Can X(3915) be the tensor partner of the X(3872)?

It has been proposed recently (Phys. Rev. Lett. 115 (2015), 022001) that the charmoniumlike state named X(3915) and suggested to be a $0^{++}$ scalar, is just the helicity-0 realisation of the $2^{++}$ tensor state $\chi_{c2}(3930)$. This scenario would call for a helicity-0 dominance, which were at odds with the properties of a conventional tensor charmonium, but might be compatible with some exotic structure of the $\chi_{c2}(3930)$. In this paper, we investigate, if such a scenario is compatible with the assumption that the $\chi_{c2}(3930)$ is a $D^*\bar D^*$ molecular state - a spin partner of the $X(3872)$ treated as a shallow bound state. We demonstrate that for a tensor molecule the helicity-0 component vanishes for vanishing binding energy and accordingly for a shallow bound state a helicity-2 dominance would be natural. However, for the $\chi_{c2}(3930)$, residing about 100 MeV below the $D^*\bar D^*$ threshold, there is no a priori reason for a helicity-2 dominance and thus the proposal formulated in the above mentioned reference might indeed point at a molecular structure of the tensor state. Nevertheless, we find that the experimental data currently available favour a dominant contribution of the helicity-2 amplitude also in this scenario, if spin symmetry arguments are employed to relate properties of the molecular state to those of the X(3872). We also discuss what research is necessary to further constrain the analysis.Comment: LaTeX2e, 23 pages, 2 figures, version to appear in JHE

Remarks on the pion-nucleon sigma-term

The pion-nucleon $\sigma$-term can be stringently constrained by the combination of analyticity, unitarity, and crossing symmetry with phenomenological information on the pion-nucleon scattering lengths. Recently, lattice calculations at the physical point have been reported that find lower values by about $3\sigma$ with respect to the phenomenological determination. We point out that a lattice measurement of the pion-nucleon scattering lengths could help resolve the situation by testing the values extracted from spectroscopy measurements in pionic atoms.Comment: 5 pages, 2 figures; version published in PL

Effective Field Theory calculations of NN→NNπNN\to NN\pi

In this review we present the recent advances for calculations of the reactions $NN\to NN\pi$ using chiral effective field theory. Discussed are the next-to-next-to leading order loop contributions with nucleon and Delta-isobar for near threshold s-wave pion production. Results of recent experimental pion-production data for energies close to the threshold are analyzed. Several particular applications are discussed: (i) it is shown how the measured charge symmetry violating pion-production reaction can be used to extract the strong-interaction contribution to the proton-neutron mass difference; (ii) the role of $NN\to NN\pi$ for the extraction of the pion-nucleon scattering lengths from pionic atoms data is illuminated.Comment: 68 pages, 23 figures, to be published in Int. J. Mod. Phys.

Data Science R&D: Current Activities, Future Directions

https://www.youtube.com/watch?v=MNcx2Iwt_v

Charge symmetry breaking as a probe for the real part of eta--nucleus scattering lengths

We demonstrate that one can use the occurrence of charge symmetry breaking as a tool to explore the eta--nucleus interaction near the eta threshold. Based on indications that the cross section ratio of pi+ and pi0 production on nuclei deviates from the isotopic value in the vicinity of the eta production threshold, due to, e.g., pi0-eta mixing, we argue that a systematic study of this ratio as a function of the energy would allow to pin down the sign of the real part of the eta-nucleus scattering length. This sign plays an important role in the context of the possible existence of eta-nucleus bound states.Comment: 4 pages, 1 figur

PENINGKATAN KESADARAN HUKUM MASYARAKAT UNTUK AKTA PERKAWINAN STUDI KASUS TERHADAP MASYARAKAT DISTRIKAIFAT UTARA KABUPATEN MAYBRAT

Penelitian ini bertujuan untuk mengetahui tingkat kesadaran hukum masyarakat di distrik Aifat Utara kabupaten Maybrat terhadap kepemilikan akta nikah dan untuk mengetahui faktor-faktor yang menyebabkan masyarakat di Distrik Aifat Utara Kabupaten Maybrat Jenis Penelitian ini yaitu penelitian deskriptif kualitatif. Informan dalam penelitian ini adalah pasangan yang tidak memiliki akta nikah dan yang memiliki akta nikah yang berjumlah 20 KK yaitu 10 KK yang tidak memiliki akta nikah dan 10 KK yang memiliki akta nikah yang dilakukan secara sengaja dengan kriteria tertentu dengan menggunakan teknik purposive sampling. Pengumpulan data dilakukan dengan cara wawancara, observasi, dan dokumentasi. Hasil penelitian kesadaran hukum masyarakat dalam kepemilikan akta nikah di Distrik Aifat Utara Kabupaten Maybrat tergolong tinggi. Hal ini terbukti dari tinggihnya sikap hukum, dan perilaku hukum serta berbanding jauhnya jumlah Kepala Keluarga yang memiliki akta nikah dibandingkan Kepala Keluarga yang tidak memilimi akta nikah yaitu sebanyak 1616 (98,12%)pasangan yang memiliki akta nikah sedangkan pasangan yang tidak memiliki akta nikah sebanyak 31 (1.88 %)