Emergence of a Complete Heavy-Quark Spin Symmetry Multiplet: Seven Molecular Pentaquarks in Light of the Latest LHCb Analysis.

A recent analysis by the LHCb Collaboration suggests the existence of three narrow pentaquarklike states-the P_{c}(4312), P_{c}(4440), and P_{c}(4457)-instead of just one in the previous analysis [the P_{c}(4450)]. The closeness of the P_{c}(4312) to the D[over ¯]Σ_{c} threshold and the P_{c}(4440) and P_{c}(4457) to the D[over ¯]^{*}Σ_{c} threshold suggests a molecular interpretation of these resonances. We show that these three pentaquarklike resonances can be naturally accommodated in a contact-range effective field theory description that incorporates heavy-quark spin symmetry. This description leads to the prediction of all the seven possible S-wave heavy antimeson-baryon molecules [that is, there should be four additional molecular pentaquarks in addition to the P_{c}(4312), P_{c}(4440), and P_{c}(4457)], providing the first example of a heavy-quark spin symmetry molecular multiplet that is complete. If this is confirmed, it will not only give us an impressive example of the application of heavy-quark symmetries and effective field theories in hadron physics, it will also uncover a clear and powerful ordering principle for the molecular spectrum, reminiscent of the SU(3)-flavor multiplets to which the light hadron spectrum conforms.

Inhibitory assay for degradation of collagen IV by cathepsin B with a surface plasmon resonance sensor.

We describe a simple method for evaluating the inhibition of collagen IV degradation by cathepsin B with a surface plasmon resonance (SPR) biosensor. The change in the SPR signal decreased with an increase in the concentration of cathepsin B inhibitors. The order of the inhibitory constant (Ki) obtained by the SPR method was CA074Me≈Z-Phe-Phe-FMK < leupeptin. This order was different from that obtained by benzyloxycarbonyl-Phe-Phe-Fluoromethylketone (Z-Phe-Phe-FMK) as a peptide substrate. The comparison of Ki suggested that CA074 and Z-Phe-Phe-FMK inhibited exopeptidase activity, and leupeptin inhibited the endopeptidase activity of cathepsin B more strongly.

Exotic hadrons in s-wave chiral dynamics.

We study s-wave scattering of a hadron and a Nambu-Goldstone boson induced by the model-independent low energy interaction in the flavor SU(3) symmetric limit. Establishing the general structure of the interaction based on group theoretical arguments, we find that the interaction in the exotic channels are in most cases repulsive, and that for possible attractive channels the coupling strengths are weak and uniquely given independent of channel. Solving the scattering problem, we show that the attraction in the exotic channels is not strong enough to generate a bound state.