Searcharxiv⌕ Search

arXiv subjects

C. A. Garcia Canal

Publications and source records attributed to C. A. Garcia Canal.

At least 19 recordsLinked to original sources
arXiv2022

Relation between the Berry phase in quantum hermitian and non-hermitian systems and the Hannay phase in the equivalent classical systems

The well-known geometric phase present in the quantum adiabatic evolution discovered by Berry many years ago has its analogue, the Hannay phase, in the classical domain.We calculate the Berry phase with examples for quantum hermitian and non-hermitian $PT$-symmetric Hamiltonians and compare with the Hannay phase in their classical equivalents.We use the analogy to propose resonant electric circuits which reproduce the theoretical solutions in simulated laboratory experiments.

quant-ph↗
arXiv2021

Measuring the Hannay geomatric phase

An electric network whose dynamics is entirely equivalent to the Foucault pendulum is presented. This circuit allows one to measure in a simulation of the circuit, and eventually in a built circuit in the laboratory, the Hannay geometric phase. This phase corresponds, via the equivalence discussed in the text, exactly to the latitude effect on the rotation of the oscillation plane of the pendulum. The circuit includes a gyrator, that introduces a non-reciprocal character to the network.

physics.class-ph↗
arXiv2016

The role of heavy quarks in light hadron fragmentation

We investigate the role of heavy quarks in the production of light flavored hadrons and in the determination of the corresponding non perturbative hadronization probabilities. We define a general mass variable flavor number scheme for fragmentation functions that accounts for heavy quark mass effects, and perform a global QCD analysis to an up-to-date data set including very precise Belle and BaBar results. We show that the mass dependent picture provides a much more accurate and consistent description of data.

hep-ph↗
arXiv2015

Photoproduction total cross section and shower development

The total photoproduction cross section at ultra-high energies is obtained using a model based on QCD minijets and soft-gluon resummation and the ansatz that infrared gluons limit the rise of total cross sections. This cross section is introduced into the Monte Carlo system AIRES to simulate extended air-showers initiated by cosmic ray photons. The impact of the new photoproduction cross section on common shower observables, especially those related to muon production, is compared with previous results.

hep-ph↗
arXiv2013

Production and propagation of heavy hadrons in air-shower simulators

Very energetic charm and bottom hadrons may be produced in the upper atmosphere when a primary cosmic ray or the leading hadron in an extensive air shower collide with a nucleon. At $E\approx 10^8$ GeV their decay length becomes of the order of 10 km, implying that they tend to interact in the air instead of decaying. Since the inelasticity in these collisions is much smaller than the one in proton and pion collisions, there could be rare events where a heavy-hadron component transports a significant amount of energy deep into the atmosphere. We have developed a module for the detailed simulation of these processes and have included it in a new version of the air shower simulator AIRES. We study the frequency, the energy distribution and the depth of charm and bottom production, as well as the depth and the energy distribution of these quarks when they decay. As an illustration, we consider the production and decay of tau leptons (from $D_s$ decays) and the lepton flux at PeV energies from a 30 EeV proton primary. The proper inclusion of charm and bottom hadrons in AIRES opens the possibility to search for air-shower observables that are sensitive to heavy quark effects.

astro-ph.HE↗
arXiv2011

Building Gauge Theories: The Natural Way

The construction of a gauge field theory for elementary particles usually starts by promoting global invariance of the matter action to a local one, this in turn implying the introduction of gauge fields. We present here a procedure that runs the other way: starting from the action for gauge fields, matter is gauge invariantly coupled on the basis of Lorentz invariance and charge conservation. This natural approach prevents using the concept of particles separated from gauge fields that mediate interactions.

math-ph↗
arXiv2011

Equivalence between classical and quantum dynamics. Neutral kaons and electric circuits

An equivalence between the $\mathrm{Schr\ddot{o}dinger}$ dynamics of a quantum system with a finite number of basis states and a classical dynamics is presented. The equivalence is an isomorphism that connects in univocal way both dynamical systems. We treat the particular case of neutral kaons and found a class of electric networks uniquely related to the kaon system finding the complete map between the matrix elements of the effective Hamiltonian of kaons and those elements of the classical dynamics of the networks. As a consequence, the relevant $ε$ parameter that measures CP violation in the kaon system is completely determined in terms of network parameters.

quant-ph↗
arXiv2009

Testing hadronic interaction packages at cosmic ray energies

A comparative analysis of the secondary particles output of the main hadronic interaction packages used in simulations of extensive air showers is presented. Special attention is given to the study of events with very energetic leading secondary particles, including diffractive interactions.

astro-ph.HE↗
arXiv2006

The Landau Distribution for Charged Particles Traversing Thin Films

The Landau distribution as well as its first and second momenta are well suited for describing the energy loss of charged particles traversing a thin layer of matter. At present, just rational approximations and asymptotic expressions for these functions were obtained. In this paper we present a direct calculation of the integral representation of these functions obtaining perturbative and nonperturvative solutions expressed in terms of fast convergent series. We also provide a simple numerical algorithm which allows to control speed and precision of the results. The testing runs have provided, in reasonable computing times, correct results up to 13-14 significant digits on the density and distribution functions and 9-10 on the first and second momenta. If necessary, this accuracy could be improved by adding more coefficients to the algorithm.

hep-ph↗
arXiv2005

Approximate solutions for the single soliton in a Skyrmion-type model with a dilaton scalar field

We consider the analytical properties of the single-soliton solution in a Skyrmion-type Lagrangian that incorporates the scaling properties of quantum chromodynamics (QCD) through the coupling of the chiral field to a scalar field interpreted as a bound state of gluons. The model was proposed in previous works to describe the Goldstone pions in a dense medium, being also useful for studying the properties of nuclear matter and the in-medium properties of mesons and nucleons. Guided by an asymptotic analysis of the Euler-Lagrange equations, we propose approximate analytical representations for the single soliton solution in terms of rational approximants exponentially localized. Following the Padé method, we construct a sequence of approximants from the exact power series solutions near the origin. We find that the convergence of the approximate representations to the numerical solutions is considerably improved by taking the expansion coefficients as free parameters and then minimizing the mass of the Skyrmion using our ansätze for the fields. We also perform an analysis of convergence by computation of physical quantities showing that the proposed analytical representations are very useful useful for phenomenological calculations.

hep-ph↗
arXiv2004

Influence of diffractive interactions on cosmic ray air showers

A comparative study of commonly used hadronic collision simulation packages is presented. The characteristics of the products of hadron-nucleus collisions are analyzed from a general perspective, but focusing on their correlation with diffractive processes. One of the purposes of our work is to give quantitative estimations of the impact that different characteristics of the hadronic models have on air shower observables. Several sets of shower simulations using different settings for the parameters controlling the diffractive processes are used to analyze the correlations between diffractivity and shower observables. We find that the relative probability of diffractive processes during the shower development have a non negligible influence over the longitudinal profile as well as the distribution of muons at ground level. The implications on experimental data analysis are discussed.

hep-ph↗
arXiv2004

Analysis of Sunspot Number Fluctuations

Monthly averages of the sunspot number visible on the sun, observed from 1749, Zurich Observatory, and from 1848 other observatories, have been analyzed. This time signal presents a frequency power spectra with a clear $1/f^α$ behavior with $α\simeq 0.8 \pm 0.2$. The well known cycle of approximately 11 years, clearly present in the spectrum, does not produce a sensible distortion of that behavior. The eventual characterization of the sunspot time series as a fractal is analyzed by means of the detrended fluctuation analysis. The jump size distribution of the signal is also studied.

nlin.AO↗
arXiv2003

NLO Scale Dependence of Semi-Inclusive Processes

We discuss the order α_s^2 gluon initiated QCD corrections to one particle inclusive deep inelastic processes. We focus in the NLO evolution kernels relevant for the non homogeneous QCD scale dependence of these cross sections and factorization.

hep-ph↗
arXiv2001

Approximate solutions for the skyrmion

We reconsider the Euler-Lagrange equation for the Skyrme model in the hedgehog ansatz and study the analytical properties of the solitonic solution. In view of the lack of a closed form solution to the problem, we work on approximate analytical solutions. We show that Pade approximants are well suited to continue analytically the asymptotic representation obtained in terms of a power series expansion near the origin, obtaining explicit approximate solutions for the Skyrme equations. We improve the approximations by applying the 2-point Pade approximant procedure whereby the exact behaviour at spatial infinity is incorporated. An even better convergence to the exact solution is obtained by introducing a modified form for the approximants. The new representations share the same analytical properties with the exact solution at both small and large values of the radial variable r.

hep-ph↗
arXiv1999

Deep inelastic scattering, diffraction, and all that

These lectures include an introduction to the partonic description of the proton, the photon and the `colour singlet', as seen in inclusive and semi-inclusive DIS, in $e^+e^-$ collisions, and in diffractive processes, respectively. Their formal treatment using structure, fragmentation, and fracture functions is outlined giving an insight into the perturbative QCD framework for these functions. Examples and comparisons with experimental data from LEP, HERA, and Tevatron are also covered.

hep-ph↗
arXiv1999

Influence of the LPM effect and dielectric suppression on particle air showers

An analysis of the influence of the Landau-Migdal-Pomeranchuk (LPM) effect on the development of air showers initiated by astroparticles is presented. The theory of Migdal is studied and compared with other theoretical methods, particularly the Blankenbecler and Drell approach. By means of realistic computer simulations and using algorithms that emulate Migdal's theory, including also the so-called dielectric suppression, we study the behavior of the relevant observables in the case of ultra-high energy primaries. We find that the LPM effect can significantly modify the development of high energy electromagnetic showers in certain cases.

astro-ph↗