Oscillations of Mossbauer neutrinos
Joachim Kopp
Max-Planck-Institut fur Kernphysik, Heidelberg
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, January 8th, 2009 at 16:00
Abstract
Recently, Raghavan has proposed an experiment to study neutrinos emitted and absorbed in recoil-free processes. We discuss the theory of these “Mössbauer neutrinos”, paying special attention to the oscillation phenomenology. In particular, we will show that, in spite of the extremely good energy resolution of the proposed experiment,
Mossbauer neutrinos can oscillate. After giving quantum mechanical arguments to support this statement, we will compute the oscillation probability of Mossbauer neutrinos, including localization and decoherence terms, in a
quantum mechanical wave packet model. We will then proceed to the calculation of the combined rate of Mossbauer neutrino emission, propagation and absorption in the framework of quantum field theory. This approach allows us to avoid making any a priori assumptions on the neutrino wave function, and it can easily describe the various effects that broaden the neutrino emission and absorption lines. Finally, we will also address the unrealistic, but theoretically extremely interesting, case of Mossbauer neutrinos affected only by natural line broadening and not by solid state effects.
Non-standard neutrino interactions — future bounds and models
Toshihiko Ota
Uni Wuerzburg
Sala Seminarios IFIC (Edf. Institutos Paterna)
Tuesday, January 27th, 2009 at 16:00
Abstract
We discuss possible models for non-standard neutrino interactions by decomposing all possible dimension six and eight effective operators by their tree-level mediators. Taking into account the constraints from four charged lepton interactions, electroweak precision data, lepton universality, and the non-unitarity of the lepton mixing matrix, we find that large non-standard neutrino interactions from dimension eight operators are phenomenologically allowed in all flavour channels, and show that at least two new mediator particles and some cancellation conditions are required.
Sneutrino LSPs in R-parity violating mSUGRA Models and feasibility study at the LHC
Siba Prasad Das
Uni Bonn
Sala de Juntas
Friday, January 23rd, 2009 at 12:00
Abstract
We consider R-parity violating minimal supergravity (mSUGRA) models with a lepton number violating “L_i Q_j \bar D_k” operator at the GUT scale. This can alter the superparticles mass spectra at the weak scale due to the renormalization group equations. We found that sneutrino, the superpartner of neutrino, happens to be the lightest supersymmetric
particle (LSP) in a large region of mSUGRA parameter space. We consider the constraints from neutrino masses, the muon anomalous magnetic moment, “b -> s \gamma” and other precision measurements. We then give examples for
characteristic signatures at hadron colliders. Furthermore, we present the prospects for probing this scenario from the decay of lighter top squark at the LHC.
Growth of cosmological magnetic fields
Dr. Victor Semikoz
Izmiran
Sala de Juntas del IFIC Paterna
Friday, May 8th, 2009 at 12:00
Abstract
Multiwavelength constraints on e+e- excess from Dark Matter annihilations
Marco Taoso
INFN Padua
Sala de Reuniones del IFIC – 2 planta baja
Thursday, March 12th, 2009 at 16:00
Abstract
Dark Matter annihilations have been proposed at the origin of the e+e- excess recently reported by Pamela and ATIC. We constraint this interpretation comparing the gamma ray fluxes and synchrotron emission originated by Dark Matter annihilations with multiwavelength observations of the galactic center and dwarf spheroidals. For the most common Dark Matter density profiles, the models that provide a good fit to the PAMELA and ATIC data are ruled out.
Bimaximal Neutrino Mixing and Weak Complementarity with S4 Discrete Symmetry
Mr. Luca Merlo
Dipartimento di Fisica “G. Galilei”
Sala de Reuniones del IFIC – 2 planta baja
Tuesday, March 24th, 2009 at 15:00
Abstract
In view of the fact that the data on neutrino mixing are still compatible with
a situation where Bimaximal mixing is valid in first approximation and it is
then corrected by terms of order of the Cabibbo angle, arising from the
diagonalization of the charged lepton masses, we construct a model based on
the discrete group S4 where these properties are naturally realized. The model
is supersymmetric in 4-dimensions and the complete flavour group is S4 x Z4 x
U(1)_FN, which also allows to reproduce the hierarchy of the charged lepton
spectrum. The only fine tuning needed in the model is to reproduce the small
observed value of r, the ratio between the neutrino mass squared differences.
Once the relevant parameters are set to accommodate r then the spectrum of
light neutrinos shows a moderate normal hierarchy and is compatible, within
large ambiguities, with the constraints from leptogenesis as an explanation of
the baryon asymmetry in the Universe.
Magnetic field in early galaxies
Prof. Dmitry Sokoloff
Moscow State Univ
Sala Seminarios IFIC (Edf. Institutos Paterna)
Wednesday, April 22nd, 2009 at 12:00
Abstract
In the context of models of galaxy formation and evolution, the cosmological evolution of large- and small-scale magnetic fields inside galaxies is discussed. We use the dynamo theory to derive the timescales of amplification and ordering of magnetic fields in disk and puffy galaxies. Turbulence in protogalactic halos generated by thermal virialization can drive an efficient turbulent dynamo. The turbulent (small-scale) dynamo was able to amplify a weak seed magnetic field in halos of protogalaxies to a few μG strength within a few 108 yr. This turbulent field served as a seed to the mean-field (large-scale) dynamo. Galaxies similar to the Milky Way formed their disks at z≈10 and regular fields of μG strength and a few kpc coherence length were generated within 2 Gyr (at z≈3), but field-ordering on the coherence scale of the galaxy size required an additional 6 Gyr (at z≈0.5). Giant galaxies formed their disks at z≈10, allowing more efficient dynamo generation of strong regular fields (with kpc coherence length) already at z≈4. However, the age of the Universe is short for fully coherent fields in giant galaxies larger than 15 kpc to have been achieved. Dwarf galaxies should have hosted fully coherent fields at z≈1. After a major merger, the strength of the turbulent field is enhanced by a factor of a few. This evolutionary scenario can be tested by measurements of polarized synchrotron emission and Faraday rotation with the planned Square Kilometre Array (SKA).
How to determine the SUSY CP phases?
Alfred Bartl
Uni Viena
Sala de Juntas del IFIC Paterna
Thursday, March 26th, 2009 at 16:00
Abstract
In this talk I will give a review of our recent work on the determination of complex SUSY parameters in the MSSM with flavour conservation in the sfermion sector. We have first studied he parameter dependence of CP-even observables and have shown how they can be used to obtain information on the CP phases. We have then proposed several CP-odd observables which are based on triple product correlations and have studied their parameter dependence. They will allow us to obtain more precise information on the CP phases.
Tri-bi-maximal mixing and the seesaw mechanism: Strong Hierarchy or Quasi-Degeneracy?
Dr. Ivo de Medeiros Varzielas
CFTP, IST Lisboa
Sala de Juntas del IFIC Paterna
Tuesday, May 5th, 2009 at 12:00
Abstract
The observed leptonic mixing is close to tri-bi-maximal, with large mixing angles. This contrasts greatly with the observed quark mixing.
In this talk I discuss two possibilities that can explain the disparity between quark and lepton mixing:
In Sequential Dominance, strongly hierarchical right-handed neutrinos strongly affect the neutrino mixing angles through the see-saw mechanism, leading characteristically to a strong hierarchy of the effective neutrino masses.
SO(10) vs flavor symmetries:possible strategies to describe fermion mixings and mass hierarchies
Dr. Federica Bazzocchi
Vrije Universiteit Amsterdam
Sala de Juntas del IFIC Paterna
Thursday, May 7th, 2009 at 15:30
Abstract
Following a bottom-up approach the main difficulties that arise
trying to build an SO(10) GUT model combined with a Flavour
Symmetry (FS) are discussed. Two possible realizations SO(10) x FS
are then presented, based on two different FSs, A4 and Delta27
respectively. The two models realize at leading order tri-bi
maximal mixing in the lepton sector and correctly reproduce the
CKM and all the fermion mass hierarchies.
Non-standard neutrino interactions from low-scale seesaw models
Dr. Zhang He
Royal Institute of Technology (KTH)
Sala de Reuniones del IFIC – 2 planta baja
Wednesday, May 6th, 2009 at 12:00
Abstract
I will briefly review the motivations and drawbacks of low-scale seesaw models. Two typically interesting phenomena, the non-unitary neutrino mixing and non-standard neutrino interactions will be discussed in detail. I will show that sizable non-standard interactions can be generated as a consequence of a nearly degenerate neutrino mass spectrum in the type-II seesaw. As for the fermionic seesaw, the inverse seesaw model turns out to be the most natural one, and could be well tested at the future long baseline neutrino oscillation experiments and the LHC.
Exclusion of black hole disaster scenarios at the LHC
Ben Koch
Universidad Catolica de Chile, Santiago de Chile
Sala Seminarios IFIC (Edf. Institutos Paterna)
Wednesday, July 8th, 2009 at 16:00
Abstract
In the near future the Large Hadron Collider at Cern
will start to operate in an energy region which has
never been reached by a man made machine.
This outstanding scientific effort is accompanied
by great fears in the public that possibly produced
mini black holes might destroy the earth.
In this talk the scientific background for the conjectured
mini black holes will be explained and
it will be shown why there is no reason for such fears whatsoever.
Intermediate mass scales in the non-supersymmetric SO(10) grand unification: a reappraisal
Dr. Michal Malinsky
Royal Institute of Technology (KTH)
Sala de Reuniones del IFIC – 2 planta baja
Friday, July 10th, 2009 at 00:00
Abstract
The current status of the various non-supersymmetric SO(10) GUTs is discussed from the point of view of the high scale unification of the running gauge couplings. The new refined analysis shows that, on the contrary to the common lore, several breaking chains are still perfectly compatible with the current phenomenological constraints imposed namely by the absolute neutrino mass scale and the proton decay rate.
Type-III Seesaw with 2HDM
Manimala Mitra
Harish-Chandra Research Institute
Sala de Reuniones del IFIC – 2 planta baja
Thursday, July 16th, 2009 at 12:00
Abstract
Proof of neutrino masses and mixing from a series of outstanding experimental efforts have opened a window to physics beyond the standard model of particle physics. There must be some underlying theory which explains the very particular neutrino mass difference and mixing. It is well known that Seesaw mechanism has its success in explaining the smallness of neutrino mass. While many works have been recently done in the context of Type-III Seesaw which requires a fermionic triplet, we have concentrated on Type-III Seesaw in the presence of an additional Higgs doublet and on $\mu-\tau$ symmetry. In this context we have studied the phenomenological predictions and the model signatures which Type-III Seesaw with 2HDM offers.
Constraints on Dark Matter large annihilation cross-section from the early Universe
Fabio Iocco
IAP & IPHT CEA Paris
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, October 8th, 2009 at 12:30
Abstract
I will show how it is possible to place stringent constraints on high DM self annihilation cross sections making use of cosmological observables. Current CMB measurements do in fact allow the possibility to limit down to the thermal values for particle masses of few GeV, with constraints that depend only on cosmological paramaters, and are not affected by astrophysical uncertainties. It is also possible to place strong constraints on self–annihilation cross sections by using observations related to the Epoch of Reionization, relying in this case on structure formation scenarios.
Cosmic-ray signatures of dark matter decay
Dr. Alejandro Ibarra
Tech Univ of Munich
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, June 25th, 2009 at 12:00
Abstract
Present evidence for dark matter in our Galaxy and in the Universe at large does not exclude the possibility that the dark matter particles could be unstable. If this is the case, their decays into positrons, antiprotons or gamma rays might occur at rate sufficiently large to allow indirect dark matter detection through an anomalous contribution to the high-energy cosmic-ray fluxes. In this talk we discuss the implications for the scenario of decaying dark matter of the excess in the positron fraction reported by the PAMELA collaboration and the excess in the total electron plus positron flux reported by the Fermi collaboration. We also discuss the constraints on the properties of the dark matter particles which stem from the non-observation of an exotic contribution in the antiproton flux. Finally, we estimate the contributions to the diffuse gamma-ray background from dark matter decay, which will be tested in the near future by the Fermi Large Area Telescope.
Cosmological Signatures of the Interacting Dark-Energy with Massive Neutrinos
Prof. Yong-Yeon Keum
Korea Univ.
Sala Seminarios IFIC (Edf. Institutos Paterna)
Thursday, September 24th, 2009 at 12:00
Abstract
We investigate whether interaction between massive neutrinos and
quintessence scalar field is the
origin of the late time accelerated expansion of the universe. We
present cosmological perturbation
theory in neutrinos probe interacting dark-energy models, and
calculate cosmic microwave background
anisotropies and matter power spectrum. In these models, the evolution
of the mass of
neutrinos is determined by the quintessence scalar field, which is
responsible for the cosmic acceleration
today. We consider several types of scalar field potentials and put
constraints on the coupling
parameter between neutrinos and dark energy. Assuming the flatness of
the universe, the constraint
we can derive from the current observation is Pm < 0.87eV at the 95 %
confidence level for the
sum over three species of neutrinos. We also discuss on the stability
issue of the our model and on
the impact of the scattering term in Boltzmann equation from the
mass-varying neutrinos.
Quark-lepton complementarity in a PS x S4 scenario
Dr. Federica Bazzocchi
Vrije Universiteit Amsterdam
Sala Seminarios IFIC (Edf. Institutos Paterna)
Wednesday, November 18th, 2009 at 15:00
Abstract
The old idea of quark-lepton complementarity is revised in the context of a Pati Salam GUT model endowed with the discrete flavor symmetry S4. Neutrino masses arise by type-II see saw mechanism that in the model is dominating with respect to type-I and quark and lepton mass hierarchies and mixings are correctly reproduced. Both the flavor scalar and higgs scalar potentials are studied in detailed to ensure the correct breaking pattern of the flavor symmetry and of the GUT symmetry respectively.
Prospects for observing CP violating Higgs at Tevatron and LHC
Siba Prasad Das
AHEP – IFIC
Sala de Juntas
Wednesday, November 25th, 2009 at 15:00
Abstract
We analyze the prospect for observing the intermediate neutral Higgs ($h_2$) boson in its decay to two lighter Higgs bosons ($h_1$) at the Hadron Colliders in the framework of the CP violating MSSM using the PYTHIA event generator. We consider the lepton+ 4-jets+ missing energy channel in the following production and decay mode: $W h_2 \ra W h_1 h_1 \ra l \nu_l b \bar b b\bar b$, with two or three tagged $b$ jets. We employed the mis-tagging criterion
for the light flavor jets. We explicitly considered all possible Standard Model backgrounds. We found that it is very hard to observe this signature in the LEP-allowed region of parameter space, even though the backgrounds are
manageable, due to the small signal efficiency at Tevatron. By applying judiciously kinematical selections, we suppressed huge backgrounds and left with a few ten signal events at LHC. Requiring $m_{h_2} \lsim 140$ GeV leads the total background comparable to signal. Moreover, the Higgs signal at LHC might be show up in the vicinity of present LEP exclusion.
Collider and Flavor Phenomenology in the Scalar sector of Warped Extra Dimensions
Dr. Manuel Toharia
University of Maryland
Sala Seminarios IFIC (Edf. Institutos Paterna)
Wednesday, December 16th, 2009 at 12:00
Abstract
I will review and present new results regarding the
phenomenology of the two (presumably) lightest scalars in the context of
warped extra dimensions: the Higgs and the radion. This last one, could
be the lightest “new physics” state to be discovered at the LHC in this
type of models. Its phenomenology is very similar to the Standard Model
(SM) Higgs. When SM fields are allowed to live in the bulk of the extra
dimension, new interesting effects appear in the scalar sector of the
model. In particular, both the Higgs and the radion can now typically
mediate Flavor Changing Neutral Currents at tree level. These will
impose bounds on the flavor structure of the model, but also allow for
interesting probes in current and future collider experiments.
Neutrino experiments and nonstandard interactions
Dr. Omar Miranda
Cinvestav Mexico
Sala de Juntas del IFIC Paterna
Wednesday, December 2nd, 2009 at 17:00
Abstract
There is currently a strong effort to build models explaining the
neutrino mass pattern observed in recent experiments. Most of these
models imply nonstandard interactions that can be parametrized in
terms of effective four-fermion operators in the low-energy limit. In
this talk I will show the status of some of the constraints to these
parameters obtained from different neutrino experiments data. I will
also discuss the perspectives of some experimental proposals to
improve these bounds.
Sneutrino dark matter in the NMSSM
Dr. David G. Cerdeño
UAM-IFT
Sala Seminarios IFIC (Edf. Institutos Paterna)
Monday, November 16th, 2009 at 15:00
Abstract
In this talk I will present the properties of the right-handed
sneutrino and its
viability as a WIMP dark matter candidate in
the Next-to-MSSM with an extra singlet superfield, included in order
to provide non-vanishing neutrino masses. I
will explain the conditions under which the
right-handed sneutrino has the correct relic abundance and the
dominant annihilation channels. The theoretical
predictions for the sneutrino-proton elastic scattering cross section
will be preesnted
and compared it with present and future experimental sensitivities.
I will show how sneutrinos with a mass in the range of 5-200 GeV can
reproduce the observed dark matter relic density without being
excluded by direct dark matter searches and for natural values of the
input parameters. Interestingly, the predicted scattering cross
section is generally within the reach of future experiments.
Neutrino oscillations in matter with varying density
Dr. Ara Ioannisyan
Yerevan Physics Institute, Armenia
Sala de Juntas del IFIC Paterna
Friday, November 13th, 2009 at 11:00
Abstract
We present a new formalism for description of neutrino oscillations in matter with varying density which is both accurate and has all advantages of a full analytic treatment. The formalism is based on the – generalized Baker-Campbell-Hausdorff (Magnus) expansion. The formulas can be applied for the propagation of solar and supernova neutrinos in earth matter and high energy accelerator neutrinos
Discrete symmetries and neutrinos
Eduardo Peinado
AHEP – IFIC
Sala de Juntas IFIC
Friday, September 4th, 2009 at 12:00
Abstract
Leptogenesis in an A4 model
Joao Esteves
CFTP, IST Lisboa
Sala de Juntas
Monday, November 23rd, 2009 at 12:00
Abstract
We consider the possibility that the baryon asymmetry of the
Universe is generated through the leptogenesis mechanism in a specific A4 model where the neutrino masses
are generated by a combination of the type-I and type-II seesaw mechanisms. One of the key ingredients of this model is therefore the existence of a Higgs boson triplet. The Boltzmann set of equations was numerically solved and we found a large region of parameter space where we can achieve the observed baryon asymmetry, while at the same time satisfying the present neutrino data (work in progress.)
Indirect detection of dark matter
Marco Taoso
AHEP – IFIC
Sala de Juntas
Wednesday, November 11th, 2009 at 15:00
Abstract
Inflation in Supergravity
Dr. Mar Bastero-Gil
U Granada
Sala Seminarios IFIC (Edf. Institutos Paterna)
Monday, December 14th, 2009 at 15:30
Abstract
A review is given of of a class of supergravity inflationary scenarios
Minimal Supersymmetric Inverse Seesaw
Dr. Albert Villanova
LPTA Montpellier
Sala Seminarios IFIC (Edf. Institutos Paterna)
Monday, December 21st, 2009 at 15:30
Abstract
We study neutrino masses in the framework of the supersymmetric inverse seesaw model. Different from the non-supersymmetric version a minimal realization with just one pair of singlets is sufficient to explain all neutrino data. We compute the neutrino mass matrix up to 1-loop order and show how neutrino data can be described in terms of the model parameters. We then calculate rates for lepton flavour violating (LFV) processes, such as $\mu \to e \gamma$, and chargino decays to singlet scalar neutrinos. The latter decays are potentially observable at the LHC and show a characteristic decay pattern dictated by the same parameters which generate the observed large neutrino angles.
Cosmic rays positrons and electron from supernova remnants and dark matter annihilation
Dr. Roberto Lineros
INFN Torino
Sala de Reuniones del IFIC – 2 planta baja
Monday, December 21st, 2009 at 12:00
Abstract
Cosmic rays observations provide new interesting information about the composition of our Galaxy. Electron and positron cosmic rays compose a small fraction of the total amount of cosmic rays that are observed at Earth. Moreover, these particles are strongly affected by energy losses increasing the sensitivity to Solar system nearby region and the importance to understand it. Latest experimental results, for instance, from PAMELA and FERMI are not encompassed with standard theoretical predictions. A possible explanation lays on the annihilation of dark matter which acts as exotic source of cosmic rays. On the other hand, supernovae are well known as cosmic ray sources. In this talk, we contrast these two hypothesis to understand better the current electron–positron puzzle.
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