arXiv subjects

G. Domokos

Publications and source records attributed to G. Domokos.

34 records · Page 2Linked to original sources

arXiv2001

Signatures of Precocious Unification in Orbiting Detectors

It has been conjectured that the string and unification scales may be substantially lower than previously believed, perhaps a few TeV. In scenarios of this type, orbiting detectors such OWL or AIRWATCH can observe spectacular phenomena at trans-GZK energies. We explore measurable signatures of the hypothesis that trans-GZK air showeres (``anomalous showers'') are originated by strongly interacting neutrinos. The results of a MC simulation of such air showers is described. A distinction between proton induced and ``anomalous'' showers becomes possible once a substantial sample of trans-GZK showers will be available.

hep-ph↗

arXiv2000

Ultrahigh Energy Neutrinos and the Highest Energy Cosmic Rays

It has been suggested that the characteristic energy of string models may be considerably lower than the observed Planck mass. In such schemes, the unification of interactions takes place around the string scale, perhaps as low as a few tens of TeV. Consequently, at energies above the string scale, neutrinos acquire interactions comparable in strength to strong interactions. While they can propagate through the CMBR essentially uninhibited, in interactions with nuclei in the atmosphere they induce air showers comparable to proton induced ones. We conjecture that air showers above the Greisen-Zatsepin-Kuzmin (GZK) cutoff in the cosmic radiation are induced by such neutrinos. A Monte Carlo simulation shows that neutrino induced "anomalous" showers are virtually indistinguishable from proton induced ones on an event-by event basis. However, given sufficient statistics in detectors (HiRes, OWL, Auger etc.), the post-GZK showers are expected to exhibit characteristics in the fluctuation pattern allowing a distinction between proton and neutrino induced showers.

hep-ph↗

arXiv1999

Energy Loss of Ultrahigh Energy Protons in Strong Magnetic Fields

Ultrahigh energy protons in magnetic fields produce pions and thus lose energy. The mean free path of such a process is worked out for Gaussian random fields. Two cases are considered: an isotropic and a cylindrically symmetric distribution. The energy loss is proportional to E^3 ; it becomes significant for protons of energies larger than about 10^19 eV and magnetic fields of about 10^9 Gauss. For energies and magnetic fields of this magnitude, a proton injected into the magnetic field loses a substantial fraction of its initial energy due to pion production.

hep-ph↗

arXiv1998

Strongly Interacting Neutrinos and the Highest Energy Cosmic Rays

Cosmic rays of energies larger than the Greisen-Zatsepin-Kuzmin (GZK) cutoff may be neutrinos if they acquire strong interactions due to a ``precocious unification'' of forces. A scenario for this to happen is outlined. There is no contradiction with precision measurements carried out at LEP and SLAC. Observable consequences at LHC and future neutrino detectors are discussed.

hep-ph↗

arXiv1998

Observation of Ultrahigh Energy Neutrino Interactions by Orbiting Detectors

Orbiting detectors will be able to observe showers initiated by neutrinos penetrating the Earth and interacting close to their exit point. There is a correlation between the impact parameter of the incident neutrino and its energy. We study the development of upward going, neutrino induced showers in the atmosphere.

hep-ph↗

arXiv1998

Neutrinos in Random Magnetic Fields: The Problem of Measuring Magnetic Moments

The existence of magnetic moments of neutrinos points to physics beyond the standard model. Given current upper limits, terrestrial measurements are difficult or completely unfeasible. However, estimates of transition moments can be obtained from observation of objects such as active galactic nuclei (AGN) by means of neutrino telescopes. We describe the way of estimating the magnitudes of transition moments from such observations.

hep-ph↗

arXiv1998

Observation of UHE Neutrinos from Outer Space

The interaction of UHE neutrinos can be observed from outer space. The advantage of the proposed method is that the Earth can be used as an energy filter as well as a target. We sketch the potentials of these observations in searching for particle physics beyond the Standard Model of elementary particle interactions as well as observations of astronomical objects such as active galactic nuclei.

hep-ph↗

arXiv1997

Tests of Basic Quantum Mechanics in Oscillation Experiments

According to standard quantum theory, the time evolution operator of a quantum system is independent of the state of the system. One can, however, consider systems in which this is not the case: the evolution operator may depend on the density operator itself. The presence of such modifications of quantum theory can be tested in long baseline oscillation experiments.

hep-ph↗

arXiv1997

Behavior of Neutrinos in Stochastic Magnetic Fields

If massive neutrinos possess magnetic moments, they can undergo spin flip in a magnetic field. The magnetic fields needed for a meaningful measurement of neutrino moments could be very high and may occur in astronomical objects such as some supernovae or active galactic nuclei: they are typically chaotic ones. We develop the general theory of the passage of neutrinos through such fields. We also develop a simple model which becomes solvable in the high energy limit. Both helicities occur with equal probability, independently of the initial distribution. Observational consequences are discussed.

hep-ph↗

arXiv1997

Neutrino Flavor Conversion in Random Magnetic Fields

If massive neutrinos possess magnetic moments, a magnetic field can cause a spin flip. In the case of Dirac neutrinos the spin flip converts an active neutrino into a sterile one and vice versa. By contrast, if neutrinos are Majorana particles, a spin flip converts them to a neutrino of a different flavor. We examine the behavior of neutrinos in a random magnetic field as it occurs, for instance, in certain astronomical objects, such as an active galactic nucleus. Both Dirac and Majorana neutrinos behave ergodically: independently of their initial density matrix, they tend towards an equipartition of the helicity states. As a result, about half of the Dirac neutrinos produced becomes sterile. For Majorana neutrinos, there will be an approximate equipartition of flavors, independently of the production mechanism.

hep-ph↗

arXiv1996

Neutrino Moments and the Magnetic Primakoff Effect

If different species of neutrinos possess transition magnetic moments, a conversion between species can occur in the Coulomb field of a nucleus. In the case of Dirac neutrinos this corresponds to an active to sterile conversion, whereas in the case of Majorana neutrinos, the conversion takes place between active species. The conversion cross sections grow with the energy of the incident neutrino. The formalism is also applied to a new type of experiment designed to test the existence of the ``KARMEN anomaly''.

hep-ph↗

arXiv1994

Field Theoretic Description of High Energy Neutrino Interactions

In this paper we begin the development of a formalism for the description of high energy neutrino interactions. It is based upon field theory quantized on a null plane. We set up the general formalism as well as some techniques needed to perform phenomenological calculations. We show that the formalism developed by Wolfenstein is recovered at the cost of making two approximations: one has to treat the charged lepton fields in the Hartree--Fock approximation and one has to take the short distance limit of the Hartree--Fock correlation function. As an example, we discuss the resonant interaction of electron neutrinos in an electron gas.

hep-ph↗

arXiv1994

Resonant Neutrino Interactions and Mixing

We investigate the resonant interaction of neutrinos in matter in the presence of mixing. At energies near the W resonance, oscillations are absent; the survival probability of electron antineutrinos is suppressed due to the presence of open inelastic channels.

hep-ph↗

arXiv1994

Semianalytic Cascade Theory

We give a simple, semianalytic theory of the development of the hadronic and neutrino/muon components of a cascade induced by a primary which produces hadrons at the initial interaction. The main purpose of the theory is to allow the user to obtain quick, but reasonably reliable estimates of the longitudinal properties of such cascades developing in a medium, such as a stellar interior, the atmosphere and/or water. As an application, we discuss the possibility of discovering physics beyond the Standard Model by means of neutrino telescopes. Some of those events may have spectacular signatures in neutrino telescopes. [LaTeX, no outside macros needed. 3 figures, available in hard copy or by E-mail as Encapsulated PostScript (EPS) files.]

hep-ph↗

arXiv1994

Unusual Events in Neutrino Telescopes: Signatures of New Physics

A class of physical phenomena outside the framework of the perturbatively treated Standard Model of electroweak and strong interactions gives rise to characteristic signatures in neutrino telescopes. In essence, the signature is a large energy deposition in the neighborhood of the telescope, giving rise to large and concentrated Cherenkov light emission, and in some cases, to energetic muon bundles.

hep-ph↗

arXiv1993

Astrophysical Limit on the Deformation of the Poincare Group

The deformed Poincaré group contains a characteristic mass, $κ$. At energies exceeding $κ$, deviations from the special theory of relativity become significant. However, small deviations from ordinary relativistic kinematics are observable even at energies substantially lower than $κ$. The observation of distant events producing ultra high energy (UHE) particles leads to a lower limit on $κ$. From an analysis of the UHE data on the burst in the binary system HER X1 in 1986, we deduce $κ> 1.3 10^{12}$~GeV.

hep-ph↗