Nuclear Theory·nucl-th

Wednesday·March 6, 2019

9 papers—3 primary·6 cross-listed

04
Twist-2 Pseudoscalar and Vector Meson Distribution Amplitudes in Light-Front Quark Model with Exponential-type Confining Potential
Nisha Dhiman🇮🇳 · Harleen Dahiya🇮🇳 · Chueng-Ryong Ji🇺🇸 · Ho-Meoyng Choi🇰🇷
We study the twist-2 distribution amplitudes (DAs) and the decay constants of pseudoscalar light ( $π$ , $K$ ) and heavy ( $D$ , $D_{s}$ , $B$ , $B_{s}$ ) mesons as well as the longitudinally and transversely polarized vector light ( $ρ$ , $K^{*}$ ) and heavy ( $D^{*}$ , $D_{s}^{*}$ , $B^{*}$ , $B_{s}^{*}$ ) mesons in the light-front quark model with the Coulomb plus exponential-type confining potential $V_{exp} = a + b e^{α r}$ in addition to the hyperfine interaction. We first compute the mass spectra of ground state pseudoscalar and vector light and heavy mesons and fix the model parameters necessary for the analysis, applying the variational principle with the trial wave function up to the first three lowest order harmonic oscillator (HO) wave functions $Φ (x, k_{⊥}) = \sum_{n = 1}^{3} c_{n} ϕ_{n S}$ . We then obtain the numerical results for the corresponding decay constants of light and heavy mesons. We estimate the DAs, analyze their variation as a function of momentum fraction and compute the first six $ξ$ -moments of the $B$ and $D$ mesons as well. We compare our results with the available experimental data as well as with the other theoretical model predictions.
↳ hep-phnucl-thPRD(2019)·35 citations
05
The doubly virtual $(π^{0}, η, η^{'}) \to γ^{*} γ^{*}$ transition form factors in the light-front quark model
Ho-Meoyng Choi🇰🇷 · Hui-Young Ryu🇰🇷 · Chueng-Ryong Ji🇺🇸
We report our investigation on the doubly virtual TFFs $F_{P γ^{*}} (Q_{1}^{2}, Q_{2}^{2})$ for the $P \to γ^{*} (q_{1}) γ^{*} (q_{2}) (P = π^{0}, η, η^{'})$ transitions using the light-front quark model (LFQM). Performing a LF calculation in the exactly solvable manifestly covariant Bethe-Salpeter (BS) model as the first illustration, we used $q_{1}^{+} = 0$ frame and found that both LF and manifestly covariant calculations produce exactly the same results for $F_{P γ^{*}} (Q_{1}^{2}, Q_{2}^{2})$ . This confirms the absence of the LF zero mode in the doubly virtual TFFs. We then mapped this covariant BS model to the standard LFQM using the more phenomenologically accessible Gaussian wave function provided by the LFQM analysis of meson mass spectra. For the numerical analyses of $F_{P γ^{*}} (Q_{1}^{2}, Q_{2}^{2})$ , we compared our LFQM results with the available experimental data and the perturbative QCD (pQCD) and the vector meson dominance (VMD) model predictions. As $(Q_{1}^{2}, Q_{2}^{2}) \to \infty$ , our LFQM result for doubly virtual TFF is consistent with the pQCD prediction, i.e. $F_{P γ^{*}} (Q_{1}^{2}, Q_{2}^{2}) \sim 1/ (Q_{1}^{2} + Q_{2}^{2})$ , while it differs far from the result of VMD model which behaves $F_{P γ^{*}}^{VMD} (Q_{1}^{2}, Q_{2}^{2}) \sim 1/ (Q_{1}^{2} Q_{2}^{2})$ . Our LFQM prediction for $F_{η^{'} γ^{*}} (Q_{1}^{2}, Q_{2}^{2})$ shows an agreement with the very recent experimental data obtained from the BaBar collaboration for the ranges of $2 < Q_{1}^{2}, Q_{1}^{2} < 60$ GeV $^{2}$ .
↳ hep-phnucl-thPRD(2019)·9 citations
06
Revisiting the lower bound on tidal deformability derived by AT 2017gfo
Kenta Kiuchi · Koutarou Kyutoku · Masaru Shibata · Keisuke Taniguchi
We revisit the lower bound on binary tidal deformability tilde{Lambda} imposed by a luminous kilonova/macronova, AT 2017gfo, by numerical-relativity simulations of models that are consistent with gravitational waves from the binary neutron star merger GW170817. Contrary to the claim made in the literature, we find that binaries with tilde{Lambda}<~400 can explain the luminosity of AT 2017gfo, as long as moderate mass ejection from the remnant is assumed as had been done in previous work. The reason is that the maximum mass of a neutron star is not strongly correlated with the tidal deformability of neutron stars with a typical mass of ~1.4M_sun. If the maximum mass is so large that the binary does not collapse into a black hole immediately after merger, the mass of the ejecta can be sufficiently large irrespective of the binary tidal deformability. We present models of binary mergers with tilde{Lambda} down to 242 that satisfy the requirement on the mass of the ejecta from the luminosity of AT 2017gfo. We further find that the luminosity of AT 2017gfo could be explained by models that do not experience bounce after merger. We conclude that the luminosity of AT 2017gfo is not very useful for constraining the binary tidal deformability. Accurate estimation of the mass ratio will be necessary to establish a lower bound using electromagnetic counterparts in the future. We also caution that merger simulations that employ a limited class of tabulated equations of state could be severely biased due to the lack of generality.
↳ astro-ph.HEgr-qcnucl-thApJL(2019)·152 citations
07
Large Transverse Momentum in Semi-Inclusive Deeply Inelastic Scattering Beyond Lowest Order
B. Wang🇺🇸 · J. O. Gonzalez-Hernandez🇺🇸 · T. C. Rogers🇺🇸 · N. Sato🇺🇸
Motivated by recently observed tension between $O (α_{s}^{2})$ calculations of very large transverse momentum dependence in both semi-inclusive deep inelastic scattering and Drell-Yan scattering, we repeat the details of the calculation through $O (α_{s}^{2})$ transversely differential cross section. The results confirm earlier calculations, and provide further support to the observation that tension exists with current parton distribution and fragmentation functions.
↳ hep-phnucl-thPRD(2019)·34 citations
08
Axial Kinetic Theory and Spin Transport for Fermions with Arbitrary Mass
Koichi Hattori🇯🇵 · Yoshimasa Hidaka🇯🇵 · Di-Lun Yang🇯🇵
We derive the quantum kinetic theory for fermions with arbitrary mass in a background electromagnetic field from the Wigner-function approach. Since spin of massive fermions is a dynamical degree of freedom, the kinetic equations with the leading-order quantum corrections describe entangled dynamics of not only the vector- and axial-charge distributions but also of the spin polarization. Therefore, we obtain one scalar and one axial-vector kinetic equations with magnetization currents pertinent to the spin-orbit interaction. We show that our results smoothly reduce to the massless limit where the spin of massless fermions is no longer an independent dynamical degree of freedom but is enslaved by the chirality and momentum and the accordingly kinetic equations turn into the chiral kinetic theory for Weyl fermions. We provide a kinetic theory covering both the massive and massless cases, and hence resolves the problem in constructing the bridge between them. Such generalization may be crucial for applications to various physical systems. Based on our kinetic equations, we discuss the anomalous currents transported by massive fermions in thermal equilibrium.
↳ hep-phhep-thnucl-thPRD(2019)·158 citations
09
Solving the three-body bound-state Bethe-Salpeter equation in Minkowski space
E. Ydrefors🇧🇷 · J.H. Alvarenga Nogueira🇧🇷 · V.A. Karmanov🇷🇺 · T. Frederico🇧🇷
The scalar three-body Bethe-Salpeter equation, with zero-range interaction, is solved in Minkowski space by direct integration of the four-dimensional integral equation. The singularities appearing in the propagators are treated properly by standard analytical and numerical methods, without relying on any ansatz or assumption. The results for the binding energies and transverse amplitudes are compared with the results computed in Euclidean space. A fair agreement between the calculations is found.
↳ hep-phnucl-thPLB(2019)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE

Twist-2 Pseudoscalar and Vector Meson Distribution Amplitudes in Light-Front Quark Model with Exponential-type Confining Potential

The doubly virtual (π0,η,η′)→γ∗γ∗ transition form factors in the light-front quark model

Revisiting the lower bound on tidal deformability derived by AT 2017gfo

Large Transverse Momentum in Semi-Inclusive Deeply Inelastic Scattering Beyond Lowest Order

Axial Kinetic Theory and Spin Transport for Fermions with Arbitrary Mass

Solving the three-body bound-state Bethe-Salpeter equation in Minkowski space

Affiliations

The doubly virtual $(π^{0}, η, η^{'}) \to γ^{} γ^{}$ transition form factors in the light-front quark model