arXiv subjects

H. Fanchiotti

Publications and source records attributed to H. Fanchiotti.

23 records · Page 2Linked to original sources

arXiv1998

LPM effect and dielectric suppression in air showers

An analysis of the influence of the Landau-Migdal-Pomeranchuck (LPM) effect on the development of air showers initiated by astroparticles, is presented. By means of computer simulations using algorithms that emulate Migdal's theory, including also the so-called dielectric suppression, we study the behaviour 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.

astro-ph↗

arXiv1996

Next to Leading Order Semi-inclusive Spin Asymmetries

We have computed semi-inclusive spin asymmetries for proton and deuteron targets including next to leading order (NLO) QCD corrections and contributions coming from the target fragmentation region. These corrections have been estimated using NLO fragmentation functions, parton distributions and also a model for spin dependent fracture functions which is proposed here. We have found that NLO corrections are small but non-negligible in a scheme where gluons are polarised and that our estimate for target fragmentation effects does not modify significantly charged asymmetries but affects the so called difference asymmetries.

hep-ph↗

arXiv1996

Temperature and Density Effects on the Nucleon Mass Splitting

The finite temperature and finite density dependence of the neutron-proton mass difference is analysed in a purely hadronic framework where the $ρ-ω$ mixing is crucial for this isospin symmetry breakdown. The problem is handled within Thermo Field Dynamics. The present results, consistent with partial chiral and charge symmetry restoration, improve the experimental data fit for the energy difference between mirror nuclei.

hep-ph↗

arXiv1995

A Method to Determine the Tau Neutrino Helicity Using Polarized Taus

A method is presented to extract the tau neutrino helicity, or equivalently, the chirality parameter $γ_{\mathrm{VA}}$, independent of any tau polarization which may be present. The method is thus well-suited to measurements using taus produced from the $Z^0$ and is complementary to analyses using tau correlations since it provides the sign of the chirality parameter which is otherwise unavailable without recourse to lower energy experiments where taus are unpolarized. Results of Monte Carlo studies and comments regarding the use of the technique in experiments are also included.

hep-ph↗

arXiv1994

Polarised parton distributions

We analyze spin dependent parton distributions consistent with the most recent measurements of the spin dependent deep inelastic scattering structure functions and obtained in the framework of the spin dilution model. Predictions for the doubly polarised proton-proton Drell-Yan asymmetry, for the high $p_{T}$ photon production mechanism and $J/Ψ$ excitation are calculated using these distributions and are shown to be particularly adequate to unveil the polarisation of partons in the proton.

hep-ph↗