H.‐W. Hammer
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View article: Modified Lüscher zeta-function and the modified effective range expansion in the presence of a long-range force
Modified Lüscher zeta-function and the modified effective range expansion in the presence of a long-range force Open
A bstract An efficient numerical algoritm is proposed for the calculation of the modified Lüscher zeta-function in the presence of a long-range force. Using the formalism developed in ref. JHEP05(2024)168 for the analysis of synthetic data…
View article: Three-body universality in the <i>B</i> meson sector
Three-body universality in the <i>B</i> meson sector Open
The charged exotic mesons Z b (10610) and observed by the Belle collaboration in 2011 are very close to the and thresholds, respectively. This suggests their interpretation as shallow hadronic molecules of…
View article: Sensitivity of nuclear clocks to new physics
Sensitivity of nuclear clocks to new physics Open
The recent demonstration of laser excitation of the ≈8eV isomeric state of Th229 is a significant step towards a nuclear clock. The low excitation energy likely results from a cancellation between electromagnetic and strong contributions, …
View article: Modified Lüscher zeta-function and the modified effective range expansion in the presence of a long-range force
Modified Lüscher zeta-function and the modified effective range expansion in the presence of a long-range force Open
An efficient numerical algoritm is proposed for the calculation of the modified Lüscher zeta-function in the presence of a long-range force. Using the formalism developed in Ref.~\cite{Bubna:2024izx} for the analysis of synthetic data on t…
View article: Exploring Efimov states in D*D*D* and DD*D* three-body systems
Exploring Efimov states in D*D*D* and DD*D* three-body systems Open
A bstract The Efimov effect is an intriguing three-body quantum phenomenon. Searching for Efimov states within the realms of nuclear and hadronic physics presents a challenge due to the inherent inability of natural physical systems to exh…
View article: Effective Theory for Strongly Attractive One-Dimensional Fermions
Effective Theory for Strongly Attractive One-Dimensional Fermions Open
We study a one-dimensional system of two-component fermions in the limit of strong attractive particle-particle interactions. First, we analyze scattering in the corresponding few-body problem, which is analytically solvable via Bethe ansa…
View article: Effective Theory for Strongly Attractive One-Dimensional Fermions
Effective Theory for Strongly Attractive One-Dimensional Fermions Open
We study a one-dimensional system of two-component fermions in the limit of strong attractive particle-particle interactions. First, we analyze scattering in the corresponding few-body problem, which is analytically solvable via Bethe ansa…
View article: Two-dimensional bosonic droplets in a harmonic trap
Two-dimensional bosonic droplets in a harmonic trap Open
We investigate a system of bosons in a two-dimensional harmonic trap. In the limit of strong attractive interactions, the bosons make a droplet insensitive to external confinement. For weak interactions, in contrast, the ground state is gi…
View article: Two-dimensional bosonic droplets in a harmonic trap
Two-dimensional bosonic droplets in a harmonic trap Open
We investigate a system of bosons in a two-dimensional harmonic trap. In the limit of strong attractive interactions, the bosons make a droplet insensitive to external confinement. For weak interactions, in contrast, the ground state is gi…
View article: Neutron-neutron distribution of the triton from pionless effective field theory
Neutron-neutron distribution of the triton from pionless effective field theory Open
We compute the neutron-neutron relative-energy distribution of the triton following the hard knockout of the proton in pionless effective field theory (EFT). This distribution can be used to study universality as well as to obtain informat…
View article: Baryon Form Factors
Baryon Form Factors Open
We review the status of baryon form factors with a special focus on the nucleon electromagnetic form factors which are known best. First, we give an introduction into the dispersive analyses and emphasize the role of unitarity and analytic…
View article: Neutron-neutron distribution of the triton from pionless EFT
Neutron-neutron distribution of the triton from pionless EFT Open
We compute the neutron-neutron relative-energy distribution of the triton following the hard knockout of the proton in pionless effective field theory. This distribution can be used to study universality as well as to obtain information on…
View article: Comparison of renormalized interactions using one-dimensional few-body systems as a testbed
Comparison of renormalized interactions using one-dimensional few-body systems as a testbed Open
Even though the one-dimensional contact interaction requires no regularization, renormalization methods have been shown to improve the convergence of numerical ab initio calculations considerably. In this work, we compare and contrast thes…
View article: On the sensitivity of nuclear clocks to new physics
On the sensitivity of nuclear clocks to new physics Open
The recent demonstration of laser excitation of the $\approx 8$ eV isomeric state of Thorium-229 is a significant step towards a nuclear clock. The low excitation energy likely results from a cancellation between electromagnetic and strong…
View article: Lüscher equation with long-range forces
Lüscher equation with long-range forces Open
A bstract We derive the modified Lüscher equation in the presence of the long-range force caused by the exchange of a light particle. It is shown that the use of this equation enables one to circumvent the problems related to the strong pa…
View article: Entanglement in Few-Nucleon Scattering Events
Entanglement in Few-Nucleon Scattering Events Open
We investigate the spin entanglement in few-nucleon scattering processes involving nucleons and deuterons. For this purpose, we consider the entanglement power introduced by Beane et al. We analyze different entanglement entropies as a bas…
View article: Lüscher equation with long-range forces
Lüscher equation with long-range forces Open
We derive the modified Lüscher equation in the presence of the long-range force caused by the exchange of a light particle. It is shown that the use of this equation enables one to circumvent the problems related to the strong partial-wave…
View article: Entanglement in few-nucleon scattering events
Entanglement in few-nucleon scattering events Open
We investigate the spin entanglement in few-nucleon scattering processes involving nucleons and deuterons. For this purpose, we consider the entanglement power introduced by Beane et al. We analyze different entanglement entropies as a bas…
View article: The proton magnetic radius: a new puzzle?
The proton magnetic radius: a new puzzle? Open
We comment on the puzzling status of the proton magnetic radius determinations.
View article: Pionic final state interactions and the hypertriton lifetime
Pionic final state interactions and the hypertriton lifetime Open
We analyze the contribution of pionic final state interactions (FSI) in the weak decay of the hypertriton. Focusing on the $$^3$$ He channel, we find a contribution of the pionic FSI of the order of $$18\%$$ . Assuming a fixed value for …
View article: An Alternative Scheme for Pionless EFT: Neutron-Deuteron Scattering in the Doublet S-Wave
An Alternative Scheme for Pionless EFT: Neutron-Deuteron Scattering in the Doublet S-Wave Open
Using the effective-range expansion for the two-body amplitudes may generate spurious sub-threshold poles outside of the convergence range of the expansion. In the infinite volume, the emergence of such poles leads to the breakdown of unit…
View article: Neutron scattering off one-neutron halo nuclei in halo effective field theory
Neutron scattering off one-neutron halo nuclei in halo effective field theory Open
Neutron scattering off neutron halos can provide important information about the internal structure of nuclei close to the neutron drip line. In this work, we use halo effective field theory to study the $s$-wave scattering of a neutron an…
View article: Pionic Final State Interactions and the Hypertriton Lifetime
Pionic Final State Interactions and the Hypertriton Lifetime Open
We analyze the contribution of pionic final state interactions (FSI) in the weak decay of the hypertriton. Focusing on the $^3$He channel, we find a contribution of the pionic FSI of the order of $18\%$. Assuming a fixed value for the bran…
View article: Universality of $nn$ distributions of $s$-wave $2n$ halos and the unitary limit
Universality of $nn$ distributions of $s$-wave $2n$ halos and the unitary limit Open
We calculate neutron-neutron relative-energy distributions of $s$-wave two-neutron ($2n$) halo nuclei using Halo Effective Field Theory (Halo EFT) at leading order. At this order these systems are described by the $2n$ separation energy, t…
View article: Neutron Scattering off One-Neutron Halo Nuclei in Halo Effective Field Theory
Neutron Scattering off One-Neutron Halo Nuclei in Halo Effective Field Theory Open
Neutron scattering off neutron halos can provide important information about the internal structure of nuclei close to the neutron drip line. In this work, we use halo effective field theory to study the $s$-wave scattering of a neutron an…
View article: Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux
Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux Open
The model of a ring threaded by the Aharonov-Bohm flux underlies our understanding of a coupling between gauge potentials and matter. The typical formulation of the model is based upon a single particle picture, and should be extended when…