Nuclear Theory·nucl-th

Friday·October 1, 2021

13 papers—5 primary·8 cross-listed

01
Solar neutrinos and the primordial Sun
W. C. Haxton🇺🇸
I discuss the possibility that the large-scale segregation of metals that accompanied planet formation might have left an imprint on the composition of the primordial Sun. Motivated in part by recent Borexino measurements of CN solar neutrinos, I stress how the additional linear metallicity dependence of this flux could be exploited to constrain the composition of the solar core. The gas in the core is arguably the earliest preserved sample of the material out of which our solar system formed.
nucl-thInnovations Platform 7, 52 (2021)·0 citations
02
Decorrelation of participant and spectator angular momenta in heavy-ion collisions
Joseph R. Adams🇺🇸 · Michael A. Lisa🇺🇸
High-energy heavy-ion collisions contain enormous angular momentum, $∣ J ∣$ , which is $O (1 0^{3} - 1 0^{6} ℏ)$ in the range of collision energy, $s_{NN}$ , spanned experimentally by the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). A fraction of $J$ is transferred to the overlapping collision region, which is indispensable for measuring observables such as vorticity-driven hadron spin alignment with $J^$ . Experiments estimate the orientation of $J^$ of the participant nucleons within the collision overlap region, $J^_{part}$ , by using that of the forward- and backward-going spectating nucleons $J^_{spec}$ . Using two models, we study the decorrelation between $J^_{part}$ and $J^_{spec}$ , driven both by angular-momentum conservation and event-by-event fluctuations, as well as by the decorrelation between the orientation of the elliptic overlap region and the $J^_{part}$ . $s_{NN}$ -dependent decorrelation is observed in both of these cases and is large enough to be an important corrective factor used when experimentally observing phenomena driven by $J$ .
nucl-thPRC(2022)·4 citations
03
The effect of charge, isospin, and strangeness in the QCD phase diagram critical end point
Krishna Aryal🇺🇸 · Constantinos Constantinou🇮🇹 · Ricardo L.S. Farias🇧🇷 · Veronica Dexheimer🇺🇸
In this work, we discuss the deconfinement phase transition to quark matter in hot/dense matter. We {examine} the effect that different charge fractions, isospin fractions, net strangeness, and chemical equilibrium with respect to leptons have on the position of the coexistence line between different phases. In particular, we investigate how different sets of conditions that describe matter in neutron stars and their mergers, or matter created in heavy-ion collisions affect the position of the critical end point, namely where the first-order phase transition becomes a crossover. We also present an introduction to the topic of critical points, including a review of recent {advances} concerning QCD critical points.
nucl-thastro-ph.HEhep-thUniverse(2021)·8 citations
04
Early time behavior of spatial and momentum anisotropies in a kinetic approach to nuclear collisions
Marc Borrell🇩🇪 · Nicolas Borghini🇩🇪
We derive a general formula for the early time dependence of a phase space distribution evolving according to the kinetic Boltzmann equation. Assuming that the early evolution of the system created in high-energy nuclear collisions can be described by kinetic theory, we calculate the scaling behaviors for the onset of various characteristics of the transverse dynamics. In particular, we show that the scaling behavior of the anisotropic flow coefficients $v_{n}$ at early times does not depend on the details of the collision kernel or the system composition, while at the same time it differs from the prediction of fluid dynamics.
nucl-thhep-phEPJC(2022)·9 citations
05
Spin Polarization Formula for Dirac Fermions at Local Equilibrium
Yu-Chen Liu🇨🇳 · Xu-Guang Huang🇨🇳
We derive a Cooper-Frye type spin polarization formula for Dirac fermions at local thermal equilibrium described by a grand canonical ensemble specified by temperature, fluid velocity, chemical potential, and spin potential. We discuss the physical meaning of different contributions to spin polarization and compare them with previous works. The present formula provides machinery to convert the spin potential computed in, e.g., relativistic spin hydrodynamics to the spin polarization observable in, e.g., heavy-ion collisions.
nucl-thhep-phnucl-exSCPMA(2022)·46 citations
06
Freezing out critical fluctuations
Maneesha Pradeep🇺🇸 · Krishna Rajagopal🇺🇸 · Misha Stephanov🇺🇸 · Yi Yin🇨🇳
We introduce a novel freeze-out procedure connecting the hydrodynamic evolution of a droplet of quark-gluon plasma (QGP) that has, as it expanded and cooled, passed close to a posited critical point on the QCD phase diagram with the subsequent kinetic description in terms of observable hadrons. The procedure converts out-of-equilibrium critical fluctuations described by extended hydrodynamics, known as Hydro+, into cumulants of hadron multiplicities that can be subsequently measured. We introduce a critical sigma field whose fluctuations cause correlations between observed hadrons due to the couplings of the sigma field to the hadrons. We match the QGP fluctuations obtained via solving the Hydro+ equations describing the evolution of critical fluctuations before freeze-out to the correlations of the sigma field. In turn, these are imprinted onto fluctuations in the multiplicities of hadrons, most importantly protons, after freeze-out via a generalization of the familiar half-a-century-old Cooper-Frye freeze-out prescription which we introduce. This framework allows us to study the effects of critical slowing down and the consequent deviation of the observable predictions from equilibrium expectations quantitatively. We can also quantify the suppression of cumulants due to the conservation of baryon number. We demonstrate the prescription in practice by freezing out the Hydro+ simulation in a simplified azimuthally symmetric and boost invariant background discussed in Rajagopal, Ridgway, Weller, Yin, 2019.
↳ hep-phnucl-thPoS(2022)·8 citations
07
Nuclear fusion catalyzed by doubly charged scalars: Implications for energy production
Evgeny Akhmedov (MPIK Heidelberg)🇩🇪
A number of popular extensions of the Standard Model of particle physics predict the existence of doubly charged scalar particles $X^{\pm\pm}$ . Such particles may be long-lived or even stable. If exist, $X^{--}$ could form atomic bound states with light nuclei and catalyze their fusion by essentially eliminating the Coulomb barrier between them. Such an $X$ -catalyzed fusion ( $X$ CF) process does not require high temperatures or pressure and may have important applications for energy production. A similar process of muon-catalyzed fusion ( $μ$ CF) has been shown not to be a viable source of energy because of the sticking of negative muons to helium nuclei produced in the fusion of hydrogen isotopes, which stops the catalytic process. We analyze $X$ CF in deuterium environments and show that the $X$ -particles can only stick to $^{6}$ Li nuclei, which are produced in the third-stage reactions downstream in the catalytic cycle. The corresponding sticking probability is very low, and, before getting bound to $^{6}$ Li, each $X$ -particle can catalyze $\sim 3.5 \cdot 1 0^{9}$ fusion cycles, producing $\sim 7 \cdot 1 0^{4}$ TeV of energy. We also discuss the ways of reactivating the $X$ -particles from the Coulomb-bound ( $^{6} Li X$ ) states, which would allow re-using them in $X$ CF reactions.
↳ hep-phastro-ph.SRhep-exnucl-ex+1PRD(2022)·4 citations
08
Nuclear fission reaction simulations in compact stars
Alex Deibel · M. E. Caplan · C. J. Horowitz
Type-Ia supernovae (SN Ia) are powerful stellar explosions that provide important distance indicators in cosmology. Recently, we proposed a new SN Ia mechanism that involves a nuclear fission chain-reaction in an isolated white dwarf [PRL 126, 1311010]. Here we perform novel reaction network simulations of the actinide-rich first solids in a cooling white dwarf. The network includes neutron-capture and fission reactions on a range of U and Th isotopes with various possible values for U-235 enrichment. We find, for modest U-235 enrichments, neutron-capture on U-238 and Th-232 can breed additional fissile nuclei so that a significant fraction of all U and Th nuclei may fission during the chain-reaction. The resulting large energy release could ignite thermonuclear carbon burning and possibly trigger a SN Ia.
↳ astro-ph.SRastro-ph.HEnucl-thPRC(2022)·3 citations
09
Heavy-quark spin polarization induced by the Kondo effect in a magnetic field
Daiki Suenaga🇯🇵 · Yasufumi Araki🇯🇵 · Kei Suzuki🇯🇵 · Shigehiro Yasui🇯🇵
We propose a new mechanism of the heavy-quark spin polarization (HQSP) in quark matter induced by the Kondo effect under external magnetic field. The Kondo effect is caused by a condensate between a heavy and a light quark called the Kondo condensate leading to a mixing of the heavy and light quark spins. Thus the HQSP is driven through the Kondo effect from light quarks coupling with the magnetic field in quark matter. For demonstration, we employ the Nambu--Jona-Lasinio type model under a magnetic field, and investigate the HQSP within the linear response theory with vertex corrections required by the $U (1)_{EM}$ electromagnetic gauge invariance. As a result, we find that the HQSP arises significantly with the appearance of the Kondo effect. Our findings are testable in future sign-problem-free lattice simulations.
↳ hep-phhep-latnucl-thPRD(2022)·6 citations
10
The MC-QTAIM: A framework for extending the atoms in molecules analysis beyond purely electronic systems
Shant Shahbazian🇮🇷
The quantum theory of atoms in molecules, QTAIM, is employed to identify AIM and quantify their interactions through the partitioning of molecule into atomic basins in the real space and it is confined only to the purely electronic systems composed of electrons as quantum particles and the nuclei as clamped point charges. The extended version of the QTAIM, called the multi-component QTAIM, MC-QTAIM, bypasses this border and makes it possible to identify AIM and quantify their interactions in systems composed of multiple quantum particles that electrons may or may not be one of their components opening a new door for the analysis of the exotic AIM and bonds. In this contribution, two conjectures, called Bader conjecture, BC, and extended Bader conjecture, EBC, are proposed as the cornerstones of the real-space partitioning of a molecule into atomic basins within the context of the QTAIM and the MC-QTAIM, respectively. A literature survey on various few-body quantum systems composed of quarks, nucleons, and elementary particles like muons and positrons is also done unraveling the fact that in all these diverse systems there are unambiguous cases of clusterizations. These clustered systems, irrespective to their components, behave as if they are molecules composed of some kind of atoms, instead of being an amorphous mixture of quantum particles. In the case of the muonic and the positronic molecules computational studies reveal that the AIM structures of these systems are well-captured by the EBC. Beyond identifying atomic basins, both QTAIM and MC-QTAIM attribute properties to AIM, which is their share from the molecular expectation values of quantum observables. It is demonstrated that not only the share from the average value of an observable may be attributed to an atomic basin, but also the fluctuation of each basin property is also quantifiable.
↳ physics.atm-clusnucl-thphysics.chem-phquant-phBook: Advances in Quantum Chemical Topolo…·0 citations
11
Hydrodynamic attractors in heavy ion collisions: a review
Alexander Soloviev🇺🇸
A review of the recent progress of relativistic hydrodynamic attractors is presented, with a focus on applications in heavy ion collisions and the quark gluon plasma. Pedagogical introductions to the effective descriptions relevant for attractors in high energy physics, namely hydrodynamics, holography and kinetic theory, are followed by highlights of some recent advances.
↳ hep-thhep-phnucl-thEPJC(2022)·81 citations
12
$P_{c} (4312)^{+}$ and $P_{c} (4337)^{+}$ as interfering $Σ_{c} D ˉ$ and $Λ_{c} D ˉ^{*}$ threshold cusps
S.X. Nakamura (Univ. of Science and Technology of China)🇨🇳 · A. Hosaka (RCNP, Osaka Univ., JAEA)🇯🇵 · Y. Yamaguchi (JAEA)🇯🇵
The recent LHCb data on $B_{s}^{0} \to J / ψ p p ˉ$ revealed a new pentaquark-like $P_{c} (4337)^{+}$ structure, while finding no evidence for $P_{c} (4312)^{+}$ discovered earlier in $Λ_{b}^{0} \to J / ψ p K^{-}$ . Though puzzling, the data actually offer an important hint to understand the nature of the pentaquark candidates. We develop a model to analyze the $B_{s}^{0} \to J / ψ p p ˉ$ data. We find that a $Σ_{c} D ˉ$ one-loop mechanism causes a threshold cusp that fits well the $P_{c} (4337)^{+}$ peak. Also, the $Σ_{c} D ˉ$ and $Λ_{c} D ˉ^{*}$ threshold cusps interfere with each other to reproduce an oscillating behavior in the proton helicity angle distribution. These results combined with our earlier analysis on $Λ_{b}^{0} \to J / ψ p K^{-}$ indicate that $P_{c} (4312)^{+}$ and $P_{c} (4337)^{+}$ are created by different interference patterns between the $Σ_{c} D ˉ$ and $Λ_{c} D ˉ^{*}$ (anomalous) threshold cusps. The proposed scenario consistently explains why the $P_{c} (4312)^{+}$ and $P_{c} (4337)^{+}$ peaks appear in $Λ_{b}^{0} \to J / ψ p K^{-}$ and $B_{s}^{0} \to J / ψ p p ˉ$ , respectively, but not vice versa or both.
↳ hep-phhep-exnucl-thPRD(2021)·41 citations
13
Probing hadronization with flavor correlations of leading particles in jets
Yang-Ting Chien🇺🇸 · Abhay Deshpande🇺🇸 · Mriganka Mouli Mondal🇺🇸 · George Sterman🇺🇸
We study nonperturbative flavor correlations between pairs of leading and next-to-leading charged hadrons within jets at the Electron-Ion Collider (EIC). We introduce a charge correlation ratio observable $r_{c}$ that distinguishes same- and opposite-sign charged pairs. Using Monte Carlo simulations with different event generators, $r_{c}$ is examined as a function of various kinematic variables for different combinations of hadron species, and the feasibility of such measurements at the EIC is demonstrated. The precision hadronization study we propose will provide new tests of hadronization models and hopefully lead to improved quantitative, and perhaps eventually analytic, understanding of nonperturbative QCD dynamics.
↳ hep-phhep-exnucl-exnucl-thPRD(2022)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE