Search results for "Meson"
showing 8 items of 1548 documents
Cubic color charge correlator in a proton made of three quarks and a gluon
2022
The three point correlation function of color charge densities is evaluated explicitly in light cone gauge for a proton on the light cone. This includes both $C$-conjugation even and odd contributions. We account for perturbative corrections to the three-quark light cone wave function due to the emission of an internal gluon which is not required to be soft. We verify the Ward identity as well as the cancellation of UV divergences in the sum of all diagrams so that the correlator is independent of the renormalization scale. It does, however, exhibit the well known soft and collinear singularities. The expressions derived here provide the $C$-odd contribution to the initial conditions for hi…
Stronger C -odd color charge correlations in the proton at higher energy
2023
The non-forward eikonal scattering matrix for dipole-proton scattering at high energy obtains an imaginary part due to a $C$-odd three gluon exchange. We present numerical estimates for the perturbative Odderon amplitude as a function of dipole size, impact parameter, their relative azimuthal angle, and light-cone momentum cutoff $x$. The proton is approximated as $\psi_\mathrm{qqq}|qqq\rangle + \psi_\mathrm{qqqg}|qqqg\rangle$, where $\psi_\mathrm{qqq}$ is a non-perturbative three quark model wave function while the gluon emission is computed in light-cone perturbation theory. We find that the Odderon amplitude increases as $x$ decreases from 0.1 to 0.01. At yet lower $x$, the reversal of t…
Estudio unificado del espectro y propiedades de mesones pesados para energı́as por debajo y por encima de umbrales mesón-mesón
2022
Asymptotic freedom and color confinement are undoubtedly the most remarkable aspects of quantum chromodynamics (QCD). Indeed, it is because of these features that QCD is universally accepted as the quantum field theory of strong interactions. On the one hand, asymptotic freedom, meaning that the theory approaches a noninteracting one in the high energy limit, allows for a perturbative treatment, so that the QCD Lagrangian can be used to derive analytical expressions describing high-energy processes. On the other hand, color confinement, implying that all observable states are color-neutral, is a purely nonperturbative phenomenon, which prevents an analytical calculation of the low-energy in…
First observation and study of the K± → π±π0e+e− decay
2018
The NA48/2 experiment at CERN reports the first observation of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay from an exposure of 1.7 x 10(11) charged kaon decays recorded in 2003-2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region, BR(K-+/- -> pi(+/-)pi(0)e(+)e(-)) = (4.24 +/- 0.14) x 10(-6). The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.
"Table 1.8" of "Probing the effects of strong electromagnetic fields with charge-dependent directed flow in Pb-Pb collisions at the LHC"
2020
Slope Dv1 D0 meson 540%
K°- K°, - D° and B° - B° oscillations in the Standard Model and beyond from unquenched Twisted Mass Lattice QCD
2013
El análisis del triángulo de unitariedad y la búsqueda de cotas restrictivas sobre las escala de nueva física requiere medidas precisas de las amplitudes de mezcla de las oscilaciones de mesones. El retículo proporciona una óptima herramienta no perturbativa para el cálculo de dichos elementos de matriz con incertidumbres del 1% y errores sistemáticos bajo control. La tesis se centra en el cálculo de los parámetros B, que controlan las oscilaciones de mesones, la masa del quark b y las constantes de desintegración fB y fBs a partir de QCD simulada en el retículo con fermiones Twisted Mass e incluyendo los efectos cuánticos de quarks dinámicos en el mar. A lo largo de esta tesis, a partir de…
MR Imaging of Uterus Didelphys Transverse Vaginal Septum Causing Hematometrocolpos and Renal Agenesis
2002
The association of uterus didelphys and unilateral blind vagina with ipsilateral renal agenesis is an infrequent urogenital malformation distinguished by a lesion of the mesonephric duct. In most patients, symptoms are present at the beginning of the menstrual cycle because a transverse vaginal septum on one side obstructs the flow of menses, which consequently collect. Magnetic resonance imaging allows a precise delineation of this congenital abnormality, clearly demonstrating the transverse vaginal septum with hematometrocolpos and uterus didelphys. Extending the magnetic resonance study to the abdomen and employing coronal sections with a wide field of view is important to search for ass…
Measurement of dielectron production in central Pb-Pb collisions at √sNN = 2.76 TeV
2019
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The first measurement of dielectron (e + e −) production in central (0 – 10 %) Pb – Pb collisions at √sNN=2.76TeV at the LHC is presented. The dielectron invariant-mass spectrum is compared to the expected contributions from hadron decays in the invariant-mass range 0 < mee < 3.5 GeV / c2. The ratio of data and the cocktail of hadronic contributions without vacuum ρ0 is measured in the invariant-mass range 0.15 < mee < 0.7 GeV / c2, w…