Report for the academic year - Libraries - Institute for Advanced Study

Institute for advanced study
In partic l( pheni imenology, Adlcr initiated a study, to be continued, of the possible role
of al ifshitt phase in gauge symmetry breaking. As a by-product, he analyzed the gener-
alization of the most attractive channel rule that is relevant to the formation of dynam-
ical fermionic condensates under the influence of scalar exchange forces. This piper
shows that in certain cases ot intrust, the sign and magnitude ol the scalar exchange
force is governed by a generalized Racah coefficient, and gives a number of possible appli-
cations to S( H 10) and E„ grand unification.
Over the next year or two, Professor Adlcr expects to continue to divide his time approxi-
mately equally between studies in quantum mechanics and studies in particle phenomenol-
ogy. The quantum mechanics work will focus on trace dynamics as a possible fundamental
pre-quantum mechanics, and on analyses of phenomenological modifications of the
Schrodingei equation. The particle phenomenology work will emphasize dynamical
symmetry breaking and possible family groups.
PROFESSOR JOHN BAHCALL again concentrated on high energy (> 1 GeV) and low
energy (< 20 MeV) neutrinos from astrophysical sources. Both subjects are the focus of
much interest by both theoretical and experimental physicists. However, the two sub-
jects have very different goals. The search for high energy neutrino sources will be car-
ried out by several new neutrino observatories under the ocean (in the Mediterranean)
or under the ice (in Antarctica). The search for high energy neutrinos is exploratory. We
do not know whether Nature provides sources of high energy neutrinos that are suffi-
^ iently intense to be observed.
Together with Sarbani Basu (IAS) and Marc Pinsonneault (Ohio State), Bahcall refined
the Standard solar model predictions for solar neutrino experiments. In addition, they
calculated for the first time the detailed time dependence of many of the important quan-
tities that characterize solar-type stars, such as luminosity, radius, effective temperature,
depth and mass of the convective zone. Future precise observations on other solar-type
stars ot different ages may test these predictions.
Bahcall continued his collaboration with Plamen Krastev (University of Wisconsin) and
Alexei Smirnov (ICrTP, Trieste); they are trying to determine what are the neutrino
properties that are manifested in solar neutrino experiments. These theorists calculated
the predictions of all of the currently allowed neutrino oscillation solutions for 10 exper-
imental quantities that will be measured by the Sudbury Neutrino Observatory (SNO), a
kiloton detector ot heavy water. The firsl ol the experimental results will be released
s timebefon the end d the year 2000. Bahcall, Krastev, and Smirnov also showed K
extensive examples the correlations that are expected between the measured values ot
different experimental quantities, depending upon what neutrino scenario is adopted.
In the more uncertain domain ol high energy astrophysical neutrinos, Peter Meszaros
(Pennsylvania State University) and Bahcall showed thai many models oi gamma ray
I -in si (< IRB) sources give rise to a potentially measurable flux of 5-10 ( ie\ neutrinos from
interactions between neutrons and protons in the GRB, Bahcall and W'axman (Weu
m. inn Institute) showed that current models of GRB's also predict a possibly measurable
flux ot wry high-energy neutrinos ( 10 U eV) neutrinos formed by the interaction ol the
photon fireball with the medium surrounding the GRB. As an extension of their work
on the connection between t IRB's and ultra-high energy cosmic rays (10 eV) and very
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