Nuclear Theory·nucl-th

Thursday·November 3, 2016

11 papers—5 primary·6 cross-listed

01
[Submitted on 2 Nov 2016]
Uncertainty propagation within the UNEDF models
T. Haverinen · M. Kortelainen
The parameters of the nuclear energy density have to be adjusted to experimental data. As a result they carry certain uncertainty which then propagates to calculated values of observables. In the present work we quantify the statistical uncertainties of binding energies, proton quadrupole moments, and proton matter radius for three UNEDF Skyrme energy density functionals by taking advantage of the knowledge of the model parameter uncertainties. We find that the uncertainty of UNEDF models increases rapidly when going towards proton or neutron rich nuclei. We also investigate the impact of each model parameter on the total error budget.
Comments:
22 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1611.00597 [pdf]
J.Phys.G(2017)·14 citations
02
[Submitted on 2 Nov 2016]
Three-body model for the two-neutron decay of $^{16}$ Be
A.E. Lovell · F.M. Nunes · I.J. Thompson
While diproton decay was first theorized in 1960 and first measured in 2002, it was first observed only in 2012. The measurement of $^{14}$ Be in coincidence with two neutrons suggests that $^{16}$ Be does decay through the simultaneous emission of two strongly correlated neutrons. In this work, we construct a full three-body model of $^{16}$ Be (as $^{14}$ Be + n + n) in order to investigate its configuration in the continuum and in particular the structure of its ground state. In order to describe the three-body system, effective n- $^{14}$ Be potentials were constructed, constrained by the experimental information on $^{15}$ Be. The hyperspherical R-matrix method was used to solve the three-body scattering problem, and the resonance energy of $^{16}$ Be was extracted from a phase shift analysis. In order to reproduce the experimental resonance energy of $^{16}$ Be within this three-body model, a three-body interaction was needed. For extracting the width of the ground state of $^{16}$ Be, we use the full width at half maximum of the derivative of the three-body phase shifts and the width of the three-body elastic scattering cross section. Our results confirm a dineutron structure for $^{16}$ Be, dependent on the internal structure of the subsystem $^{15}$ Be.
Comments:
13 pages, 9 figures, submitted to Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1611.00604 [pdf]
PRC(2017)·26 citations
03
[Submitted on 1 Nov 2016]
Determination of the number of participating nucleons in p+p interactions at SPS energies
H. Stroebele🇩🇪
In the past the analyses of inelastic p+p collision for example in terms of the hadron gas model have assumed that always both protons participate in the interaction. In this article we show that (at sqrt(s) = 17.3 GeV ) on average only 1,89 protons are interacting. Measurements of the mean multiplicities of protons, neutrons, charged pions, charged kaons and {\Lambda} hyperons allow to compute the number of initial state nucleons using conservation of baryon number, strangeness, and isospin. We further argue that once the number of initial state nucleons is given and the mean multiplicities of protons and charged pions are known in p+p interactions at center-of-mass energies below a few tens of GeV, the yields of net neutrons, kaons, and hyperons can be estimated with a precision of a few percent using again baryon and isospin conservation.
Comments:
6 pages, submitted to PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1611.00615 [pdf]
1 citation
04
[Submitted on 2 Nov 2016]
Dissipationless Hall Current in Dense Quark Matter in a Magnetic Field
E. J. Ferrer🇺🇸 · V. de la Incera🇺🇸
We show the realization of axion electrodynamics within the Dual Chiral Density Wave phase of dense quark matter in the presence of a magnetic field. The system exhibits an anomalous dissipantionless Hall current perpendicular to the magnetic field and an anomalous electric charge density. Connection to topological insulators and 3D optical lattices, as well as possible implications for heavy-ion collisions and neutron stars are outlined.
Comments:
To appear in Phys. Lett. B
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1611.00660 [pdf]
PLB(2017)·35 citations
05
[Submitted on 2 Nov 2016]
Ab Initio Excited States from the In-Medium Similarity Renormalization Group
N. M. Parzuchowski · T. D. Morris · S. K. Bogner
We present two new methods for performing ab initio calculations of excited states for closed-shell systems within the in-medium similarity renormalization group (IMSRG) framework. Both are based on combining the IMSRG with simple many-body methods commonly used to target excited states, such as the Tamm-Dancoff approximation (TDA) and equations-of-motion (EOM) techniques. In the first approach, a two-step sequential IMSRG transformation is used to drive the Hamiltonian to a form where a simple TDA calculation (i.e., diagonalization in the space of $1$ p $1$ h excitations) becomes exact for a subset of eigenvalues. In the second approach, equations-of-motion (EOM) techniques are applied to the ground-state-decoupled IMSRG Hamiltonian to access excited states. We perform proof-of-principle calculations for parabolic quantum dots in two-dimensions and the closed shell nuclei $^{16}$ O and $^{22}$ O. We find that the TDA-IMSRG approach gives better accuracy than the EOM-IMSRG when calculations converge, but is otherwise lacking the versatility and numerical stability of the latter. Our calculated spectra are in reasonable agreement with analogous EOM-coupled-cluster (EOM-CC) calculations, which paves the way for more interesting applications of the EOM-IMSRG to calculations of consistently evolved observables such as electromagnetic strength functions and nuclear matrix elements, and extensions to nuclei within 1-2 nucleons of a closed shell by generalizing the EOM ladder operator to include particle-number nonconserving terms.
Comments:
16 pages, 13 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1611.00661 [pdf]
PRC(2017)·35 citations
06
[Submitted on 1 Nov 2016] (cross-list from hep-ex)
Neutrino Interactions and Long-Baseline Experiments
Ulrich Mosel🇩🇪
The extraction of neutrino mixing parameters and the CP-violating phase requires knowledge of the neutrino energy. This energy must be reconstructed from the final state of a neutrino-nucleus reaction since all long-baseline experiments use nuclear targets. This reconstruction requires detailed knowledge of the neutrino reactions with bound nucleons and of the final state interactions of hadrons with the nuclear environment. Quantum-kinetic transport theory can be used to build an event generator for this reconstruction that takes basic nuclear properties, such as binding, into account. Some examples are discussed that show the effects of nuclear interactions on observables in long-baseline experiments
Comments:
Inv. Talk at ICHEP 16, Chicago, Aug. 3-10, 2016
Subjects:
High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1611.00373 [pdf]
PoS(2016)·1 citation
07
[Submitted on 2 Nov 2016] (cross-list from hep-ph)
Estimate on Spin Asymmetry for Drell-Yan Process at Fermilab with Tensor-Polarized Deuteron
S. Kumano🇯🇵 · Qin-Tao Song🇯🇵
There are four new structure functions for the spin-1 deuteron in comparison with the ones for the spin-1/2 proton, and they are called $b_{1}$ , $b_{2}$ , $b_{3}$ , and $b_{4}$ . The twist-2 structure functions $b_{1}$ and $b_{2}$ are expressed by tensor-polarized parton distribution functions in the deuteron. HERMES measurements of $b_{1}$ are much different from the prediction of the standard deuteron model with D-state admixture. It indicates that the structure functions $b_{1}$ and $b_{2}$ probe an interesting new aspect in the deuteron. There is an approved experiment at JLab to measure $b_{1}$ and it is expected to start in 2019. On the other hand, the measurement of tensor-polarized distributions is under consideration at Fermilab by the Drell-Yan process with the unpolarized proton beam and tensor-polarized deuteron target. It is expected to provide crucial information on tensor-polarized antiquark distributions. Since the distributions are small quantities, it is important to estimate the tensor-polarized spin asymmetry theoretically to find experimental feasibility for an actual proposal at Fermilab.
Comments:
4 pages, 3 eps figures, to be published in JPS Conf. Proc., Proceedings of the 14th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016), July 25-30, 2016, Kyoto, Japan
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1611.00474 [pdf]
JPS Conf.Proc.(2017)·2 citations
08
[Submitted on 2 Nov 2016] (cross-list from hep-ph)
The one loop gluon emission light cone wave function
Tuomas Lappi🇫🇮 · Risto Paatelainen🇪🇸
Light cone perturbation theory has become an essential tool to calculate cross sections for various small- $x$ dilute-dense processes such as deep inelastic scattering and forward proton-proton and proton-nucleus collisions. Here we set out to do one loop calculations in an explicit helicity basis in the four dimensional helicity scheme. As a first process we calculate light cone wave function for one gluon emission to one-loop order in Hamiltonian perturbation theory on the light front. We regulate ultraviolet divergences with transverse dimensional regularization and soft divergences with using a cut-off on longitudinal momentum. We show that when all the renormalization constants are combined, the ultraviolet divergences can be absorbed into the standard QCD running coupling constant, and give an explicit expression for the remaining finite part.
Comments:
V2: Typo corrections and clarifications to text, t.b.p, Annals Phys
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1611.00497 [pdf]
Annals Phys.(2017)·40 citations
09
[Submitted on 2 Nov 2016] (cross-list from hep-ph)
Heavy-Quark Diffusion Dynamics in Quark-Gluon Plasma under Strong Magnetic Fields
Koichi Hattori🇨🇳 · Kenji Fukushima🇯🇵 · Ho-Ung Yee🇺🇸 · Yi Yin🇺🇸
We discuss heavy-quark dynamics in the quark-gluon plasma under a strong magnetic field induced by colliding nuclei. By the use of the diagrammatic resummation techniques for Hard Thermal Loop and the external magnetic field, we show analytic results of heavy-quark diffusion coefficient and drag force which become anisotropic due to the preferred spatial orientation in the magnetic field. We argue that the anisotropic diffusion coefficient gives rise to an enhancement/suppression of the heavy-quark elliptic flow depending on the transverse momentum.
Comments:
4 pages. Contribution to Hard Probes 2016 in Wuhan. arXiv admin note: text overlap with arXiv:1609.00747
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1611.00500 [pdf]
Nucl.Part.Phys.Proc.(2017)·8 citations
10
[Submitted on 2 Nov 2016] (cross-list from hep-ph)
Quarkonium production at collider energies in Small- $x$ formalism
Kazuhiro Watanabe🇨🇳
I present a short review of recent studies of quarkonium production in proton-proton and proton-nucleus collisions at collider energies in Small- $x$ formalism.
Comments:
20 pages, 10 figures, uses svglov2.clo, svjour2.cls; Invited presentation at the workshop "New Observables In Quarkonium Production", ECT*, Italy, 28 February - 4 March 2016, v2: Grants info added, email address modified, v3: Published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1611.00700 [pdf]
Few Body Syst.(2017)·6 citations
11
[Submitted on 2 Nov 2016] (cross-list from hep-ph)
Cosmological Implications of QGP Bulk Viscosity
Sampurn Anand🇮🇳 · Abhishek Atreya🇮🇳 · Jitesh R. Bhatt🇮🇳
Recent studies of the hot QCD matter indicate that the bulk viscosity ( $ζ$ ) of quark-gluon plasma (QGP) rises sharply near the critical point of the QCD phase transition. In this work, we show that such a sharp rise of the bulk viscosity will lead to an effective negative pressure near the critical temperature, $T_{c}$ which in turn drives the Universe to inflate. This inflation has a natural graceful exist when the viscous effect evanesce. We estimate that, depending upon the peak value of $ζ$ , universe expands by a factor of $10$ to $80$ times in a very short span ( $Δ t \sim 1 0^{- 8}$ seconds). Another important outcome of the bulk viscosity dominated dynamics is the cavitation of QGP around $T \sim 1.5 T_{c}$ . This would lead to the phenomenon of formation of cavitation bubbles within the QGP phase. The above scenario is independent of the order of QCD phase transition. We delineate some of the important cosmological consequences of the inflation and the cavitation.
Comments:
This paper has been withdrawn. The results presented were artifacts of an error in the numerical code
Subjects:
High Energy Physics — Phenomenology (hep-ph); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1611.00701 [pdf]
1 citation

Affiliations

first authorsco-authorsvia INSPIRE