arXiv subjects

Dian-Yong Chen

Publications and source records attributed to Dian-Yong Chen.

141 records · Page 8Linked to original sources

arXiv2012

Two charged strangeonium-like structures observable in the $Y(2175) \to ϕ(1020)π^{+} π^{-}$ process

Via the Initial Single Pion Emission (ISPE) mechanism, we study the $ϕ(1020)π^{+}$ invariant mass spectrum distribution of $Y(2175) \to ϕ(1020)π^{+} π^{-}$. Our calculation indicates there exist a sharp peak structure ($Z_{s1}^+$) close to the $K\bar{K}^\ast$ threshold and a broad structure ($Z_{s2}^+$) near the $K^\ast\bar{K}^\ast$ threshold. In addition, we also investigate the $ϕ(1680) \to ϕ(1020)π^{+} π^{-}$ process due to the ISPE mechanism, where a sharp peak around the $K\bar{K}^\ast$ threshold appears in the $ϕ(1020)π^{+}$ invariant mass spectrum distribution. We suggest to carry out the search for these charged strangeonium-like structures in future experiment, especially Belle II, Super-B and BESIII.

hep-ph↗

arXiv2012

Non-strange partner of strangeonium-like state Y(2175)

Inspired by the observed Y(2175) state, we predict its non-strange partner Y(1915), which has a resonance structure with mass around 1915 MeV and width about $317\sim 354$ MeV. Experimental search for Y(1915) is proposed by analyzing the $ωf_0(980)$ or $ωππ$ invariant mass spectrum of the $e^+e^-\to ωf_0(980), ωππ$ and $J/ψ\to ηωf_0(980)$ processes, which are accessible at Belle, BaBar, BESIII and forthcoming BelleII. Considering similarity between two families, the comparison of the mass spectra of $ω$ and $ϕ$ families can provide important information on the 1D state of $ϕ$ family, $ϕ(1910)$, which has a very broad resonance structure with mass around 1910 MeV regarded as the strangeonium partner of $ω(1650)$. This also answers the question why the 1D state $ϕ(1910)$ is still missing in experiment. This is supported by our former study on the properties of Y(2175), which explains Y(2175) as the 2D strangeonium because our theoretical total width is comparable with the Belle data.

hep-ph↗

arXiv2011

Anomalous dipion invariant mass distribution of the $Υ(4S)$ decays into $Υ(1S) π^{+} π^{-}$ and $Υ(2S) π^{+} π^{-}$

To solve the discrepancy between the experimental data on the partial widths and lineshapes of the dipion emission of $Υ(4S)$ and the theoretical predictions, we suggest that there is an additional contribution which was not taken into account in previous calculations. Noticing that the mass of $Υ(4S)$ is above the production threshold of $B\bar B$, the contribution of the sequential process $Υ(4S)\to B\bar B\to Υ(nS)+S\to Υ(nS)+π^+π^-$ ($n=1,2$) may be sizable, and its interference with that from the direct production would be important. The goal of this work is to investigate if a sum of the two contributions with a relative phase indeed reproduces the data. Our numerical results on the partial widths and the lineshapes $dΓ(Υ(4S)\to Υ(2S,1S)π^+π^-)/d(m_{π^+π^-})$ are satisfactorily consistent with the measurements, thus the role of this mechanism is confirmed. Moreover, with the parameters obtained by fitting the data of the Belle and Babar collaborations, we predict the distributions $dΓ(Υ(4S)\to Υ(2S,1S)π^+π^-)/d\cosθ$ which have not been measured yet.

hep-ph↗

arXiv2011

Charged bottomonium-like structures $Z_b(10610)$ and $Z_b(10650)$

The observation of two charged bottomonium-like structures $Z_b(10610)$ and $Z_b(10650)$ has stimulated extensive studies of the properties of $Z_b(10610)$ and $Z_b(10650)$. In this talk, we briefly introduce the research status of $Z_b(10610)$ and $Z_b(10650)$ combined with our theoretical progress.

hep-ph↗

arXiv2011

Charged bottomonium-like structures in the hidden-bottom dipion decays of $Υ(11020)$

Under the Initial Single Pion Emission mechanism, we study the hidden-bottom dipion decays of $Υ(11020)$, i.e., $Υ(11020)\to Υ(nS)π^+π^-$ $(n=1,2,3)$ and $Υ(11020)\to h_b(mP)π^+π^-$ $(m=1,2)$. We predict explicit sharp peak structures close to the $B\bar{B}^*$ and $B^*\bar{B}^*$ thresholds and their reflections in the $Υ(1S)π^+$, $Υ(2S)π^+$ and $h_b(1P)π^+$ invariant mass spectrum distributions. We suggest future experiment, i.e., Belle, BaBar, and forthcoming BelleII or Super-B, carry out the search for these novel phenomena, which can provide important test to the Initial Single Emission mechanism existing in higher bottomonia.

hep-ph↗

arXiv2011

$Z_b(10610)$ and $Z_b(10650)$ structures produced by the initial single pion emission in the $Υ(5S)$ decays

We propose an unique mechanism called {\it Initial Single Pion Emission} existing in the $Υ(5S)$ decays, and further study the line shapes of $dΓ(Υ(5S\to Υ(nS)π^+π^-))/dm_{Υ(nS)π^+}$ ($n=1,2,3$) and $dΓ(Υ(5S\to h_b(mP)π^+π^-))/dm_{h_b(mP)π^+}$ ($m=1,2$). We find sharp structures around 10610 MeV and 10650 MeV in the obtained theoretical line shapes of $dΓ(Υ(5S\to Υ(nS)π^+π^-))/dm_{Υ(nS)π^+}$ and $dΓ(Υ(5S\to h_b(mP)π^+π^-))/dm_{h_b(mP)π^+}$ distributions, which could naturally correspond to the $Z_b(10610)$ and $Z_b(10650)$ structures newly observed by Belle.

hep-ph↗

arXiv2011

Charged bottomonium-like states $Z_b(10610)$ and $Z_b(10650)$ and the $Υ(5S)\to Υ(2S)π^+π^-$ decay

Inspired by the newly observed two charged bottomonium-like states, we consider the possible contribution from the intermediate $Z_b(10610)$ and $Z_b(10650)$ states to the $Υ(5S)\to Υ(2S)π^+π^-$ decay process, which naturally explains Belle's previous observation of the anomalous $Υ(2S)π^+π^-$ production near the peak of $Υ(5S)$ at $\sqrt s=10.87$ GeV [K.F. Chen {\it et al}. (Belle Collaboration), Phys. Rev. Lett. {\bf 100}, 112001 (2008)]. The resulting $dΓ(Υ(5S)\to Υ(2S)π^+π^-)/dm_{π^+π^-}$ and $dΓ(Υ(5S)\to Υ(2S)π^+π^-)/d\cosθ$ distributions agree with Belle's measurement after inclusion of these $Z_b$ states. This formalism also reproduces the Belle observation of the double-peak structure and its reflection in $Υ(2S)π^+$ invariant mass spectrum of $Υ(5S)\to Υ(2S)π^+π^-$ decay.

hep-ph↗

arXiv2011

Dipion invariant mass distribution of the anomalous $Υ(1S) π^{+} π^{-}$ and $Υ(2S) π^{+} π^{-}$ production near the peak of $Υ(10860)$

Considering the defects of the previous work for estimating the anomalous production rates of $e^+e^-\to Υ(1S)π^+π^-,\,Υ(2S)π^+π^-$ near the peak of the $Υ(5S)$ resonance at $\sqrt s=10.87$ GeV [K.F. Chen {\it et al}. (Belle Collaboration), Phys. Rev. Lett. {\bf 100}, 112001 (2008)], we suggest a new scenario where the contributions from the direct dipion transition and the final state interactions interfere to result in not only the anomalously large production rates, but also the lineshapes of the differential widths consistent with the experimental measurement when assuming the reactions are due to the dipion emission of $Υ(5S)$. At the end, we raise a new puzzle that the predicted differential width $dΓ(Υ(5S)\toΥ(2S)π^+π^-)/d\cosθ$ has a discrepant trend from the data while other predictions are well in accord with the data. It should be further clarified by more accurate measurements carried by future experiments.

hep-ph↗

arXiv2011

Predicted charged charmonium-like structures in the hidden-charm dipion decay of higher charmonia

In this work, we predict two charged charmonium-like structures close to the $D^\ast\bar{D}$ and $D^\ast\bar{D}^\ast$ thresholds, where the Initial Single Pion Emission mechanism is introduced in the hidden-charm dipion decays of higher charmonia $ψ(4040)$, $ψ(4160)$, $ψ(4415)$ and charmonium-like state Y(4260). We suggest BESIII to search for these structures in the $J/ψπ^+$, $ψ(2S)π^+$ and $h_b(1P)π^+$ invariant mass spectra of the $ψ(4040)$ decays into $J/ψπ^+π^-$, $ψ(2S)π^+π^-$ and $h_b(1P)π^+π^-$. In addition, the experimental search for these structures in the $J/ψπ^+$, $ψ(2S)π^+$ and $h_c(1P)π^+$ invariant mass spectra of the $ψ(4260)$ hidden-charm dipion decays will be accessible at Belle and BaBar.

hep-ph↗

arXiv2011

A novel explanation of charmonium-like structure in $e^+e^-\to ψ(2S)π^+π^-$

We first present a non-resonant description to charmonium-like structure $Y(4360)$ in the $ψ(2S)π^+π^-$ invariant mass spectrum of the $e^+e^-\to ψ(2S)π^+π^-$ process. The $Y(4360)$ structure is depicted well by the interference effect of the production amplitudes of $e^{+} e^{-} \to ψ(2S) π^+ π^-$ via the intermediate charmonia $ψ(4160)/ψ(4415)$ and direct $e^+e^-$ annihilation into $ψ(2S)π^+ π^-$. This fact shows that $Y(4360)$ is not a genuine resonance, which naturally explains why $Y(4360)$ was only reported in its hidden-charm decay channel $ψ(2S)π^+π^-$ and was not observed in the exclusive open-charm decay channel or $R$-value scan.

hep-ph↗

arXiv2011

Nonresonant explanation for the Y(4260) structure observed in the $e^+e^-\to J/ψπ^+π^-$ process

In this work, we proposed a nonresonant explanation for the Y(4260) structure observed in the $e^+e^-\to J/ψπ^+π^-$ process, i.e., Y(4260) is not a genuine resonance. Our result indicates that the Y(4260) structure can be reproduced by the interference of production amplitudes of the $e^+e^-\to J/ψπ^+π^-$ processes via direct $e^+e^-$ annihilation and through intermediate charmonia $ψ(4160)/ψ(4415)$. Besides describing Y(4260) line shape in $e^+e^-\to J/ψπ^+π^-$ well, such a nonresonant explanation for the Y(4260) structure naturally answers why there is no evidence of Y(4260) in the exclusive open-charm decay channel and $R$-value scan.

hep-ph↗

arXiv2010

Long-distant contribution and $χ_{c1}$ radiative decays to light vector meson

The discrepancy between the PQCD calculation and the CLEO data for $χ_{c1}\to γV$ ($V=ρ^0,\,ω,\,ϕ$) stimulates our interest in exploring extra mechanism of $χ_{c1}$ decay. In this work, we apply an important non-perturbative QCD effect, i.e., hadronic loop mechanism, to study $χ_{c1}\to γV$ radiative decay. Our numerical result shows that the theoretical results including the hadronic loop contribution and the PQCD calculation of $χ_{c1}\to γV$ are consistent with the corresponding CLEO data of $χ_{c1}\to γV$. We expect further experimental measurement of $χ_{c1}\to γV$ at BES-III, which will be helpful to test the hadronic loop effect on $χ_{c1}$ decay.

hep-ph↗

arXiv2010

Understanding the branching ratios of χ_{c1}\toϕϕ, ωω, ωϕobserved at BES-III

In this work, we discuss the contribution of the mesonic loops to the decay rates of $χ_{c1}\to ϕϕ,\,ωω$ which are suppressed by the helicity selection rules and $χ_{c1}\to ϕω$ which is a double-OZI forbidden process. We find that the mesonic loop effects naturally explain the clear signals of $χ_{c1}\to ϕϕ,\,ωω$ decay modes observed by the BES collaboration. Moreover, we investigate the effects of the $ω-ϕ$ mixing which may result in the order of magnitude of the branching ratio $BR(χ_{c1} \to ωϕ)$ being $10^{-7}$. Thus, we are waiting for the accurate measurements of the $BR(χ_{c1} \to ωω)$, $BR(χ_{c1} \to ϕϕ)$ and $BR(χ_{c1} \to ωϕ)$, which may be very helpful for testing the long-distant contribution and the $ω-ϕ$ mixing in $χ_{c1}\toϕϕ,\,ωω,\,ωϕ$ decays.

hep-ph↗

arXiv2009

Two-photon Exchange Corrections to Single Spin Asymmetry of Neutron and $^3$He

In a simple hadronic model, the two-photon exchange contributions to the single spin asymmetries for the nucleon and the $^3$He are estimated. The results show that the elastic contributions of two-photon exchange to the the single spin asymmetries for the nucleon are rather small while those for the $^3$He are relatively large. Besides the strong angular dependence, the two-photon contributions to the single spin asymmetry for the $^3$He are very sensitive to the momentum transfer.

nucl-th↗

arXiv2009

Nucleon Form Factors in a Light-Cone Quark Model with Two-Photon Exchange

We estimate the two-photon exchange corrections to both proton and neutron electromagnetic physical observables in a relativistic light cone quark model. At a fixed momentum transfer the corrections are found to be small in magnitudes, but with a strong angular dependence. Our results are comparable to those from simple hadronic model in a moderate momentum transfer region.

nucl-th↗