Tue·Mar 1, 2016Tuesday·March 1, 2016

1. 01*

   The $\mathbf{\Lambda p}$ interaction studied via femtoscopy in p + Nb reactions at $\sqrt{{\mathbf{s}}_{\mathbf{NN}}}=3.18\mathbf{GeV}$

   J. Adamczewski-Musch · G. Agakishiev · O. Arnold · E.T. Atomssa · C.Behnke · J.C. Berger-Chen · J. Biernat · A. Blanco · C. Blume · M. Böhmer · P. Bordalo · S. Chernenko and 94 other authors

   We report on the first measurement of $p\Lambda$ and $pp$ correlations via the femtoscopy method in p+Nb reactions at $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}=3.18\mathrm{GeV}$, studied with the High Acceptance Di-Electron Spectrometer (HADES). By comparing the experimental correlation function to model calculations, a source size for $pp$ pairs of $r_{0,pp}=2.02\pm 0.01(\mathrm{stat}{)}_{-0.12}^{+0.11}(\mathrm{sys})\mathrm{fm}$ and a slightly smaller value for $p\Lambda$ of $r_{0,\Lambda p}=1.62\pm 0.02(\mathrm{stat}{)}_{-0.08}^{+0.19}(\mathrm{sys})\mathrm{fm}$ is extracted. Using the geometrical extent of the particle emitting region, determined experimentally with $pp$ correlations as reference together with a source function from a transport model, it is possible to study different sets of scattering parameters. The $p\Lambda$ correlation is proven sensitive to predicted scattering length values from chiral effective field theory. We demonstrate that the femtoscopy technique can be used as valid alternative to the analysis of scattering data to study the hyperon-nucleon interaction.

   nucl-exPRC(2016)·46 citations
2. 02*

   Parton distribution functions from Lattice QCD

   Constantia Alexandrou (Univ. of Cyprus & The Cyprus Inst.)🇨🇾

   We present recent results on the first moments of parton distributions using gauge configurations generated with two degenerate flavors of light twisted mass quarks with pion mass fixed approximately to its physical value. We also present a first study of the vector parton distribution function using a twisted mass ensemble at pion mass of 373 MeV.

   ↳ hep-lathep-phnucl-exnucl-thFew Body Syst.(2016)·11 citations
3. 03*

   Can $X(5568)$ be a tetraquark state?

   Wei Wang🇨🇳 · Ruilin Zhu🇨🇳

   Very recently, the D0 collaboration has reported the observation of a narrow structure, $X(5568)$, in the decay process $X(5568)\to B_s^0{\pi }^{\pm }$ using the 10.4${\mathrm{fb}}^{-1}$ data of $p\bar{p}$ collision at $\sqrt{s}=1.96$ TeV. This structure is of great interest since it is the first hadronic state with four different valence quark flavors, $b,s,u,d$. In this work, we investigate tetraquarks with four different quark flavors. Based on the diquark-antidiquark scheme, we study the spectroscopy of the tetraquarks with one heavy bottom/charm quark and three light quarks. We find that the lowest-lying S-wave state, a tetraquark with the flavor $[su][\bar{b}\bar{d}]$ and the spin-parity $J^P=0^{+}$, is about 150 MeV higher than the $X(5568)$. Further detailed experimental and theoretical studies of the spectrum, production and decays of tetraquark states with four different flavors in the future are severely needed towards a better understanding its nature and the classification of hadron exotic states.

   ↳ hep-phhep-exnucl-exnucl-thCPC(2016)·66 citations
4. 04*

   Rapidity bin multiplicity correlations from a multi-phase transport model

   Mei-Juan Wang🇨🇳 · Gang Chen🇨🇳 · Yuan-Fang Wu🇨🇳 · Guo-Liang Ma🇨🇳

   The central-arbitrary bin and forward-backward bin multiplicity correlation patterns for Au+Au collisions at $\sqrt{s_{NN}}$= $7.7-62.4$ GeV are investigated within a multi-phase transport (AMPT) model. An interesting observation is that for $\sqrt{s_{NN}}<19.6$ GeV Au+Au collisions, these two correlation patterns both have an increase with the pseudorapidity gap, while for $\sqrt{s_{NN}}>19.6$ GeV Au+Au collisions, they decrease. We mainly discuss the influence of different evolution stages of collision system on the central-arbitrary bin correlations, such as the initial conditions, partonic scatterings, hadronization scheme and hadronic scatterings. Our results show that the central-arbitrary bin multiplicity correlations have different responses to partonic phase and hadronic phase, which can be suggested as a good probe to explore the dynamical evolution mechanism of the hot dense matter in high-energy heavy-ion collisions.

   ↳ nucl-thnucl-exEPJA(2016)·1 citation
5. 05*

   Decoding the $X(5568)$ as a fully open-flavor $su\bar{b}\bar{d}$ tetraquark state

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

   We investigate the recent evidence for a charged $X(5568)$ meson as an exotic open-flavor tetraquark state $su\bar{b}\bar{d}$ with $J^P=0^{+}/1^{+}$ in the framework of QCD sum rules. We use the color antisymmetric $[{\bar{3}}_{\mathbf{c}}{]}_{su}\otimes [3_{\mathbf{c}}{]}_{\bar{b}\bar{d}}$ tetraquark currents in both scalar and axial-vector channels to perform evaluations and numerical analyses. Our results imply that the $X(5568)$ can be interpreted as both the scalar $su\bar{b}\bar{d}$ tetraquark state and the axial-vector one, which are in good agreement with the experimental measurement. We also discuss the possible decay patterns of the $X(5568)$ and suggest to search for its neutral partner in the radiative decay into $B_s^0\gamma$ and $B_s^{\ast }\gamma$, which can be used to determine its spin-parity quantum numbers. Moreover, we predict its charmed partner state around $2.55$ GeV with the quark content $su\bar{c}\bar{d}$ and $J^P=0^{+}/1^{+}$.

   ↳ hep-phhep-exhep-latnucl-exPRL(2016)·85 citations
6. 06*

   Dipole oscillation modes in light $\alpha$-clustering nuclei

   W. B. He · Y. G. Ma🇨🇳 · X. G. Cao🇨🇳 · X. Z. Cai🇨🇳 · G. Q. Zhang🇨🇳

   The $\alpha$ cluster states are discussed in a model frame of extended quantum molecular dynamics. Different alpha cluster structures are studied in details, such as ${}^8$Be two-$\alpha$ cluster structure, ${}^{12}$C triangle structure, ${}^{12}$C chain structure, ${}^{16}$O chain structure, ${}^{16}$O kite structure, and ${}^{16}$O square structure. The properties studied, include as the width of wave packets for different $\alpha$ clusters, momentum distribution, and the binding energy among $\alpha$ clusters. It is also discussed how the $\alpha$ cluster degree of freedom affects nuclear collective vibrations. The cluster configurations in ${}^{12}$C and ${}^{16}$O are found to have corresponding characteristic spectra of giant dipole resonance (GDR), and the coherences of different $\alpha$ clusters's dipole oscillation are described in details. The geometrical and dynamical symmetries of $\alpha$-clustering configurations are responsible for the number and centroid energies of peaks of GDR spectra. Therefore, the GDR can be regarded as an effective probe to diagnose different $\alpha$ cluster configurations in light nuclei.

   ↳ nucl-thnucl-exPRC(2016)·47 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.