166 research outputs found
Fast-time Variations of Supernova Neutrino Fluxes and Detection Perspectives
AbstractIn the delayed explosion scenario of a core-collapse supernova, the accretion phase shows pronounced convective over-turns and a low-multipole hydrodynamic instability, the so-called standing accretion shock instability (SASI). Neutrino signal variations from the first full-scale three-dimensional core-collapse supernova simulations with sophisticated neutrino transport are presented as well as their detection perspectives in IceCube and Hyper-Kamiokande
Supernova neutrino three-flavor evolution with dominant collective effects
Neutrino and antineutrino fluxes from a core-collapse galactic supernova are
studied, within a representative three-flavor scenario with inverted mass
hierarchy and tiny 1-3 mixing. The initial flavor evolution is dominated by
collective self-interaction effects, which are computed in a full three-family
framework along an averaged radial trajectory. During the whole time span
considered (t=1-20 s), neutrino and antineutrino spectral splits emerge as
dominant features in the energy domain for the final, observable fluxes. Some
minor or unobservable three-family features (e.g., related to the
muonic-tauonic flavor sector) are also discussed for completeness. The main
results can be useful for SN event rate simulations in specific detectors.Comment: 22 pages, including 9 figures (1 section with 3 figures added).
Accepted for publication in JCA
Metric-like Lagrangian Formulations for Higher-Spin Fields of Mixed Symmetry
We review the structure of local Lagrangians and field equations for free
bosonic and fermionic gauge fields of mixed symmetry in flat space. These are
first presented in a constrained setting extending the metric formulation of
linearized gravity, and then the (-)trace constraints on fields and
gauge parameters are eliminated via the introduction of auxiliary fields. We
also display the emergence of Weyl-like symmetries in particular classes of
models in low space-time dimensions.Comment: 136 pages, LaTeX. References added. Final version to appear in La
Rivista del Nuovo Cimento
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
Radiomic analysis in contrast-enhanced spectral mammography for predicting breast cancer histological outcome
Contrast-Enhanced Spectral Mammography (CESM) is a recently introduced mammographic method with characteristics particularly suitable for breast cancer radiomic analysis. This work aims to evaluate radiomic features for predicting histological outcome and two cancer molecular subtypes, namely Human Epidermal growth factor Receptor 2 (HER2)-positive and triple-negative. From 52 patients, 68 lesions were identified and confirmed on histological examination. Radiomic analysis was performed on regions of interest (ROIs) selected from both low-energy (LE) and ReCombined (RC) CESM images. Fourteen statistical features were extracted from each ROI. Expression of estrogen receptor (ER) was significantly correlated with variation coefficient and variation range calculated on both LE and RC images; progesterone receptor (PR) with skewness index calculated on LE images; and Ki67 with variation coefficient, variation range, entropy and relative smoothness indices calculated on RC images. HER2 was significantly associated with relative smoothness calculated on LE images, and grading tumor with variation coefficient, entropy and relative smoothness calculated on RC images. Encouraging results for differentiation between ER+/ER−, PR+/PR−, HER2+/HER2−, Ki67+/Ki67−, High-Grade/Low-Grade and TN/NTN were obtained. Specifically, the highest performances were obtained for discriminating HER2+/HER2− (90.87%), ER+/ER− (83.79%) and Ki67+/Ki67− (84.80%). Our results suggest an interesting role for radiomics in CESM to predict histological outcomes and particular tumors’ molecular subtype
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