The Nuclear Theory Group hosts a series of seminars
in the Department of
Physics of the
University of
Arizona.
The current format is joint with the Particle Theory Group.
See
current schedule.
(A preliminary schedule is in
Thomas's
page,
and previous schedules can be found in
Enberg's
and
Goh's
pages).
Past Seminars
Thursday, Sept 8, 2005,
3:00-4:00pm, PAS 218
Baha Balantekin, University of Wisconsin-Madison
"Neutrino-Nucleus Interactions"
I will present an overview of theory of neutrino-nucleus interactions and
describe various ongoing experimental efforts to measure them. I will also
describe extraction of counter-terms in the effective field theory approach to
the neutrino-deuteron interaction from the solar neutrino data.
Wednesday, May 4, 2005,
4:00-5:00pm, PAS 218
Renato Higa, Jefferson Lab
"Two-pion exchange and peripheral NN scattering"
In the first part of this talk I will discuss the problem of the
HBChPT formalism applied to the construction of an NN potential,
and compare their expressions with ours, based on the relativistic
formalism by Becher and Leutwyler. In the second part I will present
both results for phase shifts in peripheral waves ($L\geq 3$), and
how they are influenced by the input parameters of the potential
(LECs).
Monday, May 2, 2005,
4:00-5:00pm, PAS 218
Ken Hicks, Ohio University
"Pentaquarks: are they real or not?"
A new class of particles made from four quarks and one antiquark,
called pentaquarks, are allowed by the rules of QCD. However, until
a few years ago, there was no evidence for such particles. In 2003-4,
over 10 experiments announced positive evidence for a narrow resonance
near 1535 MeV, which had quantum numbers characteristic of a pentaquark.
Soon after, a number of high-energy experiments showed null results to
detect this particle. Could this exotic particle also be so fragile
that it could not be seen as a result of the production of hadrons
at high-energy, known as fragmentation? Recently, an experiment at
the Thomas Jefferson National Accelerator Facility was announced for
the near-threshold reaction $\gamma p \to K^+ K^0 (n)$ which also
shows a null result for this resonance. In this seminar, the question
of whether pentaquarks exist as narrow resonances is discussed in
light of the recent experiments.
Thursday, Mar 31, 2005, 2:30-3:30pm,
PAS 274
Darius Germanas, Institute of Physics, Vilnius,
Lithuania
"Lower bounds on the triton and alpha particle"
A method for lower bounds calculation for the binding energies of
the lightest nuclei is introduced. The algorithm is based upon the
factorization of the antisymmetrizer and Hamiltonian operators,
allowing an efficient computation of both lower and upper bounds
for binding energies. In large model spaces, both bounds converge
to exact values. For Hamiltonians which include two-body interactions only,
I will illustrate the applicability of the method to three- and
four-body systems.
Thursday, Feb 24, 2005,
3:30-4:30pm, PAS 218
Harald Griesshammer, TU Muenchen
"An Effective Tale of A Few Nucleons"
With new high-precision experiments offering detailed insight into Nuclear
Physics, nucleons and atomic nuclei prove an outstanding theoretical
challenge: The theory of strong interactions, Quantum Chromo Dynamics (QCD),
looks deceptively simple at very short distances, but at distance scales of
more than $\approx 0.2 \times 10^{-15} \mathrm{m}$, the search for direct
solutions becomes formidable. Here, Effective Field Theory allows for simple,
model-independent, systematic and rigorous computations of the properties of
nuclear systems, deeply rooted in QCD. I outline the central ideas of this
approach and then focus on three applications I am involved in:
(1) Extracting observables from lattice simulations of QCD.
(2) Predicting and parameterising the electro-magnetic structure of nucleons,
as described by their polarisabilities, a measure for their stiffness against
deformations.
(3) Developing and applying the theory at very low energies, where it becomes
particularly simple and a plethora of processes exist which are interesting
both for fundamental and astrophysical questions, e.g. big-bang
nucleo-synthesis, three-nucleon forces, and deuteron and neutron properties.
Wednesday, Feb 16, 2005,
3:00-4:00pm
Andreas Nogga, Forschungzentrum Juelich
"The quantum mechanical four-body problem"
Accurate and reliable solutions of the quantum mechanical
four-body problem can be obtained using several techniques
nowadays. One method is to rewrite the Schrödinger equation
to Yakubovsky equations and solve them in momentum space.
It is argued that for a variety of problems of interest, this
is a specifically powerful approach. As an example, I will discuss
some results for the alpha particle and four-body hypernuclei
and their implications.
The extension to scattering is formulated and an outlook to
upcoming applications will be given.
Monday, Feb 14, 2005,
3:00-4:00pm
Hans Hammer, Institute for Nuclear Theory
"Universality in Few-Body Systems with Large Scattering Length"
Effective Field Theory (EFT) is a powerful method to calculate universal
properties associated with a separation of scales in physical systems.
Few-body systems with large scattering length are particularly interesting.
They display a geometric spectrum of three-body bound states (so-called
Efimov states) and log-periodic dependence of observables on the low-energy
parameters characterizing the system. I will discuss an effective theory
for three- and four-body systems and give an overview of applications in
cold atoms and light nuclei. Two-dimensional systems, which are qualitatively
very different, will also be discussed.
Thursday, Feb 10, 2005,
3:00-4:00pm
Gautam Rupak, Los Alamos National Laboratory
"Nuclear Physics from lattice QCD: Finite lattice
spacing and volume effects"
Numerical calculation of Quantum
Chromodynamics (QCD) using lattice QCD is the only
method currently available for calculating low-energy
hadronic observables directly from the fundamental
theory of QCD. However, these numerical simulations
are still a long way from calculating hadronic matrix
elements with physically relevant light up and down
quark masses. Chiral perturbation theory (ChPT) could
provide a controlled, systematic extrapolation of the
lattice data to the physical region. In this talk I
will describe extensions of chiral perturbation theory
relevant for lattice QCD that include dependence on
the lattice spacing 'a' to quadratic order. Besides
large quark masses and lattice spacing, finite volume
effects need to be small to extract physical
observables from lattice QCD. I will describe how one
can use ChPT (with some modification) to extract
nucleon mass from lattice calculations done even on a
small volume.
Wednesday, Feb 2, 2005,
3:00-4:00pm
Sean Fleming, UC San Diego
"Soft-Collinear Effective Theory"
Much progress has been made in understanding QCD through the use of
effective field theory (EFT). In this talk I present a new EFT that
has been generating quite a bit of excitement recently:
soft collinear effective theory (SCET). SCET describes the limit of QCD
where highly energetic particles move through a soft background;
a configuration which is typical in high energy scattering,
and in the decay of a heavy particle to light particles.
I motivate SCET by considering the specific example of the decay
$B\to X_s \gamma$. The important properties of SCET are highlighted,
and used in the example to illustrate some of the novel aspects of the theory.
I then discuss my vision for the future of SCET, and the work that I have done
which leads to the goals I outline. In that context I discuss
applications of SCET to radiative $\Upsilon$ decays,
to $J/\psi$ production at Belle and Babar, and
to $J/\psi$ production in $\gamma$ nucleon collisions.
Monday, Jan 24, 2005,
3:00-4:00pm
Achim Schwenk, Indiana University
"Nuclear interactions from the renormalization group"
I discuss applications of the renormalization group (RG) to nuclear
forces and nucleonic matter. The RG unifies all microscopic
interactions used in nuclear structure applications. The resulting
low-momentum interaction, called V_{low k}, restricts interactions
to low momenta. This leads to perturbative three-nucleon interactions
and perturbative nuclear matter. The RG thus enhances the strengths of
Effective Field Theory interactions for many-body applications with
theoretical error estimates. In many-body systems, the RG can also
be used to decimate towards the Fermi surface as proposed by Shankar.
I present results of this approach for neutron matter and show how
the method is successfully applied in condensed matter physics. We
predict S- and P-wave superfluid gaps in neutron matter, which are
consistent with data when used in cooling simulations of neutron stars.
Thursday, Jan 20, 2005,
3:00-4:00
Raju Venugopalan, Brookhaven National Laboratory
"The demise of the structure function:
K_t factorization and beyond in QCD at high energies"
A novel window of semi-hard physics opens up at collider energies.
The physics of this regime, which dominates high energy
cross-sections, is not easily described in the standard collinear
factorization approach of perturbative QCD. It is naturally
described in a classical effective theory called the Color Glass
Condensate (CGC). We discuss in this framework, gluon and
quark production in pp, pA and AA collisions. Cross-sections at
low and moderate parton densities are described by universal "dipole"
structures which obey K_t factorization. At high parton densities,
"multipole" operators contribute thereby breaking K_t factorization.
The renormalization group running of these multipole operators will
provide a sensitive test of the CGC at future colliders.
Tuesday, Nov 2, 2004,
3:30-4:30pm
Carlos Bertulani, University of Arizona
"Mission not yet accomplished: Back to QED"
In the past years several new laboratories for the study of QED
and strong interactions have started to produce results. I will explore
the opportunities for study of QED under conditions of very strong
fields made possible by the Heavy Ion Colliders, RHIC and the LHC.
Thursday, April 8, 2004,
3:30-4:30pm --- PAS274
Jerry Miller, University of Washington
"Even Parity Pentaquark
and Stable Strange Nuclear Matter"
Tuesday, Mar 9, 2004,
3:30-4:30pm
Michael Ramsey-Musolf,
California Institute of Technology
"Sub-Z Supersymmetry"
Tuesday, Feb 10, 2004,
3:30-4:30pm
Bira van Kolck, University of Arizona
"The up-down quark mass difference in pion
production"
Tuesday, Sept 23, 2003,
3:30-4:30pm
Boris Gelman, University of Arizona
"Exotic Hadrons"
The spectrum of quantum chromodynamics (QCD)---the
fundamental theory of strong interactions---is dominated by states
with quantum numbers of either quark-antiquark (qqbar) pairs---mesons
or systems of three quarks---baryons. However, these are not
the only states that one expects to exist. Other states that can't be
described as qqbar or qqq systems are refferred to as QCD ''exotics''.
A number of recent experiments have seen signals for such states. I
will discuss a number of possible new exotic hadrons that can exist
and can be detected in the future.
Monday, May 12, 2003
Roy
Frieden, University of Arizona
"Fisher
Information and Physics"
Fisher information FI is
the original "information", dating from about 1925.
(Shannon's form was
invented some 20 years later.) Until recently FI was
merely used to diagnose
the quality of an estimate of a parameter, such as
the position of an
electron. The basis for this is the so-called Cramer-Rao
error inequality: the
mean-squared error in any such estimate must equal or
exceed one divided by the
FI. More recently, FI has
been shown to provide a basis for deriving the wave equations and
distribution functions of physics.
See the book "Physics from Fisher Information" ,
B.R. Frieden (Cambridge Univ. Press, 1998). These physical effects
ultimately connect with FI because they describe
the behavior of unknown
parameters, whose errors therefore obey the C-R inequality above.
We show specifically that
the following physical effects derive from the use
of FI: (a) the Heisenberg
uncertainty principle; (b) the Schroedinger wave equation; (c) Newton's
2nd law and the Virial theorem of classical mechanics;
and (d) the wave equation
for gluons in QCD (time permitting).
Wednesday,
May 7, 2003
Richard
Lebed, Arizona State University
"Baryons
in 1/N_c: The Classic and the Nouveau"
The 1/N_c expansion (N_c
the number of QCD colors) this year
celebrates its 30th
anniversary; its modern quantitative application to
baryons, using operator
methods, celebrates its 10th. The first part of
this talk reviews some of
the classic works, in order to inform the audience
of these methods and
their successes. Recently a new phase opened, that of
treating baryon
resonances in 1/N_c as poles in meson-nucleon scattering
amplitudes (which is
indeed the way they are experimentally observed). This
new approach, originally
based on intuition gleaned from chiral soliton
models but later found to
be much more general, generates simple
relationships between
resonance masses and widths. But moreover, this
approach is shown to be
fully compatible with the operator methods, and also
explains in a natural way
such phenomena as the small N(1535) partial width
to pi-N.
Monday,
April 7, 2003
Romas
Kalinauskas, Institute of Physics,Vilnius, Lithuania
"Techniques
for nuclear structure calculations"
I will present some
results which I do hope can be effective when
elaborating the no-core
shell-model approach.
Wednesday,
April 2, 2003
Kirill
Tuchin, Institute for Nuclear Theory
"QCD
at high energies at work: DIS and Heavy-ion collisions"
Experimental data on Deep
Inelastic Scattering at low x shows that parton
structure functions of a
hadron grow fast as x decreases. Since the
probability to find a
parton with given x is finite, there should be a QCD
mechanism taming that
growth. I discuss the physical nature of that
mechanism which is known
as the theory of Color Glass Condensate. I argue
that ultimately the
parton densities saturate which results in a certain
predictions for
experiments with hadrons at high energies. I emphasize the
role of parton saturation
in Deep Inelastic Scattering and Heavy-Ion
Collisions.
Tuesday,
April 1, 2003
Shmuel
Nussinov, Tel-Aviv University
"A
simple physicist approach to complex problems"
"Complex Problems"
involving a large number, n, of elements and for which any general
method of solution (presumably!) requires a large number
(growing faster than any
finite power of n) of elementary steps, and the P=(?)NP issue are
briefly described. This is done in the context of a
"proverbial" n students
in a dorm example - a laymen description of the largest "clique"
problem. We suggest a simple physical analog model which
is easy to simulate. The
n students or n vertices in a graph are represented by n points in d=n-1
dimensions, initially residing at the n
vertices of a symmetric
n-1 simplex and which move due to (constant) attractive/repulsive forces
introduced between
compatible/incompatible
students or between connected/disconnected vertices in the graph. The
deterministic evolution of the n points is free from
local minima traps, easy
to simulate, and helps with the following problems: 1) The Heuristic
problem of finding "clusters" in a network, i.e,
in graphs or in
communication, commercial, biological, etc. systems) by physically
(geometrically) clustering the representative points. 2) The
Graph isomorphism problem
by evolving independently via identical dynamics the simplexes
corresponding to the two graphs and checking the (geometric)
congruence of the later.
3) The largest clique problem.
These problems are of
increasing intrinsic difficulty and this reflects in our "Solutions". We
briefly speculate on possible extensions to other
"Complex Problems" such
as the Traveling Salesman or Hamiltonian circuit problem and on possible
implications in sociology, biology, neural-nets and
other areas.
No previous background
beyond the most elementary geometry and physics (the latter even at the
Aristotelean level) is required.
Thursday,
March 27, 2003
Ionel
Stetcu, Louisiana State University
"Can
we trust the random phase approximation?"
Our understanding of
nuclear structure is built upon mean-field theories
such as Hartree-Fock and
time-dependent Hartree-Fock. The small-amplitude
limit of the latter is
the random phase approximation (RPA), which is
widely used to model
giant resonances in nuclei. Despite this popularity,
RPA has been mostly
validated against toy models; tests against complex
models are scarce in the
literature. We perform a thorough test of the RPA
against full
$0\hbar\omega$ shell model (SM) calculations. We allow
deformed Hartree-Fock
solutions and compare results for spherical and
deformed nuclei. We find
reasonable agreement between RPA and SM, albeit
with some significant
failures. We also prove that a long-standing
"theorem" regarding RPA
is violated in the case of deformation. Moreover,
we bring evidence that
the symmetries are only approximatively and
unreliably restored.
Wednesday, March 26, 2003
Matthias Burkardt, New Mexico
State University
"Hadron Tomography"
High-energy Compton scattering experiments allow
probing so-called generalized parton distributions (GPDs).
These GPDs are related to the distribution of partons
in impact parameter space.
High-energy Compton scattering thus allows us to
develop three dimensional images of the nucleons and nuclei,
which describe how partons carrying different
momentum fraction x are distributed in the transverse plane.
Wednesday,
March 12, 2003
Simon
Catterall, Syracuse University
"Lattice
Supersymmetry and Topological Field Theory"
It is known that certain theories with extended supersymmetry can be discretized in such a way as to preserve an exact fermionic symmetry. In the simplest model of this kind, we show that this residual supersymmetric invariance is actually a BRST symmetry associated with gauge fixing an underlying local shift symmetry. Furthermore, the starting lattice action is then seen to be entirely a gauge fixing term. The corresponding continuum theory is known to be a topological field theory.
We look, in detail, at
one example - supersymmetric quantum mechanics
which possesses two such
BRST symmetries. In this case, we show that the
lattice theory can be
obtained by blocking out of the continuum in a
carefully chosen
background metric. Such a procedure will not change the
Ward identities
corresponding to the BRST symmetries since they correspond
to topological
observables. Thus, at the quantum level, the continuum BRST
symmetry is preserved in
the lattice theory. Similar conclusions are
reached for the
two-dimensional comple Wess-Zumino model and imply that
all the supersymmetric
Ward identities are satisfied exactly on the lattice. Numerical
results supporting these conclusions are presented.
Thursday,
March 6, 2003
Christian
Forssén, Chalmers University of Technology
"On
the few-body character of light exotic nuclei"
The exploration of exotic
nuclei is one of the most intriguing and
fastest expanding fields
in modern nuclear physics. In the studies of
light nuclei having
extreme N/Z ratios and small binding energies, many
nuclear phenomena not
encountered closer to stability have revealed
themselves. Our story
begins in Copenhagen 1936 and ends with a
discussion of the 8B
contributiuon to the solar neutrino problem. Along
the way, we will discuss
the peculiar electric dipole response of the
Borromean systems 6He,
11Li and 14Be.
Wednesday,
March 5, 2003
Giorgio
Torrieri, University of Arizona
"Hadron
freeze-out and particle spectra"
It is now generally
accepted that a statistical hadronization
model explains both
abundacies and transverse momentum
spectra of hadrons
produced in heavy ion collisions. However,
in published fits to
experimental data, several different
variants of statistical
models have been used. Some of the ways
these models differ
include assumptions about chemical equilibrium,
proper and improper
consideration of hadron resonance contributions,
and different assumptions
regarding the freeze-out spatial geometry.
I will discuss how these
model features relate to different physical
assumptions about the
freeze-out dynamics of a new state of matter
such as quark gluon
plasma. I will then show, using both Monte Carlo
simulations and the
actual RHIC experiemental data, that fits to
hadron spectra are
capable of constraining freeze-out dynamics
and distinguishing
between the key physical features of the
freeze-out models.
Friday,
Feb 28, 2003
Marco
Huertas, College of William & Mary
"Applications
of effective field theory/density functional theory approach
to
properties of nuclei far from stability"
A new approach to the
description of the nuclear-many body system that
combines elements of
effective field theory and density functional theory
and which is fit along
the valley of stability is applied to
study properties of
nuclei far from stability. Results of predictions for
total binding energy,
single-particle and single-hole binding energies,
spins and parities, as
well as beta transition rates of selected nuclei
are presented.
Tuesday,
Jan 28, 2003
Tom
Luu, Institute for Nuclear Theory
"Perturbative
Effective Theory within an Oscillator Basis"
The nuclear many-body
effective interactions problem has been known to be
highly non-perturbative.
However, I show that the sources of the
non-perturbative
behaviour can be identified and systematically removed.
The remaining theory
exhibits perturbative behaviour. I present results
for the deuteron and He3.
Tuesday,
Jan 21, 2003
Urs
Heller, American Physical Society & Brookhaven National Laboratory
"Thermodynamics
Simulations with Improved Staggered Quarks"
We
explore the QCD phase diagram at finite temperature using an improved
staggered
fermion action, the Asqtad action. We motivate the choice of
action
by demonstrating that it significantly reduces lattice artifacts
at
finite lattice spacing. The thermodynamics simulations are done
with
(a) 3 degenerate flavors with mass down to 1/5 the strange quark
mass,
and (b) 2+1 flavors with 1 mass fixed at the strange quark mass
and
the mass of the other two flavors as low as 1/5 m_s. We also
report
on first computations of quark number susceptibilities with
the
improved Asqtad staggered quark action. These susceptibilities are
of
interest because they can be related to event-by-event fluctuations
in
heavy ion collision experiments. Use of the improved quark action
leads
to a substantial reduction in lattice artifacts. This can be seen
already
for free fermions and carries over into our results for QCD.
Wednesday,
Dec 11, 2002
David Cardamone, University of Arizona
"Two-State Model for the Decay of Superdeformed Nuclei"
The process by which
superdeformed nuclei decay into a normal-deformed band
is still an unresolved issue among the nuclear physics community. Most
prominent theoretical models used to explain this phenomenon are based
on
incorrect physics: they are neither self-consistent nor correct. An
alternative two-state model, originally suggested in 1999 by Stafford
&
Barrett, has the advantage of being simple, straightforward, and
exactly
solvable. Furthermore, the results are not too much altered by the
relaxation of the two-level approximation to three or even more levels.
Finally, the two-level model makes specific, experimentally testable
predictions.
Wednesday, Dec 4, 2002
Aron Soha, Stanford University/SLAC
"Branching Fraction and CP Asymmetry in B0 ->
J/psi pi0"
CP violation has recently been
firmly established in the B meson system,
in excellent agreement with Standard Model
predictions. The opportunity
now exists to probe details of the underlying
mechanisms. This talk
presents measurements of the branching fraction
and time-dependent
CP-violating asymmetry in B^0 -> J/psi pi^0
decays. The decay amplitude
for this channel features both tree and penguin
diagram contributions, the
interference of which can yield a result for the
asymmetry differing from
that found in the "golden mode" B^0 -> J/psi
Ks. The results are presented
for data collected during 1999-2002 using the
BaBar detector at the PEP-II
asymmetric-energy B Factory at SLAC.
Wednesday, Nov 20, 2002
Yasushi Nara, University of Arizona
"Non-perturbative computation of gluon productions
from the Color Glass Condensate in high
energy heavy ion collisions"
I will present some results
from the computation of
classical Yang-Mills equations on the lattice.
We extend previous work on high energy nuclear
collisions in the Color
Glass Condensate model to study collisions of
finite ultrarelativistic
nuclei. The change implemented is imposition of
color neutrality condition
at the nucleon level.
The centrality dependence of gluon multiplicity,
transverse energy,
and elliptic flow will be shown.
Wednesday, Nov 13, 2002
Xavier Calmet, California Institute of
Technology
"Non-Constant Fine Structure Constant and Grand
Unified Theories"
Data coming from astrophysical
measurements seems to indicate that the
fine structure constant might undergo a small
cosmological time
shift. We discuss the implications that this
result, if confirmed,
would have on grand unified theories (GUTs). A
connection to the
symmetry breaking mechanism of the GUT gauge
group will be
discussed. A laboratory test of this measurement
is described. Finally
we study the implications of a time dependence of
fundamental
parameters for baryogenesis.
Wednesday, Oct. 30, 2002
Bira van Kolck, University of Arizona
"EFT of Halo Nuclei"
I will present the extension of EFT ideas from
few-nucleon systems to
halo nuclei. The power counting for low-lying bound states and
resonances will be discussed. As a specific example, observables in
nucleon-alpha scattering near threshold will be described. I will end
with prospects for other applications, such as Borromean systems.
Wednesday, Oct. 16, 2002
Irina Mocioiu, University of Arizona
"Neutrino Oscillations and Matter Effects"
During the last few years experiments have provided
strong evidence of
neutrino oscillations. This is the first evidence of physics beyond the
Standard Model.
I will give a brief overview of the results of neutrino experiments.
and explain how all these can be understood in terms of neutrino masses
and oscillations in vacuum and in matter. A brief discussion of
possible
scenarios which give small neutrino masses will also be given. I will
describe resonant oscillations in matter and the importance of treating
a
full three-flavor mixing scenario.
All this will be applied to several scenarios for future long baseline
neutrino oscillation experiments
Wednesday, Oct 2, 2002
Boris Gelman, University of Arizona
"Heavy Baryons in the Combined Large N and Heavy
Quark Expansion"
A description of hadrons---the strongly bound states
of quarks and
gluons---directly from QCD requires a use of non-perturbative methods.
I will
briefly review two such methods---the large-N QCD framework and the
heavy
quark expansion. The main focus of the talk is on the heavy
baryons---baryons
containing a single heavy quark. The combined large N and heavy quark
limit
allows a model-independent description of the heavy baryons and their
low-lying excited states in terms of an effective theory. The effective
theory is based on an approximate symmetry---a contracted O(8)
symmetry---exhibited by heavy baryons and their low-lying excited
states
near the combined large N and heavy quark limit. In addition to the
excitation energies the effective theory can be used to describe the
semi-leptonic form factors and radiative decay rates of the heavy
baryons.
Wednesday, April 24, 2002
Hans Hammer, Ohio State University
"Effective field theory: from nuclear physics to
cold atoms".
Effective Field Theory (EFT) provides a powerful framework that exploits a separation of scales in physical systems to perform systematically improvable, model-independent calculations. Particularly interesting are three-body systems with large two-body scattering length. These systems display universal features such as a logarithmic spectrum of shallow three-body bound states (so-called Efimov states) and a discrete scale invariance. In the EFT, a three-body force with limit cycle behavior is required at leading order for consistent renormalization.
This EFT has a wide range
of applications and successfully describes
phenomena ranging from nuclear physics to the physics of cold atoms. I
will discuss applications to the neutron-deuteron and Lambda-deuteron
systems in nuclear physics, as well as recent results for cold 4He
atoms
and alkali atoms in a BEC. The case of alkali atoms is particularly
interesting, because their scattering length a can be tuned
experimentally using Feshbach resonances. This allows one to test the
dramatic a-dependence predicted by the EFT.