Nuclear Theory·nucl-th

Thursday·October 6, 2016

10 papers—5 primary·5 cross-listed

01
[Submitted on 4 Oct 2016]
Manifestation of the $P$ -wave diproton resonance in single-pion production in $pp$ collisions
M. N. Platonova🇷🇺 · V. I. Kukulin🇷🇺
It is demonstrated that many important features of single-pion production in $pp$ collisions at intermediate energies ( $T_{p} ≃ 400$ - $800$ MeV) can naturally be explained by supposing excitation of intermediate diproton resonances in $pp$ channels $^{1} D_{2}$ , $^{3} F_{3}$ and $^{3} P_{2}$ , in addition to conventional mechanisms involving an intermediate $Δ$ -isobar. We predict for the first time the crucial role of the $^{3} P_{2}$ diproton resonance, found in recent experiments on the single-pion production reaction $pp \to pp (^{1} S_{0}) π^{0}$ , in reproducing the proper behavior of spin-correlation parameters in the reaction $pp \to d π^{+}$ which were poorly described by conventional meson-exchange models to date. The possible quark structure of the $P$ -wave diproton resonances is also discussed.
Comments:
Version accepted for publication in Physical Review D
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1610.01207 [pdf]
PRD(2016)·18 citations
02
[Submitted on 5 Oct 2016]
High-density kaonic-proton matter (KPM) composed of Lambda* equiv K-p multiplets and its astrophysical connections
Yoshinori Akaishi🇯🇵 · Toshimitsu Yamazaki🇯🇵
We propose and examine a new high-density composite of $Λ^{*} \equiv K^{-} p = (s u ˉ) \otimes (uu d)$ , which may be called {\it Kaonic Proton Matter (KPM)}, or simply, {\it $Λ^{*}$ -Matter}, where substantial shrinkage of baryonic bound systems originating from the strong attraction of the $(K ˉ N)^{I = 0}$ interaction takes place, providing a ground-state neutral baryonic system with a huge energy gap. The mass of an ensemble of $(K^{-} p)_{m}$ , where $m$ , the number of the $K^{-} p$ pair, is larger than $m \approx 10$ , is predicted to drop down below its corresponding neutron ensemble, $(n)_{m}$ , since the attractive interaction is further increased by the Heitler-London type molecular covalency, as well as by chiral symmetry restoration of the QCD vacuum. Since the seed clusters ( $K^{-} p$ , $K^{-} pp$ and $K^{-} K^{-} pp$ ) are short-lived, the formation of such a stabilized relic ensemble, $(K^{-} p)_{m}$ , may be conceived during the Big-Bang Quark Gluon Plasma (QGP) period in the early universe before the hadronization and $q u a r k$ - $an t i$ - $q u a r k$ annihilation proceed. At the final stage of baryogenesis a substantial amount of primordial ( $u ˉ, d ˉ$ )'s are transferred and captured into {\it KPM}, where the anti-quarks find places to survive forever. The expected {\it KPM} state may be {\it cold, dense and neutral $q ˉ q$ -hybrid ({\it Quark Gluon Bound (QGB)}) states, $[s (u ˉ \otimes u) u d]_{m}$ ,} to which the relic of the disappearing anti-quarks plays an essential role as hidden components. The {\it KPM} may also be produced during the formation and decay of neutron stars.
Comments:
5 pages, 5 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1610.01249 [pdf]
PLB(2017)·17 citations
03
[Submitted on 5 Oct 2016]
Chiral potential renormalized in harmonic-oscillator space
C.-J. Yang🇫🇷
We renormalize the chiral effective field theory (EFT) potential in harmonic-oscillator (HO) model space. The low energy constants (LECs) are utilized to absorb not just the ultra-violet part of the physics due to the cutoff, but also the infrared part due to the truncation of model space. We use the inverse J-matrix method to reproduce the nucleon-nucleon (NN) scattering phase shifts in the given model space. We demonstrate that by including the NLO correction, the nucleon-nucleon scattering in the continuum could be well reproduced in the truncated HO trap space up to laboratory energy $T_{l ab} = 100$ MeV with number of HO basis $n_{ma x}$ as small as 10. A perturbative power counting starts at subleading order is adopted in this work, and how to extract the perturbative contribution is demonstrated. Our work serves as the input to perform ab-initio calculations.
Comments:
published version. 23 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1610.01350 [pdf]
PRC(2016)·25 citations
04
[Submitted on 4 Oct 2016]
Towards a Unified Model of Neutrino-Nucleus Reactions for Neutrino Oscillation Experiments
S.X. Nakamura (Osaka Univ.)🇯🇵 · H. Kamano (KEK, J-PARC)🇯🇵 · Y. Hayato (ICRR, Univ. of Tokyo)🇯🇵 · M. Hirai (Nippon Inst. Tech.)🇯🇵 · W. Horiuchi (Hokkaido Univ.)🇯🇵 · S. Kumano (KEK, J-PARC)🇯🇵 · T. Murata (Osaka Univ.)🇯🇵 · K. Saito (Tokyo Univ. of Sci.)🇯🇵 · M. Sakuda (Okayama Univ.)🇯🇵 · T. Sato (Osaka Univ., J-PARC)🇯🇵 · Y. Suzuki (Niigata Univ., RIKEN)🇯🇵
A precise description of neutrino-nucleus reactions will play a key role in addressing fundamental questions such as the leptonic CP violation and the neutrino mass hierarchy through analyzing data from next-generation neutrino oscillation experiments. The neutrino energy relevant to the neutrino-nucleus reactions spans a broad range and, accordingly, the dominant reaction mechanism varies across the energy region from quasi-elastic scattering through nucleon resonance excitations to deep inelastic scattering. This corresponds to transitions of the effective degree of freedom for theoretical description from nucleons through meson-baryon to quarks. The main purpose of this review is to report our recent efforts towards a unified description of the neutrino-nucleus reactions over the wide energy range; recent overall progress in the field is also sketched. Starting with an overview of the current status of neutrino-nucleus scattering experiments, we formulate the cross section to be commonly used for the reactions over all the energy regions. A description of the neutrino-nucleon reactions follows and, in particular, a dynamical coupled-channels model for meson productions in and beyond the $Δ$ (1232) region is discussed in detail. We then discuss the neutrino-nucleus reactions, putting emphasis on our theoretical approaches. We start the discussion with electroweak processes in few-nucleon systems studied with the correlated Gaussian method. Then we describe quasi-elastic scattering with nuclear spectral functions, and meson productions with a $Δ$ -hole model. Nuclear modifications of the parton distribution functions determined through a global analysis are also discussed. Finally, we discuss issues to be addressed for future developments.
Comments:
68 pages, 33 figures; (v2) reference added, author name in metadata corrected; (v3) Discussion extended in Sec. I and IV, Fig. 10 added to compare with a previous result on two-pion productions, Table I extended to include a comparison with a recent T2K result on coherent pion production
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1610.01464 [pdf]
Rept.Prog.Phys.(2017)·42 citations
05
[Submitted on 4 Oct 2016]
$D ˉ D$ meson pair production in antiproton-nucleus collisions
R. Shyam🇮🇳 · K. Tsushima🇧🇷
We study the $D ˉ D$ ( $D ˉ^{0} D^{0}$ and $D^{-} D^{+}$ ) charm meson pair production in antiproton ( $p ˉ$ ) induced reactions on nuclei at beam energies ranging from threshold to several GeV. Our model is based on an effective Lagrangian approach that has only the baryon-meson degrees of freedom and involves the physical hadron masses. The reaction proceeds via the $t$ -channel exchanges of $Λ_{c}^{+}$ , $Σ_{c}^{+}$ , and $Σ_{c}^{++}$ baryons in the initial collision of the antiproton with one of the protons of the target nucleus. The medium effects on the exchanged baryons are included by incorporating in the corresponding propagators, the effective charm baryon masses calculated within a quark-meson coupling (QMC) model. The wave functions of the bound proton have been determined within the QMC model as well as in a phenomenological model where they are obtained by solving the Dirac equation with appropriate scalar and vector potentials. The initial- and final-state distortion effects have been approximated by using an eikonal approximation-based procedure. Detailed numerical results are presented for total and double differential cross sections for the $D ˉ^{0} D^{0}$ and $D^{-} D^{+}$ production reactions on $^{16}$ O and $^{90}$ Zr targets. It is noticed that at $p ˉ$ beam momenta of interest to the $P ˉ A N D A$ experiment, medium effects lead to noticeable enhancements in the charm meson production cross sections.
Comments:
23 pages, 8 figures, Journal print version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1610.01473 [pdf]
PRD(2016)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE

Manifestation of the P-wave diproton resonance in single-pion production in pp collisions

High-density kaonic-proton matter (KPM) composed of Lambda* equiv K-p multiplets and its astrophysical connections

Chiral potential renormalized in harmonic-oscillator space

Towards a Unified Model of Neutrino-Nucleus Reactions for Neutrino Oscillation Experiments

DˉD meson pair production in antiproton-nucleus collisions

Affiliations

Manifestation of the $P$ -wave diproton resonance in single-pion production in $pp$ collisions

$D ˉ D$ meson pair production in antiproton-nucleus collisions