Nuclear Theory·nucl-th

Monday·October 24, 2022

19 papers—10 primary·9 cross-listed

01
[Submitted on 21 Oct 2022]
Neutron star mass formula with nuclear saturation parameters for asymmetric nuclear matter
Hajime Sotani · Shinsuke Ota
Low-mass neutron stars are directly associated with the nuclear saturation parameters because their central density is definitely low. We have already found a suitable combination of nuclear saturation parameters for expressing the neutron star mass and gravitational redshift, i.e., $η \equiv (K_{0} L^{2})^{1/3}$ with the incompressibility for symmetric nuclear matter, $K_{0}$ , and the density-dependent nuclear symmetry energy, $L$ . In this study, we newly find another suitable combination given by $η_{τ} \equiv (- K_{τ} L^{5})^{1/6}$ with the isospin dependence of incompressibility for asymmetric nuclear matter, $K_{τ}$ , and derive the empirical relations for the neutron star mass and gravitational redshift as a function of $η_{τ}$ and the normalized central number density. With these empirical relations, one can evaluate the mass and gravitational redshift of the neutron star, whose central number density is less than threefold the saturation density, within $\sim 10%$ accuracy, and the radius within a few \% accuracies. In addition, we discuss the neutron star mass and radius constraints from the terrestrial experiments, using the empirical relations, together with those from the astronomical observations. Furthermore, we find a tight correlation between $η_{τ}$ and $η$ . With this correlation, we derive the constraint on $K_{τ}$ as $- 348 \leq K_{τ} \leq - 237$ MeV, assuming that $L = 60 \pm 20$ and $K_{0} = 240 \pm 20$ MeV.
Comments:
Accepted for publication in RPD. arXiv admin note: text overlap with arXiv:2203.09004
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2210.11651 [pdf]
PRD(2022)·22 citations
02
[Submitted on 21 Oct 2022]
Renormalization of One-Pion Exchange in Higher Partial Waves in Chiral Effective Field Theory for Antinucleon-Nucleon System
Daren Zhou🇨🇳
The renormalization of iterated one-pion exchange (OPE) has been studied in Chiral Effective Field Theory ( $χ$ EFT) for the antinucleon-nucleon ( $N N$ ) scattering in some partial waves (Phys. Rev. C 105, 054005 (2022)). We go further for the other higher partial waves but with total angular momenta $J \leq 3$ in this paper. Contact interactions are represented by a complex spherical well in coordinate space. Changing the radius of the spherical well means changing the cutoff. We check the cutoff dependence of the phase shifts, inelasticities, and mixing angles for the partial waves, and show that contact interactions are needed at leading order in channels where the singular tensor potentials of OPE are attractive. Results are compared with the energy-dependent partial-wave analysis of $N N$ scattering data. Comparisons between our conclusions and applications of $χ$ EFT to the nucleon-nucleon system are discussed as well.
Comments:
26 pages, 3 tables and 13 figures. References are added according to the published version and the related texts are added or modified. arXiv admin note: substantial text overlap with arXiv:2203.06840
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2210.11683 [pdf]
CPC(2023)·0 citations
03
[Submitted on 21 Oct 2022]
Investigating the cluster production mechanism with isospin triggering: Thermal models versus coalescence models
Apiwit Kittiratpattana🇩🇪 · Tom Reichert🇩🇪 · Pengcheng Li🇨🇳 · Ayut Limphirat🇹🇭 · Christoph Herold🇹🇭 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
Isospin triggering allows to distinguish coalescence from thermal production of light clusters in heavy ion collisions. Triggering on $Y (π^{-}) - Y (π^{+})$ allows to select very neutron or proton rich final states. The deuteron (cluster) production with coalescence ( $d \propto n \cdot p$ ) leads then to an inverse parabolic dependence of the deuteron yield on $Δ Y_{π}$ . In contrast, in a thermal model, cluster production is independent on $Δ Y_{π}$ . The observation of a maximum deuteron (cluster) yield as function of $Δ Y_{π}$ provides confirmation of the coalescence mechanism.
Comments:
6 pages, 5 figures, version accepted and published by Physical Review C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2210.11699 [pdf]
PRC(2023)·1 citation
04
[Submitted on 21 Oct 2022]
Minimal Length, Nuclear Matter, and Neutron Stars
I. Prasetyo · I. H. Belfaqih · A. B. Wahidin · A. Suroso · A. Sulaksono
In this paper, we employ one variant of the Generalized Uncertainty Principle (GUP) model, i.e., the Kempf-Mangano-Mann (KMM) model, and discuss the impact of GUP on the EoS of nuclear and neutron star matter based on the Relativistic Mean Field (RMF) model. We input the result in the Serrano-Liška (SL) gravity theory to discuss the corresponding Neutron Star (NS) properties. We have shown that the upper bound for the GUP parameter from nuclear matter properties is $β \leq 2 \times 1 0^{- 7}$ MeV $^{- 2}$ . If we used this $β$ upper bound to calculate NS matter, and considering SL parameter $c ~$ as an independent parameter, we have found that the upper bound for the SL parameter, which modifies the Einstein field equation, is $c ~ \leq 1 0^{7}$ m $^{2}$ . This beta upper bound is determined by considering the anisotropy magnitude smaller than the pressure magnitude. By employing $β = 2 \times 1 0^{- 7}$ MeV $^{- 2}$ and $c ~ = 1 0^{7}$ m $^{2}$ , we obtain the mass-radius relation that satisfies NICER data for both PSR J0740+6620 (whose mass is $\sim 2.1 M_{⊙}$ ) and PSR J0030+0451 ( $M \sim 1.4 M_{⊙}$ ). Our GUP parameter upper bound perfectly matches the constraint from $^{87}$ Rb cold-atom-recoil experiment. If we consider that the same strength from the additional logarithmic term in the entropy from both GUP and SL model are dependent, for $β < 2 \times 1 0^{- 7}$ MeV $^{- 2}$ , it is clear that SL parameter lower bound is $c ~ > - 16 \times 1 0^{- 34}$ m $^{2}$ . The magnitude of this bound is $1 0^{- 40}$ smaller than the upper bound magnitude of SL parameter considering as independent parameter i.e., $c ~ \leq 1 0^{7}$ m $^{2}$ .
Comments:
14 pages, 5 figures, published in EPJC
Subjects:
Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc)
arXiv:
2210.11727 [pdf]
EPJC(2022)·16 citations
05
[Submitted on 21 Oct 2022]
Spatial Structure of the $^{12}$ C Nucleus in a 3 $α$ Model with Deep Potentials Containing Forbidden States
E. M. Tursunov · M. Z. Saidov · M. M. Begijonov
The spatial structure of the lowest 0 $_{1}^{+}$ , 0 $_{2}^{+}$ , 2 $_{1}^{+}$ and 2 $_{2}^{+}$ states of the $^{12}$ C nucleus is studied within the 3 $α$ model with the Buck, Friedrich, and Wheatley $α α$ potential with Pauli forbidden states in the $S$ and $D$ waves. The Pauli forbidden states in the three-body system are treated by the exact orthogonalization method. The largest contributions to the ground and excited 2 $_{1}^{+}$ bound states energies come from the partial waves $(λ, ℓ) = (2, 2)$ and $(λ, ℓ) = (4, 4)$ . As was found earlier, these bound states are created by the critical eigenstates of the three-body Pauli projector in the 0 $^{+}$ and 2 $^{+}$ functional spaces, respectively. These special eigenstates of the Pauli projector are responsible for the quantum phase transitions from a weakly bound "gas-like" phase to a deep "quantum liquid" phase. In contrast to the bound states, for the Hoyle resonance 0 $_{2}^{+}$ and its analog state 2 $_{2}^{+}$ , dominant contributions come from the $(λ, ℓ) = (0, 0)$ and $(λ, ℓ) = (2, 2)$ configurations, respectively. The estimated probability density functions for the $^{12}$ C(0 $_{1}^{+}$ ) ground and 2 $_{1}^{+}$ excited bound states show mostly a triangular structure, where the $α$ particles move at a distance of about 2.5 fm from each other. However, the spatial structure of the Hoyle resonance and its analog state have a strongly different structure, like $^{8}$ Be + $α$ . In the Hoyle state, the last $α$ particle moves far from the doublet at the distance between $R = 3.0$ fm and $R = 5.0$ fm. In the Hoyle analog 2 $_{2}^{+}$ state the two alpha particles move at a distance of about 15 fm, but the last $α$ particle can move far from the doublet at the distance up to $R = 30.0$ fm.
Comments:
12 pages, 4 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex); Quantum Physics (quant-ph)
arXiv:
2210.11763 [pdf]
Phys.Atom.Nucl.(2022)·0 citations
06
[Submitted on 21 Oct 2022]
Energy dependence of light hypernuclei production in heavy-ion collisions from a coalescence and statistical-thermal model perspective
Tom Reichert🇩🇪 · Jan Steinheimer🇩🇪 · Volodymyr Vovchenko🇩🇪 · Benjamin Dönigus🇩🇪 · Marcus Bleicher🇩🇪
A comparison of light hypernuclei production, from UrQMD+coalescence and the thermal model, in heavy ion collisions over a wide range of beam energies and system sizes is presented. We find that both approaches provide generally similar results, with differences in specific details. Especially the ratios of hypertriton to $Λ$ are affected by both the source radius $Δ r$ of the coalescence procedure as well as canonical effects. On the other hand, the double ratio $S_{3}$ is almost independent of canonical effects, which is in contrast to coalescence. Thus, both the beam energy dependence and centrality dependence of $S_{3}$ can be used to constrain the hypertriton source radius. To do so the currently available data is not yet sufficient. Elliptic flow is shown to be unaffected by the source size of the nuclei and an almost perfect mass scaling of the elliptic flow is observed. Our predictions further suggest that the existence of the H-dibaryon ( $ΛΛ$ ) seems ruled out by ALICE data.
Comments:
10 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2210.11876 [pdf]
PRC(2023)·33 citations
07
[Submitted on 21 Oct 2022]
The exploration of hot and dense nuclear matter: Introduction to relativistic heavy-ion physics
Hannah Elfner🇩🇪 · Berndt Müller🇺🇸
This article summarizes our present knowledge about nuclear matter at the highest energy densities and its formation in relativistic heavy ion collisions. We review what is known about the structure and properties of the quark-gluon plasma and survey the observables that are used to glean information about it from experimental data.
Comments:
110 pages
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2210.12056 [pdf]
J.Phys.G(2023)·81 citations
08
[Submitted on 21 Oct 2022]
Collective enhancement in the exciton model
M. R. Mumpower🇺🇸 · D. Nuedecker🇺🇸 · H. Sasaki🇺🇸 · T. Kawano🇺🇸 · A. E. Lovell🇺🇸 · M. W. Herman🇺🇸 · I. Stetcu🇺🇸 · M. Dupuis🇫🇷
The pre-equilibrium reaction mechanism is considered in the context of the exciton model. A modification to the one-particle one-hole state density is studied which can be interpreted as a collective enhancement. The magnitude of the collective enhancement is set by simulating the Lawrence Livermore National Laboratory (LLNL) pulsed-spheres neutron-leakage spectra. The impact of the collective enhancement is explored in the context of the highly deformed actinide, 239-Pu. A consequence of this enhancement is the removal of fictitious levels in the Distorted-Wave Born Approximation often used in modern nuclear reaction codes.
Comments:
7 pages, 7 figures. Comments welcome!
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2210.12105 [pdf]
PRC(2023)·5 citations
09
[Submitted on 21 Oct 2022]
Nuclear data activities for medium mass and heavy nuclei at Los Alamos
M. R. Mumpower · T. M Sprouse · T. Kawano · M. W. Herman · A. E. Lovell · G. W. Misch · D. Neudecker · H. Sasaki · I. Stetcu · P. Talou
Nuclear data is critical for many modern applications from stockpile stewardship to cutting edge scientific research. Central to these pursuits is a robust pipeline for nuclear modeling as well as data assimilation and dissemination. We summarize a small portion of the ongoing nuclear data efforts at Los Alamos for medium mass to heavy nuclei. We begin with an overview of the NEXUS framework and show how one of its modules can be used for model parameter optimization using Bayesian techniques. The mathematical framework affords the combination of different measured data in determining model parameters and their associated correlations. It also has the advantage of being able to quantify outliers in data. We exemplify the power of this procedure by highlighting the recently evaluated 239-Pu cross section. We further showcase the success of our tools and pipeline by covering the insight gained from incorporating the latest nuclear modeling and data in astrophysical simulations as part of the Fission In R-process Elements (FIRE) collaboration.
Comments:
6 pages, 5 figures, Nuclear Data (2022) conference proceedings. Comments welcome!
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2210.12136 [pdf]
EPJ Web Conf.(2023)·2 citations
10
[Submitted on 21 Oct 2022]
Assessing the theory-data tension in neutrino-induced charged pion production: the effect of final-state nucleon distortion
Alexis Nikolakopoulos🇺🇸 · Raúl González-Jiménez🇪🇸 · Natalie Jachowicz🇧🇪 · José Manuel Udías🇪🇸
Pion production on nuclei constitutes a significant part of the total cross section in experiments involving few-GeV neutrinos. Combined analyses of data on deuterium and heavier nuclei points to tensions between the bubble chamber data and the data of the MINER $ν$ A experiment, which are often ascribed to unspecified nuclear effects. To understand the origin of these tensions, a microscopic quantum mechanical framework is needed to compute nuclear matrix elements. We use the local approximation to the relativistic distorted wave impulse approximation (RDWIA) to assess the role of final-state nucleon distortion. To perform this comparison under conditions relevant to neutrino experiments, we compute cross sections for the MINER $ν$ A and T2K charged pion production datasets. The inclusion of nucleon distortion leads to a reduction of the cross section up to 10\%, but to no significant change in shape of the flux-averaged cross sections. Results with and without distortion compare favorably to experimental data, with the exception of the low- $Q^{2}$ MINER $ν$ A $π^{+}$ data. We point out that hydrogen target data from BEBC is also overpredicted at low- $Q^{2}$ , and that the discrepancy is similar in shape and magnitude to what is found in comparison to MINER $ν$ A data. Including nucleon distortion alone cannot explain the overprediction of low- $Q^{2}$ cross sections measured by MINER $ν$ A. The similar overprediction of BEBC data on hydrogen means that it is impossible to ascribe this discrepancy solely to a nuclear effect. Axial couplings and their $Q^{2}$ dependence should ideally be derived from more precise data on hydrogen and deuterium.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2210.12144 [pdf]
PRD(2023)·13 citations
11
[Submitted on 21 Aug 2022] (cross-list from hep-ph)
Open Charm mesons in magnetized nuclear matter -- effects of (inverse) magnetic catalysis
Sourodeep De · Amruta Mishra
The in-medium masses of the open charm ( $D$ and $D ˉ$ ) mesons in magnetized isospin asymmetric nuclear matter are investigated within a chiral effective model, including the contributions of the Dirac sea (DS) to the self-energies of the nucleons. Within the model, the masses of these mesons are calculated from their interactions with the nucleons and the scalar ( $σ \sim (⟨ u ˉ u ⟩ + ⟨ d ˉ d ⟩)$ , $ζ \sim ⟨ s ˉ s ⟩$ and $δ \sim (⟨ u ˉ u ⟩ - ⟨ d ˉ d ⟩)$ ) fields. The Dirac sea contributions are observed to lead to an enhancement (reduction) of the quark condensates with increase in magnetic field, an effect called `(inverse) magnetic catalysis'. These contributions are observed to appreciably modify the open charm meson masses calculated within the chiral effective model. In the presence of an external magnetic field, there is mixing of the pseudoscalar and the vector mesons (PV mixing), leading to as a drop (increase) in the mass of the pseudoscalar (longitudinal component of the vector) meson. The effects of the (inverse) magnetic catalysis, in addition to the PV mixing and Landau level contribtuions (for charged mesons) are observed to lead to significant modifications to the masses of the open charm mesons. These can modify the decay widths of the charmonium states to open charm mesons, e.g., $ψ (3770) \to D D ˉ$ , as well as $D^{*} \to D π$ (and $D^{*} ˉ \to D ˉ π$ ), which can affect the production of the open charm and charmonium states in ultra relativistic peripheral heavy ion collision experiments, where the created magnetic field is huge.
Comments:
19 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2208.09820 [pdf]
PRC(2023)·18 citations
12
[Submitted on 31 Aug 2022] (cross-list from hep-ph)
Masses of Heavy Quarkonium states in magnetized matter -- effects of PV mixing and (inverse) magnetic catalysis
Ankit Kumar🇮🇳 · Amruta Mishra🇮🇳
We study the in-medium masses of the heavy quarkonium (charmonium and bottomonium) states in isospin asymmetric nuclear matter in presence of an external magnetic field. The mass modifications of the heavy quarkonia are obtained from the medium modifications of a scalar dilaton field, $χ$ , calculated within a chiral effective model. The dilaton field is introduced in the model through a scale invariance breaking logarithmic potential, and, simulates the gluon condensates of QCD. Within the chiral effective model, the values of the dilaton field along with the scalar (isoscalar, $σ (\sim ⟨ u ˉ u ⟩ + ⟨ d ˉ d ⟩)$ , isoscalar $ζ (\sim ⟨ s ˉ s ⟩$ ) and isovector $δ (\sim ⟨ u ˉ u ⟩ - ⟨ d ˉ d ⟩)$ ) fields, are solved from their coupled equations of motion. These are solved accounting for the effects of the Dirac sea (DS) as well as anomalous magnetic moments (AMMs) of the nucleons. The Dirac sea contributions are observed to lead to enhancement (reduction) of the quark condensates (through $σ$ and $ζ$ fields) with increase in magnetic field, an effect called the (inverse) magnetic catalysis. The magnetic field effects on the masses of the heavy quarkonia include the mixing of the pseudoscalar (spin 0) and vector (spin 1) states (PV mixing), as well as, the effects from (inverse) magnetic catalysis. These effects are observed to be significant for large values of the magnetic field. This should have observable consequences on the production of the heavy quarkonia and open heavy flavour mesons, resulting from ultra-relativistic peripheral heavy ion collision experiments, where the created magnetic field can be huge.
Comments:
25 pages, 14 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2208.14962 [pdf]
5 citations
13
[Submitted on 17 Oct 2022] (cross-list from hep-ph)
Dirac sea effects on Heavy Quarkonia decay widths in magnetized matter -- a field theoretic model of composite hadrons
Amruta Mishra🇮🇳 · S. P. Misra🇮🇳
We study the partial decay widths of charmonium (bottomonium) states to $D D ˉ (B B ˉ)$ mesons in magnetized (nuclear) matter using a field theoretical model of composite hadrons with quark (and antiquark) constituents. These are computed from the mass modifications of the decaying and produced mesons within a chiral effective model, including the nucleon Dirac sea effects. The mass modifications of the open charm (bottom) mesons are calculated from their interactions with the nucleons and the scalar mesons, whereas the mass shift of the heavy quarkonium state is obtained from the medium change of a scalar dilaton field, $χ$ , which mimics the gluon condensates of QCD. The Dirac sea contributions are observed to lead to a rise (drop) in the quark condensates as the magnetic field is increased, an effect called the (inverse) magnetic catalysis. These effects are observed to be significant and the anomalous magnetic moments (AMMs) of the nucleons are observed to play an important role. For $ρ_{B}$ =0, there is observed to be magnetic catalysis (MC) without and with AMMs, whereas, for $ρ_{B} = ρ_{0}$ , the inverse magnetic catalysis (IMC) is observed when the AMMs are taken into account, contrary to MC, when the AMMs are ignored. In the presence of a magnetic field, there are also mixings of spin 0 (pseudoscalar) and spin 1 (vector) states (PV mixing) which modify the masses of these mesons. The magnetic field effects on the heavy quarkonium decay widths should have observable consequences on the production the heavy flavour mesons, which are created in the early stage of ultra-relativistic peripheral heavy ion collisions, at RHIC and LHC, when the produced magnetic fields can still be extremely large.
Comments:
42 pages, 7 figures, version published in Phys. Rev. D 107 (2023) 074003
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2210.09192 [pdf]
PRD(2023)·9 citations
14
[Submitted on 20 Oct 2022] (cross-list from hep-th)
Emergent higher-form symmetry in Higgs phases with superfluidity
Yoshimasa Hidaka🇯🇵 · Dan Kondo🇯🇵
We address emergent higher-form symmetry in Higgs phases with superfluidity. The emergent symmetry appears if a matter field is invariant under a transformation of a common subgroup of gauge and global $U (1)$ symmetries. We explicitly construct the symmetry generator that is topological and gauge invariant in a low-energy effective theory. Such emergent symmetry is helpful to distinguish the Higgs and other phases with superfluidity, such as phases of QCD at finite density. We also discuss the possibility of phase transition between these phases.
Comments:
5 pages, no figure
Subjects:
High Energy Physics — Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2210.11492 [pdf]
10 citations
15
[Submitted on 21 Oct 2022] (cross-list from astro-ph.HE)
Core-collapse supernova simulations with reduced nucleosynthesis networks
Gerard Navó · Moritz Reichert · Martin Obergaulinger · Almudena Arcones
We present core-collapse supernova simulations including nuclear reaction networks that impact explosion dynamics and nucleosynthesis. The different composition treatment can lead to changes in the neutrino heating in the vicinity of the shock by modifying the number of nucleons and thus the neutrino-opacity of the region. This reduces the ram pressure outside the shock and allows an easier expansion. The energy released by the nuclear reactions during collapse also slows down the accretion and aids the shock expansion. In addition, nuclear energy generation in the postshocked matter produces up to $20%$ more energetic explosions. Nucleosynthesis is affected due to the different dynamic evolution of the explosion. Our results indicate that the energy generation from nuclear reactions helps to sustain late outflows from the vicinity of the proto-neutron star, synthesizing more neutron-rich species. Furthermore, we show that there are systematic discrepancies between the ejecta calculated with in-situ and ex-situ reaction networks. These differences stem from the intrinsic characteristics of evolving the composition in hydrodynamic simulations or calculating it with Lagrangian tracer particles. The mass fractions of some Ca, Ti, Cr, and Fe isotopes are consistently underproduced in postprocessing calculations, leading to different nucleosynthesis paths. Our results suggest that large in-situ nuclear reaction networks are important for a realistic feedback of the energy generation, the neutrino heating, and a more accurate ejecta composition.
Comments:
Submitted to ApJ. Received 2022 October 20; revised 2023 May 13; accepted 2023 May 15
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2210.11848 [pdf]
ApJ(2023)·23 citations
16
[Submitted on 21 Oct 2022] (cross-list from hep-ph)
Chiral extrapolation of hadronic vacuum polarization and isospin-breaking corrections
Martin Hoferichter🇨🇭 · Gilberto Colangelo🇨🇭 · Bai-Long Hoid🇨🇭 · Bastian Kubis🇩🇪 · Jacobo Ruiz de Elvira🇪🇸 · Dominik Stamen🇩🇪 · Peter Stoffer🇨🇭
By far the biggest contribution to hadronic vacuum polarization (HVP) arises from the two-pion channel. Its quark-mass dependence can be evaluated by combining dispersion relations with chiral perturbation theory, providing guidance on the functional form of chiral extrapolations, or even interpolations around the physical point. In addition, the approach allows one to estimate in a controlled way the isospin-breaking (IB) corrections that arise from the pion mass difference. As an application, we present an updated estimate of phenomenological expectations for electromagnetic and strong IB corrections to the HVP contribution to the anomalous magnetic moment of the muon. In particular, we include IB effects in the $K ˉ K$ channel, which are enhanced due to the proximity of the $K ˉ K$ threshold and the $ϕ$ resonance. The resulting estimates make it unlikely that the current tension between lattice-QCD and data-driven evaluations of the HVP contribution is caused by IB corrections.
Comments:
9 pages, 1 figure; proceedings of the 39th International Symposium on Lattice Field Theory (LATTICE2022)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2210.11904 [pdf]
PoS(2023)·20 citations
17
[Submitted on 21 Oct 2022] (cross-list from hep-ph)
Exclusive $ρ$ and $J /Ψ$ photoproduction in ultraperipheral $pO$ and $O O$ collisions at energies available at the CERN Large Hadron Collider
Victor P. Goncalves🇩🇪 · Bruno D. Moreira🇧🇷 · Luana Santana🇧🇷
Collisions with Oxygen ions at the LHC opens the possibility of investigating the description of the QCD dynamics in an unexplored regime, complementary to those performed in $pp$ , $pP b$ and $P b P b$ collisions. In this paper we estimate the exclusive $ρ$ and $J /Ψ$ photoproduction in ultraperipheral $pO$ and $O O$ collisions at the Large Hadron Collider using the color dipole formalism and considering distinct models for the dipole - target scattering amplitude and different approaches for the modelling of the vector meson wave function. We present our predictions for the rapidity and transverse momentum distributions, as well as for the total cross sections considering the rapidity ranges covered by the ALICE and LHCb detectors. Such results indicate that a future experimental analysis of these final states is feasible and that its study can be useful to improve our understanding of the QCD dynamics at high energies.
Comments:
11 pages, 7 figures, 2 tables. Improved and enlarged version to be published in Physical Review C
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2210.11911 [pdf]
PRC(2023)·8 citations
18
[Submitted on 21 Oct 2022] (cross-list from hep-ph)
Neutron Lifetime Anomaly and Big Bang Nucleosynthesis
Tammi Chowdhury🇨🇦 · Seyda Ipek🇨🇦
We calculate the Big Bang Nucleosynthesis abundances for helium-4 and deuterium for a range of neutron lifetimes, $τ_{n} = 840 - 1050$ s, using the state-of-the-art Python package \textsc{PRyMordial}. We show the results for two different nuclear reaction rates, calculated by NACRE II [1] and the PRIMAT [2] collaborations.
Comments:
v2: References added, plot slightly updated. Matches the version to be published in Canadian Journal of Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th)
arXiv:
2210.12031 [pdf]
Can.J.Phys.(2024)·14 citations
19
[Submitted on 21 Oct 2022] (cross-list from quant-ph)
Minimal Entanglement and Emergent Symmetries in Low-energy QCD
Qiaofeng Liu🇺🇸 · Ian Low🇺🇸 · Thomas Mehen🇺🇸
We study low-energy scattering of spin-1/2 baryons from the perspective of quantum information science, focusing on the correlation between entanglement minimization and the appearance of accidental symmetries. The baryon transforms as an octet under the SU(3) flavor symmetry and its interactions below the pion threshold are described by contact operators in an effective field theory (EFT) of QCD. Despite there being 64 channels in the 2-to-2 scattering, only six independent operators in the EFT are predicted by SU(3). We show that successive entanglement minimization in SU(3)-symmetric channels are correlated with increasingly large emergent symmetries in the EFT. In particular, we identify scattering channels whose entanglement suppression are indicative of emergent SU(6), SO(8), SU(8), and SU(16) symmetries. We also observe the appearance of non-relativistic conformal invariance in channels with unnaturally large scattering lengths. Improved precision from lattice simulations could help determine the degree of entanglement suppression, and consequently the amount of accidental symmetry, in low-energy QCD.
Comments:
42 pages, 3 figures
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2210.12085 [pdf]
PRC(2023)·91 citations

Affiliations

first authorsco-authorsvia INSPIRE