Wed·Mar 11, 2015Wednesday·March 11, 2015

1. 01*

   $a_1(1420)$ resonance as a tetraquark state and its isospin partner

   Hua-Xing Chen🇨🇳 · Er-Liang Cui🇨🇳 · Wei Chen🇨🇦 · T. G. Steele🇨🇦 · Xiang Liu🇨🇳 · Shi-Lin Zhu🇨🇳

   We systematically construct tetraquark currents of $I^G{J}^{PC}=1^{-}{1}^{++}$ and classify them into types $\mathbf{A}$ (antisymmetric), $\mathbf{S}$ (symmetric) and $\mathbf{M}$ (mixed), based on flavor symmetries of diquarks and antidiquarks composing the tetra quark currents. We use tetraquark currents of type $\mathbf{M}$ to perform QCD sum rule analyses, and find a tetraquark current ${\eta }_{5\mu }^M$ with quark contents $qs\bar{q}\bar{s}$($q=u$ or $d$) leading to a mass of $1.44\pm 0.08$ GeV consistent with the $a_1(1420)$ state recently observed by the COMPASS collaboration. Our results support tetraquark explanations for both $a_1(1420)$ and $f_1(1420)$, assuming that they are isospin partners. We also study their possible decay patterns. As tetraquark candidates, the possible decay modes of $a_1(1420)$ are $S$-wave $a_1(1420)\to K^{\ast }(892)K$ and $P$-wave $a_1(1420)\to f_0(980)\pi$ while the possible decay patterns of $f_1(1420)$ are $S$-wave $f_1(1420)\to K^{\ast }(892)K$ and $P$-wave $f_1(1420)\to a_0(980)\pi$. We speculate that $a_1(1420)$ is partly responsible for the large isospin violation in the $\eta (1405)\to f_0(980){\pi }_0$ decay mode which is reported by BESIII collaboration in the $J/\psi \to \gamma 3\pi$ process.

   ↳ hep-phhep-exnucl-exPRD(2015)·28 citations
2. 02*

   Antihyperon potentials in nuclei via exclusive antiproton-nucleus reactions at FAIR

   Alicia Sanchez Lorente🇩🇪 · Sebastian Bleser🇩🇪 · Marcell Steinen🇩🇪 · Josef Pochodzalla🇩🇪

   The exclusive production of hyperon-antihyperon pairs close to their production threshold in antiproton - nucleus collisions offers a unique and hitherto unexplored opportunity to elucidate the behaviour of antihyperons in nuclei. For the first time we analyse these reactions in a microscopic transport model using the the Gießen Boltzmann-Uehling-Uhlenbeck transport model. The calculation take the delicate interplay between the strong absorption of antihyperons, their rescattering and refraction at the nuclear surface as well as the Fermi motion of the struck nucleon into account. We find a substantial sensitivity of transverse momentum correlations of coincident $\Lambda \overline{\Lambda }$-pairs to the assumed depth of the $\overline{\Lambda }$-potential. Because of the high cross section for this process and the simplicity of the experimental method our results are highly relevant for future activities at the international Facility for Antiproton and Ion Research (FAIR).

   ↳ nucl-thnucl-exPLB(2015)·7 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.