerlas, permitiendo la obtención de una distribución de tiempo de desintegración pura para cada canal. Tras la selección y el ajuste de masas, se obtienen 4200 sucesos de Bs0→φγ y 25700 de B0→K*γ para el ajuste de tiempo propio. La sustracción de fondos se realiza utilizando la técnica de sPlot.
Una vez purificadas las muestras, se categorizan en bins utilizando un algoritmo adaptativo para minimizar la dispersión en las colas exponenciales de las distribuciones antes de la división de los canales de señal y control. Este cociente se ajusta minimizando una figura de chi-cuadrado y se obtiene un valor de AΔ =-0.85[+0.43-0.46](stat)[+0.21-0.22](syst), compatible a dos desviaciones estandar con la prediccion del SM de AΔ=0.047[+0.029-0.025]
Search for direct CP violation in D-0 -> h(-)h(+) modes using semileptonic B decays
A search for direct CP violation in D-0 -> h(-)h(+) (where h = K or pi) is presented using data corresponding to an integrated luminosity of 1.0 fb(-1) collected in 2011 by LHCb in pp collisions at a centre-of-mass energy of 7 TeV. The analysis uses D-0 mesons produced in inclusive semileptonic b-hadron decays to the D-0 mu X final state, where the charge of the accompanying muon is used to tag the flavour of the D-0 meson. The difference in the CP-violating asymmetries between the two decay channels is measured to be Delta A(CP) = A(CP)(K-K+) - A(CP)(pi(-)pi(+)) = (0.49 +/- 0.30 (stat) +/- 0.14 (syst))%.
This result does not confirm the evidence for direct CP violation in the charm sector reported in other analyses.We express our gratitude to our colleagues in the CERN accelerator. departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3 and Region Auvergne (France); BMBF, DFG, HGF and MPG (Germany); SFI (Ireland); INFN (Italy); FOM and NWO (The Netherlands); SCSR (Poland); ANCS/IFA (Romania); MinES, Rosatom, RFBR and NRC "Kurchatov Institute" (Russia); MinECo, XuntaGal and GENCAT (Spain); SNSF and SER (Switzerland); NAS Ukraine (Ukraine); STFC (United Kingdom); NSF (USA). We also acknowledge the support received from the ERC under FP7. The Tier1 computing centres are supported by IN2P3 (France), KIT and BMBF (Germany), INFN (Italy), NWO and SURF (The Netherlands), PIC (Spain), GridPP (United Kingdom). We are thankful for the computing resources put at our disposal by Yandex LLC (Russia), as well as to the communities behind the multiple open source software packages that we depend on.Peer reviewe
Integració de models de patrimoni cultural en un SIG
L’objectiu principal del projecte és desenvolupar una eina que permeti integrar models 3D de
patrimoni cultural en Sistemes d’Informació Geogrà fica, per tal de facilitar la inspecció
d’aquests models, juntament amb altres capes, en el seu context (terreny que l’envolta
Precision measurement of D meson mass differences
Using three- and four-body decays of D mesons produced in semileptonic b-hadron decays, precision measurements of D meson mass differences are made together with a measurement of the D-0 mass. The measurements are based on a dataset corresponding to an integrated luminosity of 1.0 fb(-1) collected in pp collisions at 7 TeV. Using the decay D-0 -> K+K-K-pi(+), the D-0 mass is measured to be M(D-0) = 1864.75 +/- 0.15 (stat) +/- 0.11 (syst) MeV/c(2). The mass differences M(D+) - M(D-0) = 4.76 +/- 0.12 (stat) +/- 0.07 (syst) MeV/c(2), M(D-s(+)) - M(D+) = 98.68 +/- 0.03 (stat) +/- 0.04 (syst) MeV/c(2) are measured using the D-0 -> K+K-pi(+)pi(-) and D-(s)(+) -> K+K-pi(+) modes.We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3 and Region Auvergne (France); BMBF, DFG, HGF and MPG (Germany); SFI (Ireland); INFN (Italy); FOM and NWO (The Netherlands); SCSR (Poland); ANCS/IFA (Romania); MinES, Rosatom, RFBR and NRC "Kurchatov Institute" (Russia); MinECo, XuntaGal and GENCAT (Spain); SNSF and SER (Switzerland); NAS Ukraine (Ukraine); STFC (United Kingdom); NSF (U.S.A.). We also acknowledge the support received from the ERC under FP7. The Tier1 computing centres are supported by IN2P3 (France), KIT and BMBF (Germany), INFN (Italy), NWO and SURF (The Netherlands), PIC (Spain), GridPP (United Kingdom). We are thankful for the computing resources put at our disposal by Yandex LLC (Russia), as well as to the communities behind the multiple open source software packages that we depend on.Peer reviewe
A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states
A first study of CP violation in the decay modes B-+/- -> [(KSK +/-)-K-0 pi(-/+)](D)h(+/-) and B-+/- -> [(KSK +/-)-K-0 pi(-/+)](D)h(+/-), where h labels a K or pi meson and D labels a D-0 or (D) over bar (0) meson, is performed. The analysis uses the LHCb data set collected in pp collisions, corresponding to an integrated luminosity of 3 fb(-1). The analysis is sensitive to the CP-violating CKM phase gamma through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of gamma using other decay modes
Measurement of charged particle multiplicities and densities in pp collisions root s=7 TeV in the forward region
Charged particle multiplicities are studied in proton-proton collisions in the forward region at a centre-of-mass energy of TeV with data collected by the LHCb detector. The forward spectrometer allows access to a kinematic range of in pseudorapidity, momenta greater than and transverse momenta greater than . The measurements are performed using events with at least one charged particle in the kinematic acceptance. The results are presented as functions of pseudorapidity and transverse momentum and are compared to predictions from several Monte Carlo event generators
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