We study the feasibility of having the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>1430</mn><mo stretchy="false">)</mo></math> state, predicted within the chiral unitary approach and recently reported by the Belle Collaboration, as corresponding to a state of a nonmolecular nature. Starting from this assumption, since the state is observed in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi mathvariant="normal">Λ</mi></math> channel, we allow the coupling to this state and relate the coupling to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mi>N</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi mathvariant="normal">Σ</mi></math> using <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><mo stretchy="false">)</mo></math> symmetry arguments. We find that it is possible to have such a state with negligible coupling to the molecular components with a bare mass of the state very close to the physical mass of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>1430</mn><mo stretchy="false">)</mo></math>. Yet this has consequences on other observables, since the width obtained is extremely small and incompatible with the Belle observations, and it leads to abnormally large values of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mi>N</mi></math> effective range. Conversely, such mismatches do not appear for large values of the bare mass of the state, but in this case, we observe that the state develops large molecular components. While one can rule out a largely nonmolecular nature for this state, its properties and detailed nature will need further experimental developments which one can anticipate will be coming in the near future.

China

Spain

Jia-Xin Lin

Jing Song

Miguel Albaladejo

Albert Feijoo

Eulogio Oset

Testing the nature of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>1430</mn><mo stretchy="false">)</mo></math>

We conduct a theoretical study of the $$ D_{s1}(2460) \rightarrow D_s \pi ^+ \pi ^- $$ decay from the perspective that the $$D_{s1}$$ is a molecular state, built mostly from the $$D^* K$$ and $$D_s^* \eta $$ components. The $$D^*$$ and $$D_s^*$$ mesons are allowed to decay into two pseudoscalars, with one of them merging with the other pseudoscalar that forms the $$D_{s1}$$ state, ultimately leading to the $$\pi ^+ \pi ^- D_s$$ final state. This results in a triangle diagram mechanism where all theoretical ingredients are well-known, leading to a free parameter framework. We evaluate the mass distributions of particle pairs and find good agreement with the experimental distributions of a recent LHCb experiment, providing strong support to the molecular picture of the $$D_{s1}(2460)$$ state. We also discuss the role played by the scalar mesons $$f_0(500)$$ and $$f_0(980)$$ , at odds with the interpretation of the experimental analysis.

Luis Roca

Brazil

Jorgivan Dias

The $$D_{s1}(2460) \rightarrow D_s \pi ^+ \pi ^- $$ decay from a $$D_{s1}$$ molecular perspective

We study the $$\Lambda _{b}\rightarrow \Lambda _{c}\bar{D}^{0}K^{-}$$ and $$\Lambda _{b}\rightarrow \Lambda _{c}D^{-}\bar{K}^{0}$$ decays which proceed via a Cabibbo and $$N_c$$ favored process of external emission, and we determine the $$\bar{D}^{0}K^{-}$$ and $$D^{-}\bar{K}^{0}$$ mass distributions close to the $$\bar{D} \bar{K}$$ threshold. For this, we use the tree level contribution plus the rescattering of the meson-meson components, using the extension of the local hidden gauge approach to the charm sector that produces the $$D^*_{s0}(2317)$$ resonance. We observe a large enhancement of the mass distributions close to threshold due to the presence of this resonance below threshold. Next we undertake the inverse problem of extracting the maximum information on the interaction of the $$\bar{D} \bar{K}$$ channels from these distributions, and using the resampling method we find that from these data one can obtain precise values of the scattering lengths and effective ranges, the existence of an $$I=0$$ bound state with a precision of about $$4 \;\mathrm MeV$$ in the mass, plus the $$\bar{D} \bar{K}$$ molecular probability of this state with reasonable precision. Given the fact that the $$\Lambda _{b}\rightarrow \Lambda _{c}\bar{D}^{0}K^{-}$$ decay is already measured by the LHCb collaboration, it is expected that in the next runs with more statistics of the decay, these mass distributions can be measured with precision and the method proposed here can be used to determine the nature of the $$D^*_{s0}(2317)$$ , which is still an issue of debate.

Hai-Peng Li

Wei-Hong Liang

Chu-Wen Xiao

Ju-Jun Xie

Determination of the binding and $\textit{DK}$ probability of the $$D^{*}_{s0}(2317)$$ from the $$(\bar{D}\bar{K})^-$$ mass distributions in $$\Lambda _{b}\rightarrow \Lambda _{c} (\bar{D}\bar{K})^-$$ decays

We look into the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mo>+</mo></msup><mi>ϕ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mo>+</mo></msup><mi>ω</mi></math> weak decays recently measured by the BESIII collaboration, which proceed very differently in a first step of the weak decay. While the first reaction proceeds directly via external emission, the second one does not go via external nor internal emission, what prompted the experimental team to claim that it proceeds via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>W</mi></mrow></math>-annihilation. We show in this work that the unexpectedly large rate of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mo>+</mo></msup><mi>ω</mi></math> has a different explanation since is it naturally obtained once final state interaction of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ρ</mi><mo>+</mo></msup><mi>ϕ</mi><mo>,</mo><msup><mi>ρ</mi><mo>+</mo></msup><mi>ω</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mrow><mo>*</mo><mo>+</mo></mrow></msup><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> channels is taken into consideration. The interaction of these channels produces the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>1710</mn><mo stretchy="false">)</mo></math> resonance, predicted long ago as a molecular state of these coupled channels, and only recently observed, and it is the presence of this resonance what makes the effect of the final state interaction very important in the weak decays and provides a natural explanation of the experimental decay rates at a quantitative level. We also take into account the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mo>+</mo></msup><mi>ω</mi></math> decay in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>P</mi></mrow></math>- and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>D</mi></mrow></math>-waves empirically, and show that a good reproduction of the experimental results is obtained in this case.

Zi-Ying Yang

Role of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>a</mi></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>1710</mn><mo stretchy="false">)</mo></mrow></math> in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mo>+</mo></msup><mi>ϕ</mi><mo>,</mo><msup><mi>ρ</mi><mo>+</mo></msup><mi>ω</mi></math> decays

We study the scattering parameters of the $$K^+\bar{K}^0$$ system through the analysis of the $$D^+\rightarrow \bar{K}^0\pi ^+\eta $$ reaction, aiming at determining the scattering length $$a$$ and effective range $$r_0$$ of the $$K^+\bar{K}^0$$ interaction. These parameters are extracted by analyzing and fitting the mass distributions of the pairs in the final $$\bar{K}^0\pi ^+\eta $$ state. To ensure the reliability of the results, we apply resampling techniques to evaluate statistical uncertainties and improve the precision of the scattering parameters. The obtained results are compared with previous theoretical predictions and experimental data, providing new insights into the $$K^+\bar{K}^0$$ interaction at low energies.

Determination of the $$K^+\bar{K}^0$$ scattering length and effective range from the $$D^+\rightarrow \bar{K}^0\pi ^+\eta $$ reaction

We study the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>−</mo></msup><mo stretchy="false">→</mo><msup><mi>D</mi><mo>−</mo></msup><msup><mi>D</mi><mn>0</mn></msup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup></math> reaction, recently analyzed by the LHCb Collaboration, where a clear signal for the exotic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mi>s</mi><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>2870</mn><mo stretchy="false">)</mo></math> state was reported. We call attention to a small peak in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mn>0</mn></msup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup></math> mass distribution that could correspond to a state of the same nature as the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mi>s</mi><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>2870</mn><mo stretchy="false">)</mo></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>*</mo></msup><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> nature in the molecular picture), but with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>J</mi><mi>P</mi></msup><mo>=</mo><msup><mn>2</mn><mo>+</mo></msup></math>. In order to magnify the signal for the state, we calculate the moments of the angle-mass distribution, which are linear in the resonance signal, rather than quadratic for the angle integrated mass distribution. We find spectra for the moments with a strength far bigger than that for the angle integrated mass distribution, which should encourage the evaluation of these moments from the present measurements of the reaction.

Searching for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>2</mn><mo>+</mo></msup></math> partner of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mi>s</mi><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>2870</mn><mo stretchy="false">)</mo></math> in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>−</mo></msup><mo stretchy="false">→</mo><msup><mi>D</mi><mo>−</mo></msup><msup><mi>D</mi><mn>0</mn></msup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup></math> reaction

We have studied the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>N</mi><msup><mrow><mi>D</mi></mrow><mrow><mo>*</mo></mrow></msup><msup><mrow><mover accent="true"><mrow><mi>K</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mo>*</mo></mrow></msup></mrow></math> system in the framework of the fixed center approximation to the Faddeev equations, taking the exotic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>*</mo></msup><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> system as the cluster and allowing the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi></math> to interact with the components of the cluster. Previous studies have determined the existence of three states of spin 0, 1, 2 for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>*</mo></msup><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> system, the one of spin 0 associated to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>X</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>2900</mn><mo stretchy="false">)</mo></math> state observed by the LHCb Collaboration. From this perspective, we find five states with total spin <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>/</mo><mn>2</mn><mo>,</mo><mn>3</mn><mo>/</mo><mn>2</mn><mo>,</mo><mn>5</mn><mo>/</mo><mn>2</mn></math>, with bindings from 10 to 30 MeV and widths below 60 MeV, which could be well identified. We also discuss the decay channels of these states that should help in future experimental searches for these states.

Qing-Yu Zhai

Raquel Molina

Li-Sheng Geng

Study of the exotic three-body <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>N</mi><msup><mrow><mi>D</mi></mrow><mrow><mo>*</mo></mrow></msup><msup><mrow><mover accent="true"><mrow><mi>K</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mo>*</mo></mrow></msup></mrow></math> system

This paper investigates the decay process <math altimg='si1.svg'><msub><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mi>b</mi></mrow></msub><mo stretchy='false'>&#8594;</mo><msubsup><mrow><mi mathvariant='normal'>&#931;</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup><msup><mrow><mi>D</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo></mrow></msup></math> with the objective of finding a predicted molecular state with isospin <math altimg='si2.svg'><mi>I</mi><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>1</mn></math>, <math altimg='si3.svg'><msup><mrow><mi>J</mi></mrow><mrow><mi>P</mi></mrow></msup><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> of <math altimg='si4.svg'><msup><mrow><mi>D</mi></mrow><mrow><mo>&#8270;</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo>&#8270;</mo></mrow></msup></math> nature, plus finding support for the <math altimg='si5.svg'><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi></mrow></msub><mo stretchy='false'>(</mo><mn>4312</mn><mo stretchy='false'>)</mo></math> state as made out of <math altimg='si6.svg'><msub><mrow><mi mathvariant='normal'>&#931;</mi></mrow><mrow><mi>c</mi></mrow></msub><mover accent='true'><mrow><mi>D</mi></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></math>. The mass distribution of the <math altimg='si7.svg'><msup><mrow><mi>D</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo></mrow></msup></math> system shows distinct features as a consequence of the existence of this <math altimg='si8.svg'><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> state, while the <math altimg='si6.svg'><msub><mrow><mi mathvariant='normal'>&#931;</mi></mrow><mrow><mi>c</mi></mrow></msub><mover accent='true'><mrow><mi>D</mi></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></math> distribution exhibits a significant peak near the threshold, much bigger than phase space expectations, which is linked to our assumed <math altimg='si6.svg'><msub><mrow><mi mathvariant='normal'>&#931;</mi></mrow><mrow><mi>c</mi></mrow></msub><mover accent='true'><mrow><mi>D</mi></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></math> nature of the <math altimg='si5.svg'><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi></mrow></msub><mo stretchy='false'>(</mo><mn>4312</mn><mo stretchy='false'>)</mo></math> state below the <math altimg='si6.svg'><msub><mrow><mi mathvariant='normal'>&#931;</mi></mrow><mrow><mi>c</mi></mrow></msub><mover accent='true'><mrow><mi>D</mi></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></math> threshold. The reaction has been measured at LHCb Collaboration, but only the branching ratio is measured. The present study shows that much valuable information can be obtained about the predicted <math altimg='si8.svg'><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> <math altimg='si9.svg'><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi><mover accent='true'><mrow><mi>s</mi></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></mrow></msub><mo stretchy='false'>(</mo><mn>2834</mn><mo stretchy='false'>)</mo></math> of <math altimg='si4.svg'><msup><mrow><mi>D</mi></mrow><mrow><mo>&#8270;</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo>&#8270;</mo></mrow></msup></math> nature and the <math altimg='si5.svg'><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi></mrow></msub><mo stretchy='false'>(</mo><mn>4312</mn><mo stretchy='false'>)</mo></math> states from the measurements of the mass distributions in this reaction, which will be accessible in the planned updates of LHCb.

Searching for signals of an exotic <italic>I</italic>&#8239;=&#8239;1, <italic>J</italic> <italic>P</italic>&#8239;=&#8239;2 + state of <italic>D</italic> &#8270; <italic>K</italic> &#8270; nature and the structure of the <italic>P</italic> <inf><italic>c</italic></inf>(4312) in the <math altimg='si1.svg'><msub><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mi>b</mi></mrow></msub><mo stretchy='false'>&#8594;</mo><msubsup><mrow><mi mathvariant='normal'>&#931;</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup><msup><mrow><mi>D</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo></mrow></msup></math> reaction

We study from the theoretical point of view the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Λ</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><mi>η</mi><mi mathvariant="normal">Λ</mi></math> reaction, recently measured by the Belle and BESIII Collaborations, where clear signals are observed for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi><mo stretchy="false">(</mo><mn>1670</mn><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1385</mn><mo stretchy="false">)</mo></math> excitation. By considering the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi><mo stretchy="false">(</mo><mn>1670</mn><mo stretchy="false">)</mo></math> as dynamically generated resonances from the meson meson and meson baryon interaction, respectively, we are able to determine their relative production strengths in the reaction, which is also tied to the strength of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mo>+</mo></msup><mi>η</mi><mi mathvariant="normal">Λ</mi></math> 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 <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi><mo stretchy="false">(</mo><mn>1670</mn><mo stretchy="false">)</mo></math> are generated. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Σ</mi><mo stretchy="false">(</mo><mn>1385</mn><mo stretchy="false">)</mo></math> 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.

Man-Yu Duan

Wen-Tao Lyu

En Wang

Dian-Yong Chen

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">→</mo><mi>η</mi><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><mi mathvariant="normal">Λ</mi></mrow></math> reaction and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">Λ</mi><msubsup><mrow><mi>a</mi></mrow><mrow><mn>0</mn></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><mi mathvariant="normal">Λ</mi><mo stretchy="false">(</mo><mn>1670</mn><mo stretchy="false">)</mo></mrow></math> contributions

We report on the reactions $$\psi (3770)\rightarrow \bar{\Omega }^+ \bar{K} \Xi $$ and $$\psi (3770)\rightarrow \bar{\Omega }^+ \bar{K}\Xi ^*(1530) \;(\Xi ^*(1530)\rightarrow \pi \Xi $$ ), and calculate the mass distributions $$\frac{\textrm{d}\Gamma }{\textrm{d}M_\text {inv}(\bar{K}\Xi )}$$ and $$\frac{\textrm{d}\Gamma }{\textrm{d}M_\text {inv}(\bar{K}\Xi ^*)}$$ , respectively. We obtain clear peaks corresponding to the $$\Omega (2012)$$ . From the decay of $$\psi (3770)\rightarrow \bar{\Omega }^+ \bar{K}\Xi ^*$$ , we also get a second, broader, peak around $$2035\,\mathrm MeV$$ , which comes from the $$\Omega (2012)$$ decay to $$\bar{K}\Xi ^*$$ . This second peak is closely tied to the molecular picture of the $$\Omega (2012)$$ with the $$\bar{K}\Xi ^*(1530)$$ and $$\eta \Omega $$ components. Its observation would provide a boost to the molecular picture of the $$\Omega (2012)$$ .

Testing the molecular nature of the $$\Omega (2012)$$ with the $$\psi (3770) \rightarrow \bar{\Omega } \bar{K} \Xi $$ and $$\psi (3770) \rightarrow \bar{\Omega } \bar{K} \Xi ^*(1530) (\bar{\Omega } \bar{K} \pi \Xi )$$ reactions