Nuclear Theory·nucl-th

Thursday·December 23, 2021

11 papers—1 primary·10 cross-listed

01
Neutron stars with crossover to color superconducting quark matter
D. Blaschke🇵🇱 · E.-O. Hanu🇷🇴 · S. Liebing🇷🇺
We follow the idea that the QCD phase diagram may be described by a crossover from a hadron resonance gas to perturbative QCD using the switch function ansatz of Albright, Kapusta and Young [1]. While the switch function could be calibrated at vanishing baryon chemical potential with data from lattice QCD simulations, it has been suggested recently by Kapusta and Welle [2] that in the zero temperature limit, the switch function parameter $μ_{0}$ could be constrained by neutron star phenomenology, in particular by massive pulsars like PSR J0740+6620 with a mass exceeding $2 M_{⊙}$ . In this work we demonstrate that this procedure to constrain the QCD phase diagram does crucially depend on the fact that cold dense quark matter is very likely in a color superconducting state.
nucl-thastro-ph.HEPRC(2022)·27 citations
02
The Piezoaxionic Effect
Asimina Arvanitaki🇨🇦 · Amalia Madden🇨🇦 · Ken Van Tilburg🇺🇸
Axion dark matter (DM) constitutes an oscillating background that violates parity and time-reversal symmtries. Inside piezoelectric crystals, where parity is broken spontaneously, this axion background can result in a stress. We call this new phenomenon "the piezoaxionic effect". When the frequency of axion DM matches the natural frequency of a bulk acoustic normal mode of the piezoelectric crystal, the piezoaxionic effect is resonantly enhanced and can be read out electrically via the piezoelectric effect. We explore all axion couplings that can give rise to the piezoaxionic effect -- the most promising one is the defining coupling of the QCD axion, through the anomaly of the strong sector. We also point our another, subdominant phenomenon present in all dielectrics, namely the "electroaxionic effect". An axion background can produce an electric displacement field in a crystal which in turn will give rise to a voltage across the crystal. The electroaxionic effect is again largest for the axion coupling to gluons. We find that this model independent coupling of the QCD axion may be probed through the combination of the piezoaxionic and electroaxionic effects in piezoelectric crystals with aligned nuclear spins, with near-future experimental setups applicable for axion masses between $1 0^{- 11} eV$ and $1 0^{- 7} eV$ , a challenging range for most other detection concepts.
↳ hep-phhep-exnucl-thPRD(2024)·32 citations
03
Cool quark matter with perturbative quark masses
Tyler Gorda🇩🇪 · Saga Säppi🇮🇹
In perturbative thermal calculations, introducing nonzero quark masses causes considerable complications. In this article we describe an approximation scheme valid for sufficiently light masses which significantly simplifies the relevant calculations with only a small loss in accuracy. We apply the scheme to Quantum Chromodynamics, with two massless and one massive flavor, obtaining analytic results which are in excellent agreement with numerical non-approximated results. Our results are accurate to $O (g^{5})$ in the strong coupling parameter $g$ , as long as either the chemical potential $μ$ of the quark species with nonzero mass $m$ satisfies $m = O (g μ)$ or if the temperature $T$ satisfies $m = O (g T)$ . We find that these conditions are always satisfied for the three lightest quarks for the values of $μ$ , $T$ where Quantum Chromodynamics is perturbatively convergent.
↳ hep-phnucl-thPRD(2022)·32 citations
04
Bottomonium suppression and elliptic flow in heavy-ion collisions
Michael Strickland🇺🇸
In this proceedings contribution I review recent progress concerning the suppression of bottomonium production in the quark-gluon plasma. Making use of open quantum system methods applied to potential non-relativistic quantum chromodynamics one can show that the dynamics of heavy-quarkonium bound states satisfying the scale hierarchy 1/a_0 >> pi T ~ m_D >> E obey a Lindblad equation whose solution provides the quantum evolution of the heavy-quarkonium reduced density matrix. To solve the resulting Lindblad equation we use a quantum trajectories algorithm which allows one to include all possible angular momentum states of the quark-antiquark probe in a scalable manner. We solve the Lindblad equation using a tuned 3+1D dissipative hydrodynamics code for the background temperature evolution. We then consider a large number of Monte-Carlo sampled bottomonium trajectories embedded in this background. This allows us to extract the centrality- and p_T-dependence of the nuclear suppression factor R_AA[Upsilon] and elliptic flow v_2[Upsilon]. We find good agreement between our model predictions and available sqrt(s_NN) = 5.02 TeV Pb-Pb collision experimental data from the ALICE, ATLAS, and CMS collaborations.
↳ hep-phnucl-thRev.Mex.Fis.Suppl.(2022)·2 citations
05
The Impact of Neutron Transfer Reactions on Heating and Cooling of Accreted Neutron Star Crusts
H. Schatz · Z. Meisel · E. F. Brown · S. S. Gupta · G. W. Hitt · W. R. Hix · R. Jain · R. Lau · P. Möller · W.-J. Ong · P. S. Shternin · Y. Xu · M. Wiescher
Nuclear reactions heat and cool the crust of accreting neutron stars and need to be understood to interpret observations of X-ray bursts and of long-term cooling in transiently accreting systems. It was recently suggested that previously neglected neutron transfer reactions may play a significant role in the nuclear processes. We present results from full nuclear network calculations that now include these reactions and determine their impact on crust composition, crust impurity, heating, and cooling. We find that a large number of neutron transfer reactions indeed occur and impact crust models. In particular, we identify a new type of reaction cycle that brings a pair of nuclei across the nuclear chart into equilibrium via alternating neutron capture and neutron release, interspersed with a neutron transfer. While neutron transfer reactions lead to changes in crust model predictions, and need to be considered in future studies, previous conclusions concerning heating, cooling, and compositional evolution are remarkably robust.
↳ astro-ph.HEnucl-thApJ(2022)·10 citations
06
Nuclear History, Politics, and Futures from (A)toms-to(Z)oom: Design and Deployment of a Remote-Learning Special-Topics Course For Nuclear Engineering Education
Aaron J. Berliner · Jake Hecla
To address the lack of familiarity with nuclear history common among nuclear engineers and physicists, we outline the design and deployment of a special-topics course entitled "NE290: Nuclear History, Politics, and Futures" across which we contextualize the importance of the field at its inception, in current affairs, and in future endeavors. We begin by outlining the gaps in secondary educational offerings for nuclear history and their importance in consideration with nontechnical engineering guidelines. We then outline a number ABET specifications as pedagogical goals for NE290 from which we derive a list of target student learning objectives. Next, we outline the NE290 syllabus in terms of assignments and an overview of course content in the form of a class timeline. We provide an extensive description of the materials and teaching methodologies for the four units of NE290: 20th-Century Physics, Physics in WWII, the Early Cold War, and the Late Cold War and Modern Era. We detail the sequence of lectures across the course and historical timelines -- leading up to a showcasing of NE290 final projects which mirror in creativity the novelty of course offering. Because NE290 was first offered during Spring 2021 during the COVID-19 pandemic, additional measures in the form of new tools were used to augment the mandate of remote learning such as videoconferencing technology to recruit geographically diverse guest lecturers, and used the MIRO tool for virtual whiteboarding. Lastly, we provide an accounting of course outcomes drawn from student feedback which -- in tandem with the complete distribution of course material -- facilitates the integration of nuclear history into the curriculum for the wider nuclear engineering and physics communities.
↳ physics.ed-phnucl-th0 citations
07
Parton distribution function uncertainties in theoretical predictions for far-forward tau neutrinos at the Large Hadron Collider
Weidong Bai🇨🇳 · Milind Diwan🇺🇸 · Maria Vittoria Garzelli🇩🇪 · Yu Seon Jeong🇰🇷 · Fnu Karan Kumar🇺🇸 · Mary Hall Reno🇺🇸
New experiments to measure neutrinos in the far-forward region at the Large Hadron Collider (LHC) are under design or already in preparation. Two of them, FASER $ν$ and SND@LHC, are expected to be active during Run 3 and have the potential to detect neutrinos that come from high-energy collisions in one of the LHC interaction points, extracted along the direction tangent to the beam line. Tau neutrinos and antineutrinos come predominantly from $D_{s}^{\pm}$ production in $pp$ collisions, followed by the leptonic decay of these mesons. Neutrino pseudorapidities in the range of $η > 6.9$ and $η > 8.9$ are relevant to these future experiments. At such pseudorapidities at high energies, theoretical predictions for the flux of tau neutrinos rely on parton distribution functions (PDFs) in a combination of very small and large parton $- x$ values. We evaluate PDF uncertainties in a next-to-leading order (NLO) QCD calculation of the flux of $ν_{τ}$ + $ν ˉ_{τ}$ produced by $D_{s}^{\pm}$ decay in the far forward region at the LHC. The theoretical uncertainty associated with the 40 PDF sets of the PROSA19 group amounts to $\pm (20 - 30)$ \% for the ( $ν_{τ}$ + $ν ˉ_{τ}$ ) number of charged-current (CC) events. Scale uncertainties are much larger, resulting in a range of CC event predictions from $\sim 70%$ lower to $\sim 90%$ higher than the central prediction. A comparison of the predictions with those obtained using as input the central PDFs from the 3-flavour NLO PDF sets of the CT14, ABMP16 and NNPDF3.1 collaborations show that far-forward neutrino energy distributions vary by as much as a factor of $\sim 2 - 4$ relative to the PROSA19 predictions at TeV neutrino energies. The Forward Physics Facility in the high luminosity LHC era will provide data capable of constraining NLO QCD evaluations with these PDF sets.
↳ hep-phhep-exnucl-exnucl-thJHEP(2022)·36 citations
08
Effects of weak magnetic field and finite chemical potential on the transport of charge and heat in hot QCD matter
Shubhalaxmi Rath🇮🇳 · Sadhana Dash🇮🇳
We have studied the effects of weak magnetic field and finite chemical potential on the transport of charge and heat in hot QCD matter by estimating their respective response functions, such as the electrical conductivity ( $σ_{el}$ ), the Hall conductivity ( $σ_{H}$ ), the thermal conductivity ( $κ_{0}$ ) and the Hall-type thermal conductivity ( $κ_{1}$ ). The expressions of charge and heat transport coefficients are obtained by solving the relativistic Boltzmann transport equation in the relaxation time approximation at weak magnetic field and finite chemical potential. The interactions among partons are incorporated through their thermal masses. We have observed that $σ_{el}$ and $κ_{0}$ decrease and $σ_{H}$ and $κ_{1}$ increase with the magnetic field in the weak magnetic field regime. On the other hand, the presence of a finite chemical potential increases these transport coefficients. The effects of weak magnetic field and finite chemical potential on aforesaid transport coefficients are found to be more conspicuous at low temperatures, whereas at high temperatures, they have only a mild dependence on magnetic field and chemical potential. We have found that the presence of finite chemical potential further extends the lifetime of the magnetic field. Furthermore, we have explored the effects of weak magnetic field and finite chemical potential on the Knudsen number, the elliptic flow coefficient and the Wiedemann-Franz law.
↳ hep-phhep-thnucl-thEPJA(2023)·21 citations
09
Neural-Network Quantum States for Periodic Systems in Continuous Space
Gabriel Pescia🇨🇭 · Jiequn Han🇺🇸 · Alessandro Lovato🇺🇸 · Jianfeng Lu🇺🇸 · Giuseppe Carleo🇨🇭
We introduce a family of neural quantum states for the simulation of strongly interacting systems in the presence of spatial periodicity. Our variational state is parameterized in terms of a permutationally-invariant part described by the Deep Sets neural-network architecture. The input coordinates to the Deep Sets are periodically transformed such that they are suitable to directly describe periodic bosonic systems. We show example applications to both one and two-dimensional interacting quantum gases with Gaussian interactions, as well as to $^{4}$ He confined in a one-dimensional geometry. For the one-dimensional systems we find very precise estimations of the ground-state energies and the radial distribution functions of the particles. In two dimensions we obtain good estimations of the ground-state energies, comparable to results obtained from more conventional methods.
↳ quant-phcond-mat.str-elnucl-thPRResearch(2022)·47 citations
10
Testing the molecular nature of $ϕ (2170)$
A. Martínez Torres🇧🇷 · Brenda B. Malabarba🇧🇷 · Xiu-Lei Ren🇩🇪 · K. P. Khemchandani🇧🇷
In this talk we show our recent results on the decay widths of $ϕ (2170)$ to final states formed by an anti-Kaon and a Kaonic resonance, in particular, $K (1460)$ , $K_{1} (1270)$ and $K_{1} (1400)$ , considering a molecular description for $ϕ (2170)$ . Branching fraction ratios are obtained and compared with the recent results found by the BESIII collaboration, finding compatible results.
↳ hep-phnucl-thRev.Mex.Fis.Suppl.(2022)·0 citations
11
Ensembles of unified crust and core equations of state in a nuclear-multimessenger astrophysics environment
William G. Newton🇺🇸 · Lauren Balliet🇺🇸 · Srdan Budimir🇺🇸 · Gabriel Crocombe🇺🇸 · Brianna Douglas🇺🇸 · Thomas Blake Head🇺🇸 · Zach Langford🇺🇸 · Luis Rivera🇺🇸 · Josh Sanford🇺🇸
We present an ensemble of unified neutron star crust and core equations of state, constructed using an extended Skyrme energy density functional through the crust and outer core, and appended by two piecewise polytropes at higher densities. The equations of state are parameterized by the first three coefficients in the density expansion of the symmetry energy $J, L$ and $K_{sym}$ , the moment of inertia of a 1.338 M $_{⊙}$ star $I_{1.338}$ and the maximum neutron star mass $M_{max}$ . We construct an ensemble with uniform priors on all five parameters, and then apply data filters to the ensemble to explore the effect of combining neutron skin data from PREX with astrophysical measurements of radii and tidal deformabilities from NICER and LIGO/VIRGO. Neutron skins are calculated directly using the EDFs. We demonstrate that both the nuclear data and astrophysical data play a role in constraining crust properties such as the mass, thickness and moment of inertia of the crust and the nuclear pasta layers therein, and that astrophysical data better constrains $K_{sym}$ than PREX data.
↳ astro-ph.HEnucl-thEPJA(2022)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE