Nuclear Theory·nucl-th

Wednesday·February 13, 2019

7 papers—2 primary·5 cross-listed

03
Reactor Neutrinos: Toward Oscillations
Petr Vogel🇺🇸
I shall sketch the history of reactor neutrino physics over five decades since the Reines-Cowan proof of neutrino existence in the late 50s, till the advent of the present era of precision reactor neutrino oscillation experiments. There are three chapters of this story: i) Exploration of possibilities of the reactor neutrinos in the 60s and 70s; ii) Looking for oscillations under the streetlamp in the 80s and 90s; iii) Exploring oscillations in detail with known (almost) $Δ m_{a t m}^{2}$ and $Δ m_{so l}^{2}$ .}
↳ hep-phnucl-exnucl-thphysics.ins-det1 citation
04
Hadron tomography in meson-pair production and gravitational form factors
S. Kumano🇯🇵 · Qin-Tao Song🇯🇵 · O. V. Teryaev
Generalized parton distributions (GPDs) are 3-dimensional (3D) structure functions for hadrons, and they are important for solving the proton spin puzzle including partonic orbital-angular-momentum contributions. The $s$ - $t$ crossed quantities of the GPDs are generalized distribution amplitudes (GDAs). Here, $s$ and $t$ are Mandelstam variables. The GDAs can be studied in two-photon processes ( $γ^{*} γ \to h h ˉ$ ) at KEKB. A GDA describes the amplitude from quark and antiquark to the hadron pair $h h ˉ$ . In 2016, the Belle collaboration reported measurements for pion-pair production in electron-positron collision, and the pion GDAs were determined in this work by analyzing the Belle data. In our analysis, the pion GDAs are expressed by a few parameters, which are determined by analyzing the Belle data. From the obtained GDAs, form factors of energy-momentum tenor, so called gravitational form factors, are calculated for pion in the timelike region. The spacelike gravitational form factors are calculated from the timelike ones by using the dispersion relation. Then, the mass radius is calculated as 0.32-0.39 fm and the mechanical radius, defined by the slope of the form factor $Θ_{1}$ , is calculated as 0.82-0.88 fm for the pion by using the spacelike form factors. This is the first study on gravitational form factors and radii of hadrons from actual experimental measurements. In 2019, the Belle II collaboration will start collecting data by the higher luminosity Super KEKB, so that the GDAs of other hadrons should also be investigated in the near future. Our studies are valuable in understanding 3D structure and gravitational properties of hadrons.
↳ hep-phhep-exhep-latnucl-thPoS(2019)·2 citations
05
Forbidden Nuclear Reactions
Péter Kálmán🇭🇺 · Tamás Keszthelyi🇭🇺
Exothermal nuclear reactions which become forbidden due to Coulomb repulsion in the\ $ε \to 0$ limit ( $lim_{ε \to 0} σ (ε) = 0$ ) are investigated. ( $σ (ε)$ is the cross section and $ε$ is the center of mass energy.) It is found that any perturbation may mix states with small but finite amplitude to the initial state resulting finite cross section (and rate) of the originally forbidden nuclear reaction in the limit. The statement is illustrated by modification of nuclear reactions due to impurities in a gas mix of atomic state. The change of the wavefunction of reacting particles in nuclear range due to their Coulomb interaction with impurity is determined using standard time independent perturbation calculation of quantum mechanics. As an example, cross section, rate and power densities of impurity assisted nuclear $p d$ reaction are numerically calculated. With the aid of astrophysical factors cross section and power densities of the impurity assisted $d (d, n)_{2}^{3} H e$ , $d (d, p) t$ , $d (t, n)_{2}^{4} H e$ , , $_{3}^{6} L i (p, α)_{2}^{3} H e$ , , $_{3}^{7} L i (p, α)_{2}^{4} H e$ , , $_{4}^{9} B e (p, d)_{4}^{8} B e$ , , $_{5}^{10} B (p, α)_{4}^{7} B e$ and reactions are also given. The affect of gas mix-wall interaction on the process is considered too.
↳ physics.gen-phnucl-thPRC(2019)·10 citations
06
Non-eikonal corrections to multi-particle production in the Color Glass Condensate
Pedro Agostini🇪🇸 · Tolga Altinoluk🇵🇱 · Néstor Armesto🇪🇸
We consider the non-eikonal corrections to particle production in the Color Glass Condensate stemming from the relaxation of the shockwave approximation for the target that acquires a finite longitudinal dimension. We derive a modified expression of the Lipatov vertex which takes into account this finite target width. This expression is employed to compute single, double and triple gluon production in the Glasma graph limit valid for the scattering of two dilute objects, at all orders in the expansion in the number of colors. We justify and generalize previous results, and discuss the possible implications on two particle correlations of these non-eikonal corrections that induce differences between the away- and near-side peaks.
↳ hep-phnucl-thEPJC(2019)·57 citations
07
Inferring neutron star properties from GW170817 with universal relations
Bharat Kumar🇮🇳 · Philippe Landry🇺🇸
Because all neutron stars share a common equation of state, tidal deformability constraints from the compact binary coalescence GW170817 have implications for the properties of neutron stars in other systems. Using equation-of-state insensitive relations between macroscopic observables like moment of inertia ( $I$ ), tidal deformability ( $Λ$ ) and stellar compactness, we derive constraints on these properties as a function of neutron-star mass based on the LIGO-Virgo collaboration's canonical deformability measurement, $Λ_{1.4} = 19 0_{- 120}^{+ 390}$ . Specific estimates of $Λ$ , $I$ , dimensionless spin $χ$ , and stellar radius $R$ for a few systems targeted by radio or X-ray studies are extracted from the general constraints. We also infer the canonical neutron-star radius as $R_{1.4} = 10. 9_{- 1.5}^{+ 1.9}$ km at 90 $%$ confidence. We further demonstrate how a gravitational-wave measurement of $Λ_{1.4}$ can be combined with independent measurements of neutron-star radii to tighten constraints on the tidal deformability as a proxy for the equation of state. We find that GW170817 and existing observations of six thermonuclear bursters in low-mass X-ray binaries jointly imply $Λ_{1.4} = 19 6_{- 63}^{+ 92}$ at the 90 $%$ confidence level.
↳ gr-qcastro-ph.HEnucl-thPRD(2019)·108 citations

Affiliations

first authorsco-authorsvia INSPIRE

Reactor Neutrinos: Toward Oscillations

Hadron tomography in meson-pair production and gravitational form factors

Forbidden Nuclear Reactions

Non-eikonal corrections to multi-particle production in the Color Glass Condensate

Inferring neutron star properties from GW170817 with universal relations

Affiliations