arXiv subjects

Y. K. Hsiao

Publications and source records attributed to Y. K. Hsiao.

At least 19 recordsLinked to original sources

arXiv2026

Charmed $Λ_c^+$ baryon decays into light scalar mesons in the topological $SU(3)_f$ framework

Using the topological-diagram approach based on $SU(3)$ flavor symmetry, we investigate two-body $Λ_c^+\to {\bf B}S$ decays, where ${\bf B}$ denotes the final-state baryon and $S$ refers to a light scalar meson, such as $f_0/f_0(980)$, $a_0/a_0(980)$, $σ_0/f_0(500)$, or $κ/K_0^*(700)$. Our analysis indicates that interpreting the light scalar mesons as tetraquark states provides a more consistent description of the currently available experimental data. In particular, this framework naturally accommodates the experimentally observed branching fraction ${\cal B}(Λ_c^+ \to Λa_0^+)$, which exceeds predictions based solely on long-distance effects by an order of magnitude. Within the tetraquark scenario, we predict ${\cal B}(Λ_c^+\to Σ^+ f_0)=(4.9\pm 1.9)\times 10^{-2}$ and ${\cal B}(Λ_c^+\to p f_0)=(3.6\pm 1.4)\times 10^{-3}$. Owing to $f_0-σ_0$ mixing, ${\cal B}(Λ_c^+\to Σ^+ σ_0)$ and ${\cal B}(Λ_c^+\to pσ_0)$ are suppressed to the levels of $1\times 10^{-3}$ and $5\times 10^{-5}$, respectively. These modes therefore provide sensitive probes of the internal structure of the light scalar mesons. More generally, the remaining branching ratios of $Λ_c^+ \to {\bf B} S$ are found to be comparable to those of $Λ_c^+ \to {\bf B}M$, where $M$ denotes a pseudoscalar meson. Their predicted sizes suggest that these decay modes should be accessible to ongoing and near-future experimental studies at BESIII, Belle II, and LHCb.

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arXiv2025

Topological $SU(3)_f$ approach for two-body $Ω_c$ weak decays

We explore the two-body non-leptonic weak decays of $Ω_c^0$ into final states ${\bf B}^{(*)}M$ and ${\bf B}^{(*)}V$, where ${\bf B}^{(*)}$ denotes an octet (a decuplet) baryon and $M(V)$ represents a pseudoscalar (vector) meson. We employ the topological $SU(3)_f$ approach to depict and parameterize the $W$-emission and $W$-exchange processes. We find that the topological parameters can be associated and combined, making them extractable for calculation. Consequently, we explain the partially measured branching fractions relative to ${\cal B}(Ω_c^0\to Ω^-π^+)$, recombined or kept as the following ratios: ${\cal B}(Ω_c^0\toΞ^{*0}\bar K^{*0})/{\cal B}(Ω_c^0\toΩ^-ρ^+)=0.28\pm 0.11$, ${\cal B}(Ω_c^0\toΞ^-π^+)/{\cal B}(Ω_c^0\toΞ^{0}\bar K^{0})=0.10\pm 0.02$, and ${\cal B}(Ω_c^0 \to Ω^- K^+)/{\cal B}(Ω_c^0 \to Ω^- π^+)=0.06\pm 0.01$. In particular, we present ${\cal B}(Ω_c^0 \to Ξ^0 π^0)=(2.3\pm0.2)\times 10^{-4}$ as half the value of ${\cal B}(Ω_c^0 \to Ξ^- π^+)$ in the approximate isospin relation, and highlight potential candidates for testing $SU(3)_f$ symmetry breaking.

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arXiv2022

Equivalent $SU(3)_f$ approaches for two-body anti-triplet charmed baryon decays

For the two-body ${\bf B}_c\to{\bf B}M$ decays, where ${\bf B}_c$ denotes the anti-triplet charm baryon and ${\bf B}(M)$ the octet baryon (meson), there exist two theoretical studies based on the $SU(3)$ flavor [$SU(3)_f$] symmetry. One is the irreducible $SU(3)_f$ approach (IRA). In the irreducible $SU(3)_f$ representation, the effective Hamiltonian related to the initial and final states forms the amplitudes for ${\bf B}_c\to{\bf B}M$. The other is the topological-diagram approach (TDA), where the $W$-boson emission and $W$-boson exchange topologies are drawn and parameterized for the decays. As required by the group theoretical consideration, we present the same number of the IRA and TDA amplitudes. We can hence relate the two kinds of the amplitudes, and demonstrate the equivalence of the two $SU(3)_f$ approaches. We find a specific $W$-boson exchange topology only contributing to $Ξ_c^0\to{\bf B}M$. Denoted by $E_M$, it plays a key role in explaining ${\cal B}(Ξ_c^0\to Λ^0 K_S^0,Σ^0 K_S^0,Σ^+ K^-)$. We consider that $Λ_c^+ \to n π^+$ and $Λ_c^+ \to pπ^0$ proceed through the constructive and destructive interfering effects, respectively, which leads to ${\cal B}(Λ_c^+ \to n π^+)\gg{\cal B}(Λ_c^+ \to pπ^0)$ in agreement with the data. With the exact and broken $SU(3)_f$ symmetries, we predict the branching fractions of ${\bf B}_c\to{\bf B}M$ to be tested by future measurements.

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arXiv2020

Two-body charmed baryon decays involving decuplet baryon in the quark-diagram scheme

In the quark-diagram scheme, we study the charmed baryon decays of ${\bf B}_c\to {\bf B}^* M$, where ${\bf B}_c$ is $Λ_c^+$ or $Ξ_c^{+(0)}$, together with ${\bf B}^*$ ($M$) the decuplet baryon (pseudoscalar meson). It is found that only two $W$-exchange processes are allowed to contribute to ${\bf B}_c\to {\bf B}^* M$. Particularly, we predict ${\cal B}(Λ_c^+ \to Σ^{*0(+)} π^{+(0)})=(2.8\pm 0.4)\times 10^{-3}$, which respects the isospin symmetry. Besides, we take into account the $SU(3)$ flavor symmetry breaking, in order to explain the observation of ${\cal B}(Λ_c^+\to Σ^{*+}η)$. For the decays involving $Δ^{++}(uuu)$, we predict ${\cal B}(Λ_c^+\to Δ^{++} π^-,Ξ_c^+ \to Δ^{++} K^-) =(7.0\pm 1.4,13.5\pm 2.7)\times 10^{-4}$ as the largest branching fractions in the singly Cabibbo-suppressed $Λ_c^+,Ξ_c^+\to{\bf B}^*M$ decay channels, respectively, which are accessible to the LHCb, BELLEII and BESIII experiments.

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arXiv2020

Resonant $a_0(980)$ state in triangle rescattering $D_s^+\to π^+π^0η$ decays

We study the $D_s^+\to π^+(a_0(980)^0\to)π^0η$, $π^0(a_0(980)^+\to)π^+η$ decays, which have been recently measured by the BESIII collaboration. We propose that $D_s^+\to π^{+(0)}(a_0(980)^{0(+)}\to)π^{0(+)}η$ receives the contributions from the triangle rescattering processes, where $M^0$ and $ρ^+$ in $D_s^+\to M^0 ρ^+$, by exchanging $π^{0(+)}$, are formed as $a_0(980)^{0(+)}$ and $π^{+(0)}$, respectively, with $M^0=(η,η')$. Accordingly, we calculate that ${\cal B}(D_s^+\to a_0(980)^{0(+)}π^{+(0)})=(1.7\pm 0.2\pm 0.1)\times 10^{-2}$ and ${\cal B}(D_s^+\to π^{+(0)}(a_0(980)^{0(+)}\to)π^{0(+)}η)=(1.4\pm 0.1\pm 0.1)\times 10^{-2}$, being consistent with the data.

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arXiv2020

Direct CP violation in internal W-emission dominated baryonic B decays

The observation of CP violation has been experimentally verified in numerous $B$ decays but is yet to be confirmed in final states with half-spin particles. We focus our attention on baryonic $B$-meson decays mediated dominantly through internal $W$-emission processes and show that they are promising processes to observe for the first time the CP violating effects in $B$ decays to final states with half-spin particles. Specifically, we study the $\bar B^0\to p\bar pπ^0(ρ^0)$ and $\bar B^0\to p\bar pπ^+π^-$ decays. We obtain ${\cal B}(\bar B^0\to p\bar pπ^0)=(5.0\pm 2.1)\times 10^{-7}$, in agreement with current data, and ${\cal B}(\bar B^0\to p\bar pρ^0)\simeq {\cal B}(\bar B^0\to p\bar pπ^0)/3$. Furthermore, we find ${\cal A}_{CP}(\bar B^0\to p\bar pπ^0,p\bar pρ^0,p\bar pπ^+π^-) =(-16.8\pm 5.4,-12.6\pm 3.0,-11.4\pm 1.9)\%$. With measured branching fractions ${\cal B}(\bar B^0\to p\bar pπ^0,p\bar pπ^+π^-)\sim {\cal O}(10^{-6})$, we point out that ${\cal A}_{CP}\sim -(10-20)\%$ can be new observables for CP violation, accessible to the Belle~II and/or LHCb experiments.

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arXiv2020

Testing the W-exchange mechanism with two-body baryonic B decays

The role of $W$-exchange diagrams in baryonic $B$ decays is poorly understood, and often taken as insignificant and neglected. We show that charmful two-body baryonic $B\to {\bf B}_c \bar {\bf B}'$ decays provide a good test-bed for the study of the $W$-exchange topology, whose contribution is found to be non-negligible; here ${\bf B}_c$ is an anti-triplet or a sextet charmed baryon, and ${\bf \bar B}'$ an octet charmless (anti-)baryon. In particular, we calculate that ${\cal B}(\bar B^0\toΣ_c^{+}\bar p)=(2.9^{+0.8}_{-0.9})\times 10^{-6}$ in good agreement with the experimental upper bound. Its cousin $\bar B_s^0$ mode, $\bar B_s^0\toΛ^+_c\bar p$, is a purely $W$-exchange decay, hence is naturally suited for the study of the role of the $W$-exchange topology. We predict ${\cal B}(\bar B_s^0\toΛ^+_c\bar p)=(0.8\pm 0.3)\times 10^{-6}$, a relatively large branching ratio to be tested with a future measurement by the LHCb collaboration. Other predictions, such as ${\cal B}(\bar B^0\toΞ_c^+\barΣ^-)=(1.1\pm 0.4)\times 10^{-5}$, can be tested with future Belle II measurements.

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arXiv2020

A diagrammatic analysis of two-body charmed baryon decays with flavor symmetry

We study the two-body anti-triplet charmed baryon decays based on the diagrammatic approach with $SU(3)$ flavor symmetry. We extract the two $W$-exchange effects as $E_{\bf B}$ and $E^\prime$ that contribute to the $Λ_c^+ \to Ξ^0 K^+$ decay, together with the relative phases, where $E_{\bf B}$ gives the main contribution. Besides, we find that ${\cal B}(Λ_c^+\to pπ^0)=(0.8 ^{+0.9}_{-0.8})\times 10^{-4}$, which is within the experimental upper bound. Particularly, we obtain ${\cal B}(Ξ_c^+\toΞ^{0} π^{+})=(9.3 \pm 3.6)\times 10^{-3}$, ${\cal B}(Ξ_c^0\to Ξ^-π^+,Λ^0\bar K^0)=(19.3 \pm 2.8,8.3 \pm 5.0)\times 10^{-2}$ and ${\cal B}(Ξ_c^0\to Ξ^- K^+)=(5.6 \pm 0.8)\times 10^{-4}$, which all agree with the data. For the singly Cabibbo suppressed $Λ_c^+$ decays, we predict that ${\cal B}(Λ_c^+ \to n π^{+},p η^\prime,Σ^{+} K^{0}) =(7.7\pm 2.0,7.1 \pm 1.4,19.1 \pm 4.8)\times 10^{-4}$, which are accessible to the experiments at BESIII, BELLEII and LHCb.

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arXiv2019

Study of $B^-\to Λ\bar pη^{(')}$ and $\bar B^0_s\to Λ\barΛη^{(')}$ decays

We study the three-body baryonic $B\to {\bf B\bar B'}M$ decays with $M$ representing the $η$ or $η'$ meson. Particularly, we predict that ${\cal B}(B^-\toΛ\bar pη,Λ\bar pη')=(5.3\pm 1.4,3.3\pm 0.7)\times 10^{-6}$ or $(4.0\pm 0.7,4.6\pm 1.1)\times 10^{-6}$, where the errors arise from the non-factorizable effects as well as the uncertainties in the $0\to {\bf B\bar B'}$ and $B\to{\bf B\bar B'}$ transition form factors, while the two different results are due to overall relative signs between the form factors, causing the constructive and destructive interference effects. For the corresponding baryonic $\bar B_s^0$ decays, we find that ${\cal B}(\bar B^0_s\to Λ\bar Λη,Λ\bar Λη')=(1.2\pm 0.3,2.6\pm 0.8)\times 10^{-6}$ or $(2.1\pm 0.6,1.5\pm 0.4)\times 10^{-6}$ with the errors similar to those above. The decays in question are accessible to the experiments at BELLE and LHCb.

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arXiv2019

Three-body charmed baryon Decays with SU(3) flavor symmetry

We study the three-body anti-triplet ${\bf B_c}\to {\bf B_n}MM'$ decays with the $SU(3)$ flavor ($SU(3)_f$) symmetry, where ${\bf B_c}$ denotes the charmed baryon anti-triplet of $(Ξ_c^0,-Ξ_c^+,Λ_c^+)$, and ${\bf B_n}$ and $M(M')$ represent baryon and meson octets, respectively. By considering only the S-wave $MM'$-pair contributions without resonance effects, the decays of ${\bf B_c}\to {\bf B_n}MM'$ can be decomposed into irreducible forms with 11 parameters under $SU(3)_f$, which are fitted by the 14 existing data, resulting in a reasonable value of $χ^2/d.o.f=2.8$ for the fit. Consequently, we find that the triangle sum rule of ${\cal A}(Λ_c^+\to n\bar K^0 π^+)-{\cal A}(Λ_c^+\to pK^- π^+)-\sqrt 2 {\cal A}(Λ_c^+\to p\bar K^0 π^0)=0$ given by the isospin symmetry holds under $SU(3)_f$, where ${\cal A}$ stands for the decay amplitude. In addition, we predict that ${\cal B}(Λ_c^+\to n π^{+} \bar{K}^{0})=(0.9\pm 0.8)\times 10^{-2}$, which is $3-4$ times smaller than the BESIII observation, indicating the existence of the resonant states. For the to-be-observed ${\bf B_c}\to {\bf B_n}MM'$ decays, we compute the branching fractions with the $SU(3)_f$ amplitudes to be compared to the BESIII and LHCb measurements in the future.

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arXiv2019

Two-body charmed baryon decays involving vector meson with $SU(3)$ flavor symmetry

We study the two-body anti-triplet charmed baryon decays of ${\bf B}_c\to {\bf B}_n V$, with ${\bf B}_c=(Ξ_c^{0},-Ξ_c^{+},Λ_c^+)$ and ${\bf B}_n(V)$ the baryon (vector meson) states. Based on the $SU(3)$ flavor symmetry, we predict that ${\cal B}(Λ^{+}_{c}\to Σ^{+}ρ^{0},Λ^0 ρ^+)=(0.61\pm 0.46,0.74\pm 0.34)\%$, in agreement with the experimental upper bounds of $(1.7,6)\%$, respectively. We also find ${\cal B}(Λ^+_c \to Ξ^0 K^{*+},Σ^0 K^{*+},Λ^0 K^{*+}) =(8.7 \pm 2.7,1.2\pm 0.3,2.0\pm 0.5)\times 10^{-3}$ to be compatible with the pseudoscalar counterparts. For the doubly Cabibbo-suppressed decay $Ξ^+_c \to pϕ$, measured for the first time, we predict its branching ratio to be $(1.5\pm 0.7)\times 10^{-4}$, together with ${\cal B}(Ξ^+_c \to p \bar K^{*0},Σ^+ ϕ) =(7.8 \pm 2.2,1.9\pm0.9)\times 10^{-3}$. The ${\bf B}_c\to{\bf B}_n V$ decays with ${\cal B}\simeq {\cal O}(10^{-4}-10^{-3})$ are accessible to the BESIII, BELLEII and LHCb experiments.

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arXiv2019

Baryon decays to purely baryonic final states

The LHCb collaboration has presented first experimental evidence that spin-carrying matter and antimatter differ. The study looked at four-body decays of the $Λ_b^0$ baryon. Differences in the behaviour of matter and antimatter are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as $C\!P$ violation. We discuss purely baryonic decay processes, i.e. decay processes involving only spin-carrying particles. They are yet unexplored elementary processes. Their study opens a new chapter of flavour physics in the route towards a better understanding of $C\!P$ violation. It may help us to understand the observed matter and antimatter asymmetry of the Universe.

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arXiv2018

SU(3) symmetry breaking in charmed baryon decays

We explore the breaking effects of the $SU(3)$ flavor symmetry in the singly Cabibbo-suppressed anti-triplet charmed baryon decays of ${\bf B}_c\to {\bf B}_n M$, with ${\bf B}_c=(Ξ_c^0,Ξ_c^+,Λ_c^+)$ and ${\bf B}_n(M)$ the baryon (pseudo-scalar) octets. We find that these breaking effects can be used to account for the experimental data on the decay branching ratios of ${\cal B}(Λ_c^+\to Σ^{0} K^{+},Λ^{0} K^{+})$ and $R'_{K/π}$=${\cal B}(Ξ^0_c \to Ξ^- K^+)$/${\cal B}(Ξ^0_c \to Ξ^- π^+)$. In addition, we obtain that ${\cal B}(Ξ_{c}^{0} \to Ξ^{-} K^{+},Σ^{-} π^{+})=(4.6 \pm 1.7,12.8 \pm 3.1)\times 10^{-4}$, ${\cal B}(Ξ_c^0\to pK^-,Σ^+π^-)=(3.0 \pm 1.0, 5.2 \pm 1.6)\times 10^{-4}$ and ${\cal B}(Ξ_c^+\to Σ^{0(+)} π^{+(0)})=(10.3 \pm 1.7)\times 10^{-4}$, which all receive significant contributions from the breaking effects, and can be tested by the BESIII and LHCb experiments.

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arXiv2018

Simultaneous extractions of $|V_{ub}|$ and $|V_{cb}|$ with only the exclusive $Λ_b$ decays

We perform the simultaneous $|V_{ub}|$ and $|V_{cb}|$ extractions with only the exclusive $Λ_b$ decays of $Λ_b\to (p,Λ_c^+)μ\bar ν_μ$, $Λ_b\to pπ^-$ and $Λ_b\to Λ_c^+ (π^-, D^-)$. We obtain that $|V_{ub}|=(3.7\pm 0.3)\times 10^{-3}$ and $|V_{cb}|=(45.9\pm 2.7)\times 10^{-3}$. Our value of $|V_{ub}|$ is larger than that of $(3.27\pm 0.15\pm 0.16\pm 0.06)\times 10^{-3}$, previously extracted by the LHC Collaboration from the exclusive $Λ_b$ decays also, but nearly identical to $(3.72\pm 0.19)\times 10^{-3}$ from the exclusive $B$ decays. On the other hand, our extracted result of $|V_{cb}|$ favors the value of $(42.2\pm 0.8)\times 10^{-3}$ from the inclusive $B$ decays.

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arXiv2018

Charmed Baryon Weak Decays with SU(3) Flavor Symmetry

We study the semileptonic and non-leptonic charmed baryon decays with $SU(3)$ flavor symmetry, where the charmed baryons can be ${\bf B}_{c}=(Ξ_c^0,Ξ_c^+,Λ_c^+)$, ${\bf B}'_{c}=(Σ_c^{(++,+,0)},Ξ_{c}^{\prime(+,0)},Ω_c^0)$, ${\bf B}_{cc}=(Ξ_{cc}^{++},Ξ_{cc}^+,Ω_{cc}^+)$, or ${\bf B}_{ccc}=Ω^{++}_{ccc}$. With ${\bf B}_n^{(\prime)}$ denoted as the baryon octet (decuplet), we find that the ${\bf B}_{c}\to {\bf B}'_n\ell^+ν_\ell$ decays are forbidden, while the $Ω_c^0\to Ω^-\ell^+ν_\ell$, $Ω_{cc}^+\toΩ_c^0\ell^+ν_\ell$, and $Ω_{ccc}^{++}\to Ω_{cc}^+\ell^+ν_\ell$ decays are the only existing Cabibbo-allowed modes for ${\bf B}'_{c}\to {\bf B}'_n\ell^+ν_\ell$, ${\bf B}_{cc}\to {\bf B}'_c\ell^+ν_\ell$, and ${\bf B}_{ccc}\to {\bf B}_{cc}^{(\prime)}\ell^+ν_\ell$, respectively. We predict the rarely studied ${\bf B}_{c}\to {\bf B}_n^{(\prime)}M$ decays, such as ${\cal B}(Ξ_c^0\toΛ^0\bar K^0,\,Ξ_c^+\toΞ^0π^+)=(8.3\pm 0.9,8.0\pm 4.1)\times 10^{-3}$ and ${\cal B}(Λ_c^+\to Δ^{++}π^-,\,Ξ_c^0\toΩ^- K^+)=(5.5\pm 1.3,4.8\pm 0.5)\times 10^{-3}$. For the observation, the doubly and triply charmed baryon decays of $Ω_{cc}^{+}\to Ξ_c^+\bar K^0$, $Ξ_{cc}^{++}\to (Ξ_c^+π^+$, $Σ_c^{++}\bar K^0)$, and $Ω_{ccc}^{++}\to (Ξ_{cc}^{++}\bar K^0,Ω_{cc}^+π^+,Ξ_c^+ D^+)$ are the favored Cabibbo-allowed decays, which are accessible to the BESIII and LHCb experiments.

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arXiv2018

Anti-triplet charmed baryon decays with SU(3) Flavor Symmetry

We study the decays of the anti-triplet charmed baryon state $(Ξ_c^0,Ξ_c^+,Λ_c^+)$ based on the $SU(3)$ flavor symmetry. In particular, after predicting ${\cal B}(Ξ_c^0\to Ξ^-π^+)=(15.7 \pm 0.7)\times 10^{-3}$ and ${\cal B}(Ξ_c^+\toΞ^-π^+π^+)=(14.7\pm 8.4)\times 10^{-3}$, we extract that ${\cal B}(Ξ_c^0\toΛK^-π^+,ΛK^+K^-,Ξ^- e^+ν_e)=(16.8\pm 2.3,0.45\pm 0.11,48.7\pm 17.4)\times 10^{-3}$ and ${\cal B}(Ξ_c^+\to p K_s^0 K_s^0,Σ^+ K^-π^+,Ξ^0π^+π^0,Ξ^0 e^+ν_e)=(1.3\pm 0.8,13.8\pm 8.0,33.8\pm 21.9,33.8^{+21.9}_{-22.6})\times 10^{-3}$. We also find that ${\cal B}(Ξ_c^0\to Ξ^{0} η,Ξ^{0} η')=(1.7 ^{+ 1.0 }_{- 1.7 },8.6 ^{+ 11.0 }_{-\;\,6.3 })\times 10^{-3}$, ${\cal B}(Ξ_c^0\to Λ^{0} η,Λ^{0} η')=(1.6 ^{+ 1.2 }_{- 0.8 },9.4 ^{+ 11.6 }_{-\;\,6.8 })\times 10^{-4}$ and ${\cal B}(Ξ_c^+\to Σ^{+} η,Σ^{+} η')=(28.4 ^{+ 8.2 }_{- 6.9 },13.2 ^{+ 24.0 }_{- 11.9 })\times 10^{-4}$. These $Ξ_c$ decays with the branching ratios of $O(10^{-4}-10^{-3})$ are clearly promising to be observed by the BESIII and LHCb experiments.

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arXiv2017

Non-leptonic two-body weak decays of $Λ_c(2286)$

We study the non-leptonic two-body weak decays of $Λ_c^+(2286)\to {\bf B}_n M$ with ${\bf B}_n$ ($M$) representing as the baryon (meson) states. Based on the $SU(3)$ flavor symmetry, we can describe most of the data reexamined by the BESIII Collaboration with higher precisions. However, our result of ${\cal B}(Λ_c^+ \to pπ^0)=(5.6\pm 1.5)\times 10^{-4}$ is larger than the current experimental limit of $3\times10^{-4}$ (90\% C.L.) by BESIII. In addition, we find that ${\cal B}(Λ_c^+ \to Σ^+ K^0)=(8.0\pm 1.6)\times 10^{-4}$, ${\cal B}(Λ_c^+ \to Σ^+ η^\prime)=(1.0^{+1.6}_{-0.8})\times 10^{-2}$, and ${\cal B}(Λ_c^+ \to p η^\prime)=(12.2^{+14.3}_{-\,\,\,8.7})\times 10^{-4}$, which are accessible to the BESIII experiments.

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arXiv2017

Pentaquarks in semileptonic $Λ_b$ decays

In terms of ${\cal P}_{c1,c2}={\cal P}_c(4380,4450)^+$ as the hidden charm pentaquark states to consist of $c\bar c uud$, we study the semileptonic $Λ_b\to ({\cal P}_{c1,c2}\to)J/ψp \ell^-\bar ν_\ell$ decays. In our discussion, while the main contribution to $Λ_b\to K^-J/ψp$ is from the non-perturbative process via the doubly charmful $b\to c\bar cs$ transition, we propose that the $Λ_b\to {\cal P}_{c1,c2}\to J/ψp$ transitions are partly contribute to the $Λ_b\to K^-({\cal P}_{c1,c2}\to)J/ψp$ decays, in which the required $c\bar c$ pair is formed by the sea quarks, intrinsic charm, or both. We predict that ${\cal B}(Λ_b\to J/ψp \ell^-\bar ν_\ell)=(2.04^{+4.82}_{-1.57},1.75^{+4.14}_{-1.35})\times 10^{-6}$ for $\ell=(e,μ)$, which are about two orders of magnitude smaller than the observed decay of $Λ_b\to pμ\bar ν_μ$. We also explore the angular correlations for the $J/ψp$ and $\ell^-\bar ν_\ell$ pairs. Our results of the decay branching ratios and angular asymmetries in $Λ_b\to J/ψp \ell^-\bar ν_\ell$, accessible to the ongoing experiments at the LHCb, can be used to improve the understanding of the hidden charm pentaquark states.

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