0000000000446877

AUTHOR

Ugo Aglietti

showing 3 related works from this author

The Two Loop Crossed Ladder Vertex Diagram with Two Massive Exchanges

2008

We compute the (three) master integrals for the crossed ladder diagram with two exchanged quanta of equal mass. The differential equations obeyed by the master integrals are used to generate power series expansions centered around all the singular (plus some regular) points, which are then matched numerically with high accuracy. The expansions allow a fast and precise numerical calculation of the three master integrals (better than 15 digits with less than 30 terms in the whole real axis). A conspicuous relation with the equal-mass sunrise in two dimensions is found. Comparison with a previous large momentum expansion is made finding complete agreement.

Power seriesgeneralized harmonic polilogarithmsNuclear and High Energy Physicsmaster integrals530 PhysicsDifferential equationFOS: Physical sciencesloop calculationsMomentumnon planar two loop massive vertexsymbols.namesakeMultiHigh Energy Physics - Phenomenology (hep-ph)Quantum mechanicsFeynman diagramLaporta method3106 Nuclear and High Energy PhysicsFeynman diagramsPhysicsDiagramMathematical analysisLoop (topology)High Energy Physics - Phenomenology10231 Institute for Computational SciencesymbolsVertex (curve)Complex planenon planar two loop massive vertex; Laporta method; generalized harmonic polilogarithms; master integrals
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Renormalization of the effective theory for heavy quarks at small velocity

1995

The slope of the Isgur-Wise function at the normalization point, $\xi^{(1)}(1)$,is one of the basic parameters for the extraction of the $CKM$ matrix element $V_{cb}$ from exclusive semileptonic decay data. A method for measuring this parameter on the lattice is the effective theory for heavy quarks at small velocity $v$. This theory is a variant of the heavy quark effective theory in which the motion of the quark is treated as a perturbation. In this work we study the lattice renormalization of the slow heavy quark effective theory. We show that the renormalization of $\xi^{(1)}(1)$ is not affected by ultraviolet power divergences, implying no need of difficult non-perturbative subtraction…

QuarkSemileptonic decayPhysicsNuclear and High Energy Physicsheavy quark effective theory; small quark velocities; renormalizationComputationHigh Energy Physics::LatticeHigh Energy Physics::PhenomenologyHigh Energy Physics - Lattice (hep-lat)Perturbation (astronomy)FísicaFOS: Physical sciencesRenormalizationHigh Energy Physics - LatticeLattice (order)Effective field theoryHeavy quark effective theoryMathematical physics
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Analytic results for virtual QCD corrections to Higgs production and decay

2006

We consider the production of a Higgs boson via gluon-fusion and its decay into two photons. We compute the NLO virtual QCD corrections to these processes in a general framework in which the coupling of the Higgs boson to the external particles is mediated by a colored fermion and a colored scalar. We present compact analytic results for these two-loop corrections that are expressed in terms of Harmonic Polylogarithms. The expansion of these corrections in the low and high Higgs mass regimes, as well as the expression of the new Master Integrals which appear in the reduction of the two-loop amplitudes, are also provided. For the fermionic contribution, we provide an independent check of the…

CouplingQuantum chromodynamicsPhysicsCondensed Matter::Quantum GasesNuclear and High Energy PhysicsParticle physicsPhotonHigh Energy Physics::LatticeScalar (mathematics)High Energy Physics::PhenomenologyFOS: Physical sciencesHarmonic (mathematics)FermionPseudoscalarHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)Higgs bosonHigh Energy Physics::Experiment
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