arXiv subjects

D. Fargion

Publications and source records attributed to D. Fargion.

At least 73 records · Page 4Linked to original sources

arXiv2004

Test results of a prototype designed to detect horizontal cosmic ray flux

In this paper we report test results from a prototype designed to detect muons from horizontal air shower at large zenith angle, $86^{0}<Θ<93^{0}$. To detect horizontal tracks and their directions we select them according the muon vertical equivalent charge and we measure the time of flight with a time resolution of 800 ps. Several measurements are collected at different zenith angles. The background studies performed with two modules show that the main source is due to tracks crossing the module at the same time. The upper limit of background flux for a single twin module is estimated to be $10^{-9} cm^{-2}$ $s^{-1}$ $sr^{-1} (90%CL)$. We estimated the size of the surface array necessary to detect the shower flux of the order of $10^{-9} cm^{-2}$ $yr^{-1}$ $sr^{-1}$ if originated by Tau Air-Showers secondaries of GZK neutrino Tau below the horizons.

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arXiv2004

Gamma rays precursors and afterglows surrounding UHECR events: Z-burst model is still alive

The Z-burst model and the direct propagation of UHE proton in negligible extragalactic magnetic fields produce gamma-rays afterglows and precursors halos, respectively at GeVs and TeV energy band a few degree around the UHECR arrival direction. The possible correlation of UHECR clusters (doublet, triplet) with nearby BL Lac sources at E_p = 4*10^19 eV offer a test for this necessary Gamma-UHECR trace. We estimate the secondary gamma energy and spectra and we suggest how to disentangle between the different scenarios. We show why Z-Burst model is still the most realistic model to explain UHECR behaviour and their correlation to known BL Lac sources.

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arXiv2004

Muon and Gamma Bundles tracing Up-going Tau Neutrino Astronomy

Up-going and Horizontal Tau Air-Showers, UpTaus and HorTaus, may trace Ultra High Energy Neutrino Tau Earth Skimming at the edge of the horizons. Their secondaries muon, electron pairs, and gamma bundles flashes might trace their nature over UHECR secondaries in horizontal showers. Indeed the atmosphere act as a perfect amplifier as well as a filter for showers: down-ward and horizontal muon bundles may still be originated by far Ultra High Energy Cosmic Rays skimming the terrestrial atmosphere but their rich gamma component will be exponentially suppressed. At large zenith angles after crossing a large slant depth X > 3 10^3 g cm^-2 the number of muons and secondary gamma (produced by the electron pair from muon decay in flight) is comparable. On the other hand, up-ward muon bundles from UpTaus and HorTaus may arise within a young shower with a larger gamma-muon ratio 10^2, leaving a characteristic imprint. We estimate the UpTaus and HorTaus rate from the Earth and we evaluate the consequent event rate of muons, electrons pairs andgamma bundles. We show that such events even for minimal GZK neutrino fluxes could be detected by scintillator arrays placed on mountains at 1-5km and pointing to the horizon. The required arrayareas are within tens-hundreds of square meters. The ideal structure is an array of crown-like twin detectors facing the horizons. We argue that such detectors will be able to detect both muonic bundles at a minimal average flux of 10^-11 cm-2 s^-1 sr^-1 and electromagnetic particles gamma and electron pairs 3 10^-9 cm^-2 s^-1 sr^-1, a few times each year for GZK neutrino fluxes.

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arXiv2004

Discovering Tau and Muon Solar Neutrino Flares above backgrounds

Solar neutrino flares astronomy is at the edge of its discover. High energy flare particles (protons, alpha) whose self scattering within the solar corona is source of a rich prompt charged pions are also source of sharp solar neutrino "burst" (at tens-hundred MeV) produced by their pion-muon primary decay in flight. This brief (minute) solar neutrino "burst" at largest peak overcome by four-five order of magnitude the steady atmospheric neutrino noise at the Earth. Later on, solar flare particles hitting the terrestrial atmosphere may marginally increase the atmospheric neutrino flux without relevant consequences. Largest prompt "burst" solar neutrino flare may be detected in present or better in future largest neutrino underground neutrino detectors. Our estimate for the recent and exceptional October - November 2003 solar flares gives a number of events above or just near unity for Super-Kamiokande. The neutrino spectra may reflect in a subtle way the neutrino flavour mixing in flight. A surprising tau appearance may even occur for a hard ({E}_{nu}_{mu}--> {E}_{nu}_{tau} > 4 GeV) flare spectra. A comparison of the solar neutrino flare (at their birth place on Sun and after oscillation on the arrival on the Earth) with other neutrino foreground is here described and it offer an independent road map to disentangle the neutrino flavour puzzles and its secret flavour mixing angles .

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arXiv2004

Muon and Tau Neutrinos Spectra from Solar Flares

Solar neutrino flares and mixing are considered. Most power-full solar flare as the ones occurred on 23th February 1956, September 29th 1989, 28th October and on 2nd-4th November 2003 are sources of cosmic rays, X, gamma and neutrino bursts. These flares took place both on front or in the edge and in the hidden solar disk. The observed and estimated total flare energy should be a source of a prompt secondary neutrino burst originated, by proton-proton-pion production on the sun itself; a more delayed and spread neutrino flux signal arise by the solar charged flare particles reaching the terrestrial atmosphere. Our first estimates of neutrino signals in largest underground detectors hint for few events in correlation with, gamma,radio onser. Our approximated spectra for muons and taus from these rare solar eruption are shown over the most common background. The muon and tau signature is very peculiar and characteristic over electron and anti-electron neutrino fluxes. The rise of muon neutrinos will be detectable above the minimal muon threshold of 113 MeV. The rarest tau appearence will be possible only for hardest solar neutrino energies above 3.471 GeV

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arXiv2004

Upward Tau Air Showers from Earth

We estimate the rate of observable Horizontal and Upward Tau Air-Showers (HORTAUs, UPTAUS) considering both the Earth opacity and the finite size of the terrestrial atmosphere. We calculate the effective target volumes and masses for Tau air-showers emerging from the Earth. The resulting model-independent masses for satellite experiments such as EUSO may encompass at E_nu_tau = 10^19 eV a very large volume, V= 1020 km^3. Adopting simple power law neutrino fluxes, E^-2 and E^-1, calibrated to GZK-like and Z-Burst-like models, we estimate that at E= 10^19 eV nearly half a dozen horizontal shower events should be detected by EUSO in three years of data collection by the "guaranteed" GZK neutrino flux. We also find that the equivalent mass for an Earth outer layer made of rock is dominant compared to the water, contrary to simplified all-rock/all-water Earth models and previous Montecarlo simulations. Therefore we expect an enhancement of neutrino detection along continental shelves nearby the highest mountain chains, also given the better geometrical acceptance for Earth skimming neutrinos. The Auger experiment might reveal such a signature at E_nu= 10^{18} eV (with 26 events in 3 yr) towards the Andes, if the angular resolution at the horizon (both in azimuth and zenith) would reach an accuracy of nearly one degree needed to disentangle tau air showers from common UHECR. The number of events increases at lower energies; therefore we suggest an extension of the EUSO and Auger sensitivity down to (or even below) E_nu = 10^19 eV and E_nu = 10^18 eV respectively.

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arXiv2004

Detecting Solar Neutrino Flares and Flavors

Intense solar flares originated in sun spots produce high energy particles (protons, $α$) well observable by satellites and ground-based detectors. The flare onset produces signals in different energy bands (radio, X, gamma and neutrons). The most powerful solar flares as the ones occurred on 23 February 1956, 29 September 1989 and the more recent on October 28th, and the 2nd, 4th, 13th of November 2003 released in sharp times the largest flare energies (${E}_{FL} \simeq {10}^{31}÷{10}^{32} erg). The high energy solar flare protons scatter within the solar corona and they must be source of a prompt neutrino burst through the production of charged pions. Later on, solar flare particles hitting the atmosphere may marginally increase the atmospheric neutrino flux. The prompt solar neutrino flare may be detected in the largest underground $ν$ detectors. Our estimate for the October - November 2003 solar flares gives a number of events above the unity. The electron/muon $ν$ signals and spectra may reflect the neutrino flavour mixing. A surprising tau appearance may occur for a hard {E}_nu_mu}} \to {E}_{ν_τ}\simeq> 4 GeV$) flare spectra.

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arXiv2003

Neutrino induced showering from the Earth

Ultra High Energy, UHE, Neutrino Astronomy should be soon tested looking toward the Earth. At present High Energy Neutrino Astronomy is searched by AMANDA, ANTARES underground detectors looking for its consequent unique muons secondary track. We suggest a higher energy Tau Neutrino Astronomy based on Horizontal and Upward Tau Air-Showers escaping from the Earth. These Tau air-showers greatly amplifies the single tau track by an abundant secondary tail (billions of electron pairs, gamma and tens of millions muon bundles) spread in huge areas (kilometer size) easily observable (even partially) from high mountains, balloon or satellite array detectors. Possible early evidence of such a New Neutrino UPTAUs or HORTAUs (Upward or Horizontal Tau Air-Showers) Astronomy may be already found in rare BATSE gamma records of brief up-going gamma showers named Terrestrial Gamma Flashes (TGF). The TGF features, energy and arrival clustering are well tuned to upward tau air-showers. Future confirmation of the Neutrino Tau Astronomy must be found in detectors as EUSO, seeking for Upward-Horizontal air-shower events: indeed even minimal, guaranteed, GZK neutrino fluxes may be observed if EUSO threshold reaches 10^{19} eV or lower energies by enlarging its telescope size

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arXiv2003

Primordial bound systems of superheavy particles as the source of ultra-high energy cosmic rays

Annihilation of superheavy particles in primordial bound systems is considered as the source of Ultra High Energy Cosmic Rays (UHECR).Charge conservation makes them to be produced in pairs, and the estimated separation of particle and antiparticle in such pair is shown to be in some cases much smaller than the average separation determined by the averaged number density of considered particles. If the new U(1) charge is the source of a long range field similar to electromagnetic field, the particle and antiparticle, possessing that charge, can form primordial bound system with annihilation timescale, which can satisfy the conditions, assumed for this type of UHECR sources. These conditions severely constrain the possible properties of considered particles. So, the proposed mechanism of UHECR origin is impossible to realise, if the U(1) charged particles share ordinary weak, strong or electromagnetic interactions. It makes the proposed mechanism of pairing and binding of superheavy U(1) charged particles an effective theoretical tool in the probes of the physics of very early Universe and of the hidden sector of particle theory, underlying it.

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arXiv2003

Ultra High Energy Particle Astronomy, Neutrino Masses and Tau Airshowers

Ultra High Energy (UHE) neutrino Astronomy and relic Neutrino masses may play a key role in solving the Ultra High Energy Cosmic Ray (UHECR) puzzle within the Z-Showering model. Tau air-shower originated by UHE neutrino in matter may probe and amplify this expected UHE neutrino Astronomy. The discover of upcoming and horizontal tau air-showers (UPTAUs, HORTAUs), born by UHE, nu_tau interacting inside mount chains or along Earth Crust crown masses at the Horizons edges, will greatly amplify the single UHE nu_tau track. Observing UPTAUs and HORTAUs along their line of showering, from higher balloons or satellites, at Greisen-Zatsepin-Kuzmin (GZK) energies above 10^19 eV, may test a calorimeter mass exceeding 150 km^3 (water equivalent). Observing Horizontal Shower by EUSO will probe even larger ring areas generated in huge terrestrial volumes larger than 2360 km^3. These highest GZK energies nu_tau astronomy are well tuned to test the needed abundant nu fluence in GZK Z-Showering model where ZeV (above 10^21 eV) Ultra High Energy neutrinos hit on relic light (near 0.1-3 eV masses) anti-neutrinos, in hot dark matter halos, creating boosted UHE Z bosons. Their nucleon decay in flight may born secondaries observed on Earth atmosphere as UHECR. The wide EUSO acceptance may test easily Z-showering fluxes as well as GZK neutrinos at their minimal granted fluence. The rare (78) observed upcoming terrestrial gamma flashes observed by BATSE satellite during last decade may be also be traces of such UPTAUs and HORTAUs.

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arXiv2003

The Rise of High Energy Neutrino Astronomy at Horizon

High Energy Neutrino Astronomy energy windows may be ruled by a new Upward and Horizontal Tau Air-Showers (UpTaus, HorTaus) detectors (scintillators and optical arrays) located a few kilometers beyond facing High Mountains Chains, or located above their top or flying on Planes, on Balloons and on Satellites facing downward to the Earth Crust Horizon. While looking downward to the Earth seeking for Upward and Horizontal Tau Air-Showers the same optical detectors may often capture cosmic rays Cherenkov lights reflected or diffused by downward Shower cosmic rays hitting the Earth soil (a sea,a lake, ice lands, desert or ground). These new detectors may be built up as a circular hybrid crown array at high quota facing to horizon in correlation with present largest telescopes, like Magic or Shalon or ASHRA ones, if able to look below the Earth edge. The UpTaus and HorTau Astronomy at 10^15 eV up to 10^19 eV energy windows may test the largest primary neutrino fluxes in Z-Burst neutrino model needed to solve the GZK puzzle or even the smaller but inevitable GZK neutrino flux secondary of the same GZK cut-off. These HorTus signals might well be observed in future EUSO experiment.

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arXiv2003

Rebrightening in GRBs by Precessing Jet

A clear gamma polarization in the gamma signals from GRB021206 probes the presence of a very thin collimated jet (opening angle Deltaθ< 0.6^o, (DeltaΩ)Ω< 2.5 10^-5) in Gamma Ray Burst, GRBs. The last and well proved GRB030329/SN2003dh time and space coincidence confirms definitively the earliest GRB980425/SN1998bw connection among GRB and Supernova. The apparent extreme GRBs luminosity is just the extreme beamed blazing gamma Jet observed in axis during a Supernova birth. The late relic GRBs sources may be found in compact SNRs core, as NS or BH jets; at much later epoch, their lower power gamma jets may be within detectability only from nearby galactic distances, as Soft Gamma Repeaters (SGRs) or anomalous X-ray Pulsars, AXPs. This common Jet nature explain some connection between GRBs and SGRs spectra. The geometrical multi-precessing beaming and their reappearance to the observer may explain the puzzling presence of X-Ray precursors in GRBs as well as in SGRs. A mysterious re-brightening afterglows observed in early and late GRB 030329 optical transient, like in the 27 August 1998 and 18 April 2001 SGR 1900+14 events, might be understood as the damped oscillatory imprint left by such a multi-precessing gamma-X-Optical and Radio Jet.

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arXiv2003

Puzzling afterglow's oscillations in GRBs and SGRs: tails of precessing Jets

Damped oscillating afterglows in GRB 030329 and in SGR 1900+14 find a natural explanation in precessing gamma Jet model for both GRBs and SGRs. The very thin Jet cone (solid angle ratio Delta Omega/Omega less or near 10^{-8}) combines at once the Supernova power and the apparent huge GRBs output: {dE/dt}_{GRBs} comparable to {dE/dt}_{SN}* Omega/(Delta Omega), leading to a better understanding of their remarkable GRB-Super Nova connection shown in early GRB980425/SN1998bw event and in most recent GRB030329/SN2003dh one. The same thin beaming offer a understanding of the apparent SGR-X-Pulsar power connection: {dE/dt}_{SGRs} comparable to {dE/dt}_{Xpuls}*Omega/(Delta Omega). The precessing Jet model for both GRBs and SGRs, at their different luminosity,explains the existence of a few identical energy spectra and time evolution of these two sources leading to their unified understanding. The spinning-precessing Jet explains the rare mysterious X-Ray precursors in GRBs and SGRs. The Multi-precessing Jet at peak activity in all band may explain the puzzling X or optical re-brightening bumps found in last GRB030329 and earliest SGR 1900+ 14 on 27 August 1998 and on 18 April 2001, as well as the multi-bump radio light-curve observed in GRB980425 and GRB030329. Rarest micro-quasars in our galaxy as SS433, and Herbig Haro objects describe these thin precessing Jet imprint in their 3D relic nebulae shapes.

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arXiv2003

Ultra High Energy Cosmic Rays, Z-Shower and Neutrino Astronomy by Horizontal-Upward Tau Air-Showers

Ultra High Cosmic Rays (UHECR) Astronomy may be correlated to a primary parental Neutrino Astronomy: indeed any far BL Lac Jet or GRB, sources of UHECR, located at cosmic edges, may send its signal, overcoming the severe GZK cut-off, by help of UHE ZeV energetic neutrino primary. These UHE neutrino scattering on relic light ones (spread on wide Hot Local Groups Halos) maybe fine-tuned : E_(nu) =(M_Z)^2/m_(nu) = 4 10^(22) eV *((0.1eV)/m_(nu)), to combine at once the observed light neutrino masses and the UHECR spectra, leading to a relativistic Z-Shower in Hot Dark Halos (e few tens Mpc wide) whose final nuclear component traces the UHECR event on Earth. Therefore UHECR (with no longer volme GZK constrains) may point to far BL Lac sources. This Z-Burst (Z-Shower) model calls for large neutrino fluxes. Even if Nature do not follow the present Z-model, UHECR while being cut-off by Big Bang Radiation, must produce a minimal UHE neutrino flux, the GZK neutrino secondaries. For both reasons such UHE Neutrino Astronomy must be tested on Earth. Lowest High Energy Astronomy is searched by AMANDA, ANTARES underground deterctors by muons tracks. We suggest a complementary higher energy Neutrino Tau Astronomy inducing Horizontal and Upward Tau AirShowers. Possible early evidence of such a New Neutrino UPTAUs (Upward Tau Showers at PeVs energies) Astronomy may be in BATSE records of Upward Terrestrial Gamma Flashes. Future signals must be found in detectors as EUSO, seeking Upward-Horizontal events: indeed even minimal, guaranteed, GZK neutrino fluxes may be better observed if EUSO threshold reaches 10^(19) eV by enlarging its telescope size.

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arXiv2003

Highest Energy Neutrino Showers in EUSO

EUSO experiment, while monitoring the downward Earth atmosphere layers, may observe among common Ultra High Energy Cosmic Rays, UHECR, also High Energy Neutrino-Induced Showers either blazing upward to the detectors at high (PeVs) energies or at much higher GZK E >= 10^19 eV energies, showering horizontally in air or vertically downward. A small fraction of these upward, horizontal and vertical Shower maybe originated by direct astrophysical UHE neutrino interacting on terrestrial air layers itself; however the dominant UHE neutrino signal are Upward and Horizontal Tau Air-Showers, UPTAUS and HORTAUs (or Earth skimming neutrinos), born within widest Earth Crust Crown (Sea or Rock) Areas, by UHE nu_tau + Nuclei--> tau interactions, respectively at PeVs and GZK energies: their rate and signatures are shown in a neutrino fluence map for EUSO thresholds versus other UHE air interacting neutrino signals and backgrounds. The effective target Masses originating HORTAUs seen by EUSO may exceed (on sea) at 10^19 eV energy a wide and huge ring volume above 1/2*A_Euso*l_tau*(L_nu/2R_Earth)^2= 5130 km^3. The consequent HORTAUS event rate (even at 10% EUSO duty cycle lifetime) may deeply test the expected Z-Burst models by at least a hundred of yearly events. Even rarest but inescapable GZK neutrinos (secondary of photopion production of observed cosmic UHECR) might be discovered in a few (or a tens) horizontal shower events; in this view an extension of EUSO detectability up to E > 10^19 eV threshold is to be preferred. A wider collecting EUSO telescope (3m diameter) might be considered.

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arXiv2003

Upward and Horizontal Tau Air-showers from Earth Crust Crowns: Traces of Highest Energy Neutrinos Beam Dump in Widest Volumes

The expected Ultra High Energy Neutrino signals from PeVs up to GZK energies may arise as Upward and Horizontal Tau air Showers, UPTAUS and HORTAUS, flashing toward mountain peaks, airplanes, balloons and satellites. The Areas, Volumes and Masses from these Terrestrial Corona at each height are estimated for present and future Tau Air-Showering experiments. While observing from high mountains these masses are comparable to few km^3 volumes above EeVs neutrino energies and they may even exceed 150 km^3 at GZK energies, (E > = 10^19 eV), while being recording from a satellite looking toward terrestrial Horizontal Crown edges from orbit altitudes.

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arXiv2002

High Energy Neutrino and Tau Airshowers in Standard and New Physics

High Energy Neutrino may lead to a New High Energy Astronomy. Neutrino interaction in matter at PeVs- EeVs may behave differently from Standard Model predictions because possible TeV Gravity scenario. While traditional km^3 neutrino underground detector will be uneasy to disentangle the Gravity TeV scenario any new Horizontal Tau Air-Shower detectors at PeVs tau energy, beyond Mountain Chains, will be greatly enhanced and it may probe fruit-fully the New TeV Physics imprint. Moreover observing upcoming and horizontal tau air-showers {UPTAUS, HORTAUS} from high mountains toward Mount Chains or along widest Earth Crust crown masses at the Horizons edges, Ultra High Energy,UHE, nu_{tau} and its consequent tau lepton decay in flight, will greatly amplify any single UHE nu_{tau} track and it will test, at highest energies, huge volumes comparable to underground km^3 ones; observing UPTAUS and HORTAUs from higher balloons or satellites at orbit altitudes, at GZK energies, the Horizontal Crown effective Masses may even exceed 150 km^3. These Highest energies (10^{19} eV) nu astronomy are tuned to test the needed abundant nu fluence in GZK Z-Showering model: in this scenario ZeV Ultra High Energy neutrino are hitting on relic light (0.1-5 eV masses) anti-neutrinos, clustered in dark hot halos, creating UHE Z bosons whose decay in flight may be the hadronic secondaries observed on Earth atmosphere as UHECR, isotropically spread along the cosmic edges and clustered toward few correlated BL Lac sources.

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arXiv2002

Invisible Higgs Boson Decay into Massive Neutrinos of 4th Generation

Results from several recent experiments provide inderect evidences in the favor of existence of a 4th generation neutrino. Such a neutrino of mass about 50 GeV is compatible with current physical and astrophysical constraints and well motivated in the framework of superstring phenomenology. If sufficiently stable the existence of such a neutrino leads to the drastic change of Higgs boson physics: for a wide range of Higgs boson masses the dominant mode of Higgs boson decay is invisible and the branching ratios for the most promising modes of Higgs boson search are significantly reduced. The proper strategy of Higgs boson searches in such a framework is discussed. It is shown that in the same framework the absence of a signal in the search for invisible Higgs boson decay at LEP means either that the mass of Higgs is greater than 113.5 GeV or that the mass difference between the Higgs mass and doubled neutrino mass is small.

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