Nuclear Theory·nucl-th

Friday·December 13, 2019

17 papers—7 primary·10 cross-listed

08
[Submitted on 11 Dec 2019] (cross-list from hep-ph)
Nucleon-to-meson transition distribution amplitudes in impact parameter space
Bernard Pire🇫🇷 · Kirill Semenov-Tian-Shansky🇷🇺 · Lech Szymanowski🇵🇱
Recent analyses of backward meson electroproduction support the validity of a collinear QCD factorization framework for these hard exclusive reactions. This opens a way to the extraction of nucleon-to-meson transition distribution amplitudes (TDAs) from the experimental data. Similarly to the generalized parton distributions, TDAs - after the Fourier transform in the transverse plane - carry valuable information on the transverse location of hadron constituents. We address the properties of integrated nucleon-to-meson TDAs in the impact parameter representation. We argue that the emerging picture provides an intuitive interpretation for the hadron structural information contained in nucleon-to-meson TDAs and allows to study diquark-quark contents of fast moving hadrons in the transverse plane.
Comments:
6 pages, 2 figures. LC2019 - QCD on the light cone: from hadrons to heavy ions, 16-20 September 2019, Ecole Polytechnique, Palaiseau, France
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1912.05165 [pdf]
PoS(2019)·6 citations
09
[Submitted on 11 Dec 2019] (cross-list from hep-ph)
T-dependence of the axion mass when the U_A(1) and chiral symmetry breaking are tied
Dubravko Klabučar🇭🇷 · Davor Horvatić🇭🇷 · Dalibor Kekez🇭🇷
Modulo the scale of spontaneous breaking of Peccei-Quinn symmetry, the axion mass $m_{a} (T)$ is given by the QCD topological susceptibility $χ (T)$ at all temperatures $T$ . From an approach tying the $U_{A} (1)$ and chiral symmetry breaking and getting good $T$ -dependence of $η$ and $η$ mesons, we get $χ (T)$ for an effective Dyson-Schwinger model of nonperturbative QCD. Comparison with lattice results for $χ (T)$ , and thus also for $m_{a} (T)$ , shows good agreement for temperatures ranging from zero up to the double of the chiral restoration temperature $T_{c}$ .
Comments:
appolb.cls, 6 pages, 1 figure, condensed version of the part of arXiv:1909.09879 presented at Excited QCD 2019, to appear in Acta Physica Polonica B Proceedings Supplement
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1912.05619 [pdf]
Acta Phys.Polon.Supp.(2020)·0 citations
10
[Submitted on 12 Dec 2019] (cross-list from astro-ph.HE)
A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
Thomas E. Riley🇳🇱 · Anna L. Watts🇳🇱 · Slavko Bogdanov🇺🇸 · Paul S. Ray🇺🇸 · Renee M. Ludlam🇺🇸 · Sebastien Guillot🇫🇷 · Zaven Arzoumanian🇺🇸 · Charles L. Baker🇺🇸 · Anna V. Bilous🇳🇱 · Deepto Chakrabarty🇺🇸 · Keith C. Gendreau🇺🇸 · Alice K. Harding🇺🇸 and 4 other authors
We report on Bayesian parameter estimation of the mass and equatorial radius of the millisecond pulsar PSR J0030 $+$ 0451, conditional on pulse-profile modeling of Neutron Star Interior Composition Explorer (NICER) X-ray spectral-timing event data. We perform relativistic ray-tracing of thermal emission from hot regions of the pulsar's surface. We assume two distinct hot regions based on two clear pulsed components in the phase-folded pulse-profile data; we explore a number of forms (morphologies and topologies) for each hot region, inferring their parameters in addition to the stellar mass and radius. For the family of models considered, the evidence (prior predictive probability of the data) strongly favors a model that permits both hot regions to be located in the same rotational hemisphere. Models wherein both hot regions are assumed to be simply-connected circular single-temperature spots, in particular those where the spots are assumed to be reflection-symmetric with respect to the stellar origin, are strongly disfavored. For the inferred configuration, one hot region subtends an angular extent of only a few degrees (in spherical coordinates with origin at the stellar center) and we are insensitive to other structural details; the second hot region is far more azimuthally extended in the form of a narrow arc, thus requiring a larger number of parameters to describe. The inferred mass $M$ and equatorial radius $R_{eq}$ are, respectively, $1.3 4_{- 0.16}^{+ 0.15}$ M $_{⊙}$ and $12.7 1_{- 1.19}^{+ 1.14}$ km, whilst the compactness $GM / R_{eq} c^{2} = 0.15 6_{- 0.010}^{+ 0.008}$ is more tightly constrained; the credible interval bounds reported here are approximately the $16%$ and $84%$ quantiles in marginal posterior mass.
Comments:
Appears in ApJ Letters Focus Issue on NICER Constraints on the Dense Matter Equation of State; 76 pages, 24 figures, 7 tables, 8 figure sets (available in the online journal or from the authors)
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
1912.05702 [pdf]
ApJL(2019)·1829 citations
11
[Submitted on 12 Dec 2019] (cross-list from astro-ph.HE)
A NICER view of PSR J0030+0451: Implications for the dense matter equation of state
G. Raaijmakers🇳🇱 · T. E. Riley🇳🇱 · A. L. Watts🇳🇱 · S. K. Greif🇩🇪 · S. M. Morsink🇨🇦 · K. Hebeler🇩🇪 · A. Schwenk🇩🇪 · T. Hinderer🇳🇱 · S. Nissanke🇳🇱 · S. Guillot🇫🇷 · Z. Arzoumanian🇺🇸 · S. Bogdanov🇺🇸 and 5 other authors
Both the mass and radius of the millisecond pulsar PSR J0030+0451 have been inferred via pulse-profile modeling of X-ray data obtained by NASA's NICER mission. In this Letter we study the implications of the mass-radius inference reported for this source by Riley et al. (2019) for the dense matter equation of state (EOS), in the context of prior information from nuclear physics at low densities. Using a Bayesian framework we infer central densities and EOS properties for two choices of high-density extensions: a piecewise-polytropic model and a model based on assumptions of the speed of sound in dense matter. Around nuclear saturation density these extensions are matched to an EOS uncertainty band obtained from calculations based on chiral effective field theory interactions, which provide a realistic description of atomic nuclei as well as empirical nuclear matter properties within uncertainties. We further constrain EOS expectations with input from the current highest measured pulsar mass; together, these constraints offer a narrow Bayesian prior informed by theory as well as laboratory and astrophysical measurements. The NICER mass-radius likelihood function derived by Riley et al. (2019) using pulse-profile modeling is consistent with the highest-density region of this prior. The present relatively large uncertainties on mass and radius for PSR J0030+0451 offer, however, only a weak posterior information gain over the prior. We explore the sensitivity to the inferred geometry of the heated regions that give rise to the pulsed emission, and find a small increase in posterior gain for an alternative (but less preferred) model. Lastly, we investigate the hypothetical scenario of increasing the NICER exposure time for PSR J0030+0451.
Comments:
Appears in ApJ Letters Focus Issue on NICER Constraints on the Dense Matter Equation of State, 17 pages, 5 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
1912.05703 [pdf]
ApJL(2019)·300 citations
12
[Submitted on 12 Dec 2019] (cross-list from astro-ph.HE)
PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
M. C. Miller🇺🇸 · F. K. Lamb🇺🇸 · A. J. Dittmann🇺🇸 · S. Bogdanov🇺🇸 · Z. Arzoumanian🇺🇸 · K. C. Gendreau🇺🇸 · S. Guillot🇫🇷 · A. K. Harding🇺🇸 · W. C. G. Ho🇺🇸 · J. M. Lattimer🇺🇸 · R. M. Ludlam🇺🇸 · S. Mahmoodifar🇺🇸 and 9 other authors
Neutron stars are not only of astrophysical interest, but are also of great interest to nuclear physicists, because their attributes can be used to determine the properties of the dense matter in their cores. One of the most informative approaches for determining the equation of state of this dense matter is to measure both a star's equatorial circumferential radius $R_{e}$ and its gravitational mass $M$ . Here we report estimates of the mass and radius of the isolated 205.53 Hz millisecond pulsar PSR J0030+0451 obtained using a Bayesian inference approach to analyze its energy-dependent thermal X-ray waveform, which was observed using the Neutron Star Interior Composition Explorer (NICER). This approach is thought to be less subject to systematic errors than other approaches for estimating neutron star radii. We explored a variety of emission patterns on the stellar surface. Our best-fit model has three oval, uniform-temperature emitting spots and provides an excellent description of the pulse waveform observed using NICER. The radius and mass estimates given by this model are $R_{e} = 13.0 2_{- 1.06}^{+ 1.24}$ km and $M = 1.4 4_{- 0.14}^{+ 0.15} M_{⊙}$ (68%). The independent analysis reported in the companion paper by Riley et al. (2019) explores different emitting spot models, but finds spot shapes and locations and estimates of $R_{e}$ and $M$ that are consistent with those found in this work. We show that our measurements of $R_{e}$ and $M$ for PSR J0030 $+$ 0451 improve the astrophysical constraints on the equation of state of cold, catalyzed matter above nuclear saturation density.
Comments:
49 pages, 16 figures, part of The Astrophysical Journal Letters focus issue on the Neutron Star Interior Composition Explorer
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1912.05705 [pdf]
ApJL(2019)·1995 citations
13
[Submitted on 12 Dec 2019] (cross-list from hep-ph)
Quark Transverse Parton Distribution at the Next-to-Next-to-Next-to-Leading Order
Ming-xing Luo🇨🇳 · Tong-Zhi Yang🇨🇳 · Hua Xing Zhu🇨🇳 · Yu Jiao Zhu🇨🇳
We report a calculation of the perturbative matching coefficients for the transverse-momentum-dependent parton distribution functions for quark at the next-to-next-to-next-to-leading order in QCD, which involves calculation of non-standard Feynman integrals with rapidity divergence. We introduce a set of generalized Integration-By-Parts equations, which allows an algorithmic evaluation of such integrals using the machinery of modern Feynman integral calculation.
Comments:
v1:5+19 pages, 2 figures; v2: references added; v3: fig. 3 added. journal version; v4: Coefficient for d33 in (A.13) corrected, fig. 2 updated, ancillary files updated, numerical fitting added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1912.05778 [pdf]
PRL(2020)·144 citations
14
[Submitted on 12 Dec 2019] (cross-list from hep-ph)
Potential analysis of holographic Schwinger effect in the magnetized background
Zhou-Run Zhu🇨🇳 · De-fu Hou (CCNU)🇨🇳 · Xun Chen🇨🇳
We study the holographic Schwinger effect with magnetic field at RHIC and LHC energies by using the AdS/CFT correspondence. We consider both weak and strong magnetic field cases with $B ≪ T^{2}$ and $B ≫ T^{2}$ solutions respectively. Firstly, we calculate separating length of the particle pairs at finite magnetic field. It is found that for both weak and strong magnetic field solutions the maximum value of separating length decreases with the increase of magnetic field , which can be inferred that the virtual electron-positron pairs become real particles more easily. We also find that the magnetic field reduces the potential barrier and the critical field for the weak magnetic field solution, thus favors the Schwinger effect. With strong magnetic field solution, the magnetic field enhances the Schwinger effect when the pairs are in perpendicular to the magnetic field although the magnetic field increases the critical electric field.
Comments:
21 pages with 9 figures in Revtex; one new section and 4 figures added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1912.05806 [pdf]
EPJC(2020)·24 citations
15
[Submitted on 12 Dec 2019] (cross-list from nucl-ex)
Jets as precision probes in electron-nucleus collisions at the Electron-Ion Collider
Miguel Arratia🇺🇸 · Youqi Song🇺🇸 · Felix Ringer🇺🇸 · Barbara V. Jacak🇺🇸
We discuss the prospects of using jets as precision probes in electron-nucleus collisions at the future Electron-Ion Collider. Jets produced in deep-inelastic scattering can be calibrated by a measurement of the scattered electron. Such electron-jet "tag and probe" measurements call for an approach that is orthogonal to most HERA jet measurements as well as previous studies of jets at the future EIC. We present observables such as the electron-jet momentum balance, azimuthal correlations and jet substructure, which can provide constraints on the parton transport coefficient in nuclei. We compare simulations and analytical calculations and provide estimates of the expected medium effects. Implications for detector design at the future EIC are discussed.
Comments:
published version
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1912.05931 [pdf]
PRC(2020)·66 citations
16
[Submitted on 12 Dec 2019] (cross-list from nucl-ex)
$^{78}$ Ni revealed as a doubly magic stronghold against nuclear deformation
R. Taniuchi · C. Santamaria🇫🇷 · P. Doornenbal · A. Obertelli🇫🇷 · K. Yoneda · G. Authelet🇫🇷 · H. Baba · D. Calvet🇫🇷 · F. Château🇫🇷 · A. Corsi🇫🇷 · A. Delbart🇫🇷 · J.-M. Gheller🇫🇷 and 59 other authors
Nuclear magic numbers, which emerge from the strong nuclear force based on quantum chromodynamics, correspond to fully occupied energy shells of protons, or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. While the sequence of magic numbers is well established for stable nuclei, evidence reveals modifications for nuclei with a large proton-to-neutron asymmetry. Here, we provide the first spectroscopic study of the doubly magic nucleus $^{78}$ Ni, fourteen neutrons beyond the last stable nickel isotope. We provide direct evidence for its doubly magic nature, which is also predicted by ab initio calculations based on chiral effective field theory interactions and the quasi-particle random-phase approximation. However, our results also provide the first indication of the breakdown of the neutron magic number 50 and proton magic number 28 beyond this stronghold, caused by a competing deformed structure. State-of-the-art phenomenological shell-model calculations reproduce this shape coexistence, predicting further a rapid transition from spherical to deformed ground states with $^{78}$ Ni as turning point.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1912.05978 [pdf]
Nature(2019)·182 citations
17
[Submitted on 12 Dec 2019] (cross-list from nucl-ex)
Comment on "Direct Observation of Proton Emission in $^{11}$ Be"
H.O.U. Fynbo · Z. Janas · C. Mazzocchi · M. Pfuetzner · J. Refsgaard · K. Riisager · N. Sokolowska
We argue that conclusions of [PRL 123, 082501 (2019)] are incorrect. The authors present the direct observation of beta-delayed proton emission in the beta decay of 11Be. From the determined branching ratio for this process and from the energy spectrum of emitted protons the existence of a so far unobserved narrow resonance in 11Be was deduced. The given beta strength for the transition to this state is however wrong. In addition, we show that the combination of peak position and branching ratio is in strong disagreement with models considered by the authors. Furthermore, we identify several deficiencies in the analysis, and we provide possible sources of background, that could explain the error.
Comments:
1 page, 1 figure
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1912.06064 [pdf]
3 citations

Affiliations

first authorsco-authorsvia INSPIRE