The minimum width condition for neutrino conversion in matter

We find that for small vacuum mixing angle $\theta$ and low energies ($s\ll M^2_Z$) the width of matter, $d_{1/2}$, needed to have conversion probability $P\geq 1/2$ should be larger than $d_{min}= \pi/(2\sqrt{2} G_{F} \tan 2 \theta)$: $d_{1/2}\geq d_{min}$. Here $G_F$ is the Fermi constant, $s$ is the total energy squared in the center of mass and $M_Z$ is the mass of the $Z$ boson. The absolute minimum $d_{1/2}=d_{min}$ is realized for oscillations in a uniform medium with resonance density. For all the other density distributions (monotonically varying density, castle wall profile, etc.) the required width $d_{1/2}$ is larger than $d_{min}$. The width $d_{min}$ depends on $s$, and for $Z$-resonance channels at $s\sim M^2_Z$ we get that $d_{min}(s)$ is 20 times smaller than the low energy value. We apply the minimum width condition, $d\geq d_{min}$, to high energy neutrinos in matter as well as in neutrino background. Using this condition, we conclude that the matter effect is negligible for neutrinos propagating in AGN and GRBs environments. Significant conversion can be expected for neutrinos crossing dark matter halos of clusters of galaxies and for neutrinos produced by cosmologically distant sources and propagating in the universe.Comment: 35 pages, latex, 5 figures, structure of the paper is slightly changed, typos correcte

Signatures of supernova neutrino oscillations in the Earth mantle and core

The Earth matter effects on supernova (SN) neutrinos can be identified at a single detector through peaks in the Fourier transform of their ``inverse energy'' spectrum. The positions of these peaks are independent of the SN models and therefore the peaks can be used as a robust signature of the Earth matter effects, which in turn can distinguish between different neutrino mixing scenarios. Whereas only one genuine peak is observable when the neutrinos traverse only the Earth mantle, traversing also the core gives rise to multiple peaks. We calculate the strengths and positions of these peaks analytically and explore their features at a large scintillation detector as well as at a megaton water Cherenkov detector through Monte Carlo simulations. We propose a simple algorithm to identify the peaks in the actual data and quantify the chances of a peak identification as a function of the location of the SN in the sky.Comment: 17 pages, 9 figure

Cosmic Strings as Emitters of Extremely High Energy Neutrinos

We study massive particle radiation from cosmic string kinks, and its observability in extremely high energy neutrinos. In particular, we consider the emission of moduli --- weakly coupled scalar particles predicted in supersymmetric theories --- from the kinks of cosmic string loops. Since kinks move at the speed of light on strings, moduli are emitted with large Lorentz factors, and eventually decay into many pions and neutrinos via hadronic cascades. The produced neutrino flux has energy $E \gtrsim 10^{11} \rm{GeV}$, and is affected by oscillations and absorption (resonant and non-resonant). It is observable at upcoming neutrino telescopes such as JEM-EUSO, and the radio telescopes LOFAR and SKA, for a range of values of the string tension, and of the mass and coupling constant of the moduli.Comment: 13 pages, 2 figure

Operative Treatment of Cervical Myelopathy: Cervical Laminoplasty

Cervical spondylotic myelopathy (CSM) is a degenerative process which may result in clinical signs and symptoms which require surgical intervention. Many treatment options have been proposed with various degrees of technical difficulty and technique sensitive benefits. We review laminoplasty as a motion-sparing posterior decompressive method. Current literature supports the use of laminoplasty for indicated decompression. We also decribe our surgical technique for an open-door, or “hinged”, laminoplasty

The skulls of Borgo Cerreto (Perugia): medical, surgical, and anatomical activity of Baronio Vincenzi (XVII century)

In the Sixties of the last century the vault of a 17th century private chapel was opened, revealing three isolated skulls with evidence of surgical and anatomical activity. The chapel was built by Baronio Vincenzi, who lived and practiced medicine in Borgo Cerreto, a village in the province of Perugia, between the 16th and the 17th century. The skull bc 01 belongs to an adult male, aged 25-35 years. It shows a hole on the left front-parietal region (30 x 31 mm), that can be identified as the result of a skull trepanation. The margins of the lesion are regularly smoothed and inclined internally and the diplopic tissues result almost completely obliterated by a cicatricial bone. A bone splinter (10 x 8 mm), completely reabsorbed, can be observed on the right side of the hole. These findings are the proof of a long survival of the subject. X-ray examination confirms a regular process of ossification, without infection. Trepanation was performed with a Hippocratic trypanon, largely used in cranial surgery of Modern Age. The specimen bc 02 is without skullcap and the right upper part of the face; it belongs to an adult male, 25-30 years aged. The cuts were produced by a bone saw with a thin blade. The choice of these regions suggests the willingness to study the basal skull, the right eye cavity and the paranasal sinuses. The skull bc 03 consists only in a skullcap of an adult individual, which shows the signs of a bone saw. In conclusion, the recovery of a trepanned skull, at present the first specimen of this type recovered so far in Umbria, together with two others skulls with the signs of postmortem examination, inside the Vincenzi family vault can be probably related to the professional activity of Baronio. He was an experienced surgeon and a skilled anatomist, who certainly experienced the empirical surgery of the nearby surgical School of Preci, famous throughout Europe for the treatment of urinary bladder stones, cataract as well as the ability in skull trepanation

Diffuse supernova neutrinos: oscillation effects, stellar cooling and progenitor mass dependence

We estimate the diffuse supernova neutrino background (DSNB) using the recent progenitor-dependent, long-term supernova simulations from the Basel group and including neutrino oscillations at several post-bounce times. Assuming multi-angle matter suppression of collective effects during the accretion phase, we find that oscillation effects are dominated by the matter-driven MSW resonances, while neutrino-neutrino collective effects contribute at the 5-10% level. The impact of the neutrino mass hierarchy, of the time-dependent neutrino spectra and of the diverse progenitor star population is 10% or less, small compared to the uncertainty of at least 25% of the normalization of the supernova rate. Therefore, assuming that the sign of the neutrino mass hierarchy will be determined within the next decade, the future detection of the DSNB will deliver approximate information on the MSW-oscillated neutrino spectra. With a reliable model for neutrino emission, its detection will be a powerful instrument to provide complementary information on the star formation rate and for learning about stellar physics.Comment: 19 pages, including 4 figures and 1 table. Clarifying paragraphs added; results unchanged. Matches published version in JCA