Nuclear Theory·nucl-th

Monday·January 17, 2022

9 papers—3 primary·6 cross-listed

04
Gluon transversity and TMDs for spin-1 hadrons
S. Kumano🇯🇵 · Qin-Tao Song🇨🇳
We explain a gluon transversity, transverse-momentum-dependent parton distribution functions (TMDs), and parton distribution functions (PDFs) for spin-1 hadrons. The gluon transversity exists in hadrons with spin more than or equal to one, and it does not exist in the spin-1/2 nucleons. Since there is no direct contribution from the nucleons, it is an appropriate quantity to probe an exotic component in the spin-1 deuteron beyond a simple bound system of the nucleons. We show how the gluon transversity can be measured at hadron accelerator facilities by the Drell-Yan process in addition to lepton-accelerator experiments. Next, possible TMDs are explained for the spin-1 hadrons at the twists 3 and 4 in addition to twist-2 ones by considering tensor polarizations. We found that 30 TMDs exist in the tensor-polarized spin-1 hadron at the twists 3 and 4 in addition to 10 TMDs at the twist 2. There are 3 collinear PDFs at the twists 3 and 4. We also indicate that the corresponding TMD fragmentation functions exist at the twists 3 and 4. Due to the time-reversal invariance in the collinear PDFs, there are new sum rules on the time-reversal odd TMDs. In addition, we obtained a useful twist-2 relation, a sum rule, and relations with multiparton distribution functions by using the operator product expansion and the equation of motion for quarks. These findings are valuable for experimental investigations on polarized deuteron structure functions in 2020's and 2030's at world accelerator facilities.
↳ hep-phhep-exhep-latnucl-thRev.Mex.Fis.Suppl.(2022)·1 citation
05
Model-based quantitative methods to predict irradiation-induced swelling in alloys
Wei Ge · Shijun Zhao · Chenxu Wang · Haocheng Liu · Yue Su · Jia Huang · Zhiying Gao · Jianming Xue · Steven J. Zinkle · Yugang Wang
Predicting volume swelling of structural materials in nuclear reactors under high-dose neutron irradiations based on existing low-dose experiments or irradiation data with high-dose-rate energetic particles has been a long-standing challenge for safety evaluation and rapidly screening irradiation-resistant materials in nuclear energy systems. Here, we build an Additional Defect Absorption Model that describes the irradiation-induced swelling effects produced by energetic electrons, heavy-ions, and neutrons by considering additional defect sinks inherent in the irradiation process. Based on this model, we establish quantitative methods to predict high-dose swelling from low-dose behavior and obtain the equivalent irradiation dose for different energetic particles when the dose rates differ by several orders of magnitude. Furthermore, we propose a universal parameter to characterize the swelling resistance of various alloys and predict their radiation tolerances under different radiation conditions. This work provides quantitative prediction methods for evaluating irradiation-induced swelling effects of structural materials, which is critical to the safety and material development for advanced nuclear reactors.
↳ cond-mat.mtrl-scinucl-thphysics.app-ph0 citations
06
Strangeness $S = - 2$ baryon-baryon interactions and femtoscopic correlation functions in covariant chiral effective field theory
Zhi-Wei Liu🇨🇳 · Kai-Wen Li🇨🇳 · Li-Sheng Geng🇨🇳
We study the baryon-baryon interactions with strangeness $S = - 2$ and corresponding momentum correlation functions in leading order covariant chiral effective field theory. The relevant low energy constants are determined by fitting to the latest HAL QCD simulations, taking into account all the coupled channels. Extrapolating the so-obtained strong interactions to the physical point and considering both quantum statistical effects and the Coulomb interaction, we calculate the $ΛΛ$ and $Ξ^{-} p$ correlation functions with a spherical Gaussian source and compare them with the recent experimental data. We find remarkable agreement between our predictions and the experimental measurements by using the source radius determined in proton-proton correlations, which demonstrates the consistency between theory, experiment, and lattice QCD simulations. Moreover, we predict the $Σ^{+} Σ^{+}$ , $Σ^{+} Λ$ , and $Σ^{+} Σ^{-}$ interactions and corresponding momentum correlation functions. We further investigate the influence of the source shape and size of the hadron pair on the correlation functions studied and show that the current data are not very sensitive to the source shape. Future experimental measurement of the predicted momentum correlation functions will provide a non-trivial test of not only SU(3) flavor symmetry and its breaking but also the baryon-baryon interactions derived in covariant chiral effective field theory.
↳ hep-phhep-exhep-latnucl-thCPC(2023)·42 citations
07
Renormalization Group Flows for Track Function Moments
Max Jaarsma🇳🇱 · Yibei Li🇨🇳 · Ian Moult🇺🇸 · Wouter Waalewijn🇳🇱 · Hua Xing Zhu🇨🇳
Track functions describe the collective effect of the fragmentation of quarks and gluons into charged hadrons, making them a key ingredient for jet substructure measurements at hadron colliders, where track-based measurements offer superior angular resolution. The first moment of the track function, describing the average energy deposited in charged particles, is a simple and well-studied object. However, measurements of higher-point correlations of energy flow necessitate a characterization of fluctuations in the hadronization process, described theoretically by higher moments of the track function. In this paper we derive the structure of the renormalization group (RG) evolution equations for track function moments. We show that energy conservation gives rise to a shift symmetry that allows the evolution equations to be written in terms of cumulants, $κ (N)$ , and the difference between the first moment of quark and gluon track functions, $Δ$ . The uniqueness of the first three cumulants then fixes their all-order evolution to be DGLAP, up to corrections involving powers of $Δ$ , that are numerically suppressed by an effective order in the perturbative expansion for phenomenological track functions. However, at the fourth cumulant and beyond there is non-trivial RG mixing into products of cumulants such as $κ (4)$ into $κ (2)^{2}$ . We analytically compute the evolution equations up to the sixth moment at $O (α_{s}^{2})$ , and study the associated RG flows. These results allow for the study of up to six-point correlations in energy flow using tracks, paving the way for precision jet substructure at the LHC.
↳ hep-phnucl-thJHEP(2022)·65 citations
08
TMDs for spin-1 hadrons
S. Kumano🇯🇵 · Qin-Tao Song🇨🇳
Transverse-momentum-dependent parton distribution functions (TMDs) were investigated at the twists 3 and 4 for spin-1 hadrons in addition to the twist-2 ones. They were found by studying all the possible decomposition of a quark correlation function in a Lorentz-invariant way with the Hermiticity and parity invariance. The time-reversal invariance was not imposed for the TMDs due to an active role of gauge links; however, they were used for collinear parton distribution functions (PDFs) by integrating the TMDs over the transverse momentum. We found that 30 TMDs exist in the tensor-polarized spin-1 hadron at the twists 3 and 4, whereas there are 10 TMDs at the twist 2. We also showed that there are 3 collinear PDFs at the twists 3 and 4. The corresponding TMD fragmentation functions exist sat the twists 2, 3, and 4 simply by changing function names and variables. Since the time-reversal invariance is valid in the collinear PDFs, the integrals of time-reversal-odd TMDs over the transverse momentum should vanish. It leads to the sum rules $\int d^{2} k_{T} h_{1 L T} (x, k_{T}^{2}) = \int d^{2} k_{T} g_{L T} (x, k_{T}^{2}) = \int d^{2} k_{T} h_{LL} (x, k_{T}^{2}) = \int d^{2} k_{T} h_{3 LL} (x, k_{T}^{2}) = 0$ on the time-reversal odd TMDs at the twists 3 and 4.
↳ hep-phhep-exhep-latnucl-thJPS Conf.Proc.(2022)·4 citations
09
Multiparticle-hole excitations in nuclei near N = Z = 20: $^{41}$ K
E. Rubino · S. L. Tabor · Vandana Tripathi · R. S. Lubna · B. Abromeit · J. m. Allmond · L. T. Baby · D. D. Caussyn · K. Kravvaris · A. Volya
This experimental study of high-spin structure near N = Z = 20 nuclei was focused on $^{41}$ K, but will also mention three newly observed $γ$ transitions in $^{41}$ Ca observed in the same reaction. High-spin states were populated using the $^{26}$ Mg( $^{18}$ O, $p 2 nγ$ ) $^{41}$ K and $^{26}$ Mg( $^{18}$ O, $3 nγ$ ) $^{41}$ Ca reactions. The experiment was carried out at an incident beam energy of 50 MeV at the Florida State University (FSU) John D. Fox Superconducting Linear Accelerator Laboratory and used the FSU high-purity germanium detector array. The $^{41}$ K level scheme was extended to 12325 keV, possibly with J $^{π}$ = 25/2 $^{-}$ or 27/2 $^{+}$ , by means of 25 new transitions and that of $^{41}$ Ca to 9916 keV. Linear polarization and a measure of angular distribution results are also reported and used to provide information on the spins and parities of several states in the $^{41}$ K decay scheme. The results have been compared to the $s p s d p f$ cross-shell FSU shell model interaction calculations. The theoretical results from configurations involving no or one additional nucleon promoted from the $s d$ to the $f p$ shell agree relatively well with the energies of known states, while those that involve multi-particle excitations paint an interesting and complex picture of interplay between single-particle excitations, collective pairing, and deformation. This presents an interesting challenge for future theory.
↳ nucl-exnucl-thEPJA(2022)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Gluon transversity and TMDs for spin-1 hadrons

Model-based quantitative methods to predict irradiation-induced swelling in alloys

Strangeness S=−2 baryon-baryon interactions and femtoscopic correlation functions in covariant chiral effective field theory

Renormalization Group Flows for Track Function Moments

TMDs for spin-1 hadrons

Multiparticle-hole excitations in nuclei near N = Z = 20: 41K

Affiliations

Strangeness $S = - 2$ baryon-baryon interactions and femtoscopic correlation functions in covariant chiral effective field theory

Multiparticle-hole excitations in nuclei near N = Z = 20: $^{41}$ K