1,412 research outputs found
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 scalar, is
just the helicity-0 realisation of the tensor state .
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 . In this paper, we
investigate, if such a scenario is compatible with the assumption that the
is a molecular state - a spin partner of the
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 , residing about 100 MeV below the 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 -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 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
In this review we present the recent advances for calculations of the
reactions 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 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
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 %)
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
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