Nuclear Theory·nucl-th

Monday·December 30, 2019

12 papers—7 primary·5 cross-listed

08
[Submitted on 25 Dec 2019] (cross-list from hep-ph)
The $σ$ and $ρ$ coupling constants for the charmed and beauty mesons
Hee-Jin Kim🇰🇷 · Hyun-Chul Kim🇰🇷
We investigate the $σ$ and $ρ$ coupling constants for the $D D$ and $D^{*} D^{*}$ interactions, based on correlated $2 π$ exchange in the $D D$ and $D^{*} D^{*}$ interactions. Starting from the $D D ˉ \to π π$ and $D^{*} D ˉ^{*} \to π π$ amplitudes derived in the pseudophysical region ( $4 m_{π}^{2} \leq t \leq 52 m_{π}^{2}$ ) with the $S$ - and $P$ -wave $2 π$ correlations considered, we obtain the spectral functions for the $D D \to D D$ and $D^{*} D^{*} \to D^{*} D^{*}$ amplitude with correlated $S$ - and $P$ -wave $2 π$ exchanges. Using the pole approximation, we estimate the $D D σ$ , $D D ρ$ , $D^{*} D^{*} σ$ , and $D^{*} D^{*} ρ$ coupling constants. We extended phenomenologically the present results to the region in $t \leq 0$ and compare them with those from lattice QCD. The results are also compared with those of other models. We also present the results of the $B B σ$ , $B B ρ$ , $B^{*} B^{*} σ$ , and $B^{*} B^{*} ρ$ coupling constants. We observe that it is unlikely that the $σ$ and $ρ$ coupling constants for the $B$ and $B^{*}$ mesons are the same as those for the $D$ and $D^{*}$ mesons. On the contrary, they are quite larger than those for the charmed mesons.
Comments:
19 pages. 10 figures. Discussion part was revised
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1912.11622 [pdf]
PRD(2020)·9 citations
09
[Submitted on 26 Dec 2019] (cross-list from hep-ph)
Triangle singularity appearing as an $X (3872)$ -like peak in $B \to (J / ψ π^{+} π^{-}) K π$
Satoshi X. Nakamura (University of Science and Technology of China)🇨🇳
We consider a triangle diagram for $B^{0} \to (J / ψ π^{+} π^{-}) K^{+} π^{-}$ where an $X (3872)$ peak has been observed experimentally. We demonstrate that a triangle singularity inherent in the triangle diagram creates a sharp peak in the $J / ψ π^{+} π^{-}$ invariant mass distribution when the final $(J / ψ π^{+} π^{-}) π$ invariant mass is at and around the $D^{*} D ˉ^{*}$ threshold. The position and width of the peak is 3871.68 MeV (a few keV above the $D^{* 0} D ˉ^{0}$ threshold) and $\sim$ 0.4 MeV, respectively, in perfect agreement with the precisely measured $X (3872)$ mass and width: $3871.69 \pm 0.17$ MeV and $< 1.2$ MeV. This remarkable agreement is virtually parameter-free. The result indicates that the considered mechanism has to be understood in advance when separating an $X (3872)$ -pole contribution from $B^{0} \to (J / ψ π^{+} π^{-}) K^{+} π^{-}$ data; the separation yields an $X (3872) π$ lineshape that could be used to determine the $X (3872)$ mass. We suggest a method to set a constraint on the triangle mechanism by analyzing a charge analogous process $B^{0} \to (J / ψ π^{0} π^{-}) K^{+} π^{0}$ where a similar triangle singularity generates an $X^{-} (3876)$ -like peak.
Comments:
9 pages, 7 figures; In v2, conclusion changed, new contents and figures added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1912.11830 [pdf]
PRD(2020)·23 citations
10
[Submitted on 26 Dec 2019] (cross-list from nucl-ex)
Analysis of $^{4}$ He( $γ, p)$ T and $^{4}$ He( $γ, n)$ $^{3}$ He Reactions with Linearly Polarized Photons in the Energy Range up to 100\,MeV
Yu.P.Lyakhno
In a number of investigations, one can find the data on the $^{4}$ He( $γ$ ,p)T and $^{4}$ He( $γ$ ,n) $^{3}$ He reaction cross sections in the collinear geometry, which are due to spin {\it S}=1 transitions of the final-state particles. The ratio of the differential cross section in the collinear geometry to the differential reaction cross section at the nucleon emission angle $θ_{N}$ =90 $^{\circ}$ , and specified by the {\it S}=0 electric dipole transition at photon energies in the range 20 $\leq E_{γ} \leq$ 100\,MeV, is independent of the photon energy, within the experimental error. In the meantime, experiments were made to measure the asymmetry of the cross section $Σ (θ_{N})$ , for the mentioned reactions with linearly polarized photons. It has been found that in the energy range between 20 and 90\,MeV, the $Σ (θ_{N})$ value is also independent of the photon energy, within the experimental error. These data are in agreement with the assumption that transitions with spin {\it S}=1 can be due to the contribution of $^{3} P_{0}$ states of the $^{4}$ He nucleus, and are inconsistent with the assumption that the spin-flip of the particle system occurred during the reaction as a result of the meson exchange current contribution. The available measured data on the collinear geometry reaction cross sections and the ones on the cross-section asymmetry of the reaction with linearly polarized photons do not agree between themselves. The above mentioned reactions seem to be more convenient for measuring the degree of photon beams linear polarization than the deuteron photodisintegration reactions.
Comments:
7 pages, 5 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1912.11865 [pdf]
0 citations
11
[Submitted on 27 Dec 2019] (cross-list from nucl-ex)
Exclusive Hard Processes for Studying Hadron Structures at J-PARC
Wen-Chen Chang🇹🇼
With an appropriate hard scale, exclusive hadronic processes could provide novel information of the internal quark-gluon configurations of hadrons. The availability of 10-20 GeV secondary meson beam in the coming high-momentum beam line of Hadron Hall at J-PARC offers an unique opportunity to carry out the measurements of the exclusive hard processes. We address this interesting approach by two possibilities: (a) $π^{-} p \to K^{0} Λ (1405)$ for the constituent quark structure of $Λ (1405)$ , and (b) exclusive pion-induced Drell-Yan process $π^{-} p \to γ^{*} n \to l^{+} l^{-} n$ for the generalized parton distributions (GPDs) of nucleons. Realization of such measurements at J-PARC will open up a new way of accessing the internal quark structure of exotic hadrons and also the nucleon GPDs based on a solid theoretical foundation of perturbative QCD.
Comments:
8 pages, 5 figures; contribution to the proceedings of the 3rd J-PARC Symposium (J-PARC 2019), September 23-26, 2019, Tsukuba, Japan
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1912.11962 [pdf]
JPS Conf.Proc.(2021)·0 citations
12
[Submitted on 27 Dec 2019] (cross-list from hep-ph)
Photoproduction of hidden-bottom pentaquark and related topics
Xu Cao🇨🇳 · Feng-Kun Guo🇨🇳 · Yu-Tie Liang🇨🇳 · Jia-Jun Wu🇨🇳 · Ju-Jun Xie🇨🇳 · Ya-Ping Xie🇨🇳 · Zhi Yang🇨🇳 · Bing-Song Zou🇨🇳
Due to the discovery of the hidden-charm pentaquark $P_{c}$ states by the LHCb collaboration, the interests on the candidates of hidden-bottom pentaquark $P_{b}$ states are increasing. They are anticipated to exist as the analogues of the $P_{c}$ states in the bottom sector and predicted by many models. We give an exploration of searching for a typical $P_{b}$ in the $γ p \to Υ p$ reaction, which shows a promising potential to observe it at an electron-ion collider. The possibility of searching for $P_{b}$ in open-bottom channels are also briefly discussed. Meanwhile, the $t$ -channel non-resonant contribution, which in fact covers several interesting topics at low energies, is systematically investigated.
Comments:
18 pages,, publication version, references updated
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1912.12054 [pdf]
PRD(2020)·37 citations

Affiliations

first authorsco-authorsvia INSPIRE

The σ and ρ coupling constants for the charmed and beauty mesons

Triangle singularity appearing as an X(3872)-like peak in B→(J/ψπ+π−)Kπ

Analysis of 4He(γ,p)T and 4He(γ,n)3He Reactions with Linearly Polarized Photons in the Energy Range up to 100\,MeV

Exclusive Hard Processes for Studying Hadron Structures at J-PARC

Photoproduction of hidden-bottom pentaquark and related topics

Affiliations

The $σ$ and $ρ$ coupling constants for the charmed and beauty mesons

Triangle singularity appearing as an $X (3872)$ -like peak in $B \to (J / ψ π^{+} π^{-}) K π$

Analysis of $^{4}$ He( $γ, p)$ T and $^{4}$ He( $γ, n)$ $^{3}$ He Reactions with Linearly Polarized Photons in the Energy Range up to 100\,MeV