Neutrinos self interactions in Supernovae

Oscillations of neutrino emerging from a supernova core are studied. In this extremely high density region neutrino self interactions induce collective flavor transitions. When collective transitions are decoupled from matter oscillations, as for our chosen matter profile, an analytical interpretation of the collective effects is possible, by means of a mechanical analogy with a spherical pendulum. For inverted neutrino hierarchy the neutrino propagation can be divided in three regimes: synchronization, bipolar oscillations, and spectral split. Our simulation shows that averaging over neutrino trajectories does not alter the nature of these three regimes.Comment: 6 pages, 7 figures, to appear in the Proceedings of the 43rd Rencontres de Moriond EW session, La Thuile, Italy, 1-8 March 200

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

Supernova neutrinos and antineutrinos: ternary luminosity diagram and spectral split patterns

In core-collapse supernovae, the nu_e and anti-nu_e species may experience collective flavor swaps to non-electron species nu_x, within energy intervals limited by relatively sharp boundaries ("splits"). These phenomena appear to depend sensitively upon the initial energy spectra and luminosities. We investigate the effect of generic variations of the fractional luminosities (l_e, l_{anti-e}, l_x) with respect to the usual "energy equipartition" case (1/6, 1/6, 1/6), within an early-time supernova scenario with fixed thermal spectra and total luminosity. We represent the constraint l_e+l_{anti-e}+4l_x=1 in a ternary diagram, which is explored via numerical experiments (in single-angle approximation) over an evenly-spaced grid of points. In inverted hierarchy, single splits arise in most cases, but an abrupt transition to double splits is observed for a few points surrounding the equipartition one. In normal hierarchy, collective effects turn out to be unobservable at all grid points but one, where single splits occur. Admissible deviations from equipartition may thus induce dramatic changes in the shape of supernova (anti)neutrino spectra. The observed patterns are interpreted in terms of initial flavor polarization vectors (defining boundaries for the single/double split transitions), lepton number conservation, and minimization of potential energy.Comment: 24 pages, including 14 figures (1 section with 2 figures added). Accepted for publication in JCA

Application of colloidal gold-based immunochromatographic assay in the rapid detection of Urinary CK19 and Plasma D-dimer

血浆D-二聚体是交联纤维蛋白的特异性降解产物，是继发性纤溶亢进的敏感和特异指标。在各种单层上皮细胞中广泛分布的细胞角蛋白(cytokeratin，CK)19片段，已经成为膀胱移行细胞癌诊断和预后的指标。本课题将胶体金免疫层析法应用于尿液CK19及血浆D-二聚体的检测，探索研制了两种试剂盒：一种适用于膀胱癌高危患者的廉价、快速、简便的初筛，另一种适用于排除疑为血栓性疾病（如肺栓塞）患者进一步做静脉造影或超声检查的快速、简便、有效的筛查诊断。为了达到理想效果，本课题从胶体金的制备、胶体金溶液pH值调节、标金抗体和包膜抗体的选择、标金抗体用量、标金抗体的浓度以及包膜抗体和二抗的浓度等方面对胶体金免疫...Plasma D-dimer generated from the degradation of cross-linked fibrin, are specific markers of the activation of coagulation. Cytokeratin 19 (CK19) are wildly distributed in various epithelial cells. Urinary CK19 has become a prognostic and diagnostic marker for transitional cell carcinoma (TCC) of the bladder. The objective of the study is to establish a colloid gold-based immunochromatographic...学位：理学硕士院系专业：生命科学学院生物化学与生物技术系_生物化学与分子生物学学号：20032609

Collective neutrino flavor transitions in supernovae and the role of trajectory averaging

Non-linear effects on supernova neutrino oscillations, associated with neutrino self-interactions, are known to induce collective flavor transitions near the supernova core for theta_13 \neq 0. In scenarios with very shallow electron density profiles, these transformations have been shown to couple with ordinary matter effects, jointly producing spectral distortions both in normal and inverted hierarchy. In this work we consider a complementary scenario, characterized by higher electron density, as indicated by post-bounce shock-wave simulations. In this case, early collective flavor transitions are decoupled from later, ordinary matter effects. Moreover, such transitions become more amenable to both numerical computations and analytical interpretations in inverted hierarchy, while they basically vanish in normal hierarchy. We numerically evolve the neutrino density matrix in the region relevant for self-interaction effects. In the approximation of averaged intersection angle between neutrino trajectories, our simulations neatly show the collective phenomena of synchronization, bipolar oscillations, and spectral split, recently discussed in the literature. In the more realistic (but computationally demanding) case of non-averaged neutrino trajectories, our simulations do not show new significant features, apart from the smearing of ``fine structures'' such as bipolar nutations. Our results seem to suggest that, at least for non-shallow matter density profiles, averaging over neutrino trajectories plays a minor role in the final outcome. In this case, the swap of nu_e and nu_{\mu,\tau} spectra above a critical energy may represent an unmistakable signature of the inverted hierarchy, especially for theta_{13} small enough to render further matter effects irrelevant.Comment: v2 (27 pages, including 9 eps figures). Typos removed, references updated. Minor comments added. Corrected numerical errors in Eq.(6). Matches the published versio

Damping of supernova neutrino transitions in stochastic shock-wave density profiles

Supernova neutrino flavor transitions during the shock wave propagation are known to encode relevant information not only about the matter density profile but also about unknown neutrino properties, such as the mass hierarchy (normal or inverted) and the mixing angle theta_13. While previous studies have focussed on "deterministic" density profiles, we investigate the effect of possible stochastic matter density fluctuations in the wake of supernova shock waves. In particular, we study the impact of small-scale fluctuations on the electron (anti)neutrino survival probability, and on the observable spectra of inverse-beta-decay events in future water-Cherenkov detectors. We find that such fluctuations, even with relatively small amplitudes, can have significant damping effects on the flavor transition pattern, and can partly erase the shock-wave imprint on the observable time spectra, especially for sin^2(theta_13) > O(10^-3).Comment: v2 (23 pages, including 6 eps figures). Typos removed, references updated, matches the published versio

3 neutrino oscillations past present and future

After a first part devoted to the description of the main steps in the discovery of neutrino oscillations, in the second part the results of a recent global analysis of solar, reactor, accelerator and atmospheric neutrino oscillation experiments is reported, searching for the first indications about the still unknown parameters, the mass hierarchy, the q23 octant and the CP-violating phase d . Concerning the hierarchy, no significant difference emerges between normal and inverted mass ordering. A slight overall preference is found for q23 in the first octant and for nonzero CP violation with sind < 0. In the third part the prospects of the future experimental searches for q13, q13 and its octant, dCP and the neutrino mass hierarchy:sign(Dm 2 ) are briefly discussed

Symmetries and Group Theory in Particle Physics: An Introduction to Space-Time and Internal Symmetries /

Symmetries, coupled with the mathematical concept of group theory, are an essential conceptual backbone in the formulation of quantum field theories capable of describing the world of elementary particles. This primer is an introduction to and survey of the underlying concepts and structures needed in order to understand and handle these powerful tools. Specifically, in Part I of the book the symmetries and related group theoretical structures of the Minkowskian space-time manifold are analyzed, while Part II examines the internal symmetries and their related unitary groups, where the interactions between fundamental particles are encoded as we know them from the present standard model of particle physics. This book, based on several courses given by the authors, addresses advanced graduate students and non-specialist researchers wishing to enter active research in the field, and having a working knowledge of classical field theory and relativistic quantum mechanics. Numerous end-of-chapter problems and their solutions will facilitate the use of this book as self-study guide or as course book for topical lectures