Nuclear Theory·nucl-th

Tuesday·October 27, 2015

17 papers—9 primary·8 cross-listed

01
[Submitted on 25 Oct 2015]
Nuclear Chiral EFT in the Precision Era
Evgeny Epelbaum🇩🇪
Chiral effective field theory has established itself as the method of choice to study nuclear forces and low-energy nuclear dynamics. I review the status and prospects of this approach and discuss ongoing efforts to advance the precision frontier for ab initio description of few-nucleon systems. Special emphasis is put on the precise determination of the two-nucleon force at fifth order in the chiral expansion, role of the chiral symmetry, the convergence pattern of the chiral expansion and the quantification of the theoretical uncertainties. The discussed topics are essential for ongoing studies towards elucidating the structure of the three-nucleon force which will be briefly addressed as well.
Comments:
20 pages, 10 figures, proceedings of 8th International Workshop on Chiral Dynamics, Pisa, Italy
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1510.07036 [pdf]
PoS(2016)·16 citations
02
[Submitted on 25 Oct 2015]
Nuclear electric dipole moment of light nuclei in the gaussian expansion method
Nodoka Yamanaka🇯🇵 · Emiko Hiyama🇯🇵
The nuclear electric dipole moment is a very sensitive probe of CP violation beyond the standard model, and for light nuclei, it can be evaluated accurately using few-body calculational methods. In this talk, we present the deuteron, $^{3}$ He, $^{3}$ H, $^{6}$ Li, and $^{9}$ Be electric dipole moments calculated using the Gaussian expansion method with a realistic nuclear force, and assuming the one-meson exchange model for the P, CP-odd nuclear force. We then give future prospects for models beyond the standard model such as the supersymmetry.
Comments:
10 pages, 1 figure. Proceedings of the 8th International Workshop on Chiral Dynamics 2015, published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1510.07215 [pdf]
PoS(2016)·0 citations
03
[Submitted on 26 Oct 2015]
Interaction of antiprotons with nuclei
J. Hrtánková🇨🇿 · J. Mareš🇨🇿
We performed fully self-consistent calculations of $p ˉ$ -nuclear bound states using a complex $p ˉ$ -nucleus potential accounting for $p ˉ$ -atom data. While the real part of the potential is constructed within the relativistic mean-field (RMF) model, the $p ˉ$ annihilation in the nuclear medium is described by a phenomenological optical potential. We confirm large polarization effects of the nuclear core caused by the presence of the antiproton. The $p ˉ$ annihilation is treated dynamically, taking into account explicitly the reduced phase space for annihilation from deeply bound states as well as the compressed nuclear density due to the antiproton. The energy available for the products of $p ˉ$ annihilation in the nuclear medium is evaluated self-consistently, considering the additional energy shift due to transformation from the $p ˉ N$ system to $p ˉ$ -nucleus system. Corresponding $p ˉ$ widths in the medium are significantly suppressed, however, they still remain considerable for the $p ˉ$ potential consistent with experimental data.
Comments:
preprint submitted to Nuclear Physics A
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1510.07409 [pdf]
NPA(2016)·15 citations
04
[Submitted on 26 Oct 2015]
Baryon resonances in the strangeness production
Ju-Jun Xie🇨🇳 · En Wang🇨🇳 · Jia-Jun Wu🇦🇺
We have studied the $N^{*} (2120)$ , $Δ^{*} (1940)$ , and the possible $Σ^{*} (1380)$ resonances in the $γ p \to K^{+} Λ (1520)$ , $pp \to n K^{+} Σ (1385)$ , and $Λ p \to Λ p π^{0}$ reactions within the resonance model and the effective Lagrangian approach. It is shown that when the contributions from these baryonic states were considered, the current experimental measurement could be well reproduced. In addition, we also demonstrate that the angular distributions provide direct information of these reactions, which could be useful for the investigation of those states and may be tested by future experiments.
Comments:
Talk given at the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015), Osaka, May 25--28 2015
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1510.07413 [pdf]
JPS Conf.Proc.(2016)·0 citations
05
[Submitted on 26 Oct 2015]
The $Ξ^{*} K ˉ$ and $Ω η$ interaction within a chiral unitary approach
Siqi Xu🇨🇳 · Ju-Jun Xie🇨🇳 · Xurong Chen🇨🇳 · Duojie Jia🇨🇳
In this work we study the interaction of the coupled channels $Ω η$ and $Ξ^{*} K ˉ$ within the chiral unitary approach. The systems under consideration have total isospins $0$ , strangeness $S = - 3$ , and spin $3/2$ . We studied the $s$ wave interaction which implies that the possible resonances generated in the system can have spin-parity $J^{P} = 3/ 2^{-}$ . The unitary amplitudes in coupled channels develop poles that can be associated with some known baryonic resonances. We find there is a dynamically generated $3/ 2^{-}$ $Ω$ state with mass around $1800$ MeV, which is in agreement with the predictions of the five-quark model.
Comments:
4 pages, 3 figures, published on the Communications in Theoretical Physics
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1510.07419 [pdf]
Commun.Theor.Phys.(2016)·18 citations
06
[Submitted on 26 Oct 2015]
Nuclear saturation in lowest-order Brueckner theory with two- and three-nucleon forces in view of chiral effective field theory
M. Kohno
The nuclear saturation mechanism is discussed in terms of two-nucleon and three-nucleon interactions in chiral effective field theory (Ch-EFT), using the framework of lowest-order Brueckner theory. After the Coester band, which is observed in calculating saturation points with various nucleon-nucleon (NN) forces, is revisited using modern NN potentials and their low-momentum equivalent interactions, detailed account of the saturation curve of the Ch-EFT interaction is presented. The three-nucleon force (3NF) is treated by reducing it to an effective two-body interaction by folding the third nucleon degrees of freedom. Uncertainties due to the choice of the 3NF low-energy constants $c_{D}$ and $c_{E}$ are discussed. The reduction of the cutoff-energy dependence of the NN potential is explained by demonstrating the effect of the 3NF in the $^{1}$ S $_{0}$ and $^{3}$ S $_{1}$ states.
Comments:
14 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1510.07469 [pdf]
PTEP(2015)·10 citations
07
[Submitted on 26 Oct 2015]
Heavy-flavor dynamics in relativistic p-Pb collisions at $S_{N N} = 5.02$ TeV
Yingru Xu🇺🇸 · Shanshan Cao🇺🇸 · Marlene Nahrgang🇨🇳 · Weiyao Ke🇺🇸 · Guang-You Qin🇺🇸 · Jussi Auvinen🇺🇸 · Steffen A. Bass🇺🇸
We investigate the heavy flavor dynamics in the quark-gluon plasma (QGP) medium created in p-Pb collisions at the CERN Large Hadron Collider (LHC). In the (3+1)-dimensional viscous hydrodynamics model describing QGP medium, the dynamics of heavy quarks are studied in an improved Langevin framework incorporating both collisional and radiative energy loss. The hadronization of the heavy quarks is given by a hybrid model of fragmentation and recombination. We find that the in-medium evolution of charm quarks raises the D-meson $R_{pP b}$ at low transverse momenta while it suppresses the D-meson $R_{pP b}$ at intermediate momenta. In addition, the elliptic flow of D-meson is calculated. For a diffusion coefficient which reproduces central $R_{AA}$ data at the LHC, we find a much smaller D-meson $v_{2}$ compared to the light hadrons. This observation indicates an incomplete coupling between heavy quarks with the medium, due to the reduced medium size compared to AA collisions.
Comments:
4 pages, 4 figures, proceedings for the Hard Probes 2015 conference
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1510.07520 [pdf]
Nucl.Part.Phys.Proc.(2016)·40 citations
08
[Submitted on 26 Oct 2015]
Axial-vector dominance predictions in quasielastic neutrino-nucleus scattering
J.E. Amaro🇪🇸 · E. Ruiz Arriola🇪🇸
The axial form factor plays a crucial role in quasielastic neutrino-nucleus scattering, but the error of the theoretical cross section due to uncertainties of $G_{A}$ remains to be established. Reversely, the extraction of $G_{A}$ from the neutrino nucleus cross section suffers from large systematic errors due to nuclear model dependencies, while the use of single parameter dipole fits underestimates the errors and prevents an identification of the relevant kinematics for this determination. We propose to use a generalized axial-vector-meson-dominance (AVMD) in conjunction with large- $N_{c}$ and high energy QCD constrains to model the nucleon axial form factor, as well as the half width rule as an a priori uncertainty estimate. The minimal hadronic ansatz comprises the sum of two monopoles corresponding to the lightest axial-vector mesons being coupled to the axial current. The parameters of the resulting axial form factor are the masses and widths of the two axial mesons as obtained from the averaged PDG values. By applying the half width rule in a Monte Carlo simulation, a distribution of theoretical predictions can then be generated for the neutrino-nucleus quasielastic cross section. We test the model by applying it to the $(ν_{μ}, μ)$ quasielastic cross section from $^{12}$ C for the kinematics of the MiniBooNE experiment. The resulting predictions have no free parameters. We find that the relativistic Fermi gas model globally reproduces the experimental data, giving $χ^{2} /# bin s = 0.81$ . A $Q^{2}$ -dependent error analysis of the neutrino data shows that the uncertainties in the axial form factor $G_{A} (Q^{2})$ are comparable to the ones induced by the a priori half width rule. We identify the most sensitive region to be in the range $0.2 ≲ Q^{2} ≲ 0.6 GeV^{2}$ .
Comments:
10 pages, 7 figures. Extended, revised version for Physical review D
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1510.07532 [pdf]
PRD(2016)·32 citations
09
[Submitted on 26 Oct 2015]
Large-N(c) limit reduces the number of independent few-body parity-violating low-energy constants in pionless effective field theory
Matthias R. Schindler🇺🇸 · Roxanne P. Springer🇺🇸 · Jared Vanasse🇺🇸
The symmetries of the Standard Model dictate that for very low energies, where nucleon dynamics can be described in terms of a pionless effective field theory, the leading-order parity-violating nucleon-nucleon Lagrangian contains five independent unknown low-energy constants (LECs). We find that imposing the approximate symmetry of QCD that appears when the number of colors N(c) becomes large reduces the number of independent LECs to two at leading order in the combined pionless effective field theory and large-N(c) expansions. We also find a relation between the two isoscalar LECs in the large-N(c) limit. This has important implications for the number of experiments and/or lattice calculations necessary to confirm this description of physics.
Comments:
11 pages, corrected missing factors of $sin^{2} θ_{W}$ ; conclusions unchanged
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1510.07598 [pdf]
PRC(2016)·43 citations
10
[Submitted on 23 Oct 2015] (cross-list from gr-qc)
R-mode astronomy
Kostas D. Kokkotas🇩🇪 · Kai Schwenzer🇩🇪
Next generation gravitational wave detectors will start taking data in the near future. Here we discuss the chances to detect the continuous emission from r-mode oscillations in compact stars and study which properties of compact stars we can infer from such novel data. In particular we show that the combination of the gravitational wave data with electromagnetic multi-messenger observations could give us detailed insight into compact star properties, ranging from precise mass-radius measurements to the determination of the equation of state and the phase structure of dense matter.
Comments:
15 pages, 6 figures, to be published in the EPJA Topical Issue on "Exotic Matter in Neutron Stars"
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
1510.07051 [pdf]
EPJA(2016)·35 citations
11
[Submitted on 23 Oct 2015] (cross-list from hep-ph)
Coupled-Channel Model for $K ˉ N$ Scattering in the Resonant Region
C. Fernandez-Ramirez🇺🇸 · I. V. Danilkin🇺🇸 · D. M. Manley🇺🇸 · V. Mathieu🇺🇸 · A. P. Szczepaniak🇺🇸
We present a unitary multichannel model for $K ˉ N$ scattering in the resonance region that fulfills unitarity. It has the correct analytical properties for the amplitudes once they are extended to the complex- $s$ plane and the partial waves have the right threshold behavior. To determine the parameters of the model, we have fitted single-energy partial waves up to $J = 7/2$ and up to 2.15 GeV of energy in the center-of-mass reference frame obtaining the poles of the $Λ^{*}$ and $Σ^{*}$ resonances, which are compared to previous analyses. We provide the most comprehensive picture of the $S = - 1$ hyperon spectrum to date. Important differences are found between the available analyses making the gathering of further experimental information on $K ˉ N$ scattering mandatory to make progress in the assessment of the hyperon spectrum.
Comments:
Joint Physics Analysis Center, 28 pages, 19 figures, 3 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1510.07065 [pdf]
PRD(2016)·72 citations
12
[Submitted on 25 Oct 2015] (cross-list from hep-lat)
Finite-temperature phase transition of $N_{f} = 3$ QCD with exact center symmetry
Tatsuhiro Misumi🇯🇵 · Takumi Iritani🇺🇸 · Etsuko Itou🇯🇵
For the $Z_{3}$ -symmetric lattice QCD-like theory ( $Z_{3}$ -QCD), in which $S U (3)$ gauge theory is coupled with three fundamental Wilson quarks with flavor-dependent twisted boundary conditions, we calculate the expectation values of Polyakov loop and chiral condensate as functions of temperature on $1 6^{3} \times 4$ and $2 0^{3} \times 4$ lattices with $m_{P S} / m_{V} = 0.70$ fixed. We find the first-order phase transition with respect to the $Z_{3}$ center symmetry, where the Polyakov loop exhibits a hysteresis depending on the initial condition of thermalization process. We also show that the crossover behavior of chiral condensate around the critical temperature of the center transition and the manifestation of flavor symmetry breaking in the high-temperature phase.
Comments:
7 pages, 6 figures, presented at the 33rd International Symposium on Lattice Field Theory, Lattice2015, 14-18 July 2015, Kobe International Conference Center, Kobe, JAPAN
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1510.07227 [pdf]
PoS(2016)·15 citations
13
[Submitted on 25 Oct 2015] (cross-list from hep-ph)
Towards nature of the X(3872) resonance
N.N. Achasov🇷🇺 · E.V. Rogozina🇷🇺
We construct spectra of decays of the resonance X(3872) with good analytical and unitary properties which allows to define the branching ratio of the X(3872) \to D^{*0}\bar D^0 + c.c. decay studying only one more decay, for example, the X(3872)\to\pi^+\pi^- J/\psi(1S) decay, and show that our spectra are effective means of selection of models for the resonance X(3872). Then we discuss the scenario where the X(3872 resonance is the c\bar c = \chi_{c1}(2P) charmonium which "sits on" the D^{*0}\bar D^0 threshold. We explain the shift of the mass of the X(3872) resonance with respect to the prediction of a potential model for the mass of the \chi_{c1}(2P) charmonium by the contribution of the virtual D^*\bar D+c.c. intermediate states into the self energy of the X(3872) resonance. This allows us to estimate the coupling constant of the X(7872) resonance with the D^{*0}\bar D^0 channel, the branching ratio of the X(3872) \to D^{*0}\bar D^0 + c.c. decay, and the branching ratio of the X(3872) decay into all non-D^{*0}\bar D^0 + c.c. states. We predict a significant number of unknown decays of X(3872) via two gluons:X(3872)\to gluons\ gluon\to hadrons.
Comments:
6 pages, 7 figures, N. N. Achasov's remote plenary talk, "Proceedings of the PhiPsi15, Sep. 23-26, 2015, Hefei, China"
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1510.07251 [pdf]
J.Univ.Sci.Tech.China(2016)·8 citations
14
[Submitted on 25 Oct 2015] (cross-list from hep-ph)
Strange meson-baryon interaction in hot and dense medium: recent progress for a road to GSI/FAIR
Daniel Cabrera🇩🇪 · Laura Tolos🇩🇪 · Jörg Aichelin🇫🇷 · Elena bratkovskaya🇩🇪
We report recent results on the dynamics of strange hadrons in two-body reactions relevant for near-threshold production in heavy-ion collisions at GSI/FAIR and NICA-Dubna. In particular, $K ˉ N$ scattering in hot and dense nuclear matter is studied within a chiral unitary framework in coupled channels, setting up the starting point for implementations in microscopic off-shell transport approaches. We focus on the calculation of transition rates with special attention to the excitation of hyperon resonances and isospin effects. Additionally, we explore "unconventional" strangeness generation by meson-meson and meson-baryon interactions in connection with recent HADES observations of deep sub-threshold $ϕ$ and $Ξ$ production.
Comments:
4 pages, 2 figures. To be published in the Proceedings of the 15th International Conference on Strangeness in Quark Matter (SQM2015), 6-11 July 2015, JINR, Dubna, Russia
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1510.07265 [pdf]
J.Phys.Conf.Ser.(2016)·7 citations
15
[Submitted on 26 Oct 2015] (cross-list from hep-lat)
Chiral symmetry breaking and monopoles
Adriano Di Giacomo🇮🇹 · Masayasu Hasegawa🇷🇺 · Fabrizio Pucci🇧🇪
To understand the relation between the chiral symmetry breaking and monopoles, the chiral condensate which is the order parameter of the chiral symmetry breaking is calculated in the $\mbox M S$ scheme at 2 [GeV]. First, we add one pair of monopoles, varying the monopole charges $m_{c}$ from zero to four, to SU(3) quenched configurations by a monopole creation operator. The low-lying eigenvalues of the Overlap Dirac operator are computed from the gauge links of the normal configurations and the configurations with additional monopoles. Next, we compare the distributions of the nearest-neighbor spacing of the low-lying eigenvalues with the prediction of the random matrix theory. The low-lying eigenvalues not depending on the scale parameter $Σ$ are compared to the prediction of the random matrix theory. The results show the consistency with the random matrix theory. Thus, the additional monopoles do not affect the low-lying eigenvalues. Moreover, we discover that the additional monopoles increase the scale parameter $Σ$ . We then evaluate the chiral condensate in the $\mbox M S$ scheme at 2 [GeV] from the scale parameter $Σ$ and the renormalization constant $Z_{S}$ . The final results clearly show that the chiral condensate linearly decreases by increasing the monopole charges.
Comments:
A contribution to the 8th International Workshop on Chiral Dynamics, 2015, Pisa, Italy. 8 pages and 5 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1510.07463 [pdf]
PoS(2016)·3 citations
16
[Submitted on 26 Oct 2015] (cross-list from astro-ph.HE)
Neutron Star Radii, Universal Relations, and the Role of Prior Distributions
A.W. Steiner🇺🇸 · J.M. Lattimer🇺🇸 · E.F. Brown🇺🇸
We investigate constraints on neutron star structure arising from the assumptions that neutron stars have crusts, that recent calculations of pure neutron matter limit the equation of state of neutron star matter near the nuclear saturation density, that the high-density equation of state is limited by causality and the largest high-accuracy neutron star mass measurement, and that general relativity is the correct theory of gravity. We explore the role of prior assumptions by considering two classes of equation of state models. In a first, the intermediate- and high-density behavior of the equation of state is parameterized by piecewise polytropes. In the second class, the high-density behavior of the equation of state is parameterized by piecewise continuous line segments. The smallest density at which high-density matter appears is varied in order to allow for strong phase transitions above the nuclear saturation density. We critically examine correlations among the pressure of matter, radii, maximum masses, the binding energy, the moment of inertia, and the tidal deformability, paying special attention to the sensitivity of these correlations to prior assumptions about the equation of state. It is possible to constrain the radii of $1.4 M_{⊙}$ neutron stars to a be larger than 10 km, even without consideration of additional astrophysical observations, for example, those from photospheric radius expansion bursts or quiescent low-mass X-ray binaries. We are able to improve the accuracy of known correlations between the moment of inertia and compactness as well as the binding energy and compactness. We also demonstrate the existence of a correlation between the neutron star binding energy and the moment of inertia.
Comments:
Eur. Phys. J. A (in press)
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
1510.07515 [pdf]
EPJA(2016)·117 citations
17
[Submitted on 26 Oct 2015] (cross-list from hep-ph)
Constraints on the $η η^{'}$ decay rate of a scalar glueball from gauge/gravity duality
Frederic Brünner🇦🇹 · Anton Rebhan🇦🇹
Predictions of glueball decay rates in the holographic Witten-Sakai-Sugimoto model for low-energy QCD can be uniquely extended to include finite quark masses up to an as yet undetermined parameter in the coupling of glueballs to the nonanomalous part of the pseudoscalar mass terms. The assumption of a universal coupling of glueballs to mass terms of the full nonet of pseudoscalar mesons leads to flavor asymmetries in the decay rates of scalar glueballs that agree well with experimental data for the glueball candidate $f_{0} (1710)$ and implies a vanishing decay rate into $η η^{'}$ pairs, for which only upper bounds for the $f_{0} (1710)$ meson are known at present from experiment. Relaxing this assumption, the holographic model gives a tight correlation between the decay rates into pairs of pseudo-Goldstone bosons of same type and $η η^{'}$ pairs. If $Γ (G \to K K) /Γ (G \to π π)$ is kept within the range reported currently by the Particle Data Group for the $f_{0} (1710)$ meson, the rate $Γ (G \to η η^{'}) /Γ (G \to π π)$ is predicted to be $≲ 0.04$ . The corresponding situation for $f_{0} (1500)$ is also discussed, which however is found to be much less compatible with the interpretation of a largely unmixed glueball.
Comments:
7 pages, 3 figures; v2: minor corrections, version to appear in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1510.07605 [pdf]
PRD(2015)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE