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G. Giacomelli

Publications and source records attributed to G. Giacomelli.

120 records · Page 7Linked to original sources
arXiv2000

Limits on radiative decays of solar neutrinos from a measurement during a solar eclipse

A search for possible radiative decays of solar neutrinos with emission of photons in the visible range was performed during the total solar eclipse of August 11, 1999. Due to very bad weather conditions our two telescopes were unable to collect useful data; fortunately we obtained several video camera images from a local TV station. An analysis of the digitised images is presented and limits on the lifetime for radiative decay are discussed.

hep-ex↗
arXiv2000

Neutrino physics and astrophysics with the MACRO detector

After a brief presentation of the MACRO detector we discuss the data on atmospheric neutrinos and neutrino oscillations, on high energy (E> 1 GeV) neutrino astronomy, on indirect searches for WIMPs and low energy (E >7 MeV) stellar collapse neutrinos.

hep-ex↗
arXiv2000

Total Cross Sections

The measurements of the hadron-hadron total cross sections are the first measurements performed when a new hadron accelerator opens up a new energy region; the measurements were made as function of the incoming beam momentum or c.m. energy and have often been repeated with improved accuracy and finer energy spacing.

hep-ex↗
arXiv2000

Magnetic monopole bibliography

We present a bibliography compilation on magnetic monopoles updated to include references till the end of year 1999. It is intended to contain nearly all the experimental papers on the subject and only the theoretical papers which have some specific experimental implications.

hep-ex↗
arXiv2000

Magnetic monopoles, nuclearites, Q-balls: a qualitative picture

We present qualitative pictures of the structures of magnetic monopoles (MMs), nuclearites (nuggets of strange quark matter, strangelets, surrounded by electrons) and Q-balls (supersymmetric states of squarks, sleptons and Higgs fields). In particular we discuss the relation between their mass and size. MMs, nuclearites and Q-balls could be part of the cold Dark Matter (DM); we consider astrophysical limits on the flux of these particles in the cosmic radiation.

hep-ex↗
arXiv2000

Energy Losses of Q-balls

After a short review of Q-balls properties, in this paper we discuss their interaction with matter, and their energy losses in the earth, for a large range of velocities. These calculations are used to compute the fractional angular acceptance of a detector located at Gran Sasso Laboratory. Furthermore we computed the light yield in liquid scintillators, the ionization in streamer tubes and the Restricted Energy Loss in the CR39 nuclear track detector.

hep-ex↗
arXiv2000

Magnetic monopoles

The main aim of this lecture is to give an update on the lectures on Magnetic Monopoles (MMs) of the 1995 Trieste School. The update concerns theoretical developments, searches for GUT monopoles in the penetrating cosmic radiation at ever lower fluxes, study of the energy losses of MMs in the Earth and in detectors,searches for low mass monopoles, and finally mention byproducts of MM searches.

hep-ex↗
arXiv2000

Solar panels as air Cherenkov detectors for extremely high energy cosmic rays

Increasing interest towards the observation of the highest energy cosmic rays has motivated the development of new detection techniques. The properties of the Cherenkov photon pulse emitted in the atmosphere by these very rare particles indicate low-cost semiconductor detectors as good candidates for their optical read-out. The aim of this paper is to evaluate the viability of solar panels for this purpose. The experimental framework resulting from measurements performed with suitably-designed solar cells and large conventional photovoltaic areas is presented. A discussion on the obtained and achievable sensitivities follows.

hep-ex↗
arXiv1999

General properties of propagation in chaotic systems

We conjecture that in one-dimensional spatially extended systems the propagation velocity of correlations coincides with a zero of the convective Lyapunov spectrum. This conjecture is successfully tested in three different contexts: (i) a Hamiltonian system (a Fermi-Pasta-Ulam chain of oscillators); (ii) a general model for spatio-temporal chaos (the complex Ginzburg-Landau equation); (iii) experimental data taken from a CO_2 laser with delayed feedback. In the last case, the convective Lyapunov exponent is determined directly from the experimental data.

chao-dyn↗
arXiv1999

Recent OPAL measurements in non-perturbative QCD

Using multihadronic Z0 decays recorded in 1991-1995 by the OPAL detector in e+e- collisions at LEP1, experimental analyses were made of the following subjects: (a) Bose-Einstein correlations; (b) Intermittency and correlations; (c) rho and omega spin alignments; (d) A search for the tensor glueball candidate fj(2200).

hep-ex↗
arXiv1999

Atmospheric Neutrinos and Neutrino Oscillations

After some generalities on neutrino oscillations and on neutrinos, the recent experimental results presented by Soudan 2, MACRO and SuperKamiokande at the Neutrino'98 conference are summarized and discussed.

hep-ph↗