Nuclear Theory·nucl-th

Monday·October 24, 2022

19 papers—10 primary·9 cross-listed

11
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.
↳ hep-phnucl-thPRC(2023)·18 citations
12
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.
↳ hep-phnucl-th5 citations
13
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.
↳ hep-phnucl-thPRD(2023)·9 citations
14
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.
↳ hep-thcond-mat.str-elhep-phnucl-th10 citations
15
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.
↳ astro-ph.HEastro-ph.SRnucl-thApJ(2023)·23 citations
16
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.
↳ hep-phhep-exhep-latnucl-thPoS(2023)·20 citations
17
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.
↳ hep-phhep-exnucl-thPRC(2023)·8 citations
18
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.
↳ hep-phastro-ph.COnucl-thCan.J.Phys.(2024)·14 citations
19
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.
↳ quant-phhep-lathep-phhep-th+1PRC(2023)·91 citations

Affiliations

first authorsco-authorsvia INSPIRE