Nuclear Theory·nucl-th

Tuesday·November 30, 2021

27 papers—14 primary·13 cross-listed

15
[Submitted on 26 Nov 2021] (cross-list from hep-ph)
Neutrino flavor mixing with moments
McKenzie Myers🇺🇸 · Theo Cooper🇺🇸 · MacKenzie Warren🇷🇺 · Jim Kneller🇺🇸 · Gail McLaughlin🇺🇸 · Sherwood Richers🇺🇸 · Evan Grohs🇺🇸 · Carla Frohlich🇺🇸
The successful transition from core-collapse supernova simulations using classical neutrino transport to simulations using quantum neutrino transport will require the development of methods for calculating neutrino flavor transformations that mitigate the computational expense. One potential approach is the use of angular moments of the neutrino field, which has the added appeal that there already exist simulation codes which make use of moments for classical neutrino transport. Evolution equations for quantum moments based on the quantum kinetic equations can be straightforwardly generalized from the evolution of classical moments based on the Boltzmann equation. We present an efficient implementation of neutrino transformation using quantum angular moments in the free streaming, spherically symmetric bulb model. We compare the results against analytic solutions and the results from more exact multi-angle neutrino flavor evolution calculations. We find that our moment-based methods employing scalar closures predict, with good accuracy, the onset of collective flavor transformations seen in the multi-angle results. However in some situations they overestimate the coherence of neutrinos traveling along different trajectories. More sophisticated quantum closures may improve the agreement between the inexpensive moment-based methods and the multi-angle approach.
Comments:
Accepted in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2111.13722 [pdf]
PRD(2022)·20 citations
16
[Submitted on 26 Nov 2021] (cross-list from hep-ph)
Splitting rates in QCD plasmas from a non-perturbative determination of the momentum broadening kernel $C (q_{⊥})$
Soeren Schlichting🇩🇪 · Ismail Soudi🇩🇪
We exploit a recent non-perturbative determination of the momentum broadening kernel $C (b_{⊥})$ in impact parameter space \cite{Moore:2021jwe}, to determine the momentum space broadening kernel $C (q_{⊥})$ in high-temperature QCD plasmas. We show how to use the non-pertubatively determined kernel $C (q_{⊥})$ to compute the medium-induced splitting rates in a QCD plasma of finite size. We compare the resulting in-medium splitting rates to the results obtained with leading-order and next-to-leading order perturbative determinations of $C (q_{⊥})$ , as well as with various approximations of the splitting employed in the literature. Generally, we find that the differences in the splitting rates due to the momentum broadening kernel are larger than the errors associated with approximations of the splitting rate.
Comments:
19 pages, 10 figures, pulished version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2111.13731 [pdf]
PRD(2022)·36 citations
17
[Submitted on 26 Nov 2021] (cross-list from hep-ph)
Hypermassive quark cores
Luiz L. Lopes🇧🇷 · Carline Biesdorf🇧🇷 · Débora P. Menezes🇧🇷
Using a quantum hadrodynamics (QHD) and MIT based models we construct hybrid stars within the Maxwell criteria of hadron-quark phase transition. We are able to produce a hybrid star with maximum mass of 2.15 $M_{⊙}$ . Furthermore, a 2.03 $M_{⊙}$ star with a quark core corresponding to more than $80%$ of both, its total mass and radius, is also possible.
Comments:
13 pages, 11 figures, 15 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2111.13732 [pdf]
MNRAS(2022)·29 citations
18
[Submitted on 27 Nov 2021] (cross-list from hep-lat)
Space-time symmetric qubit regularization of the asymptotically free two-dimensional O(4) model
Junzhe Zhou🇺🇸 · Hersh Singh🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Shailesh Chandrasekharan🇺🇸 · Rajan Gupta🇺🇸
We explore if space-time symmetric lattice field theory models with a finite Hilbert space per lattice site can reproduce asymptotic freedom in the two-dimensional $O (4)$ model. We focus on a simple class of such models with a five dimensional local Hilbert space. We demonstrate how even the simplest model reproduces asymptotic freedom within the D-theory formalism but at the cost of increasing the size of the Hilbert space through coupling several layers of a two-dimensional lattice. We then argue that qubit regularization can be viewed as an effective field theory (EFT) even if the continuum limit cannot be reached, as long as we can tune the model close enough to the continuum limit where perturbation theory, or other analytical techniques, become viable. We construct a simple lattice model on a single layer with a four dimensional local Hilbert space that acts like an excellent EFT of the original theory.
Comments:
11 pages, 6 figures
Subjects:
High Energy Physics — Lattice (hep-lat); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2111.13780 [pdf]
PRD(2022)·14 citations
19
[Submitted on 28 Nov 2021] (cross-list from hep-ph)
Far from equilibrium Chiral Magnetic Effect in Strong Magnetic Fields from Holography
Sebastian Grieninger🇪🇸 · Sergio Morales-Tejera🇪🇸
We study the real time evolution of the chiral magnetic effect out-of-equilibrium in strongly coupled anomalous field theories. We match the parameters of our model to QCD parameters and draw lessons of possible relevance for the realization of the chiral magnetic effect in heavy ion collisions. In particular, we find an equilibration time of about $\sim 0.35$ fm/c in presence of the chiral anomaly for plasma temperatures of order $T \sim 300 - 400$ MeV.
Comments:
8 pages, 3 figures. Contribution to the proceedings of the conference (virtual) "Quark Confinement and the Hadron Spectrum 2021" (vConf21), 2 - 6 August 2021 in Stavanger, Norway; Talk on arXiv:2105.05855
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2111.14116 [pdf]
EPJ Web Conf.(2022)·3 citations
20
[Submitted on 28 Nov 2021] (cross-list from hep-ph)
Two-photon transitions of charmonia on the light front
Yang Li🇨🇳 · Meijian Li🇫🇮 · James P. Vary🇺🇸
We investigate the two-photon transitions $H_{c c ˉ} \to γ^{*} γ$ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography and one-gluon exchange interaction within the basis light-front quantization approach. We compute the two-photon transition form factors as well as the two-photon decay widths for S- and P-wave charmonia, $η_{c}$ and $χ_{c J}$ and their excitations. Without introducing any free parameters, our predictions are in good agreement with the recent experimental measurements by BaBar and Belle, shedding light on the relativistic nature of charmonium.
Comments:
8 pages, 8 figures, 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2111.14178 [pdf]
PRD(2022)·27 citations
21
[Submitted on 29 Nov 2021] (cross-list from nucl-ex)
Precise measurement of differential cross sections of the {\Sigma}-p --> {\Lambda} n reaction in momentum range 470-650 MeV/c
J-PARC E40 Collaboration: K. Miwa🇯🇵 · J. K. Ahn🇰🇷 · Y. Akazawa🇯🇵 · T. Aramaki🇯🇵 · S. Ashikaga🇯🇵 · S. Callier🇫🇷 · N. Chiga🇯🇵 · S. W. Choi🇯🇵 · H. Ekawa🇯🇵 · P. Evtoukhovitch🇷🇺 · N. Fujioka🇯🇵 · M. Fujita🇯🇵 and 59 other authors
The differential cross sections of the {\Sigma}-p --> {\Lambda} n reaction were measured accurately for the {\Sigma}- momentum (p_{{\Sigma}}) ranging from 470 to 650 MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the {\Sigma}-p --> {\Lambda} n reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of {\Delta}cos{\theta} = 0.1. The obtained differential cross sections show slightly forward-peaking structure in the measured momentum regions.The cross sections integrated for -0.7 < cos{\theta} < 1.0 were obtained as 22.5 +- 0.68 (stat.) +- 0.65 (syst.) mb and 15.8 +-0.83(stat.) +- 0.52 (syst.) mb for 470<p_{{\Sigma}}(MeV/c)<550 and 550<p_{{\Sigma}}(MeV/c)<650, respectively. These results show a drastic improvement compared to past measurements of the hyperon-proton scattering experiments. They will play essential roles in updating the theoretical models of the baryon-baryon interactions.
Comments:
arXiv admin note: text overlap with arXiv:2104.13608
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2111.14277 [pdf]
PRL(2022)·53 citations
22
[Submitted on 29 Nov 2021] (cross-list from nucl-ex)
Narrow resonances in the continuum of the unbound nucleus $^{15}$ F
V. Girard-Alcindor (1 and 2) · A. Mercenne (3) · I. Stefan (2) · F. de Oliveira Santos (1) · N. Michel (4) · M. Płoszajczak (1) · M. Assié (2) · A. Lemasson (1) · E. Clément (1) · F. Flavigny (5) · A. Matta (5) · D. Ramos (1) and 91 other authors
The structure of the unbound $^{15}$ F nucleus is investigated using the inverse kinematics resonant scattering of a radioactive $^{14}$ O beam impinging on a CH $_{2}$ target. The analysis of $^{1}$ H( $^{14}$ O,p) $^{14}$ O and $^{1}$ H( $^{14}$ O,2p) $^{13}$ N reactions allowed the confirmation of the previously observed narrow $1/ 2^{-}$ resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2 $^{-}$ and 3/2 $^{-}$ resonances. The newly observed levels decay by 1p emission to the ground of $^{14}$ O, and by sequential 2p emission to the ground state (g.s.) of $^{13}$ N via the $1^{-}$ resonance of $^{14}$ O. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2 $^{-}$ and 3/2 $^{-}$ resonances may be collectivized by the continuum coupling to nearby 2p- and 1p- decay channels. The observed excitation function $^{1}$ H( $^{14}$ O,p) $^{14}$ O and resonance spectrum in $^{15}$ F are well reproduced in the unified framework of the GSM.
Comments:
7 pages, 4 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2111.14412 [pdf]
PRC(2022)·19 citations
23
[Submitted on 29 Nov 2021] (cross-list from hep-ph)
On the $QQ q ˉ q ˉ$ -Quark Potential in String Models
Oleg Andreev🇷🇺
We propose a string theory construction for the system of two heavy quarks and two light antiquarks. The potential of the system is a function of separation between the quarks. We define a critical separation distance below which the system can be thought of mainly as a compact tetraquark. The results show the universality of the string tension and factorization at small separations expected from heavy quark-diquark symmetry. Our estimate of the screening length is in the range of lattice QCD. We also make a comparison with the potential of the $QQq$ system. The potentials look very similar at small quark separations but at larger separations they differ. The reason for this is that the flattening of the potentials happens at two well-separated scales as follows from the two different mechanisms: string breaking by light quarks for $QQq$ and string junction annihilation for $QQ q ˉ q ˉ$ . Moreover, a similar construction can also be applied to the $Q ˉ Q ˉ q q$ system.
Comments:
20 pages, 12 Figures; v2: reference added; v3: typos corrected, reference and comments added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2111.14418 [pdf]
PRD(2022)·27 citations
24
[Submitted on 29 Nov 2021] (cross-list from physics.atom-ph)
Efimovian states of three charged particles
Yusuke Nishida
When three particles in three dimensions interact with a short-range potential fine-tuned to an infinite scattering length, they form an infinite sequence of loosely bound states obeying discrete scale invariance known as Efimov states. Here we show that analogous states are formed by three charged particles carrying two equal charges and one opposite charge in one, two, and three dimensions without any fine-tuning. Our finding is based on the Born-Oppenheimer approximation, where an effective inverse-square attraction is induced as a consequence of the dipole-charge interaction between a hydrogenlike heavy-light atom and a far-separated heavy particle. Because the resulting Efimovian states emerge toward the second or higher dissociation threshold, they are to be realized as quasibound states and may be observed by exciting hydrogen molecular ions and trions in excitonic systems. We also consider the same system but with a logarithmic Coulomb potential relevant to quantum vortices in two-dimensional superfluids, where the Efimovian states are shown to emerge as genuine bound states toward the first dissociation threshold.
Comments:
7 pages, 3 figures; (v2) expanded with new Sec $.$ III on logarithmic Coulomb potential; (v3) published version
Subjects:
Atomic Physics (physics.atom-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Nuclear Theory (nucl-th); physics.chem-ph (physics.chem-ph)
arXiv:
2111.14545 [pdf]
PRA(2022)·2 citations
25
[Submitted on 29 Nov 2021] (cross-list from hep-lat)
Progress in the determination of Mellin moments of the pion LCDA using the HOPE method
William Detmold🇺🇸 · Anthony V. Grebe🇺🇸 · Issaku Kanamori🇯🇵 · C.-J. David Lin🇹🇼 · Santanu Mondal🇺🇸 · Robert J. Perry🇹🇼 · Yong Zhao🇺🇸
The pion light-cone distribution amplitude (LCDA) is a central non-perturbative object of interest for the calculation of high-energy exclusive processes in quantum chromodynamics. In this article, we discuss the calculation of the second and fourth Mellin moment of the pion LCDA using a heavy-quark operator product expansion. The resulting value for the second Mellin moment is $⟨ ξ^{2} ⟩ (μ = 2 GeV) = 0.210 \pm 0.013 (stat.) \pm 0.034 (sys.)$ . This result is compatible with those from previous determinations of this quantity.
Comments:
17 pages, 8 Figures, 3 Tables; Talk presented at The 38th International Symposium on Lattice Field Theory, LATTICE2021 26th-30th July, 2021, Zoom/Gather@Massachusetts Institute of Technology
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2111.14563 [pdf]
PoS(2022)·4 citations
26
[Submitted on 29 Nov 2021] (cross-list from hep-ph)
The information content of jet quenching and machine learning assisted observable design
Yue Shi Lai🇺🇸 · James Mulligan🇺🇸 · Mateusz Płoskoń🇺🇸 · Felix Ringer🇺🇸
Jets produced in high-energy heavy-ion collisions are modified compared to those in proton-proton collisions due to their interaction with the deconfined, strongly-coupled quark-gluon plasma (QGP). In this work, we employ machine learning techniques to identify important features that distinguish jets produced in heavy-ion collisions from jets produced in proton-proton collisions. We formulate the problem using binary classification and focus on leveraging machine learning in ways that inform theoretical calculations of jet modification: (i) we quantify the information content in terms of Infrared Collinear (IRC)-safety and in terms of hard vs. soft emissions, (ii) we identify optimally discriminating observables that are in principle calculable in perturbative QCD, and (iii) we assess the information loss due to the heavy-ion underlying event and background subtraction algorithms. We illustrate our methodology using Monte Carlo event generators, where we find that important information about jet quenching is contained not only in hard splittings but also in soft emissions and IRC-unsafe physics inside the jet. This information appears to be significantly reduced by the presence of the underlying event. We discuss the implications of this for the prospect of using jet quenching to extract properties of the QGP. Since the training labels are exactly known, this methodology can be used directly on experimental data without reliance on modeling. We outline a proposal for how such an experimental analysis can be carried out, and how it can guide future measurements.
Comments:
Final version after journal review
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2111.14589 [pdf]
JHEP(2022)·29 citations
27
[Submitted on 29 Nov 2021] (cross-list from hep-ph)
Dynamically groomed jet radius in heavy-ion collisions
Paul Caucal🇺🇸 · Alba Soto-Ontoso🇫🇷 · Adam Takacs🇳🇴
We explore the ability of a recently proposed jet substructure technique, Dynamical Grooming, to pin down the properties of the Quark-Gluon Plasma formed in ultra-relativistic heavy-ion collisions. In particular, we compute, both analytically and via Monte-Carlo simulations, the opening angle $θ_{g}$ of the hardest splitting in the jet as defined by Dynamical Grooming. Our calculation, grounded in perturbative QCD, accounts for the factorization in time between vacuum-like and medium-induced processes in the double logarithmic approximation. We observe that the dominating scale in the $θ_{g}$ -distribution is the decoherence angle $θ_{c}$ which characterises the resolution power of the medium to propagating color probes. This feature also persists in strong coupling models for jet quenching. We further propose for potential experimental measurements a suitable combination of the Dynamical Grooming condition and the jet radius that leads to a pQCD dominated observable with a very small sensitivity ( $\leq 10%$ ) to medium response.
Comments:
21 pages, 16 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2111.14768 [pdf]
PRD(2022)·61 citations

Affiliations

first authorsco-authorsvia INSPIRE