Nuclear Theory·nucl-th

Monday·May 22, 2023

7 papers—1 primary·6 cross-listed

01
[Submitted on 19 May 2023]
The vector MIT bag model under the light of new data
Maíra Cesário Alvim Lobo · Débora Peres Menezes
In the present work we use the vector MIT bag model to describe quark matter and obtain the macroscopic properties of neutron stars. We also calculate the speed of sound of quark matter described by this model with specific parameter values and check if the results obey the conformal limit at high densities. We have seen that the vector MIT bag model produces stars with masses and radii consistent with recent data, suggesting the possible existence of massive quark (or strange) stars.
Comments:
10 pages, 5 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2305.11740 [pdf]
0 citations
02
[Submitted on 18 May 2023] (cross-list from astro-ph.HE)
Fast Neutrino Flavor Conversions can Help and Hinder Neutrino-Driven Explosions
Jakob Ehring (1,2,3)🇩🇪 · Sajad Abbar (1)🇩🇪 · Hans-Thomas Janka (2)🇩🇪 · Georg Raffelt (1)🇩🇪 · Irene Tamborra (4) ((1) MPI Physik, (2) MPI Astrophysik, (3) TUM Garching, (4) Niels Bohr Institute)🇩🇰
We present the first simulations of core-collapse supernovae in axial symmetry with feedback from fast neutrino flavor conversion (FFC). Our schematic treatment of FFCs assumes instantaneous flavor equilibration under the constraint of lepton-number conservation individually for each flavor. Systematically varying the spatial domain where FFCs are assumed to occur, we find that they facilitate SN explosions in low-mass (9-12 solar masses) progenitors that otherwise explode with longer time delays, whereas FFCs weaken the tendency to explode of higher-mass (around 20 solar masses) progenitors.
Comments:
8 pages, 4 figures, slightly modified version, accepted by PRL
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2305.11207 [pdf]
PRL(2023)·110 citations
03
[Submitted on 18 May 2023] (cross-list from hep-ph)
Constraining $η / s$ through high-p $_{⊥}$ theory and data
Bithika Karmakar🇷🇸 · Dusan Zigic🇷🇸 · Igor Salom🇷🇸 · Jussi Auvinen🇷🇸 · Pasi Huovinen🇵🇱 · Marko Djordjevic🇷🇸 · Magdalena Djordjevic🇷🇸
We study whether it is possible to use high- $p_{⊥}$ data/theory to constrain the temperature dependence of the shear viscosity over entropy density ratio $η / s$ of the matter formed in ultrarelativistic heavy-ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). We use two approaches: i) We calculate high- $p_{⊥}$ $R_{AA}$ and flow coefficients $v_{2}$ , $v_{3}$ and $v_{4}$ assuming different $(η / s) (T)$ of the fluid-dynamically evolving medium. ii) We calculate the quenching strength ( $q^/ T^{3}$ ) from our dynamical energy loss model and convert it to $η / s$ as a function of temperature. It turned out that the first approach can not distinguish between different $(η / s) (T)$ assumptions when the evolution is constrained to reproduce the low- $p_{⊥}$ data. In distinction, $(η / s) (T)$ calculated using the second approach agrees surprisingly well with the $(η / s) (T)$ inferred through state-of-the-art Bayesian analyses of the low- $p_{⊥}$ data even in the vicinity of $T_{c}$ , while providing much smaller uncertainties at high temperatures.
Comments:
25 pages, 9 figures, Version published in Physical Review C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2305.11318 [pdf]
PRC(2023)·27 citations
04
[Submitted on 18 May 2023] (cross-list from hep-lat)
Nucleon Isovector Axial Form Factors
Yong-Chull Jang🇺🇸 · Rajan Gupta🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Boram Yoon🇺🇸 · Huey-Wen Lin🇺🇸
We present results for the isovector axial vector form factors obtained using thirteen 2+1+1-flavor highly improved staggered quark (HISQ) ensembles generated by the MILC collaboration. The calculation of nucleon two- and three-point correlation functions has been done using Wilson-clover fermions. In the analysis of these data, we quantify the sensitivity of the results to strategies used for removing excited state contamination and invoke the partially conserved axial current relation between the form factors to choose between them. Our data driven analysis includes removing contributions from multihadron $N π$ states that make significant contributions. Our final results are: $g_{A} = 1.292 (53)_{stat} (24)_{sys}$ for the axial charge; $g_{S} = 1.085 (50)_{stat} (103)_{sys}$ and $g_{T} = 0.991 (21)_{stat} (10)_{sys}$ for the scalar and tensor charges; $⟨ r_{A}^{2} ⟩ = 0.439 (56)_{stat} (34)_{sys}$ fm $^{2}$ for the mean squared axial charge radius, $g_{P}^{*} = 9.03 (47)_{stat} (42)_{sys}$ for the induced pseudoscalar charge; and $g_{π N N} = 14.14 (81)_{stat} (85)_{sys}$ for the pion-nucleon coupling. We also provide a parameterization of the axial form factor $G_{A} (Q^{2})$ over the range $0 \leq Q^{2} \leq 1$ GeV $^{2}$ for use in phenomenology and a comparison with other lattice determinations. We find that the various lattice data agree within 10\% but are significantly different from the extraction of $G_{A} (Q^{2})$ from the $ν$ -deuterium scattering data.
Comments:
49 pages, 24 figures, 35 tables. Final version published in PRD
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2305.11330 [pdf]
PRD(2024)·75 citations
05
[Submitted on 19 May 2023] (cross-list from hep-ph)
Chiral anomaly in a (1+1)-dimensional Floquet system under high-frequency electric fields
Kenji Fukushima🇯🇵 · Yoshimasa Hidaka🇯🇵 · Takuya Shimazaki🇯🇵 · Hidetoshi Taya🇯🇵
We investigate the chiral anomaly in a Floquet system under a time-periodic electric field in (1+1) dimensions. Using the van~Vleck high-frequency expansion, we analytically calculate the chiral current and the pseudo-scalar condensate for massless/massive fermions and how they are balanced with the topological charge. In the high-frequency limit, we find that finite-mass effects are suppressed and the topological charge is dominated by the chirality production. Our calculations show that the information about the chiral anomaly is stored not in the static Floquet Hamiltonian but in the periodic kick operator. The computational steps are useful as the theoretical foundation for higher-dimensional generalization.
Comments:
29 pages; v2: minor changes, to appear in Annals of Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2305.11432 [pdf]
Annals Phys.(2023)·6 citations
06
[Submitted on 19 May 2023] (cross-list from hep-ph)
Survival Probability of Unstable States in Coupled-Channels -- nonexponential decay of "threshold-cusp"
Wren A. Yamada🇯🇵 · Osamu Morimatsu🇯🇵 · Toru Sato🇯🇵 · Koichi Yazaki🇯🇵
We investigate the survival probability of unstable states, the time-dependence of an initial state, in coupled channels. First, we extend the formulation of the survival probability from single channel to coupled channels (two channels). We derive an exact general expression of the two-channel survival probability using uniformization, a method which makes the coupled-channel S matrix single-valued, and the Mittag-Leffler expansion, i.e. a pole expansion. Second, we calculate the time dependence of the two-channel survival probability by employing the derived expression. It is the minimal distance between the pole and the physical region in the complex energy plane, not the imaginary part of the pole energy, which determines not only the energy spectrum of the Green's function but also the survival probability. The survival probability of the "threshold-cusp" caused by a pole on the unusual complex-energy Riemann sheet is shown to decay, not grow in time though the imaginary part of the pole energy is positive. We also show that the decay of the "threshold-cusp" is non-exponential. Thus, the "threshold-cusp" is shown to be a new type of unstable mode, which is found only in coupled channels.
Comments:
10 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2305.11695 [pdf]
PRD(2023)·6 citations
07
[Submitted on 19 May 2023] (cross-list from physics.chem-ph)
Analytic evaluation of non-adiabatic couplings within the complex absorbing potential equation-of-motion coupled-cluster method
Koushik Chatterjee · Zsuzsanna Koczor-Benda · Xintian Feng · Anna I. Krylov · Thomas-C. Jagau
We present the theory for the evaluation of non-adiabatic couplings (NACs) involving resonance states within the complex absorbing potential equation-of-motion coupled-cluster (CAP-EOM-CC) framework implemented within the singles and doubles approximation. Resonance states are embedded in the continuum and undergo rapid decay through autodetachment. In addition, nuclear motions can facilitate transitions between different resonances and between resonances and bound states. These non-adiabatic transitions affect the chemical fate of resonances and have distinct spectroscopic signatures. The NAC vector is a central quantity needed to model such effects. In the CAP-EOM-CC framework, resonance states are treated on the same footing as bound states. Using the example of fumaronitrile, which supports a bound radical anion and several anionic resonances, we analyze the non-adiabatic coupling between bound states and pseudocontinuum states, between bound states and resonances and between two resonances. We find that the NAC between a bound state and a resonance is nearly independent of the CAP strength and thus straightforward to evaluate whereas the NAC between two resonance states or between a bound state and a pseudocontinuum state is more difficult to evaluate.
Subjects:
physics.chem-ph (physics.chem-ph); Nuclear Theory (nucl-th)
arXiv:
2305.11724 [pdf]
J.Chem.Theor.Comput.(2023)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

The vector MIT bag model under the light of new data

Fast Neutrino Flavor Conversions can Help and Hinder Neutrino-Driven Explosions

Constraining η/s through high-p⊥​ theory and data

Nucleon Isovector Axial Form Factors

Chiral anomaly in a (1+1)-dimensional Floquet system under high-frequency electric fields

Survival Probability of Unstable States in Coupled-Channels -- nonexponential decay of "threshold-cusp"

Analytic evaluation of non-adiabatic couplings within the complex absorbing potential equation-of-motion coupled-cluster method

Affiliations

Constraining $η / s$ through high-p $_{⊥}$ theory and data