Nuclear Theory·nucl-th

Tuesday·November 12, 2019

11 papers—5 primary·6 cross-listed

01
[Submitted on 8 Nov 2019]
Role of the Surface Energy in Heavy-Ion Collisions
P. D. Stevenson
The surface energy is one of the fundamental properties nuclei, appearing in the simplest form of the semi-empirical mass formula. The surface enery has an influence on e.g. the shape of a nucleus and its ability to deform. This in turn could be expected to have an effect in fusion reactions around the Coulomb barrier where dynamical effects such as the formation of a neck is part of the fusion process. Frozen Hartree-Fock and Time-Dependent Hartree-Fock calculations are made for a series of effective interactions in which the surface energy is systematically varied, using $^{40}$ Ca + $^{48}$ Ca as a test case. The dynamical lowering of the barrier is greatest for the largest surface energy, contrary to naive expectations, and we speculate that this may be due to the variation in other nuclear matter properties for these effective interactions
Comments:
Submitted to proceedings of HIAS 2019
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1911.03559 [pdf]
EPJ Web Conf.(2020)·2 citations
02
[Submitted on 11 Nov 2019]
Theoretical study of $Nb$ isotope productions by muon capture reaction on $^{100} Mo$
Maureen Ciccarelli🇯🇵 · Futoshi Minato🇯🇵 · Tomoya Naito🇯🇵
The isotope $^{99} Mo$ , the generator of $^{99 m} Tc$ used for diagnostic imaging, is supplied by extracting from fission fragments of highly enriched uranium in reactors. However, a reactor-free production method of $^{99} Mo$ is searched over the world from the point of view of nuclear proliferation. Recently, $^{99} Mo$ production through a muon capture reaction was proposed and it was found that about $50 %$ of $^{100} Mo$ turned into $^{99} Mo$ through $^{100} Mo (μ^{-}, n)$ reaction [arXiv:1908.08166]. However, the detailed physical process of the muon capture reaction is not completely understood. We, therefore, study the muon capture reaction of $^{100} Mo$ by a theoretical approach. We used the proton-neutron QRPA to calculate the muon capture rate. The muon wave function is calculated with considering the electronic distribution of the atom and the nuclear charge distribution. The particle evaporation process from the daughter nucleus is calculated by a statistical model. From the model calculation, about $38 %$ of $^{100} Mo$ is converted to $^{99} Mo$ through the muon capture reaction, which is in a reasonable agreement with the experimental data. It is revealed that negative parity states, especially $1^{-}$ state, play an important role in $^{100} Mo (μ^{-}, n)^{99} Nb$ . The feasibility of $^{99} Mo$ production by the muon capture reaction is also discussed. Isotope production by the muon capture reaction strongly depends on the nuclear structure.
Comments:
9 pages, 4 figures, 4 tables, RIKEN-QHP-426, RIKEN-iTHEMS-Report-19
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1911.04084 [pdf]
PRC(2020)·8 citations
03
[Submitted on 11 Nov 2019]
Jet-fluid interaction in the EPOS3-Jet framework
Iurii Karpenko🇫🇷 · Joerg Aichelin🇫🇷 · Pol Bernard Gossiaux🇫🇷 · Martin Rohrmoser🇵🇱 · Klaus Werner🇫🇷
EPOS3-Jet is an integrated framework for jet modelling in heavy ion collisions, where the initial hard (jet) partons are produced along with soft (medium) partons in the initial state EPOS approach. The jet partons then propagate in the hydrodynamically expanding medium. The energy and momentum lost by the jet partons is added to the hydrodynamic medium via the source terms. The full evolution proceeds in a concurrent mode, without separating hydrodynamic and jet parts. In this report, we examine the medium recoil effects in Pb-Pb collisions at $s_{NN} = 2.76$ TeV LHC energy in the EPOS3-Jet framework.
Comments:
proceedings of Strangeness in Quark Matter 2019 conference (Bari, Italy, 10-15 June 2019). 4 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1911.04155 [pdf]
Springer Proc.Phys.(2020)·1 citation
04
[Submitted on 11 Nov 2019]
Mean-field calculations of charge radii in ground and isomeric states of Cd isotopes
P. Sarriguren
Quadrupole moments and charge radii in cadmium isotopes are studied from a microscopic perspective. The results obtained from self-consistent deformed Hartree-Fock+BCS calculations with Skyrme forces are compared with isomer and isotope shifts measured from high resolution laser spectroscopy experiments. The microscopic calculations reproduce fairly well the main features observed in those isotopes that include the linear increase with the neutron number of the quadrupole moments of the 11/2- isomers, as well as the parabolic behavior of the mean-square charge radii difference between isomers and ground states.
Comments:
9 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1911.04313 [pdf]
PRC(2019)·9 citations
05
[Submitted on 11 Nov 2019]
Pairing correlations and eigenvalues of two-body density matrix in atomic nuclei
Michelangelo Sambataro · Nicolae Sandulescu
The quantum phases of superconductivity and superfluidity are characterised mathematically by the Yang concept of Off-Diagonal Long Range Order (ODLRO), related to the existence of a large eigenvalue of the density matrix. We analyse how the Yang criterion applies for various Hamiltonians commonly employed to describe superfluid-type correlations in atomic nuclei. For like-particle pairing Hamiltonians the behaviour of the largest eigenvalue of two-body density matrix shows a clear evidence for a transition between a normal to a paired phase. However, this is not the case for the isoscalar proton-neutron pairing interactions acting in self-conjugate nuclei.
Comments:
22 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1911.04408 [pdf]
Annals Phys.(2020)·6 citations
06
[Submitted on 8 Nov 2019] (cross-list from hep-ph)
How well do we know neutrino-electron scattering? EFT approach
Oleksandr Tomalak🇺🇸
We determine the effective theory of neutrino-electron and neutrino-quark scattering and provide the most precise up-to-date prediction for neutrino-electron scattering cross sections quantifying errors for the first time to be of order $0.2 - 0.4 %$ . Radiative corrections in the theory with electron and neutrinos only involve three effective couplings. One is the Fermi constant which is known with sub-ppm accuracy. Another one has a small error of order $0.02 %$ . The uncertainty of the third one is limited by the knowledge of hadronic contributions to charge-isospin vector-vector correlation function.
Comments:
5 pages, 3 figures, conference proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1911.03528 [pdf]
PoS(2020)·1 citation
07
[Submitted on 10 Nov 2019] (cross-list from hep-ph)
Transverse-Momentum-Dependent Parton Distribution Functions from Large-Momentum Effective Theory
Xiangdong Ji🇨🇳 · Yizhuang Liu🇨🇳 · Yu-Sheng Liu🇨🇳
We show that transverse-momentum-dependent parton distribution functions (TMDPDFs), important non-perturbative quantities for describing the properties of hadrons in high-energy scattering processes such as Drell-Yan and semi-inclusive deep-inelastic scattering with observed small transverse momentum, can be obtained from Euclidean QCD calculations in the framework of large-momentum effective theory (LaMET). We present a LaMET factorization of the Euclidean quasi-TMDPDFs in terms of the physical TMDPDFs and off-light-cone soft function at leading order in $1/ P^{z}$ expansion, with the perturbative matching coefficient satisfying a renormalization group equation. We also discuss the implementation in lattice QCD with finite-length gauge links as well as the rapidity-regularization-independent factorization for Drell-Yan cross section.
Comments:
8 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1911.03840 [pdf]
PLB(2020)·104 citations
08
[Submitted on 10 Nov 2019] (cross-list from hep-ph)
Dark photon manifestation in the triplet-like QED processes $γ + ℓ_{i} \to ℓ_{j}^{+} ℓ_{j}^{-} + ℓ_{i}$ , $i \neq = j,$ $i = e, μ,$ $j = e, μ, τ$
G.I. Gakh🇺🇦 · M.I. Konchatnij🇺🇦 · N.P. Merenkov🇺🇦 · E. Tomasi-Gustafsson🇫🇷
The triplet-like QED processes $γ + ℓ_{i} \to ℓ_{j}^{+} ℓ_{j}^{-} + ℓ_{i}$ with $i \neq = j,$ and $i = e, μ,$ $j = e, μ, τ$ has been investigated as the reactions where a dark photon, $A^{'}$ , is produced as a virtual state with subsequent decay into a $ℓ_{j}^{+} ℓ_{j}^{-} -$ -pair. This effect arises due to the so-called kinetic mixing and is characterized by the small parameter $ϵ$ describing the coupling strength relative to the electric charge $e$ . The main advantage of searching $A^{'}$ in these processes is that the background to the $A^{'}$ signal is pure QED. Concerning $A^{'}$ , we consider its contribution in the Compton-type diagrams only since, in this case, the virtual dark photon has time-like nature and its propagator has the Breit-Wigner form. So, near the resonance, $A^{'}$ can manifest itself. The contribution of $A^{'}$ in the Borsellino diagrams is negligible since, in this case, the virtual dark photon is space-like, the $A^{'}$ propagator does not peak and the effect is proportional, at least, to $ϵ^{2}$ . We calculate the distributions over the invariant mass of the produced $ℓ_{j}^{+} ℓ_{j}^{-} -$ pair and search for the kinematical region where the Compton-type diagrams contribution is not suppressed with respect to the Borsellino ones. The value of the parameter $ϵ$ is estimated as a function of the dark photon mass for a given number of events.
Comments:
27 pages, 13 figures, accepted for publication in Phys Rev D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1911.03945 [pdf]
PRD(2020)·1 citation
09
[Submitted on 11 Nov 2019] (cross-list from hep-lat)
Long-range electroweak amplitudes of single hadrons from Euclidean finite-volume correlation functions
Raúl A. Briceño🇺🇸 · Zohreh Davoudi🇺🇸 · Maxwell T. Hansen🇨🇭 · Matthias R. Schindler🇺🇸 · Alessandro Baroni🇺🇸
A relation is presented between single-hadron long-range matrix elements defined in a finite Euclidean spacetime, and the corresponding infinite-volume Minkowski amplitudes. This relation is valid in the kinematic region where any number of two-hadron states can simultaneously go on shell, so that the effects of strongly-coupled intermediate channels are included. These channels can consist of non-identical particles with arbitrary intrinsic spins. The result accommodates general Lorentz structures as well as non-zero momentum transfer for the two external currents inserted between the single-hadron states. The formalism, therefore, generalizes the work by Christ et al.~[Phys.Rev. D91 114510 (2015)], and extends the reach of lattice quantum chromodynamics (QCD) to a wide class of new observables beyond meson mixing and rare decays. Applications include Compton scattering of the pion ( $π γ^{⋆} \to [π π, K K] \to π γ^{⋆}$ ), kaon ( $K γ^{⋆} \to [π K, η K] \to K γ^{⋆}$ ) and nucleon ( $N γ^{⋆} \to N π \to N γ^{⋆}$ ), as well as double- $β$ decays, and radiative corrections to the single- $β$ decay, of QCD-stable hadrons. The framework presented will further facilitate generalization of the result to studies of nuclear amplitudes involving two currents from lattice QCD.
Comments:
25 pages, 9 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1911.04036 [pdf]
PRD(2020)·51 citations
10
[Submitted on 11 Nov 2019] (cross-list from hep-ph)
Radiative corrections in proton--antiproton annihilation to electron-positron and their application to the PANDA experiment
Yu.M. Bystritskiy🇷🇺 · V.A. Zykunov🇷🇺 · A. Dbeyssi🇩🇪 · M. Zambrana🇩🇪 · F. Maas🇩🇪 · E. Tomasi-Gustafsson🇫🇷
Radiative corrections to the annihilation of proton--antiproton into electron--positron are revisited, including virtual and real (soft and hard) photon emission. This issue is relevant for the time-like form factors measurements planned at the PANDA experiment at the FAIR facility, in next future. The relevant formulas are given. A stand-alone Monte-Carlo integrator is developed on the basis of the calculated radiative cross section and its application to the PANDA experiment is illustrated.
Comments:
16 pages 12 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1911.04137 [pdf]
EPJA(2020)·2 citations
11
[Submitted on 11 Nov 2019] (cross-list from hep-ph)
The Rayleigh Bubble in Quark Matter under a Strong Magnetic Field
B.O. Kerbikov · M.S. Lukashov
The transition of QGP from fluid-dynamical regime to freeze-out is accompanied by the onset of instabilities. In the present paper we investigate the impact of the magnetic field on the Rayleigh instability. We show that extremely strong field generated in peripheral heavy ion collisions has an insignificant influence on the Rayleigh bubble dynamics. Magnetic "friction" turns out to be much weaker than the viscous one.
Comments:
12 pages, no figures: a completely revised v2 -- the title and the abstract are replaced, new equations with explanations are added, several insertions are made, the list of references is correspondingly enlarged
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1911.04148 [pdf]
PRD(2020)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE