Nuclear Theory·nucl-th

Thursday·September 21, 2023

10 papers—6 primary·4 cross-listed

07
3D Imaging via Polarized Jet Fragmentation Functions and Quantum Simulation of the QCD Phase Diagram
Fanyi Zhao🇺🇸
Understanding the interactions between elementary particles and mapping out the internal structure of the hadrons are of fundamental importance in high energy nuclear and particle physics. This thesis concentrates on the strong interaction, described by Quantum Chromodynamics (QCD). We introduce a novel concept called "polarized jet fragmentation functions" and develop the associated theory framework known as QCD factorization which allows us to utilize jet substructure to probe spin dynamics of hadrons, especially nucleon's three-dimensional imaging. Furthermore, non-perturbative QCD studies, particularly of the QCD phase diagram, are important for understanding the properties of hadrons. The development of quantum computing and simulators can potentially improve the accuracy of finite-temperature simulations and allow researchers to explore extreme temperatures and densities in more detail. In this thesis, I present my work in two aspects of QCD studies: (1) investigating the nucleon structure using polarized jet fragmentation functions and (2) illustrating how to apply quantum computing techniques for studying phase diagram of a low energy QCD model. The first category investigates phenomena such as hadron production inside jets, spin asymmetries, etc., providing valuable insight into the behavior of quarks and gluons in hadrons. The second category provides potential applications of quantum computing in QCD and explores the non-perturbative nature of QCD.
↳ hep-phhep-exhep-latnucl-th+11 citation
08
Rare decays of $B_{d}$ mesons into four charged leptons in the Standard Model
A. V. Danilina🇷🇺 · N. V. Nikitin🇷🇺
We present first theoretical predictions for various observables related to the $B ˉ_{d} \to μ^{+} μ^{-} e^{+} e^{-}$ decay within the framework of the Standard Model. Our study encompasses the branching ratios, differential distributions, and forward-backward leptonic asymmetries. To obtain these predictions, we account for several contributions: resonance contribution from $ρ (770)$ and significant contribution $ω (782)$ ; contributions from four charmonium resonances: $ψ (3770)$ , $ψ (4040)$ , $ψ (4160)$ , and $ψ (4415)$ ; additional contributions from the "tails" of $J / ψ$ and $ψ (2 S)$ resonances; non-resonant contributions arising from virtual photon emission by a $b$ -quark of $B_{d}$ meson, bremsstrahlung, and weak annihilation. In our calculations we employ the model of vector meson dominance (VMD) to assess the resonance contributions accurately. We provide the predictions for the branching ratio of the $B ˉ_{d} \to μ^{+} μ^{-} e^{+} e^{-}$ decay both with and without the resonant contribution from $ω (782)$ .
↳ hep-phnucl-th0 citations
09
Effects of electrons on nuclear clock transition frequency in $^{229}$ Th ions
V. A. Dzuba · V. V. Flambaum
We perform calculations of the energy shift of the nuclear clock transition frequency $^{229}$ Th as a function of the number of electrons in Th ion. We demonstrate that the dependence of the nuclear frequency on electron configuration is significant. E.g., removing one electron from the atom leads to relative shift of the nuclear frequency $\sim 1 0^{- 7}$ , which is twelve orders of magnitude larger than expected relative uncertainty of the nuclear clock transition frequency ( $\sim 1 0^{- 19}$ ). This leads to difference of the nuclear clock frequencies in Th~IV, Th~III, Th~II and Th~I. The relative change of the nuclear frequency between neutral Th and its bare nucleus is 1\%. We also calculate the field shift constants for isotopic and isomeric shifts of atomic electron transitions in Th ions.
↳ physics.atom-phhep-phnucl-thPRL(2023)·13 citations
10
Tetraquark mixing model is superior to meson molecules in explaining two light-meson nonets
Hungchong Kim🇰🇷 · K.S.Kim🇰🇷
In this work, we compare the tetraquark mixing model and meson molecules in describing the two physical nonets in the $J^{P} = 0^{+}$ channel, the light nonet [ $a_{0} (980)$ , $K_{0}^{*} (700)$ , $f_{0} (500)$ , $f_{0} (980)$ ] and the heavy nonet [ $a_{0} (1450)$ , $K_{0}^{*} (1430)$ , $f_{0} (1370)$ , $f_{0} (1500)$ ]. In particular, we focus on whether successful aspects of the tetraquark mixing model that apply to all members of each nonet can be reproduced from a model of meson molecules. By combining two mesons in the lowest-lying pseudoscalar nonet, we construct SU $_{f}$ (3) molecular nonets that can be tested for the two physical nonets. This molecular approach can make two flavor nonets just as the tetraquark mixing model but this model has some difficulties in describing the universal features of the two nonets %Because of this, this molecular model cannot reproduce successful aspects of the tetraquark mixing model, such as mass splitting between the two nonets, and enhancement or suppression of the coupling strengths of the two nonets into two pseudoscalar mesons. We also compare the fall-apart modes of the tetraquark mixing model and the two-meson modes from the molecular model. A clear distinction can be seen by the two-pion modes in the isovector resonances. The two-pion modes appear in the molecular model, but not in the tetraquark mixing model. The absence of the two-pion modes is supported by the experimental decay modes of the isovector resonances.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

3D Imaging via Polarized Jet Fragmentation Functions and Quantum Simulation of the QCD Phase Diagram

Rare decays of Bd​ mesons into four charged leptons in the Standard Model

Effects of electrons on nuclear clock transition frequency in 229Th ions

Tetraquark mixing model is superior to meson molecules in explaining two light-meson nonets

Affiliations

Rare decays of $B_{d}$ mesons into four charged leptons in the Standard Model

Effects of electrons on nuclear clock transition frequency in $^{229}$ Th ions