Neutrinos and Ultra-High Energy Cosmic Rays
Dr. Dmitry V. Semikoz
Max-Planck-Institut für Physik, Munich
Sala Seminarios IFIC (Edf. Institutos Paterna)
Tuesday, October 22nd, 2002 at 12:30
Abstract
In this talk I will discuss both neutrinos directly coming from astrophysical sources and neutrinos produced by ultra-high energy (UHE) protons in interactions with the cosmic microwave background radiation. I will also consider possible neutrino fluxes in several exotic UHE cosmic ray models and fluxes from individual sources. I will show that in a variety of cases the diffuse neutrino flux can be considerably higher than the earlier theoretical estimates. High neutrino fluxes would significantly increase the chances to detect UHE neutrinos with experiments currently under construction or in the proposal stage.
Soft Susy-breaking terms from strings
Prof. Carlos Muñoz
Univ. Autonoma de Madrid
Sala de reuniones IFIC planta baja
Thursday, October 24th, 2002 at 16:00
Abstract
Soft Susy-breaking terms from strings will be described
Introduction to Ultra-High Energy Cosmic Rays (III)
Prof. Guenter Sigl
Inst. d
Sala Seminarios IFIC (Edf. Institutos Paterna)
Monday, October 28th, 2002 at 16:00
Abstract
In the third lecture on UHECR we will discuss the connection between ultra-high energy cosmic and gamma-rays and neutrinos, as well as its application to top-down scenarios.
Dark Matter Detection in the Light of Recent Experimental Results
Prof. Carlos Muñoz
Univ. Autonoma de Madrid
Sala Seminarios IFIC
Friday, October 25th, 2002 at 00:00
Abstract
Recently, several experiments for the direct detection of dark matter have reported results. One of the collaborations actually claims that the first evidence for dark matter has already been observed, in particular in the form of Weakly Interacting Massive Particles (WIMPs). This issue will be discussed in this talk. After a brief introduction to dark matter, its direct detection through elastic scattering with nuclei in a material will be analyzed. Finally, whether or not the existing theoretical models (supersymmetry, superstrings) give rise to cross sections in the range where current dark matter detectors are sensitive, will be discussed in some detail.
Introduction to Ultra-High Energy Cosmic Rays (II)
Prof. Guenter Sigl
Inst. d
Sala Seminarios IFIC (Edf. Institutos Paterna)
Monday, October 21st, 2002 at 15:00
Abstract
The second lecture on Ultra-High Energy Cosmic Rays will be devoted to the role of cosmic magnetic fields.
Introduction to Ultra-High Energy Cosmic Rays (I)
Prof. Guenter Sigl
Inst. d
Sala Seminarios IFIC (Edf. Institutos Paterna)
Friday, October 18th, 2002 at 12:00
Abstract
This is the first of a series of lectures on the topic of Ultra-High Energy Cosmic Rays, a probe of particle physics and astrophysics at extreme energies.
Exploring Neutrino Mixing angles and Dirac and Majorana CP Violation Phases at GUT Scale
Prof. Eiichi Takasugi
Osaka Univ.
Sala Seminarios IFIC (Edf. Institutos Paterna)
Wednesday, July 31st, 2002 at 00:00
Abstract
The special aspect of the neutrino mixing matrix at $m_Z$ scale is (1)
$V_{13}\sineq 0$ and (2) $\tan^2 \theta_{\rm atm}\simeq 1$. The
recent SNO data implies that the solar mixing angle is far from the
maximal value, $\tan^2 \theta_{\rm sol}\simeq 0.37$. From these data,
it may be natural to assume that at GUT scale, the mixing angles would
be such that (1) $$V_{13}=0$ and (2) $\tan^2 \theta_{\rm atm}\simeq
1$. Then, we explore what kind of solar mixing angle would be at the
GUT scale. The model $V_{13}=0$ at GUT scale, the number of parameters
in the neutrino mass matrix is three masses, two mixing angles and two
Majorana phases. At $m_Z$ scale, $V_{13}$ as well as a Dirac phase is
induced by the radiative correction. In particular, we found that
$\sin^22\tilde\theta_{12}\leq \sin^22\theta_{\rm sol}$, where
$\theta_{12}$ and $\theta_{\rm sol}$ are mixing angles at the GUT
scale and at $m_Z$ scale resprctively. This means that if the solar
mixing angle at $m_Z$ scale is really far from maximal, $\tan^2
\theta_{\rm sol}\simeq 0.37$, then the Bi-maximal scheme can not be a
realistic model. We also discuss possible sizes of $V_{13}$ and a
Dirac CP violation phase.We also comment on the relation between the
CP violation phase and phases which appear in leptogenesis.
Supersymmetry in the Next Linear Collider
Prof. Marco A. Díaz
Univ. Católica, Chile
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, July 25th, 2002 at 12:00
Abstract
Different ways to probe for Supersymmetric physics signatures at the Next Linear Collider will be covered this talk.
Neutrino oscillations in dense neutrino media
Sergio Pastor
Max-Planck-Institut für Physik, Munich
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, June 6th, 2002 at 12:30
Abstract
In the early universe or in some regions of supernovae, the neutrino
refractive index is dominated by the neutrinos themselves. Several
previous studies have found numerically that these self-interactions
have the effect of coupling different neutrino modes in such a way as
to synchronize the flavor oscillations which otherwise would depend on
the energy of a given mode. We show a simple explanation for this
baffling phenomenon in analogy to a system of magnetic dipoles which
are coupled by their self-interactions to form one large magnetic
dipole which then precesses coherently in a weak external magnetic
field (analogous to the weak-field Zeeman effect in atoms).
Neutrinos in Cosmology
Georg Raffelt
Max-Planck-Institut für Physik, Munich
Sala Seminarios IFIC (Edf. Institutos Paterna)
Wednesday, May 8th, 2002 at 18:00
Abstract
We review the role of massive neutrinos in cosmology. At present the
most restrictive limits on the overall neutrino mass scale comes from
cosmological structure formation arguments in conjunction with
large-scale galaxy surveys. Conversely, the cosmic neutrino mass
density can be constrained by laboratory measurements of the neutrino
mass, for example in the KATRIN experiment, if the cosmic number
density of neutrinos were known. However, it depends on the unknown
cosmic neutrino degeneracy parameters. We show that neutrino
oscillations effectively lead to chemical equilibrium before big-bang
nucleosynthesis (BBN) if the favored LMA solution of the solar
neutrino problem applies. It is supported by the recent SNO
results. In this case the restrictive BBN limit on the chemical
potential of the electron neutrino applies to all flavors and the
cosmic neutrino density is tightly constrained to be within 1% of its
standard value. The primordial neutrino oscillations involve
fascinating non-linear effects due to the neutrino self-potential
which lead to a synchronization of the oscillations of different
modes. It is fascinating that solving the solar neutrino problem with
the LMA solution indirectly provides a number count of the cosmic
neutrino sea. We finally also mention leptogenesis as an important
cosmological role for Majorana neutrino masses in the experimentally
favored regime.
Neutrinos: from experiment to theory
Prof. Stephen F. King
Univ. of Southampton
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, April 25th, 2002 at 12:00
Abstract
I give a brief review of the experimental status of neutrino physics,
followed by a review of the paradigm of three active neutrinos, and a
discussion of a natural approach to neutrino mass matrices based on
the see-saw mechanism with right-handed neutrino dominance, with some
examples of unified models satisfying these criteria. I also briefly
mention leptogenesis and the idea of a neutrino factory.
Entropy-Area Relations in Field Theory
Verónica Sanz
IFIC- U. Valencia/CSIC
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, April 11th, 2002 at 12:30
Abstract
We consider the contribution to the entropy from the fluctuations of a
scalar field in the background of a curved time-independent metric. To
account for the curvature of space, we postulate a position-dependent
cutoff that depends on energy. With this cutoff, we calculate the
scalar contribution in a background anti-de Sitter space, the exterior
of a black hole, and de Sitter space.In all cases, we find results
that can be simply interpreted in terms of local energy and proper
volume, yielding insight into why a theory appears to be holographic.
Variations on the seesaw mechanism
Prof. Walter Grimus
Univ. Vienna
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, March 14th, 2002 at 12:00
Abstract
I discuss several models for neutrino masses and mixing, where the
seesaw mechanism is used as the basic ingredient. I put emphasis on
large or maximal neutrino mixing and show how such mixing angles can
be achieved either by radiative corrections or by lepton number
symmetries.
Supersymmetric Sfermion Sector with CP Violating Phases
Prof. Alfred Bartl
Univ. of Vienna
Sala Seminarios IFIC (Edf. Institutos Paterna)
Tuesday, March 12th, 2002 at 16:00
Abstract
We investigate the influence of complex SUSY parameters in the sector
of 3rd generation scalar fermions. We work in the Minimal
Supersymmetric Standard Model and take the Higgs-higgsino mass
parameter mu and the trilinear scalar coupling parameters A_f
complex. We analyse the dependence on the complex phases of the CP
conserving and CP violating observables.
CP-Matter Interplay and Measuring MNS in Neutrino Oscillations
Prof. Hisakazu Minakata
Tokyo Metropolitan Univ.
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, March 7th, 2002 at 12:00
Abstract
I discuss an overview of two different strategies toward measuring
remaining parameters in the (1-3) sector of the MNS matrix (lepton
flavor mixing matrix). One of the key point is to understand the
structure of CP-matter interplay. Then I focus on the low-energy
option and discuss the issue of parameter ambiguity and its
resolution.
Large lepton flavour violating signals in supersymmetric models at future e+e- colliders
Dr. Werner Porod
Universität Zürich
Sala Seminarios IFIC (Edf. Institutos Paterna)
Monday, March 4th, 2002 at 16:00
Abstract
We study lepton flavor violating signals at future e+ e- linear
collider within the general MSSM, allowing for the most general flavor
structure. We demonstrate that there is a large region in parameter
space with large signals, while being consistent with present
experimental bounds on rare lepton decays such as mu -> e gamma. In
our analysis, we include all possible signals from charged slepton and
sneutrino production and their decays as well as from the decays of
neutralinos and charginos. We also consider the background from the
Standard Model and the MSSM. We find that in general the signature e
tau + missing energy is the most pronounced one.
A simple connection between neutrino oscillation and leptogenesis
Dr. Werner Rodejohann
Univ. Dortmund
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, February 28th, 2002 at 16:00
Abstract
The usual see-saw formula is modified by the presence of two Higgs
triplets in left-right symmetric theories. The contribution from the
left-handed Higgs triplet to the see-saw formula can dominate over the
conventional one when the neutrino Dirac mass matrix is identified
with the charged lepton or down quark mass matrix. In this case an
analytic calculation of the lepton asymmetry, generated by the decay
of the lightest right-handed Majorana neutrino, is possible. For
typical parameters, the out-of-equilibrium condition for the decay is
automatically fulfilled. The baryon asymmetry has the correct order of
magnitude, as long as the lightest mass eigenstate is not much lighter
then 10^{-6} to 10^{-8} eV, depending on the solution of the solar
neutrino problem. A sizable signal in neutrinoless double beta decay
can be expected, as long as the smallest mass eigenstate is not much
lighter than 10^{-3} eV and the Dirac mass matrix is identified with
the charged lepton mass matrix.
Introduction to Ultra-High Energy Cosmic Rays (IV)
Prof. Guenter Sigl
Inst. d
Sala Seminarios IFIC (Edf. Institutos Paterna)
Wednesday, October 30th, 2002 at 16:00
Abstract
In the last lecture we will see how to use UHECR data to constrain and probe new particles, interactions beyond electroweak scale, and Lorentz symmetry violations.
Wave Packet Treatment of Neutrino Oscillations
Prof Carlo Giunti
U. Torino/INFN
Sala Seminarios IFIC (Edf. Institutos Paterna)
Tuesday, December 3rd, 2002 at 16:00
Abstract
The standard theory of neutrino oscillations is critically discussed. It is shown that a wave-packet treatment is necessary for a correct quantum-mechanical formulation of neutrino oscillations. A model of neutrino oscillations in the framework of quantum field theory in which the propagating neutrino and the particles participating to the production and detection processes are described by wave packets is presented. It is shown that this model confirms the correctness of the standard expression for the oscillation length of extremely relativistic neutrinos and the existence of a coherence length.
Ruling out four-neutrino oscillation interpretations of the LSND anomaly?
Dr Thomas Schwetz
Tech Univ Munich
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, December 5th, 2002 at 16:00
Abstract
Prompted by recent solar and atmospheric data, we re-analyze the four-neutrino description of current global neutrino oscillation data, including the LSND evidence for oscillations. The higher degree of rejection for non-active solar and atmospheric oscillation solutions implied by the SNO neutral current result as well as by the latest 1489-day Super-K atmospheric neutrino data allows us to rule out (2+2) oscillation schemes proposed to reconcile LSND with the rest of current neutrino oscillation data. Using an improved goodness of fit (gof) method especially sensitive to the combination of data sets we obtain a gof of only 1.6 times 10^{-6} for (2+2) schemes. Further, we re-evaluate the status of (3+1) oscillations using two different analyses of the LSND data sample. We find that also (3+1) schemes are strongly disfavoured by the data. Depending on the LSND analysis we obtain a gof of 5.6 times 10^{-3} or 7.6 times 10^{-5}. This leads to the conclusion that all four-neutrino descriptions of the LSND anomaly, both in (2+2) as well as (3+1) realizations, are highly disfavoured. Our analysis brings the LSND hint to a more puzzling status.
Bulk neutrinos and core cooling in Supernovae
Mr. Giacomo Cacciapaglia
Scuola Normale Superiore di Pisa
Sala de Reuniones Planta Baja del IFIC
Friday, November 22nd, 2002 at 12:00
Abstract
In a recent paper we discuss the phenomenology of neutrino mixing
with bulk fermions in the context of supernova physics. Following
the usual energy loss argument, the core cooling strongly constraints
the size of such extra dimensions and the mixing parameters. We show
that these constraints can be widely relaxed due to a feedback mechanism
that self-limits the loss. This mechanism also affects the protoneutron
star evolution through a non trivial interplay with neutrino diffusion.
Finally, we discuss the consistency with the SN1987A signal and possible
effects on the neutrino flux composition and the delayed explosion
scenario.
Confronting spin flavor solutions of the solar neutrino problem with current and future solar neutrino data
Dr Omar Miranda
Departamento de Fisica, CINVESTAV-IPN
Sala Reuniones Planta Baja del IFIC
Wednesday, December 18th, 2002 at 12:00
Abstract
A global analysis of spin-flavour precession (SFP) solutions to thesolar neutrino problem is given.We fix the neutrino magnetic moment to be $10^{-11}$ Bohr magneton,with a corresponding optimum self-consistent magneto-hydrodynamicsmagnetic field profile with maximum strength of 80 KGauss in theconvective zone.We find that no LOW-quasi-vacuum or vacuum solutions are present at 3sigma. In addition to the standard LMA oscillation solution, thereare two SFP solutions, in the resonant (RSFP) and non-resonant (NRSFP)regimes. These two SFP solutions have a goodness of fit slightlybetter than the LMA oscillation solution. We also discuss the role of solar anti-neutrino searches in the fit.Should KamLAND confirm the LMA solution, the SFP solutions may at bestbe present at a sub-leading level. In the event LMA is not the solution realized in nature,then experiments such as Borexino can help distinguishing LMA from theNRSFP solution and the simplest RSFP solution with no mixing.
Leptogenesis via hidden sector: unifying the visible and dark matters
Prof Zurab Berezhiani
(Univ. L’Aquila & LNGS
Sala Seminarios IFIC (Edf. Institutos Paterna)
Tuesday, November 26th, 2002 at 16:00
Abstract
We propose a mechanism in which baryon asymmetry of the universe is produced by out-of-equilibrium B-L and CP violating scattering processes that transform ordinary particles into particles of the hidden mirror sector. In the context of seesaw picture these processes can be mediated by the heavy “right-handed” neutrinos. The same mechanism produces a somewhat large baryon asymmetry also in the mirror sector particles and thus the latter could
provide a natural candidate for dark matter. Phenomenological and astrophysical implications of such a scenario is discussed.
Leptogenesis from the bottom-up
Dr Alejandro Ibarra
CERN
Sala Seminarios IFIC
Friday, December 20th, 2002 at 12:00
Abstract
After the discovery of neutrino oscillations, leptogenesis stands as one of the most appealing explanations for the observed baryon asymmetry of the Universe. This framework is usually analyzed in terms of high-energy parameters, not accessible by experiments, and hence it is difficult to extract model-independent conclusions. We present a model-independent formulation of leptogenesis in terms of low energy inputs, and study the interplay between the CP asymmetry of the Universe and the neutrino parameters. We concentrate in particular on the phase delta, that would be measured in neutrino factories, and we discuss the possible implications for leptogenesis of the measurement of this phase.”
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