Nuclear Theory·nucl-th

Tuesday·April 7, 2020

17 papers—11 primary·6 cross-listed

12
[Submitted on 4 Apr 2020] (cross-list from hep-th)
Causality and Stability Conditions of a Conformal Charged Fluid
Farid Taghinavaz🇮🇷
In this paper, I study the conditions imposed on a normal charged fluid so that the causality and stability criteria hold for this fluid. I adopt the newly developed General Frame (GF) notion in the relativistic hydrodynamics framework which states that hydrodynamic frames have to be fixed after applying the stability and causality conditions. To my purpose, I take a charged conformal matter in the flat and $3 + 1$ dimension to analyze better these conditions. The causality condition is applied by looking to the asymptotic velocity of sound hydro modes at the large wave number limit and stability conditions are imposed by looking to the imaginary parts of hydro modes as well as the Routh-Hurwitz criteria. By fixing some of the transports, the suitable spaces for other ones are derived. I have observed that in a dense medium with finite $U (1)$ charged chemical potential $μ_{0}$ , negative values for transports appear and the second law of thermodynamics has not ruled out the existence of such values. Sign of scalar transports are not limited by any constraints and just a combination of vector transports is limited by the second law of thermodynamic. Also numerically it is proved that the most favorable region for transports $γ ~_{1, 2}$ , coefficients of the dissipative terms of the current, is of negative values.
Comments:
27 pages, 9 Figures, Comments are welcomed
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2004.01897 [pdf]
JHEP(2020)·14 citations
13
[Submitted on 4 Apr 2020] (cross-list from astro-ph.HE)
Presupernova neutrinos: directional sensitivity and prospects for progenitor identification
Mainak Mukhopadhyay🇺🇸 · Cecilia Lunardini🇺🇸 · F. X. Timmes🇺🇸 · Kai Zuber🇩🇪
We explore the potential of current and future liquid scintillator neutrino detectors of O (10) kt mass to localize a pre-supernova neutrino signal in the sky. In the hours preceding the core collapse of a nearby star (at distance D < 1 kpc), tens to hundreds of inverse beta decay events will be recorded, and their reconstructed topology in the detector can be used to estimate the direction to the star. Although the directionality of inverse beta decay is weak (~8% forward-backward asymmetry for currently available liquid scintillators), we find that for a fiducial signal of 200 events (which is realistic for Betelgeuse), a positional error of ~60 degrees can be achieved, resulting in the possibility to narrow the list of potential stellar candidates to less than ten, typically. For a configuration with improved forward-backward asymmetry (~40%, as expected for a lithium-loaded liquid scintillator), the angular sensitivity improves to ~15 degrees, and - when a distance upper limit is obtained from the overall event rate - it is in principle possible to uniquely identify the progenitor star. Any localization information accompanying an early supernova alert will be useful to multi-messenger observations and to particle physics tests using collapsing stars.
Comments:
LaTeX, 16 pages, 9 figures, 7 tables. Updated to reflect published version. Minor corrections and clarifications, results unchanged
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2004.02045 [pdf]
ApJ(2020)·61 citations
14
[Submitted on 5 Apr 2020] (cross-list from hep-ph)
Brief history of the search for critical structures in heavy-ion collisions
Marek Gazdzicki🇵🇱 · Mark Gorenstein🇺🇦 · Peter Seyboth🇵🇱
The paper briefly presents history, status, and plans of the search for the critical structures - the onset of fireball, the onset of deconfinement, and the deconfinement critical point - in high energy nucleus-nucleus collisions. First, the basic ideas are introduced, the history of the observation of strongly interacting matter in heavy ion collisions is reviewed, and the path towards the quark-gluon plasma discovery is sketched. Then the status of the search for critical structures is discussed - the discovery of the onset of deconfinement, indications for the onset of fireball, and still inconclusive results concerning the deconfinement critical point. Finally, an attempt to formulate priorities for future measurements - charm quarks vs the onset of deconfinement and detailed study of the onset of fireball - closes the paper.
Comments:
38 pages, 17 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2004.02255 [pdf]
Acta Phys.Polon.B(2020)·10 citations
15
[Submitted on 6 Apr 2020] (cross-list from hep-ph)
Canonical interpretations of the newly observed $Ξ_{c} (2923)^{0}$ , $Ξ_{c} (2939)^{0}$ and $Ξ_{c} (2965)^{0}$ resonances
Qi-Fang Lü🇨🇳
Three neutral resonances $Ξ_{c} (2923)^{0}$ , $Ξ_{c} (2939)^{0}$ and $Ξ_{c} (2965)^{0}$ have been observed in the $Λ_{c}^{+} K^{-}$ mass spectrum by the LHCb Collaboration. Given the $Ξ_{c}$ and $Ξ_{c}^{'}$ mass spectra predicted by the constituent quark models, these three resonances are tentatively treated as the $λ -$ mode $Ξ_{c} (2 S)$ , $Ξ_{c}^{'} (2 S)$ , $Ξ_{c}^{' *} (2 S)$ , and $Ξ_{c}^{'} (1 P)$ states, and their strong decay behaviors are calculated within the $^{3} P_{0}$ model. Our results indicate that the $Ξ_{c} (2923)^{0}$ and $Ξ_{c} (2939)^{0}$ can be clarified into the $J^{P} = 3/ 2^{-}$ and $5/ 2^{-}$ $Ξ_{c}^{'} (1 P)$ states respectively, and the $Ξ_{c} (2965)^{0}$ can be regarded as the $J^{P} = 1/ 2^{+}$ $Ξ_{c}^{'} (2 S)$ state. Also, we suggest that the previous observed $Ξ_{c} (2930)$ may be the overlap of two structures $Ξ_{c} (2923)$ and $Ξ_{c} (2939)$ , and the $Ξ_{c} (2970)$ should be the same state as $Ξ_{c} (2965)$ . Other theoretical information on the missing $Ξ_{c} (2 S)$ , $Ξ_{c}^{' *} (2 S)$ , and $Ξ_{c}^{'} (1 P)$ states may be helpful for future experimental searches.
Comments:
7 pages, 2 figures, some important corrections, suggestions and comments are welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2004.02374 [pdf]
EPJC(2020)·32 citations
16
[Submitted on 6 Apr 2020] (cross-list from nucl-ex)
Yield ratio of hypertriton to light nuclei in heavy-ion collisions from $s_{NN}$ = 4.9 GeV to 2.76 TeV
Tianhao Shao🇨🇳 · Jinhui Chen🇨🇳 · Che Ming Ko🇺🇸 · Kai-Jia Sun🇺🇸 · Zhangbu Xu🇺🇸
We resolve the difference in the yield ratio $S_{3}$ = $\frac{N _{_{Λ}^{3} H} / N _{Λ}}{N _{^{3} He} / N _{p}}$ measured in Au+Au collisions at $s_{NN}$ = 200 GeV and in Pb-Pb collisions at $s_{NN}$ = 2.76 TeV by adopting a different treatment of the weak decay contribution to the proton yield in Au+Au collisions at $s_{NN}$ = 200 GeV. We then use the coalescence model to extract information on the $Λ$ and nucleon density fluctuations at the kinetic freeze-out of heavy ion collisions. We also show from available experimental data that the yield ratio $S_{2}$ = $\frac{N _{_{Λ}^{3} H}}{N _{Λ} N _{d}}$ is a more promising observable than $S_{3}$ for probing the local baryon-strangeness correlation in the produced medium.
Comments:
15 pages, 2 figures, 3 tables, submitted for publication
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2004.02385 [pdf]
CPC(2020)·16 citations
17
[Submitted on 6 Apr 2020] (cross-list from hep-lat)
Sparse modeling approach to obtaining the shear viscosity from smeared correlation functions
Etsuko Itou🇯🇵 · Yuki Nagai🇯🇵
We propose the sparse modeling method to estimate the spectral function from the smeared correlation functions. We give a description of how to obtain the shear viscosity from the correlation function of the renormalized energy-momentum tensor (EMT) measured by the gradient flow method ( $C (t, τ)$ ) for the quenched QCD at finite temperature. The measurement of the renormalized EMT in the gradient flow method reduces a statistical uncertainty thanks to its property of the smearing. However, the smearing breaks the sum rule of the spectral function and the over-smeared data in the correlation function may have to be eliminated from the analyzing process of physical observables. In this work, we demonstrate that the sparse modeling analysis in the intermediate-representation basis (IR basis), which connects between the Matsubara frequency data and real frequency data. It works well even using very limited data of $C (t, τ)$ only in the fiducial window of the gradient flow. We utilize the ADMM algorithm which is useful to solve the LASSO problem under some constraints. We show that the obtained spectral function reproduces the input smeared correlation function at finite flow-time. Several systematic and statistical errors and the flow-time dependence are also discussed.
Comments:
32 pages, 16 figures, attached the numerical codes, (v2) comments and references are added
Subjects:
High Energy Physics — Lattice (hep-lat); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2004.02426 [pdf]
JHEP(2020)·30 citations

Affiliations

first authorsco-authorsvia INSPIRE

Causality and Stability Conditions of a Conformal Charged Fluid

Presupernova neutrinos: directional sensitivity and prospects for progenitor identification

Brief history of the search for critical structures in heavy-ion collisions

Canonical interpretations of the newly observed Ξc​(2923)0, Ξc​(2939)0 and Ξc​(2965)0 resonances

Yield ratio of hypertriton to light nuclei in heavy-ion collisions from sNN​​ = 4.9 GeV to 2.76 TeV

Sparse modeling approach to obtaining the shear viscosity from smeared correlation functions

Affiliations

Canonical interpretations of the newly observed $Ξ_{c} (2923)^{0}$ , $Ξ_{c} (2939)^{0}$ and $Ξ_{c} (2965)^{0}$ resonances

Yield ratio of hypertriton to light nuclei in heavy-ion collisions from $s_{NN}$ = 4.9 GeV to 2.76 TeV