850 research outputs found
O(4) symmetric singular solutions and multiparticle cross sections in theory at tree level
We solve the classical euclidean boundary value problem for tree-level
multiparticle production in theory at arbitrary energies in the case
of symmetric field configurations. We reproduce known low-energy results
and obtain a lower bound on the tree cross sections at arbitrary energies.Comment: LaTeX, 9pp + 2 Postscript figures, tar-compressed and uuencoded using
uufiles; minor Postscript bug fixe
Compact extra-dimensions as solution to the strong CP problem
We show that the strong CP problem can, in principle, be solved dynamically
by adding extra-dimensions with compact topology. To this aim we consider a toy
model for QCD, which contains a vacuum angle and a strong CP like problem. We
further consider a higher dimensional theory, which has a trivial vacuum
structure and which reproduces the perturbative properties of the toy model in
the low-energy limit. In the weak coupling regime, where our computations are
valid, we show that the vacuum structure of the low-energy action is still
trivial and the strong CP problem is solved. No axion-like particle occur in
this setup and therefore it is not ruled out by astrophysical bounds.Comment: Discussion adde
Semiclassical Calculation of Multiparticle Scattering Cross Sections in Classicalizing Theories
It has been suggested in arXiv:1010.1415 that certain derivatively coupled
non-renormalizable scalar field theories might restore the perturbative
unitarity of high energy hard scatterings by classicalization, i.e. formation
of multiparticle states of soft quanta. Here we apply the semiclassical method
of calculating the multiparticle production rates to the scalar
Dirac-Born-Infeld (DBI) theory which is suggested to classicalize. We find that
the semiclassical method is applicable for the energies in the final state
above the cutoff scale of the theory L_*^{-1}. We encounter that the cross
section of the process two to N ceases to be exponentially suppressed for the
particle number in the final state N smaller than a critical particle number
N_{crit} ~ (E L_*)^{4/3}. It coincides with the typical particle number
produced in two-particle collisions at high energies predicted by
classicalization arguments.Comment: 17 pages, 4 figures, v2. Minor changes to match the published versio
Charged lepton-nucleus inelastic scattering at high energies
The composite model is constructed to describe inelastic high-energy
scattering of muons and taus in standard rock. It involves photonuclear
interactions at low as well as moderate processes and the deep
inelastic scattering (DIS). In the DIS region the neutral current contribution
is taken into consideration. Approximation formulas both for the muons and tau
energy loss in standard rock are presented for wide energy range.Comment: 5 pages, 4 figures. Presented at 19th European Cosmic Ray Symposium
(ECRS 2004), Florence, Italy, 30 Aug - 3 Sep 2004. Submitted to
Int.J.Mod.Phys.
Charged Current Neutrino Cross Section and Tau Energy Loss at Ultra-High Energies
We evaluate both the tau lepton energy loss produced by photonuclear
interactions and the neutrino charged current cross section at ultra-high
energies, relevant to neutrino bounds with Earth-skimming tau neutrinos, using
different theoretical and phenomenological models for nucleon and nucleus
structure functions. The theoretical uncertainty is estimated by taking
different extrapolations of the structure function F2 to very low values of x,
in the low and moderate Q2 range for the tau lepton interaction and at high Q2
for the neutrino-nucleus inelastic cross section. It is at these extremely low
values of x where nuclear shadowing and parton saturation effects are unknown
and could be stronger than usually considered. For tau and neutrino energies
E=10^9 GeV we find uncertainties of a factor 4 for the tau energy loss and of a
factor 2 for the charged current neutrino-nucleus cross section.Comment: 20 pages and 11 figure
Magnetic field generation in Higgs inflation model
We study the generation of magnetic field in Higgs-inflation models where the
Standard Model Higgs boson has a large coupling to the Ricci scalar. We couple
the Higgs field to the Electromagnetic fields via a non- renormalizable
dimension six operator suppressed by the Planck scale in the Jordan frame. We
show that during Higgs inflation magnetic fields with present value
Gauss and comoving coherence length of can be generated in the
Einstein frame. The problem of large back-reaction which is generic in the
usual inflation models of magneto-genesis is avoided as the back-reaction is
suppressed by the large Higgs-curvature coupling.Comment: 10 pages, RevTeX
Simulation of UHE muons propagation for GEANT3
A simulation package for the transport of high energy muons has been
developed. It has been conceived to replace the muon propagation software
modules implemented in the detector simulation program GEANT3. Here we discuss
the results achieved with our package and we check the agreement with numerical
calculations up to 10**8 GeV.Comment: 21 pages, 6 figures, 1 Table. AMSTeX document, acknowledgments adde
The indication for K geo-antineutrino flux with Borexino phase-III data
We provide the indication of high flux of K geo-antineutrino and
geo-neutrino (K-geo-()) with Borexino Phase III data.
This result was obtained by introducing a new source of single events, namely
K-geo-() scattering on electrons, in multivariate fit
analysis of Borexino Phase III data. Simultaneously we obtained the count rates
of events from Be, and CNO solar neutrinos. These count rates are
consistent with the prediction of the Low metallicity Sun model SSM B16-AGSS09.
MC pseudo-experiments showed that the case of High metallicity Sun and absence
of K-geo-() can not imitate the result of multivariate
fit analysis of Borexino Phase III data with introducing
K-geo-() events. We also provide arguments for the high
abundance of potassium in the Earth.Comment: 17 pages, 7 figures. arXiv admin note: substantial text overlap with
arXiv:2202.08531 We have corrected and expanded the section on radiogenic
heat of the Earth. Improved the quality of drawings. The results of the study
are partially described in L. B. Bezrukov, I. S. Karpikov, A. K. Mezhokh, S.
V. Silaeva and V. V. Sinev, Bulletin of the Russian Federation. 87 (7), 972
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