arXiv subjects

G. Moreno

Publications and source records attributed to G. Moreno.

9 recordsLinked to original sources

arXiv2014

Remarks on non-maximal integral elements of the Cartan plane in jet spaces

There is a natural filtration on the space of degree-$k$ homogeneous polynomials in $n$ independent variables with coefficients in the algebra of smooth functions on the Grassmannian $\mathrm{Gr}(n,s)$, determined by the tautological bundle. In this paper we show that the space of $s$-dimensional integral elements of a Cartan plane on $J^{k-1}(E,n)$, with $\mathrm{dim}\, E=n+m$, has an affine bundle structure modeled by the the so-obtained bundles over $\mathrm{Gr}(n,s)$, and we study a natural distribution associated with it. As an example, we show that a third-order nonlinear PDE of Monge-Ampère type is not contact-equivalent to a quasi-linear one.

math.DG↗

arXiv2012

The geometry of the space of Cauchy data of nonlinear PDEs

First-order jet bundles can be put at the foundations of the modern geometric approach to nonlinear PDEs, since higher-order jet bundles can be seen as constrained iterated jet bundles. The definition of first-order jet bundles can be given in many equivalent ways - for instance, by means of Grassmann bundles. In this paper we generalize it by means of flag bundles, and develop the corresponding theory for higher-oder and infinite-order jet bundles. We show that this is a natural geometric framework for the space of Cauchy data for nonlinear PDEs. As an example, we derive a general notion of transversality conditions in the Calculus of Variations.

math.DG↗

arXiv2010

Charge asymmetries in e+e- -> pi+ pi- gamma at the phi resonance

We consider the forward-backward pion charge asymmetry for the e^{+}e^{-}\toπ^{+}π^{-}γprocess. At tree level we consider bremsstrahlung and double resonance contributions. Although the latter contribution is formally sub-leading, it is enhanced at low dipion invariant mass due to $ρ$ resonant effects. We consider also four alternative models to describe the final state radiation at the loop level: Resonance Chiral Perturbation Theory, Unitarized Chiral Perturbation Theory, Kaon Loop Model and Linear Sigma Model. The last three models yield results compatible with experimental data. The Kaon Loop Model requires an energy dependent phase to achieve the agreement.

hep-ph↗

arXiv2010

The Bianchi variety

The totality Lie(V) of all Lie algebra structures on a vector space V over a field F is an algebraic variety over F on which the group GL(V) acts naturally. We give an explicit description of Lie(V) for dim V=3 which is based on the notion of compatibility of Lie algebra structures.

math.DG↗

arXiv2007

Cherenkov Flashes and Fluorescence Flares on Telescopes: New lights on UHECR Spectroscopy while unveiling Neutrinos Astronomy

Cherenkov Telescopes (as Magic, Hess and Veritas), while pointing horizontally should reveal also the fluorescence flare tails of nearby down-going air-showers. Such air-showers, born at higher (tens km) altitudes, are growing and extending up to lowest atmospheres (EeVs) or up to higher (few km) quotas (PeVs). Viceversa, as it has been foreseen and only recently observed, the opposite takes place. Fluorescence Telescopes made for UHECR detection may be blazed by inclined Cherenkov lights. The geomagnetic splitting may tag the energy as well as the inclined shower footprint as seen in a recent peculiar event in AUGER. Additional stereoscopic detection may define the event origination distance and its consequent primary composition, extending our understanding on UHECR composition, while unveling a novel tau Neutrino Astronomy.

astro-ph↗

arXiv2006

Domains in Infinite Jets: C-Spectral Sequence

Domains in infinite jets present the simplest class of diffieties with boundary. In this note some basic elements of geometry of these domains are introduced and an analogue of the C-spectral sequence in this context is studied. This, in particular, allows cohomological interpretation and analysis of initial data, boundary conditions, etc, for general partial differential equations and of transversality conditions in calculus of variations. This kind applications and extensions to arbitrary diffieties will be considered in subsequent publications.

math.DG↗

arXiv2005

Search for Exotic Baryons in 800 GeV pp (rtarrow) pXiPiX

We report the results of a high-statistics, sensitive search for narrow baryon resonances decaying to $Ξ^-π^-$, $Ξ^-π^+$, $\barΞ^+π^-$, and $\barΞ^+π^+$. The only resonances observed are the well known $Ξ^0(1530)$ and $\bar{Ξ^0}(1530)$. No evidence is found for a state near 1862 MeV, previously reported by NA49\cite{NA49}. At the 95% confidence level, we find the upper limit for the production of a Gaussian enhancement with $σ=7.6$ MeV in the $Ξ^-π^-$ effective mass spectrum to be 0.3% of the number of observed $Ξ^0(1530)\toΞ^-π^+$. We find similarly restrictive upper limits for an enhancement at 1862 MeV in the $Ξ^-π^+$, $\barΞ^+π^-$, and $\barΞ^+π^+$ mass spectra.

hep-ex↗

arXiv2003

On the mass, width and coupling constants of the f0(980)

Using the pole approach we determine the mass and width of the $f_0(980)$; in particular, we analyze the possibility that two nearby poles are associated to it. We restrict our analysis to a neighborhood of the resonance, using $ππ$ data for the phase shift and inelasticity, and the invariant mass spectrum of the $J/ψ\toϕππ, ϕK\bar K$ decays. The formalism we use is based on unitarity and a generalized version of the Breit-Wigner parameterization. We find that a single pole describes the $f_0(980)$, the precise position depending upon the $ππ$ data used. As a byproduct, values for the $g_{f_0ππ}$ and $g_{f_0K\bar K}$ coupling constants are obtained.

hep-ph↗

arXiv1999

$γγ\to π^0 π^0$ as a test for the existence of a light $σ$ meson

We work out predictions of the Linear Sigma Model for the $γγ\toπ^0 π^0$ cross section. We consider the sigma width, which is introduced in a consistent way with chiral Ward identities. The results of Chiral Perturbation Theory are recovered in the $m_σ\to \infty$ limit. A fit to existing experimental results is consistent with a light and broad $σ$ meson.

hep-ph↗