Nuclear Theory·nucl-th

Tuesday·October 18, 2022

17 papers—9 primary·8 cross-listed

10
Prospects for $γ^{⋆} γ^{⋆} \to π π$ via lattice QCD
Raúl A. Briceño🇺🇸 · Andrew W. Jackura🇺🇸 · Arkaitz Rodas🇺🇸 · Juan V. Guerrero🇺🇸
The $γ^{⋆} γ^{⋆} \to π π$ scattering amplitude plays a key role in a wide range of phenomena, including understanding the inner structure of scalar resonances as well as constraining the hadronic contributions to the anomalous magnetic moment of the muon. In this work, we explain how the infinite-volume Minkowski amplitude can be constrained from finite-volume Euclidean correlation functions. The relationship between the finite-volume Euclidean correlation functions and the desired amplitude holds up to energies where $3 π$ states can go on shell, and is exact up to exponentially small corrections that scale like $O (e^{- m_{π} L})$ , where $L$ is the spatial extent of the cubic volume and $m_{π}$ is the pion mass. In order to implement this formalism and remove all power-law finite volume errors, it is necessary to first obtain $π π \to π π$ , $π γ^{⋆} \to π$ , $γ^{⋆} \to π π$ , and $π π γ^{⋆} \to π π$ amplitudes; all of which can be determined via lattice quantum chromodynamic calculations.
↳ hep-lathep-phnucl-thPRD(2023)·8 citations
11
Evolution of collisional neutrino flavor instabilities in spherically symmetric supernova models
Zewei Xiong🇩🇪 · Meng-Ru Wu🇹🇼 · Gabriel Martínez-Pinedo🇩🇪 · Tobias Fischer🇵🇱 · Manu George🇹🇼 · Chun-Yu Lin🇹🇼 · Lucas Johns🇺🇸
We implement a multi-group and discrete-ordinate neutrino transport model in spherical symmetry which allows to simulate collective neutrino oscillations by including realistic collisional rates in a self-consistent way. We utilize this innovative model, based on strategic parameter rescaling, to study a recently proposed collisional flavor instability caused by the asymmetry of emission and absorption rates between $ν_{e}$ and $ν ˉ_{e}$ for four different static backgrounds taken from different stages in a core-collapse supernova simulation. Our results confirm that collisional instabilities generally exist around the neutrinosphere during the SN accretion and post-accretion phase, as suggested by [arXiv:2104.11369]. However, the growth and transport of flavor instabilities can only be fully captured by models with global simulations as done in this work. With minimal ingredient to trigger collisional instabilities, we find that the flavor oscillations and transport mainly affect (anti)neutrinos of heavy lepton flavors around their decoupling sphere, which then leave imprints on their energy spectra in the free-streaming regime. For electron (anti)neutrinos, their properties remain nearly intact. We also explore various effects due to the decoherence from neutrino-nucleon scattering, artificially enhanced decoherence from emission and absorption, neutrino vacuum mixing, and inhomogeneous matter profile, and discuss the implication of our work.
↳ astro-ph.HEhep-phnucl-thPRD(2023)·76 citations
12
A journey into the proton structure: Progresses and challenges
Francesco Giovanni Celiberto🇮🇹
Unraveling the inner dynamics of gluons and quarks inside nucleons is a primary target of studies at new-generation colliding machines. Finding an answer to fundamental problems of Quantum ChromoDynamics, such as the origin of nucleon mass and spin, strongly depends on our ability of reconstructing the 3D motion of partons inside the parent hadrons. We present progresses and challenges in the extraction of TMD parton densities, with particular attention to the ones describing polarization states of gluons, which still represent an largely unexplored field. Then, we highlight connections with corresponding parton densities in the high-energy limit, the so-called unintegrated gluon distributions or UGDs and, more in general, to recent developments in high-energy physics.
↳ hep-phnucl-thUniverse(2022)·23 citations
13
Probing gluon TMDs with reconstructed and tagged heavy flavor hadron pairs at EIC
Xin Dong🇺🇸 · Yuanjing Ji🇺🇸 · Matthew Kelsey🇺🇸 · Sooraj Radhakrishnan🇺🇸 · Ernst Sichtermann🇺🇸 · Yuxiang Zhao🇨🇳
Study of the transverse structure of the proton is one of the major physics goals of the upcoming Electron Ion Collider (EIC). The gluon transverse momentum dependent distributions (TMD) form an essential focus of this effort and are important towards understanding the angular momentum contribution to proton spin as well as QCD factorization. However, very limited experimental constraints on the gluon TMD exist currently. As the heavy quark production in lepton-nucleon DIS gets a dominant contribution from the photon-gluon-fusion process, heavy quark production makes an attractive tool to probe gluon distributions in nucleons. In this paper we present a study of heavy flavor hadron pair reconstruction at a future EIC detector with MAPS based inner tracking and vertexing subsystems to constrain gluon TMD. We utilize the excellent track pointing resolution provided by the detector to exclusively reconstruct heavy flavor hadron pairs via their hadronic decay channels and also to develop a heavy flavor hadron tagging algorithm. Statistical uncertainty projections on azimuthal asymmetries corresponding to gluon TMD at the EIC is evaluated. The heavy flavor tagging is found to substantially enhance the purity of heavy flavor hadron pair selection, and the statistical precision of the measurement compared to that from exclusive reconstruction. The correlation between the azimuthal angle of the transverse momentum of the gluon initiating the process and that of the corresponding heavy flavor hadron pair was also studied and found to be well correlated. This study opens up heavy flavor hadron pair measurements as an attractive channel to access gluon TMD at the EIC.
↳ hep-phnucl-exnucl-thphysics.ins-detPRD(2023)·3 citations
14
A Quantum Algorithm for the Linear Response of Nuclei
Abhishek · Nifeeya Singh · Pooja Siwach · P. Arumugam
We present a quantum algorithm to obtain the response of the atomic nucleus to a small external electromagnetic perturbation. The Hamiltonian of the system is presented by a harmonic oscillator, and the linear combination of unitaries (LCU) based method is utilized to simulate the Hamiltonian on the quantum computer. The output of the Hamiltonian simulation is utilized in calculating the dipole response with the SWAP test algorithm. The results of the response function computed using the quantum algorithm are compared with the experimental data and provide a good agreement. We show the results for $^{120}$ Sn and $^{208}$ Pb to corroborate with the experimental data in Sn and Pb region and also compare the results with those obtained using the conventional linear response theory.
↳ quant-phnucl-thIndian J.Phys.(2025)·3 citations
15
Hidden bottom pentaquark in the SU(5) version of the flavor-spin model
Fl. Stancu🇧🇪
We generalize to five distinct flavors the flavor-spin hyperfine interaction introduced previously for four flavors and used in the study of $uu d c c$ pentaquark. As a particular case here we study the lowest states of the pentaquark $uu d b b$ , of either positive or negative parity, in a constituent quark model with linear confinement and the presently extended hyperfine interaction. The positive parity states have one unit of angular momentum located in the subsystem of four quarks and are described by translationally invariant states of orbital permutation symmetry $[31]_{O}$ which requires the configuration $s^{3} p$ . The negative parity states are described by the configuration $s^{4}$ of permutation symmetry $[4]_{O}$ . We show that the lowest state has the quantum numbers $J^{P}$ = $1/ 2^{+}$ or $3/ 2^{+}$ and I = $1/2$ and is located below the $Σ_{b} B$ threshold by - 132 MeV. We present a comparison between the spectra of $uu d c c$ and $uu d b b$ pentaquarks.
↳ hep-phhep-exnucl-thFew Body Syst.(2023)·2 citations
16
Constraining the equation of state of hybrid stars using recent information from multidisciplinary physics
Swarnim Shirke🇮🇳 · Suprovo Ghosh🇮🇳 · Debarati Chatterjee🇮🇳
At the ultra-high densities existing in the core of neutron stars, it is expected that a phase transition from baryonic to deconfined quark matter may occur. Such a phase transition would affect the underlying equation of state (EoS) as well as the observable astrophysical properties of neutron stars. Comparison of EoS model predictions with astronomical data from multi-messenger signals then provides us an opportunity to probe the behaviour of dense matter. In this work, we restrict the allowed parameter space of EoS models in neutron stars for both nucleonic (relativistic mean field model) and quark matter (bag model) sectors by imposing state-of-the-art constraints from nuclear calculations, multi-messenger astrophysical data and perturbative QCD (pQCD). We systematically investigate the effect of each constraint on the parameter space of uncertainties using a cut-off filter scheme, as well as the correlations among the parameters and with neutron star astrophysical observables. Using the constraints, we obtain limits for maximum NS mass, maximum central density, as well as for NS radii and tidal deformability. Although pQCD constraints are only effective at very high densities, they significantly reduce the parameter space of the quark model. We also conclude that astrophysical data supports high values of the bag parameter B and disfavors the existence of a pure quark matter core in hybrid stars.
↳ astro-ph.HEnucl-thApJ(2023)·19 citations
17
Collision-induced flavor instability in dense neutrino gases with energy-dependent scattering
Yu-Chia Lin🇺🇸 · Huaiyu Duan (UNM)🇺🇸
We investigate the collision-induced flavor instability in homogeneous, isotropic, dense neutrino gases in the two-flavor mixing scenario with energy-dependent scattering. We uncover a simple expression of the growth rate of this instability in terms of the flavor-decohering collision rates and the electron lepton number distribution of the neutrino. This growth rate is common to the neutrinos and antineutrinos of different energies, and is independent of the mass-splitting and vacuum mixing angle of the neutrino, the matter density, and the neutrino density, although the initial amplitude of the unstable oscillation mode can be suppressed by a large matter density. Our results suggest that neutrinos are likely to experience collision-induced flavor conversions deep inside a core-collapse supernova even when both the fast and slow collective flavor oscillations are suppressed.
↳ hep-phastro-ph.HEnucl-thPRD(2023)·55 citations

Affiliations

first authorsco-authorsvia INSPIRE