26 research outputs found
Zeeman effect of the hyperfine structure levels in hydrogenlike ions
The fully relativistic theory of the Zeeman splitting of the hyperfine
structure levels in hydrogenlike ions is considered for the magnetic field
magnitude in the range from 1 to 10 T. The second-order corrections to the
Breit -- Rabi formula are calculated and discussed. The results can be used for
a precise determination of nuclear magnetic moments from factor
experiments.Comment: 13 page
Flavor Changing Supersymmetry Interactions in a Supernova
We consider for the first time R-parity violating interactions of the Minimal
Standard Supersymmetric Model involving neutrinos and quarks (``flavor changing
neutral currents'', FCNC's) in the infall stage of stellar collapse. Our
considerations extend to other kinds of flavor changing neutrino reactions as
well. We examine non-forward neutrino scattering processes on heavy nuclei and
free nucleons in the supernova core. This investigation has led to four
principal original discoveries/products: (1) first calculation of neutrino
flavor changing cross sections for spin one half (e.g. free nucleon) and spin
zero nuclear targets; (2) discovery of nuclear mass number squared (A squared)
coherent amplification of neutrino-quark FCNC's; (3) analysis of FCNC-induced
alteration of electron capture and weak/nuclear equilibrium in the collapsing
core; and (4) generalization of the calculated cross sections (mentioned in 1)
for the case of hot heavy nuclei to be used in collapse/supernova and neutrino
transport simulations. The scattering processes that we consider allow electron
neutrinos to change flavor during core collapse, thereby opening holes in the
electron neutrino sea, which allows electron capture to proceed and results in
a lower core electron fraction. A lower electron fraction implies a lower
homologous core mass, a lower shock energy, and a greater nuclear
photo-disintegration burden for the shock. In addition, unlike the standard
supernova model, the core now could have net muon and/or tau lepton numbers.
These effects could be significant even for supersymmetric couplings below
current experimental bounds.Comment: 22 pages, 7 figures, typos corrected, abstract modifided, minor
additions to conten
Status of a Supersymmetric Flavour Violating Solution to the Solar Neutrino Puzzle with Three Generations
We present a general study of a three neutrino flavour transition model based
on the supersymmetric interactions which violate R-parity. These interactions
induce flavour violating scattering reactions between solar matter and
neutrinos. The model does not contain any vacuum mass or mixing angle for the
first generation neutrino. Instead, the effective mixing in the first
generation is induced via the new interactions. The model provides a natural
interpretation of the atmospheric neutrino anomaly, and is consistent with
reactor experiments. We determine all R-parity violating couplings which can
contribute to the effective neutrino oscillations, and summarize the present
laboratory bounds. Independent of the specific nature of the (supersymmetric)
flavour violating model, the experimental data on the solar neutrino rates and
the recoil electron energy spectrum are inconsistent with the theoretical
predictions. The confidence level of the -analysis ranges between and . The incompatibility, is due to the new SNO
results, and excludes the present model. We conclude that a non-vanishing
vacuum mixing angle for the first generation neutrino is necessary in our
model. We expect this also to apply to the solutions based on other flavour
violating interactions having constraints of the same order of magnitude.Comment: 17 pages, Latex fil
Oscillation enhanced search for new interaction with neutrinos
We discuss the measurement of new physics in long baseline neutrino
oscillation experiments. Through the neutrino oscillation, the probability to
detect the new physics effects such as flavor violation is enhanced by the
interference with the weak interaction. We carefully explain the situations
that the interference can take place. Assuming a neutrino factory and an
upgraded conventional beam, we estimate the feasibility to observe new physics
numerically and point out that we can search new interactions using some
channels, for example , in these experiments. We also
discuss several models which induce the effective interactions interfering with
the weak interaction, and show that some new physics effects are large enough
to be observed in the oscillation enhanced way.Comment: 25 pages, 20 figure
Gravitational-wave research as an emerging field in the Max Planck Society. The long roots of GEO600 and of the Albert Einstein Institute
On the occasion of the 50th anniversary since the beginning of the search for
gravitational waves at the Max Planck Society, and in coincidence with the 25th
anniversary of the foundation of the Albert Einstein Institute, we explore the
interplay between the renaissance of general relativity and the advent of
relativistic astrophysics following the German early involvement in
gravitational-wave research, to the point when gravitational-wave detection
became established by the appearance of full-scale detectors and international
collaborations. On the background of the spectacular astrophysical discoveries
of the 1960s and the growing role of relativistic astrophysics, Ludwig Biermann
and his collaborators at the Max Planck Institute for Astrophysics in Munich
became deeply involved in research related to such new horizons. At the end of
the 1960s, Joseph Weber's announcements claiming detection of gravitational
waves sparked the decisive entry of this group into the field, in parallel with
the appointment of the renowned relativist Juergen Ehlers. The Munich area
group of Max Planck institutes provided the fertile ground for acquiring a
leading position in the 1970s, facilitating the experimental transition from
resonant bars towards laser interferometry and its innovation at increasingly
large scales, eventually moving to a dedicated site in Hannover in the early
1990s. The Hannover group emphasized perfecting experimental systems at pilot
scales, and never developed a full-sized detector, rather joining the LIGO
Scientific Collaboration at the end of the century. In parallel, the Max Planck
Institute for Gravitational Physics (Albert Einstein Institute) had been
founded in Potsdam, and both sites, in Hannover and Potsdam, became a unified
entity in the early 2000s and were central contributors to the first detection
of gravitational waves in 2015.Comment: 94 pages. Enlarged version including new results from further
archival research. A previous version appears as a chapter in the volume The
Renaissance of General Relativity in Context, edited by A. Blum, R. Lalli and
J. Renn (Boston: Birkhauser, 2020