Nuclear Theory·nucl-th

Wednesday·May 12, 2021

11 papers—4 primary·7 cross-listed

05
The van der Waals interaction as the starting point for an effective field theory
Daniel Odell🇺🇸 · Arnoldas Deltuva🇱🇹 · Lucas Platter🇺🇸
We consider the system of three $^{4}$ He atoms to assess whether a pure van der Waals potential can be used as a starting point for an effective field theory to describe three-body processes in ultracold atomic systems. Using a long-range van der Waals interaction in combination with short-distance two-body counterterms, we analyze the dependence of two- and three-body observables on the short-distance regulator that is required due to the singular nature of the van der Waals interaction. We benchmark our approach with results obtained with the realistic $^{4}$ He- $^{4}$ He LM2M2 interaction and find good agreement. We furthermore show that in this effective field theory approach no three-body force is required at leading order and that universal van der Waals physics leads to a universal correlation between three-body observables in the absence of an Efimov three-body parameter.
↳ cond-mat.quant-gasnucl-thPRA(2021)·7 citations
06
Improved Standard-Model prediction for $π^{0} \to e^{+} e^{-}$
Martin Hoferichter🇨🇭 · Bai-Long Hoid🇨🇭 · Bastian Kubis🇩🇪 · Jan Lüdtke🇩🇪
We present an improved Standard-Model (SM) prediction for the dilepton decay of the neutral pion. The loop amplitude is determined by the pion transition form factor for $π^{0} \to γ^{*} γ^{*}$ , for which we employ a dispersive representation that incorporates both space-like and time-like data as well as short-distance constraints. The resulting SM branching fraction, $BR [π^{0} \to e^{+} e^{-}] = 6.25 (3) \times 1 0^{- 8}$ , sharpens constraints on physics beyond the SM, including pseudoscalar and axial-vector mediators.
↳ hep-phhep-exhep-latnucl-thPRL(2022)·41 citations
07
European Spallation Source: a future for Coherent Neutrino Nucleus Scattering
Ivan Esteban🇺🇸
The European Spallation Source (ESS), currently finishing its construction, will soon provide the most intense neutron beams for multi-disciplinary science. At the same time, it will also produce a high-intensity neutrino flux with an energy suitable for precision measurements of Coherent Elastic Neutrino-Nucleus Scattering. We describe some physics prospects, within and beyond the Standard Model, of employing innovative detector technologies to take the most out of this large flux. We show that, compared to current measurements, the ESS will provide a much more precise understanding of neutrino and nuclear properties.
↳ hep-phhep-exnucl-exnucl-th3 citations
08
Model independent analysis of coupled-channel scattering: a deep learning approach
Denny Lane B. Sombillo🇵🇭 · Yoichi Ikeda🇯🇵 · Toru Sato🇯🇵 · Atsushi Hosaka🇯🇵
We develop a robust method to extract the pole configuration of a given partial-wave amplitude. In our approach, a deep neural network is constructed where the statistical errors of the experimental data are taken into account. The teaching dataset is constructed using a generic S-matrix parametrization, ensuring that all the poles produced are independent of each other. The inclusion of statistical error results into a noisy classification dataset which we should solve using the curriculum method. As an application, we use the elastic $π N$ amplitude in the $I (J^{P}) = 1/2 (1/ 2^{-})$ sector where $1 0^{6}$ amplitudes are produced by combining points in each error bar of the experimental data. We fed the amplitudes to the trained deep neural network and find that the enhancements in the $π N$ amplitude are caused by one pole in each nearby unphysical sheet and at most two poles in the distant sheet. Finally, we show that the extracted pole configurations are independent of the way points in each error bar are drawn and combined, demonstrating the statistical robustness of our method.
↳ hep-phhep-exnucl-exnucl-thPRD(2021)·28 citations
09
Influence of chiral asymmetry on phase structure of the two-color quark matter
T. G. Khunjua🇬🇪 · K. G. Klimenko🇷🇺 · R. N. Zhokhov🇷🇺
In this paper the influence of chiral chemical potential $μ_{5}$ on the phenomenon of diquark condensation and phase structure of dense quark matter altogether is contemplated in the framework of effective two-color and two-flavor Nambu--Jona-Lasinio model. We show that the duality relations, found $μ_{5} = 0$ , are also valid for any value of $μ_{5} \neq = 0$ . Hence the dualities seem to be a real fundamental feature of the phase diagram of two color quark matter, and besides they are a very powerful tool of studying the phase structure. In terms of dualities and the influence on the phase diagram chiral imbalance $μ_{5}$ stands alone from other chemical potentials. Two regimes in the phase diagram could be discerned, the first one, rather small or moderate values of chemical potentials $μ_{B}$ , $μ_{I}$ and $μ_{I 5}$ , where the picture is rather concise and elegant: each of the above phenomena is in one-to-one correspondence with some chemical potential ( $μ_{I 5}$ induces chiral symmetry breaking, $μ_{I}$ propels charged pion condensation and $μ_{B}$ leads to diquark condensation). In this regime chiral chemical potential $μ_{5}$ does not break this correspondence, it has a property of being universal catalyzer, i.e. it {\it catalyzes/enhances} all the phenomena on equal footing. The feature of chiral imbalance $μ_{5}$ to catalyze chiral symmetry breaking phenomenon was known before but its catalytic properties appeared to be more universal and it can catalyze also diquark and charged pion condensation. These happen due to the dual properties. In the second regime, when several chemical potentials reach rather large values, one could observe a rather complicated and rich phase structure, and $μ_{5}$ can be a factor that not so much catalyzes as {\it triggers} rather peculiar phases. For example, it can lead to the formation of diquark condensation at zero baryon chemical potential.
↳ hep-phnucl-thPRD(2022)·22 citations
10
Multimessenger constraints for ultra-dense matter
Eemeli Annala🇫🇮 · Tyler Gorda🇩🇪 · Evangelia Katerini🇬🇷 · Aleksi Kurkela🇳🇴 · Joonas Nättilä🇺🇸 · Vasileios Paschalidis🇺🇸 · Aleksi Vuorinen🇫🇮
Recent rapid progress in neutron-star (NS) observations offers great potential to constrain the properties of strongly interacting matter under the most extreme conditions. In order to fully exploit the current observational inputs and to study the impact of future observations of NS masses, radii, and tidal deformabilities, we analyze a large ensemble of randomly generated viable NS-matter equations of state (EoSs) and the corresponding rotating stellar structures. We discuss the compatibility and impact of various hypotheses and measurements on the EoS, including those involving the merger product of the gravitational-wave (GW) event GW170817, the binary merger components in GW190814, and radius measurements of the pulsar PSR J0740+6620. We obtain an upper limit for the dimensionless spin of a rigidly rotating NS, $∣ χ ∣ < 0.81$ , an upper limit for the compactness of a NS, $GM / (R c^{2}) < 0.33$ , and find that the conservative hypothesis that the remnant in GW170817 ultimately collapsed to a black hole strongly constrains the EoS and the maximal mass of NSs, implying $M_{TOV} < 2.53 M_{⊙}$ (or $M_{TOV} < 2.19 M_{⊙}$ if we assume that a hypermassive NS was created). Additionally, we derive a novel lower limit for the tidal deformability as a function of NS mass and provide fitting formulae that can be used to set priors for parameter estimation and to discern whether neutron stars or other compact objects are involved in future low-mass GW events. Finally, we find that the recent NICER results for the radius of the massive NS PSR J0740+6620 place strong constraints for the behavior of the EoS, and that the indicated radius values $R (2 M_{⊙}) ≳ 11$ km are compatible with moderate speeds of sound in NS matter and thus with the existence of quark matter cores in massive NSs.
↳ astro-ph.HEgr-qchep-phnucl-thPRX(2022)·199 citations
11
r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae
Xilu Wang · Adam M. Clark · John Ellis · Adrienne F. Ertel · Brian D. Fields · Zhenghai Liu · Jesse A. Miller · Rebecca Surman
The astrophysical sites where r-process elements are synthesized remain mysterious: it is clear that neutron star mergers (kilonovae (KNe)) contribute, and some classes of core-collapse supernovae (SNe) are also likely sources of at least the lighter r-process species. The discovery of 60Fe on the Earth and Moon implies that one or more astrophysical explosions have occurred near the Earth within the last few million years, probably SNe. Intriguingly, 244Pu has now been detected, mostly overlapping with 60Fe pulse. However, the 244Pu flux may extend to before 12 Myr ago, pointing to a different origin. Motivated by these observations and difficulties for r-process nucleosynthesis in SN models, we propose that ejecta from a KN enriched the giant molecular cloud that gave rise to the Local Bubble, where the Sun resides. Accelerator mass spectrometry (AMS) measurements of 244Pu and searches for other live isotopes could probe the origins of the r-process and the history of the solar neighborhood, including triggers for mass extinctions, e.g., that at the end of the Devonian epoch, motivating the calculations of the abundances of live r-process radioisotopes produced in SNe and KNe that we present here. Given the presence of 244Pu, other r-process species such as 93Zr, 107Pd, 129I, 135Cs, 182Hf, 236U, 237Np and 247Cm should be present. Their abundances and well-resolved time histories could distinguish between the SN and KN scenarios, and we discuss prospects for their detection in deep-ocean deposits and the lunar regolith. We show that AMS 129I measurements in Fe-Mn crusts already constrain a possible nearby KN scenario.
↳ astro-ph.HEhep-phnucl-exnucl-th+1ApJ(2021)·24 citations

Affiliations

first authorsco-authorsvia INSPIRE

The van der Waals interaction as the starting point for an effective field theory

Improved Standard-Model prediction for π0→e+e−

European Spallation Source: a future for Coherent Neutrino Nucleus Scattering

Model independent analysis of coupled-channel scattering: a deep learning approach

Influence of chiral asymmetry on phase structure of the two-color quark matter

Multimessenger constraints for ultra-dense matter

r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae

Affiliations

Improved Standard-Model prediction for $π^{0} \to e^{+} e^{-}$