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Wen-Tao Lyu

Publications and source records attributed to Wen-Tao Lyu.

25 records · Page 2Linked to original sources

Theoretical study of the open-flavor tetraquark $T_{c\bar{s}}(2900)$ in the process $\bar{B}_s^0 \to K^0 D^0 π^0$

Recently, the LHCb Collaboration has measured two decay processes $B^0\to\bar{D}^0D_s^+π^-$ and $B^+\to D^-D_s^+π^+$ related to isospin symmetry, where two new open-flavor tetraquark states $T_{c\bar{s}}(2900)^0$ and $T_{c\bar{s}}(2900)^{++}$ that belong to an isospin triplet were observed in the $D_s^+π^-$ and $D_s^+π^+$ invariant mass distributions. In this work, we have investigated the validity of the process $\bar{B}_s^0\to K^0D^0π^0$ as the promising process to confirm the existence of $T_{c\bar{s}}(2900)^0$ resonance. Taking into account the tetraquark state $T_{c\bar{s}}(2900)$, as well as intermediate resonances $K^*(892)$, $K_0^*(1430)$, and $K_2^*(1430)$, it has been shown that a clear peak of the open-flavor tetraquark $T_{c\bar{s}}(2900)$ appears in the $K^0D^0$ invariant mass distribution of the process $\bar{B}_s^0\to K^0D^0π^0$, which could be tested by future experiments.

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Evidence of the open-flavor tetraquark $T_{c\bar{s}2}$ in the process $B^+\to D^{*-}D_s^+π^+$

The newly observed open-flavor tetraquark $T_{c\bar{s}0}(2900)$ has attracted many attentions, and searching for its spin partners is crucial to exploring the internal structure of those states. In this work, we will show that, the $D_s^+π^+$ invariant mass distribution of the process $B^+\to D^{*-}D_s^+π^+$ measured by LHCb has a resonant-like structure around 2830~MeV, which could be associated with the predicted $T_{c\bar{s}2}$, the spin $J=2$ partner of $T_{c\bar{s}0}(2900)$. Furthermore, we have evaluated the momenta of the angular mass distribution, which are very different for each of the spin assumptions, and have larger strength at the resonant energy than the peaks seen in the angular integrated mass distribution. We make a call for the experimental determination of these magnitudes, which could be used to pin down the existence of the $T_{c\bar{s}2}$.

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Explore the properties of $Λ(1670)$ in the Cabibbo-favored process $Λ^+_c \to p K^- π^+$ decay

Recently, the Belle and LHCb Collaborations have measured the $Λ^+_c \to p K^- π^+$ decay and reported the $p K^-$ invariant mass distribution, which shows a clear cusp structure around the $ηΛ$ threshold. In this work, we have analyzed this process by considering the triangle mechanism and the $S$-wave pseudoscalar meson-octet baryon interactions within the chiral unitary approach, which dynamically generate the $Λ(1670)$. Our results are in good agreement with the Belle measurements, which implies that the cusp structure around $ηΛ$ threshold could be associated with the $Λ(1670)$ with the molecular nature.

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The $Λ_c^+\toηπ^+Λ$ reaction and the $Λa_0^+(980)$ and $π^+Λ(1670)$ contributions

We study from the theoretical point of view the $Λ_c^+\to π^+ ηΛ$ reaction, recently measured by the Belle and BESIII Collaborations, where clear signals are observed for $a_0(980)$, $Λ(1670)$, and $Σ(1385)$ excitation. By considering the $a_0(980)$ and $Λ(1670)$ as dynamically generated resonances from the meson meson and meson baryon interaction, respectively, we are able to determine their relative production strength in the reaction, which is also tied to the strength of the $π^+ ηΛ$ tree level contribution. We observe that this latter strength is very big and there are large destructive interferences between the tree level and the rescattering terms where the $a_0(980)$ and $Λ(1670)$ are generated. The $Σ(1385)$ contribution is included by means of a free parameter, the only one of the theory, up to a global normalization, when one considers only external emission, and we observe that the spin flip part of this term, usually ignored in theoretical and experimental works, plays an important role determining the shape of the mass distributions. Internal emission is also considered and it is found to play a minor role.

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Possible signal of an exotic $I=1$, $J=2$ state in the $B \to D^{*-}D^+K^+$ reaction

We study the \proc reaction, showing that a peak in the \dk mass distribution around 2834 MeV reported by LHCb could be associated with a theoretical exotic state with that mass, a width of 19 MeV and $J^P=2^+$, stemming from the interaction of the $D^{*+}K^{*+}$ and $D^{*+}_s ρ^+$ channels, which is a partner of the $0^+$ $T_{c\bar{s}}(2900)$. We show that the data is compatible with this assumption, but also see that the mass distribution itself cannot discriminate between the spins $J=0$, $1$, $2$ of the state. Then we evaluate the momenta of the angular mass distribution and show that they are very different for each of the spin assumptions, and that the momenta coming from interference terms have larger strength at the resonant energy than the peaks seen in the angular integrated mass distribution. We make a call for the experimental determination of these magnitudes, which has already been used by the LHCb in related decay reactions.

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Evidence of the low-lying baryon $Σ^*(1/2^-)$ in the process $Λ_c^+\to ηπ^+Λ$

Motivated by the Belle measurements of the process $Λ_c^+\to ηπ^+Λ$, we investigate this process by considering the contributions from the $Λ(1670)$, $a_0(980)$, and $Σ(1385)$. In addition, we also consider the predicted low-lying baryon $Σ^*(1/2^-)$. Our results involving the $Σ^*(1/2^-)$ are favored by fitting to the Belle data of the $ηΛ$ and $π^+Λ$ invariant mass distributions. Furthermore, we predict the $ηπ^+$ invariant mass distribution and the angular distribution $dΓ/d{\rm cos}θ$, which are significantly different depending on whether or not the contribution from the $Σ^*(1/2^-)$ is considered. Finally, we show that, with the contribution from the $Σ^*(1/2^-)$, the calculated Dalizt plot agrees with the Belle measurements. Future precise measurements of the process $Λ_c^+\to ηπ^+Λ$ could shed further light on the existence of the low-lying $Σ^*(1/2^-)$.

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The roles of the $T_{c\bar{s}0}(2900)^0$ and $D_0^*(2300)$ in the process $B^-\to D_s^+K^-π^-$

Motivated by the recent LHCb observations of $T_{c\bar{s}0}(2900)^0$ and $T_{c\bar{s}0}(2900)^{++}$ in the processes $B^0\to\bar{D}^0D_s^+π^-$ and $B^+\to D^-D_s^+π^+$, we have investigated the decay $B^-\to D_s^+K^-π^-$ by taking into account the contributions from the $S$-wave vector-vector interactions, and the $S$-wave $D^+_s K^-$ interactions. Our results show that the $D_s^+K^-$ invariant mass distribution has an enhancement structure near the threshold, associated with the $D^*_0(2300)$, which is in good agreement with the Belle measurements. We have also predicted the $D^+_sπ^-$ invariant mass distribution and the Dalitz plot, which show the significant signal of the $T_{c\bar{s}0}(2900)$. With the same formalism, the $D^-_sK^0_s$ invariant mass distribution of the process $B^0 \to D^-_sK^0_sπ^+$ measured by Belle could be well reproduced, and the peak of $T_{c\bar{s}0}(2900)$ is expected to be observed around 2900~MeV in the $D^-_sπ^+$ invariant mass distribution. Our results could be tested by the Belle II and LHCb experiments in the future.

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