Nuclear Theory·nucl-th

Thursday·March 9, 2023

12 papers—6 primary·6 cross-listed

07
Neutrinoless double-beta decay in the neutrino-extended Standard Model
Wouter Dekens🇺🇸 · Jordy de Vries🇳🇱 · Emanuele Mereghetti🇺🇸 · Javier Menéndez🇪🇸 · Pablo Soriano🇪🇸 · Guanghui Zhou🇨🇳
We investigate neutrinoless double-beta decay ( $0 ν β β$ ) in the minimal extension of the standard model of particle physics, the $ν$ SM, where gauge-singlet right-handed neutrinos give rise to Dirac and Majorana neutrino mass terms. We focus on the associated sterile neutrinos and argue that the usual evaluation of their contributions to $0 ν β β$ , based on mass-dependent nuclear matrix elements, is missing important contributions from neutrinos with ultrasoft and hard momenta. We identify the hadronic and nuclear matrix elements that enter the new contributions, and calculate all relevant nuclear matrix elements for $^{136}$ Xe using the nuclear shell model. Finally, we illustrate the impact on $0 ν β β$ rates in specific neutrino mass models and show that the new contributions significantly alter the $0 ν β β$ rate in most parts of the $ν$ SM parameter space.
↳ hep-phhep-exnucl-exnucl-thPRC(2023)·37 citations
08
Analogies between hadron-in-jet and dihadron fragmentation
Alessandro Bacchetta🇮🇹 · Marco Radici🇮🇹 · Lorenzo Rossi🇮🇹
We describe the formal analogies in the description of the inclusive production in hard processes of hadron pairs (based on dihadron fragmentation functions) and of a single hadron inside a jet (based on hadron-in-jet fragmentation functions). Since several observables involving dihadron fragmentation functions have been proposed in the past, we are able to suggest new interesting observables involving hadron-in-jet fragmentation functions, in lepton-hadron deep-inelastic scattering and hadronic collisions.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·7 citations
09
A possibility of existence of a pseudovector-type quark-antiquark condensate in the quark matter and Nambu-Goldstone modes on that condensate in the Nambu-Jona-Lasinio model
Kentaro Hayashi (Kochi Univ., Japan)🇯🇵 · Yasuhiko Tsue (Kochi Univ., Japan)🇯🇵
A possibility of a pseudovector-type quark-antiquark condensed phase, which leads to a quark spin polarized phase, in the quark matter is investigated taking account of the vacuum effects leading to the chiral symmetry breaking by using the Nambu-Jona-Lasinio model. Also, possible Nambu-Goldstone modes on the pseudovector-type quark-antiquark condensate and the tensortype quark-antiquark condensate, which also leads to the quark spin polarized phase, are investigated.
↳ hep-phnucl-thIJMPE(2023)·1 citation
10
Deep learning for flow observables in ultrarelativistic heavy-ion collisions
H. Hirvonen🇫🇮 · K. J. Eskola🇫🇮 · H. Niemi🇫🇮
We train a deep convolutional neural network to predict hydrodynamic results for flow coefficients, average transverse momenta and charged particle multiplicities in ultrarelativistic heavy-ion collisions from the initial energy density profiles. We show that the neural network can be trained accurately enough so that it can reliably predict the hydrodynamic results for the flow coefficients and, remarkably, also their correlations like normalized symmetric cumulants, mixed harmonic cumulants and flow-transverse-momentum correlations. At the same time the required computational time decreases by several orders of magnitude. To demonstrate the advantage of the significantly reduced computation time, we generate 10M initial energy density profiles from which we predict the flow observables using the neural network, which is trained using 5k, and validated using 90k events per collision energy. We then show that increasing the number of collision events from 90k to 10M can have significant effects on certain statistics-expensive flow correlations, which should be taken into account when using these correlators as constraints in the determination of the QCD matter properties.
↳ hep-phnucl-thPRC(2023)·16 citations
11
Scattering length and effective range of microscopic two-body potentials
Mathias Macêdo-Lima · Lucas Madeira
Scattering processes are a fundamental way of experimentally probing distributions and properties of systems in several areas of physics. Considering two-body scattering at low energies, when the de Broglie wavelength is larger than the range of the potential, partial waves with high angular momentum are typically unimportant. The dominant contribution comes from $l = 0$ partial waves, commonly known as $s$ -wave scattering. This situation is very relevant in atomic physics, e.g. cold atomic gases, and nuclear physics, e.g. nuclear structure and matter. This manuscript is intended as a pedagogical introduction to the topic while covering a numerical approach to compute the desired quantities. We introduce low-energy scattering with particular attention to the concepts of scattering length and effective range. These two quantities appear in the effective-range approximation, which universally describes low-energy processes. We outline a numerical procedure for calculating the scattering length and effective range of spherically symmetric two-body potentials. As examples, we apply the method to the spherical well, modified Pöschl-Teller, Gaussian, and Lennard-Jones potentials. We hope to provide the tools so students can implement similar calculations and extend them to other potentials.
↳ quant-phcond-mat.quant-gasnucl-thphysics.atom-phRev.Bras.Ens.Fis.(2023)·9 citations
12
Magnetic enhancement of baryon confinement modeled via a deformed Skyrmion
Shi Chen🇯🇵 · Kenji Fukushima🇯🇵 · Zebin Qiu🇯🇵
We discuss the baryon properties under a strong magnetic field. We adopt the Skyrme model and calculate the magnetic field dependence of the mass and the pressure distribution in the soliton. We elucidate a magnetically induced contribution to the pressure sum rule and interpret it as an extra confining force. We also quantize the soliton to estimate the difference between the proton and the neutron and find a simple relation between the pressure and the mass differences.
↳ hep-thnucl-thPLB(2023)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE

Neutrinoless double-beta decay in the neutrino-extended Standard Model

Analogies between hadron-in-jet and dihadron fragmentation

A possibility of existence of a pseudovector-type quark-antiquark condensate in the quark matter and Nambu-Goldstone modes on that condensate in the Nambu-Jona-Lasinio model

Deep learning for flow observables in ultrarelativistic heavy-ion collisions

Scattering length and effective range of microscopic two-body potentials

Magnetic enhancement of baryon confinement modeled via a deformed Skyrmion

Affiliations