Nuclear Theory·nucl-th

Tuesday·October 20, 2020

17 papers—12 primary·5 cross-listed

01
Ab initio benchmarks of neutrinoless double beta decay in light nuclei with a chiral Hamiltonian
J. M. Yao🇺🇸 · A. Belley🇨🇦 · R. Wirth🇺🇸 · T. Miyagi🇨🇦 · C. G. Payne🇨🇦 · S. R. Stroberg🇺🇸 · H. Hergert🇺🇸 · J. D. Holt🇨🇦
We report ab initio benchmark calculations of nuclear matrix elements (NMEs) for neutrinoless double-beta ( $0 ν β β$ ) decays in light nuclei with mass number ranging from $A = 6$ to $A = 22$ . We use the transition operator derived from light-Majorana neutrino exchange and evaluate the NME with three different methods: two variants of in-medium similarity renormalization group (IMSRG) and importance-truncated no-core shell model (IT-NCSM). The same two-plus-three-nucleon interaction from chiral effective field theory is employed, and both isospin-conserving ( $Δ T = 0$ ) and isospin-changing ( $Δ T = 2$ ) transitions are studied. We compare our resulting ground-state energies and NMEs to those of recent ab initio no-core shell model and coupled-cluster calculations, also with the same inputs. We show that the NMEs of $Δ T = 0$ transitions are in good agreement among all calculations, at the level of 10%. For $Δ T = 2$ , relative deviations are more significant in some nuclei. The comparison with the exact IT-NCSM result allows us to analyze these cases in detail, and indicates the next steps towards improving the IMSRG-based approaches. The present study clearly demonstrates the power of consistent cross-checks that are made possible by ab initio methodology. This capability is crucial for providing meaningful many-body uncertainties in the NMEs for the $0 ν β β$ decays in heavier candidate nuclei, where quasi-exact benchmarks are not available.
nucl-thhep-exhep-phnucl-exPRC(2021)·44 citations
02
Closed-form Brückner $G$ -matrix and nuclear matter in EFT( $\neq π$ )
Ting-Wei Pan🇨🇳 · Ji-Feng Yang🇨🇳
The closed-form Brükner $G$ matrix for nuclear matter is computed in the $^{1} S_{0}$ channel of EFT( $\neq π$ ) and renormalized in nonperturbative context. The nuclear medium environment yields additional constraints that are consistent with off-shell $T$ matrix renormalization, keeping the power counting intact and simplifying the running behaviors of the EFT couplings. With the $G$ obtained we computed the energy per particle for neutron and symmetric nuclear matter to demonstrate the physical relevance of certain 'physical' parameters that arise from nonperturbative renormalization. We also explored the pairing phenomenon in $^{1} S_{0}$ channel by examining the poles of the closed-form $G$ matrix with a given density, where again the physical relevance of the same set of physical parameters are clearly illustrated.
nucl-thhep-phhep-thPLB(2021)·0 citations
03
Two-particle correlations at high-energy nuclear collisions, peripheral-tube model revisited
Yogiro Hama🇧🇷 · Takeshi Kodama🇧🇷 · Wei-Liang Qian🇧🇷
In this paper, we give an account of the peripheral-tube model, which has been developed to give an intuitive and dynamical description of the so-called ridge effect in two-particle correlations in high-energy nuclear collisions. Starting from a realistic event-by-event fluctuating hydrodynamical model calculation, we first show the emergence of ridge + shoulders in the so-called two-particle long-range correlations, reproducing the data. In contrast to the commonly used geometric picture of the origin of the anisotropic flow, we can explain such a structure dynamically in terms of the presence of high energy-density peripheral tubes in the initial conditions. These tubes violently explode and deflect the near radial flow coming from the interior of the hot matter, which in turn produces a two-ridge structure in single-particle distribution, with approximately two units opening in azimuth. When computing the two-particle correlation, this will result in characteristic three-ridge structure, with a high near-side ridge and two symmetric lower away-side ridges or shoulders. Several anisotropic flows, necessary to producing ridge + shoulder structure, appear naturally in this dynamical description. Using this simple idea, we can understand several related phenomena, such as centrality dependence and trigger-angle dependence.
nucl-thhep-phJ.Phys.G(2021)·13 citations
04
Future Physics Perspectives on the Equation of State from Heavy Ion Collisions to Neutron Stars
Veronica Dexheimer🇺🇸 · Jorge Noronha🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸 · Claudia Ratti🇺🇸 · Nicolás Yunes🇺🇸
With the computational power and algorithmic improvements available today, the ongoing STAR/RHIC and HADES/GSI experiments, the future FAIR and NICA facilities becoming operational, and the new precise measurements from NICER and LIGO/VIRGO, the high-energy nuclear physics and astrophysics communities are in the unique position to set very stringent constraints on the equation of state of strongly interacting matter. We review the state-of-the-art of different approaches used in the description of hot and ultradense baryonic matter in and out of equilibrium, and discuss the regions in the phase diagram where heavy-ion collisions and neutron star mergers can overlap. Future perspectives are discussed to help define a comprehensive, multi-disciplinary strategy to map out the phase diagram of strongly interacting matter from heavy ion collisions to neutron stars.
nucl-thastro-ph.HEgr-qchep-ph+1J.Phys.G(2021)·79 citations
05
Vorticity and Spin Polarization in Heavy Ion Collisions: Transport Models
Xu-Guang Huang🇨🇳 · Jinfeng Liao🇺🇸 · Qun Wang🇨🇳 · Xiao-Liang Xia🇨🇳
Heavy ion collisions generate strong fluid vorticty in the produced hot quark-gluon matter which could in turn induce measurable spin polarization of hadrons. We review recent progress on the vorticity formation and spin polarization in heavy ion collisions with transport models. We present an introduction to the fluid vorticity in non-relativistic and relativistic hydrodynamics and address various properties of the vorticity formed in heavy ion collisions. We discuss the spin polarization in a vortical fluid using the Wigner function formalism in which we derive the freeze-out formula for the spin polarization. Finally we give a brief overview of recent theoretical results for both the global and local spin polarization of $Λ$ and $Λ ˉ$ hyperons.
nucl-thhep-phnucl-exLect.Notes Phys.(2021)·63 citations
06
Study of Decay Modes in Transfermium Isotopes
U. K. Singh · P. K. Sharma · M. Kaushik · S. K. Jain · Dashty T. Akrawy · G. Saxena
In the unknown territory of transfermium nuclei, the relativistic mean-field (RMF) theory has been applied to probe decay modes which include $α$ -decay, spontaneous fission (SF), and a less explored weak-decay. These decay modes are analyzed on equal footing for 101 $\leq$ Z $\leq$ 109 and as a consequence, the half-lives for weak-decay are indeed found comparable for several isotopes. Our prediction of decay modes and half-lives are found in excellent agreement with available experimental decay modes and half-lives along with the results of some other theories. Out of $α$ , $β^{+}$ /EC, $β^{-}$ , and SF, the most probable decay mode is anticipated along with its half-life over a wide range of odd and even nuclei to frame a novel sight into terra incognita.
nucl-thNPA(2020)·16 citations
07
Effect of electron screening on the $α$ decay
F. F. Karpeshin · M. B. Trzhaskovskaya · L. F. Vitushkin
The physical principles that determine the effect of the electron shell of an atom on the alpha decay rate of the nucleus are presented. The effect is shown to be negative. Numerical calculations of the effect in helium-like ions are performed. It accounts for more than 80% of the effect in neutral atoms. The prospects for experimental detection of the effect in the storage rings of the GSI Darmstadt, ISF Lanzhou are discussed.
nucl-th0 citations
08
Radiative and chiral corrections to elastic lepton-proton scattering in chiral perturbation theory
Pulak Talukdar🇮🇳 · Vanamali C. Shastry🇮🇳 · Udit Raha🇮🇳 · Fred Myhrer🇺🇸
A unified treatment of both chiral and radiative corrections to the low-energy elastic lepton-proton scattering processes is presented in Heavy Baryon Chiral Perturbations Theory. The proton hadronic chiral corrections include the next-to-next-to leading order corrections whereas the radiative corrections include the next-to-leading order terms in our novel power counting scheme. We find that the net fractional well-defined chiral corrections with respect to the leading order Born cross section can be as large as $10%$ ( $20%$ ) for electron (muon) scattering process for MUon proton Scattering Experiment (MUSE) kinematics. We show {\it via} our model-independent treatment of the low-energy lepton-proton kinematics, that the largest theoretical uncertainty is due to the recent different published values of the proton's rms radius while, e.g., the next higher order hadronic chiral terms are expected to give rather nominal errors. For the radiative corrections we demonstrate a systematic order by order cancellation of all infrared singularities and present our finite ultraviolet regularization results. We find that the radiative corrections for muon-proton scattering is of the order of $2%$ , whereas for electron scattering the radiative corrections could be as large as $25%$ . We attribute such a contrasting result partially to the fact that in muon scattering the leading radiative order correction goes through zero in some intermediate low-momentum transfer region, leaving the sub-leading radiative chiral order effects to play a dominant role in this particular kinematic region. For the low-energy MUSE experiment, the often neglected lepton mass as well as the Pauli form factor contributions of the relativistic leptons are incorporated in all our computations.
nucl-thhep-phPRD(2021)·15 citations
09
Hidden spin-isospin exchange symmetry
Dean Lee🇺🇸 · Scott Bogner🇺🇸 · B. Alex Brown🇺🇸 · Serdar Elhatisari🇹🇷 · Evgeny Epelbaum🇩🇪 · Heiko Hergert🇺🇸 · Morten Hjorth-Jensen🇺🇸 · Hermann Krebs🇩🇪 · Ning Li🇺🇸 · Bing-Nan Lu🇺🇸 · Ulf-G. Meißner🇩🇪
The strong interactions among nucleons have an approximate spin-isospin exchange symmetry that arises from the properties of quantum chromodynamics in the limit of many colors, $N_{c}$ . However this large- $N_{c}$ symmetry is well hidden and reveals itself only when averaging over intrinsic spin orientations. Furthermore, the symmetry is obscured unless the momentum resolution scale is close to an optimal scale that we call $Λ_{large - N_{c}}$ . We show that the large- $N_{c}$ derivation requires a momentum resolution scale of $Λ_{large - N_{c}} \sim 500$ MeV. We derive a set of spin-isospin exchange sum rules and discuss implications for the spectrum of $^{30}$ P and applications to nuclear forces, nuclear structure calculations, and three-nucleon interactions.
nucl-thhep-lathep-phnucl-exPRL(2021)·35 citations
10
On the width of the $K^{-}$ D atom ground state
N. Barnea🇮🇱 · E. Friedman🇮🇱 · A. Gal🇮🇱
Experiments at DA $Φ$ NE-Frascati and at J-PARC are scheduled to produce $K^{-}$ D atoms and observe their X-ray cascade down to the 1 $S$ ground state (g.s.), thereby measuring its strong-interaction width and shift away from a purely Coulomb state. A width $Γ_{1 S} ≲ 1$ keV will ensure good resolution of the X-ray transitions feeding the 1 $S$ g.s. Here we study the expected $K^{-}$ D 1 $S$ g.s. width from the perspective of global fits to level shifts and widths in heavier kaonic atoms across the periodic table, using $K^{-}$ nuclear optical potentials constructed from $K ˉ N$ chiral interaction models. Special attention is paid to the subthreshold energy at which the $K ˉ N$ subsystem interacts in the $K^{-}$ D atomic g.s. Within this approach we predict strong-interaction upward level shift of close to 700 eV and width of about 1.2 to 1.3 keV for the $K^{-}$ D atom 1 $S$ g.s., in fair agreement with genuinely three-body $K^{-}$ D atom calculations. Comparison is made with $π^{-}$ D atom phenomenology.
nucl-thhep-phnucl-exNPA(2021)·2 citations
11
Pairing in pure neutron matter
S. Ramanan (Department of Physics, Indian Institute of Technology Madras, Chennai, India)🇮🇳 · M. Urban (Université Paris-Saclay, CNRS-IN2P3, IJCLab, Orsay, France)🇫🇷
We review the long standing problem of superfluid pairing in pure neutron matter. For the $s$ -wave pairing, we summarize the state of the art of many-body approaches including different $nn$ interactions, medium polarization, short-range correlations and BCS-BEC crossover effects, and compare them with quantum Monte Carlo results at low-densities. We also address pairing in the $p$ -wave, which appears at higher densities and hence has large uncertainties due to the poorly constrained interactions, medium effects and many-body forces.
nucl-thastro-ph.HEcond-mat.quant-gasEur.Phys.J.ST(2021)·17 citations
12
Mass-dependent sequential freeze-out of hadrons
Sayan Mitra🇮🇳
Fluctuation measurements of hadron yields at heavy-ion collisions can reproduce the phase transition parameters of QCD matter. The fluctuation results produce accurate parameters near zero baryonic chemical potential( $μ_{B}$ ) being very sensitive in that region. In this work, using the Hadron Resonance Gas Model(HRG), we determine the freeze-out temperatures of the hadrons using individual fluctuation results and find that sequential freeze-out of hadrons during the QCD phase transition near zero $μ_{B}$ is dependent on the mass of produced hadronic species. Using recently published results of net- $Λ$ fluctuations and some other fluctuation results, we study the phase diagram at low baryonic chemical potential and center-of-mass energies ranging from 19.6 - 200 GeV/ $c^{2}$ and find significant, quantitative evidence to support our claim.
nucl-thhep-ph1 citation
13
Investigating Heavy-flavor vs Light-flavor Puzzle with Event Topology and Multiplicity in Proton+Proton Collisions at $s$ = 13 TeV using PYTHIA8
Suman Deb🇮🇳 · Raghunath Sahoo🇮🇳 · Dhananjaya Thakur🇨🇳 · Sushanta Tripathy🇲🇽 · Arvind Khuntia🇵🇱
Heavy-flavored hadrons are unique probes to study the properties of hot and dense QCD medium produced in ultra-relativistic heavy-ion collisions at RHIC and the LHC. Transverse spherocity is one of the event-topology variables used to separate jetty and isotropic events from the pool of event samples. This study aims to understand the production dynamics of heavy-flavors through the transverse momentum spectra, double differential yield and mean transverse momentum of J/ $ψ$ , $D^{0}$ and $Λ_{c}^{+}$ as a function of charged-particle multiplicity and transverse spherocity. Further to investigate the possibility of hardonization of the charm quarks, transverse spherocity dependence ratios like $Λ_{c}^{+}$ / $D^{0}$ and $Λ^{0}$ / $K^{-}$ are studied. For the current analysis, the events are generated by using 4C tuned PYTHIA8 for pp at $s$ = 13 TeV, which is quite successful in explaining the heavy-flavor particle production at the LHC energies.
↳ nucl-exhep-exhep-phhep-th+1J.Phys.G(2021)·8 citations
14
Advanced extraction of the deuteron charge radius from electron-deuteron scattering data
Jingyi Zhou🇺🇸 · Vladimir Khachatryan🇺🇸 · Haiyan Gao🇺🇸 · Douglas W. Higinbotham🇺🇸 · Asia Parker🇺🇸 · Xinzhan Bai🇺🇸 · Dipangkar Dutta🇺🇸 · Ashot Gasparian🇺🇸 · Kondo Gnanvo🇺🇸 · Mahbub Khandaker🇺🇸 · Nilanga Liyanage🇺🇸 · Eugene Pasyuk🇺🇸 · Chao Peng🇺🇸 · Weizhi Xiong🇺🇸
To extract the charge radius of the proton, $r_{p}$ , from the electron scattering data, the PRad collaboration at Jefferson Lab has developed a rigorous framework for finding the best functional forms - the fitters - for a robust extraction of $r_{p}$ from a wide variety of sample functions for the range and uncertainties of the PRad data. In this paper we utilize and further develop this framework. Herein we discuss methods for searching for the best fitter candidates as well as a procedure for testing the robustness of extraction of the deuteron charge radius, $r_{d}$ , from parametrizations based on elastic electron-deuteron scattering data. The ansatz proposed in this paper for the robust extraction of $r_{d}$ , for the proposed low- $Q^{2}$ DRad experiment at Jefferson Lab, can be further improved once there are more data.
↳ nucl-exhep-phnucl-thPRC(2021)·10 citations
15
Pulsar glitches from quantum vortex networks
Giacomo Marmorini🇯🇵 · Shigehiro Yasui🇯🇵 · Muneto Nitta🇯🇵
Neutron stars or pulsars are very rapidly rotating compact stars with extremely high density. One of the unsolved long-standing problems of these enigmatic celestial bodies is the origin of pulsars' glitches, i.e., the sudden rapid deceleration in the rotation speed of neutron stars. Although many glitch events have been reported, there is no consensus on the microscopic mechanism responsible for them. One of the important characterizations of the glitches is the scaling law $P (E) \sim E^{- α}$ of the probability distribution for a glitch with energy $E$ . Here, we reanalyse the accumulated up-to-date observation data to obtain the exponent $α \approx 0.88$ for the scaling law, and propose a simple microscopic model that naturally deduces this scaling law without any free parameters. Our model explains the appearance of these glitches in terms of the presence of quantum vortex networks arising at the interface of two different kinds of superfluids in the core of neutron stars; a $p$ -wave neutron superfluid in the inner core which interfaces with the $s$ -wave neutron superfluid in the outer core, where each integer vortex in the $s$ -wave superfluid connects to two half-quantized vortices in the $p$ -wave superfluid through structures called "boojums."
↳ astro-ph.HEhep-phnucl-thSci.Rep.(2024)·16 citations
16
On the Possibility of Dibaryon Formation near the N*(1440)N threshold -- the Isoscalar Single-Pion Production Revisited
H. Clement🇩🇪 · T. Skorodko🇩🇪 · E. Doroshkevich🇷🇺
The isoscalar single-pion production exhibits a broad bump in the energy dependence of the total cross section, which does not correspond to the usual opening of the $N^{*} (1440)$ production channel with subsequent pion decay. In arxiv:2102.05575 it was interpreted as a narrow Breit-Wigner structure, which leads in a sequential single-pion production process to a possible explanation of the $d^{*} (2380)$ resonance. We demonstrate that such an attempt fails already, when confronted with the data base for isoscalar single-pion production. We investigate whether the observed bump structure rather points to the formation of dibaryon states with $I (J^{P}) = 0 (1^{+})$ and $0 (1^{-})$ near the $N^{*} (1440) N$ threshold. This situation would be similar to the situation at the $Δ (1232) N$ threshold, where the signature of a number of dibaryonic resonances has been found.
↳ nucl-exhep-exhep-phnucl-thPRC(2022)·14 citations
17
The high energy spectrum of internal positrons from radiative muon capture on nuclei
Ryan Plestid🇺🇸 · Richard J. Hill🇺🇸
The Mu2e and COMET collaborations will search for nucleus-catalyzed muon conversion to positrons ( $μ^{-} \to e^{+}$ ) as a signal of lepton number violation. A key background for this search is radiative muon capture where either: 1) a real photon converts to an $e^{+} e^{-}$ pair "externally" in surrounding material, or 2) a virtual photon mediates the production of an $e^{+} e^{-}$ pair "internally". If the $e^{+}$ has an energy approaching the signal region then it can serve as an irreducible background. In this work we describe how the near end-point internal positron spectrum can be related to the real photon spectrum from the same nucleus, which encodes all non-trivial nuclear physics.
↳ hep-phhep-exnucl-thPRD(2021)·5 citations

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