1,433 research outputs found
Measurements of the CKM angle phi_3/gamma
We present a review on the measurements of the CKM angle gamma (phi_3) as
performed by the BABAR and Belle experiments at the asymmetric-energy e+e- B
factories colliders PEP-II and KEKB.Comment: 11 pages, 10 figures, proceedings of the 5th Flavor Physics And CP
Violation Conference (FPCP 2007
CKM fits as of winter 2009 and sensitivity to New Physics
We present the status of the CKM matrix parameters in the framework of the
Standard Model. We perform a model independent analysis to set constraints on
additional effective parameters accounting for possible New Physics effects and
to evaluate the present allowed space for these effects both from and
mesons.Comment: proceedings for the Moriond 2009 EW sessio
Resonant metamaterial absorbers for infrared spectral filtering: quasimodal analysis, design, fabrication and characterization
We present a modal analysis of metal-insulator-metal (MIM) based
metamaterials in the far infrared region. These structures can be used as
resonant reflection bandcut spectral filters that are independent of the
polarization and direction of incidence because of the excitation of quasimodes
(modes associated with a complex frequency) leading to quasi-total absorption.
We fabricated large area samples made of chromium nanorod gratings on top of
Si/Cr layers deposited on silicon substrate and measurements by Fourier
Transform spectrophotometry show good agreement with finite element
simulations. A quasimodal expansion method is developed to obtain a reduced
order model that fits very well full wave simulations and that highlights
excitation conditions of the modes.Comment: 8 pages, 7 figure
Search for rare or forbidden decays of the D0 meson
We present a search for nine lepton-number-violating and three lepton-flavor-violating neutral charm decays of the type D0âh'âhââ'+â+ and D0âh'âh+â'±ââ, where h and hâČ represent a K or Ï meson and â and ââČ an electron or muon. The analysis is based on 468 fbâ1 of e+eâ annihilation data collected at or close to the ΄(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signal is observed for any of the twelve modes, and we establish 90% confidence level upper limits on the branching fractions in the range (1.0â30.6)Ă10â7. The limits are between 1 and 3 orders of magnitude more stringent than previous measurements.publishedVersio
Light meson spectroscopy from Dalitz plot analyses of ηc decays to η0 K+Kâ , η0 Ï + Ï â , and Î·Ï + Ï â produced in two-photon interactions
We study the processes γγâηcâηâČK+Kâ, ηâČÏ+Ïâ, and ηÏ+Ïâ using a data sample of 519ââfbâ1 recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+eâ collider at center-of-mass energies at and near the ΄(nS) (n=2, 3, 4) resonances. This is the first observation of the decay ηcâηâČK+Kâ and we measure the branching fraction Î(ηcâηâČK+Kâ)/(Î(ηcâηâČÏ+Ïâ)=0.644±0.039stat±0.032sys. Significant interference is observed between γγâηcâηÏ+Ïâ and the nonresonant two-photon process γγâηÏ+Ïâ. A Dalitz plot analysis is performed of ηc decays to ηâČK+Kâ, ηâČÏ+Ïâ, and ηÏ+Ïâ. Combined with our previous analysis of ηcâKÂŻKÏ, we measure the Kâ0(1430) parameters and the ratio between its ηâČK and ÏK couplings. The decay ηcâηâČÏ+Ïâ is dominated by the f0(2100) resonance, also observed in J/Ï radiative decays. A new a0(1700)âÎ·Ï resonance is observed in the ηcâηÏ+Ïâ channel. We also compare ηc decays to η and ηâČ final states in association with scalar mesons as they relate to the identification of the scalar glueball.publishedVersio
Measurements of the absolute branching fractions of B± âk±Xc c
A study of the two-body decays B±âXcÂŻcK±, where XcÂŻc refers to one charmonium state, is reported by the BABAR Collaboration using a data sample of 424 fbâ1. The absolute determination of branching fractions for these decays are significantly improved compared to previous BABAR measurements. Evidence is found for the decay B+âX(3872)K+ at the 3Ï level. The absolute branching fraction B[B+âX(3872)K+]=[2.1±0.6(stat)±0.3(syst)]Ă10â4 is measured for the first time. It follows that B[X(3872)âJ/ÏÏ+Ïâ]=(4.1±1.3)%, supporting the hypothesis of a molecular component for this resonance.publishedVersio
Head Circumference of Infants Born to Mothers with Different Educational Levels; The Generation R Study
Objective: Head circumference (HC) reflect growth and development of the brain in early childhood. It is unknown whether socioeconomic differences in HC are present in early childhood. Therefore, we investigated the association between socioeconomic position (SEP) and HC in early childhood, and potential underlying factors. Methods: The study focused on Dutch children born between April 2002 and January 2006 who participated in The Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. Maternal educational level was used as indicator of SEP. HC measures were concentrated around 1, 3, 6 and 11 months. Associations and explanatory factors were investigated using linear regression analysis, adjusted for potential mediators. Results: The study included 3383 children. At 1, 3 and 6 months of age, children of mothers with a low education had a smaller HC than those with a high education (difference at 1 month: -0.42 SD; 95% CI: -0.54,-0.30; at 3 months: -0.27 SD; 95% CI -0.40,-0.15; and at 6 months: -0.13 SD; 95% CI -0.24,-0.02). Child's length and weight could only partially explain the smaller HC at 1 and 3 months of age. At 6 months, birth weight, gestational age and parental height explained the HC differences. At 11 months, no HC differences were found. Conclusion: Educational inequalities in HC in the first 6 months of life can be mainly explained by pregnancy-related factors, such as birth weight and gestational age. These findings further support public health policies to prevent negative birth outcomes in lower socioeconomic groups
La filiacion y la fecundacion "in vitro"
Las tecnicas de reproduccion asistida no solo representan una solucion para ayudar a superar problemas de esterilidad, sino que su practica conlleva problemas eticos y juridicos. Esta Tesis analiza los problemas que plantea la fecundacion "in vitro", desde el punto de vista de la filiacion, para determinar la paternidad y maternidad cuando se utilizan los gametos de la pareja o de un tercero. Desde este punto de vista, se estudian la situacion juridica del tercero -llamado donante- y de las madres subrogadas, asi como las acciones de filiacion Tambien se examina la problematica que plantea la congelacion de semen y embriones, al poder un hombre engendrar un hijo despues de muerto. Entre las fuentes que se analizan estan los principales informes extranjeros que han estudiado la problematica de estas tecnicas, asi como el Informe especial de..
Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires
The production of tt⟠, W+bb⟠and W+cc⟠is studied in the forward region of protonâproton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fbâ1 . The W bosons are reconstructed in the decays WââÎœ , where â denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of , and is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 0.02 \mbox{fb}^{-1}. The bosons are reconstructed in the decays , where denotes muon or electron, while the and quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
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