67 research outputs found
Efimov Physics in Atom-Dimer Scattering of Lithium-6 Atoms
Lithium-6 atoms in the three lowest hyperfine states display universal
properties when the S-wave scattering length between each pair of states is
large. Recent experiments reported four pronounced features arising from Efimov
physics in the atom-dimer relaxation rate, namely two resonances and two local
minima. We use the universal effective field theory to calculate the atom-dimer
relaxation rate at zero temperature. Our results describe the four features
qualitatively and imply there is a hidden local minimum. In the vicinity of the
resonance at 685 G, we perform a finite temperature calculation which improves
the agreement of theory and experiment. We conclude that finite temperature
effects cannot be neglected in the analysis of the experimental data.Comment: 13 pages, 5 figures, final versio
An effective-field-theory analysis of Efimov physics in heteronuclear mixtures of ultracold atomic gases
We use an effective-field-theory framework to analyze the Efimov effect in
heteronuclear three-body systems consisting of two species of atoms with a
large interspecies scattering length. In the leading-order description of this
theory, various three-body observables in heteronuclear mixtures can be
universally parameterized by one three-body parameter. We present the
next-to-leading corrections, which include the effects of the finite
interspecies effective range and the finite intraspecies scattering length, to
various three-body observables. We show that only one additional three-body
parameter is required to render the theory predictive at this order. By
including the effective range and intraspecies scattering length corrections,
we derive a set of universal relations that connect the different Efimov
features near the interspecies Feshbach resonance. Furthermore, we show that
these relations can be interpreted in terms of the running of the three-body
counterterms that naturally emerge from proper renormalization. Finally, we
make predictions for recombination observables of a number of atomic systems
that are of experimental interest.Comment: peer-reviewed and edited version, errors fixe
Effective-field-theory predictions of the muon-deuteron capture rate
We quantify the theoretical uncertainties of chiral effective-field-theory
predictions of the muon-deuteron capture rate. Theoretical error estimates of
this low-energy process is important for a reliable interpretation of
forthcoming experimental results by the MuSun collaboration. Specifically, we
estimate the three dominant sources of uncertainties that impact theoretical
calculations of this rate: those resulting from uncertainties in the pool of
fit data used to constrain the coupling constants in the nuclear interaction,
those due to the truncation of the effective field theory, and those due to
uncertainties in the axial radius of the nucleon. For the capture rate into the
channel, we find an uncertainty of approximately due to
the truncation in the effective field theory and an uncertainty of
due to the uncertainty in the axial radius of the nucleon, both of which are
similar in size to the targeted experimental precision.Comment: 4 pages, 2 figure
Range corrections in Proton Halo Nuclei
We analyze the effects of finite-range corrections in halo effective field
theory for S-wave proton halo nuclei. We calculate the charge radius to
next-to-leading order and the astrophysical S-factor for low-energy proton
capture to fifth order in the low-energy expansion. As an application, we
confront our results with experimental data for the S-factor for proton capture
on Oxygen-16 into the excited state of Fluorine-17. Our low-energy
theory is characterized by a systematic low-energy expansion, which can be used
to quantify an energy-dependent model error to be utilized in data fitting.
Finally, we show that the existence of proton halos is suppressed by the need
for two fine tunings in the underlying theory.Comment: 30pages, 12 figure
Constraining Low-Energy Proton Capture on Beryllium-7 through Charge Radius Measurements
In this paper, we point out that a measurement of the charge radius of
Boron-8 provides indirect access to the S-factor for radiative proton capture
on Beryllium-7 at low energies. We use leading-order halo effective field
theory to explore this correlation and we give a relation between the charge
radius and the S-factor. Furthermore, we present important technical aspects
relevant to the renormalization of pointlike P-wave interactions in the
presence of a repulsive Coulomb interaction.Comment: Accepted for publication in European Physical Journal A. 29 pages, 9
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