We argue that the existence of a new narrow (Gamma < 25 MeV) nucleon resonance N*(1685) is strongly supported by recent data on eta photoproduction off the nucleon. The resonance has much stronger photo-coupling to the neutron than to the proton. This nucleon resonance is a good candidate for the non-strange member of the exotic anti-decouplet of baryons -- the partner of the pentaquark Theta+. All up to date known properties of new N*(1685) are summarized.
Within the impulse approximation, the modeling of the energy of final state leptons in electron and neutrino quasielastic and pion production processes on nuclear targets in the region of the $Δ$ resonance depends on several parameters. These parameters include the removal energy of the initial state nucleon from the nucleus $ε^{P,N}$, the potentials of electrons, nucleons and pions in the Coulomb field of the nucleus $|V_{eff}|$, and the kinetic energy dependent nuclear potential for final state nucleons ($U^{QE}_{opt}$) and "nucleon plus pion" final states in the region of the $Δ$ resonance …
We present a hypothesis that the anomaly in the folding angle distribution of electron-positron pairs, emitted in the decay of the excited levels of nucleus $^{8}$Be and $^{4}$He can be related to the cluster structure of the decaying state. Furthermore, we present a hypothesis that the potentially observed boson with re st mass $m_{X}$=17 MeV can mediate the nucleon-nucleon interaction at the low-energy regime of QCD, in particular in the weakly bound cluster state p+$^{7}$Li,$^{3}$H. We present a possible equations of state of symmetric nuclear matter corresponding to the vector meson mass $…
Possibility of narrow resonances in nucleon-nucleon channels
复合态表现为束缚态、共振态或基元态，它们的性质由它们与连续统的相互作用决定。如果相互作用经历扰动，复合态可以改变其表现形式。核子-核子散射的相位分析表明在3S 1，1 S 0和3 P0通道中存在基元。电磁相互作用可以将基元从单一切割中转移，将它们转变为窄共振。我们评估这种影响的1 S 0质子-质子散射通道的Simonov-Dyson模型的框架内。我们表明，电磁相互作用把一个质量为2000 MeV的素子变成一个大约相同的质量和宽度为260 keV的重子共振。类似性质的窄共振可能发生在其他核子-核子通道中。窄共振存在的实验证实将对核子-核子相互作用理论具有重要意义。
In this work, we apply the relativistic chiral nuclear force to describe the state-of-the-art lattice simulations of the nucleon-nucleon scattering amplitude. In particular, we focus on the $^3S_1$-$^3D_1$ coupled channel for a pion mass of 469 MeV. We show that at leading order the relativistic chiral nuclear force can only describe $δ_{3S1}$ and $\varepsilon_1$ up to $T_\mathrm{lab.}\approx10$ MeV, while at the next-to-leading order it can do much better up to $T_\mathrm{lab}=200$ MeV. However, at the next-to-next-to-leading order, the description deteriorates, which can be attributed to the…
Nucleon-nucleon systems are studied with lattice quantum chromodynamics at a pion mass of $m_π\sim 450~{\rm MeV}$ in three spatial volumes using $n_f=2+1$ flavors of light quarks. At the quark masses employed in this work, the deuteron binding energy is calculated to be $B_d = 14.4^{+3.2}_{-2.6} ~{\rm MeV}$, while the dineutron is bound by $B_{nn} = 12.5^{+3.0}_{-5.0}~{\rm MeV}$. Over the range of energies that are studied, the S-wave scattering phase shifts calculated in the 1S0 and 3S1-3D1 channels are found to be similar to those in nature, and indicate repulsive short-range components of t…
Mu and Tau Neutrino Thermalization and Production in Supernovae: Processes and Timescales
我们研究了在与核心坍缩超新星和质子中子星相关的温度和密度下，$ν_μ$和$ν_τ$中微子的产生率和热化率。包括电子散射、电子正电子湮没、核子-核子韧致辐射和核子散射的贡献。对于散射过程，为了包含任意简并度下的完整散射运动学，采用Reddy等人（1998）和Burrows和Sawyer（1998）开发的结构函数形式。此外，我们还导出了非对称物质中任意核子简并度的核子-核子韧致辐射的总速率和微分速率公式。我们发现，在低中微子能量（$ε_ν\lesssim 10$ MeV）的热化过程中，电子散射占主导地位的核子散射，但核子散射总是快于或相当于电子散射以上$ε_ν\simeq10$ MeV。此外，对于$ρ\gtrsim 10^{13}$ g cm $^{-3}$、$T\lesssim14$ MeV和中微子能量$\lesssim60$ MeV，作为$ν_μ$和$ν_τ$中微子的产生机制，核子-核子韧致辐射总是支配电子正电子湮没。
Nucleon-nucleon interactions, both bare and effective, play an important role in our understanding of the non-perturbative strong interaction, as well as nuclear structure and reactions. In recent years, tremendous efforts have been seen in the lattice QCD community to derive nucleon-nucleon interactions from first principles. Because of the daunting computing resources needed, most of such simulations were still performed with larger than physical light quark masses. In the present work, employing the recently proposed covariant chiral effective field theory (ChEFT), we study the light quark …
Cross-sections for nuclide production in 56Fe target irradiated by 300, 500,750, 1000, 1500, and 2600 MeV protons compared with data on hydrogen target irradiation by 300, 500, 750, 1000, and 1500 MeV/nucleon 56Fe ions
In this talk we discuss the formation of exotic hadrons with hidden charm arising from three-body interactions. To be more specific, in the strangeness sector, we predict the existence of a mesonic state, $K^*(4307)$, which is dynamically generated from the three-body interactions of the $KD\bar{D}^*$ system, has mass around $4307$ MeV and quantum numbers $I(J^P) = 1/2\,(1^-)$. In the baryonic sector, we predict the existence of $N^*$ states, which are generated from the three-body interactions of the $ND\bar{D}^*$ system, with masses around $4400\sim 4600$ MeV, widths of $2\sim 20$ MeV and po…
Two-nucleon systems at $m_π\approx292$ MeV from lattice QCD
Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；Nanjing Normal University（南京师范大学）；School of Physics, Peking University（北京大学物理学院）；Center for High Energy Physics, Peking University（北京大学高能物理中心）；Collaborative Innovation Center of Quantum Matter（量子物质协同创新中心）；Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所南方核科学理论中心）
The importance of piN → K Lambda process for the pole structure of the P11 partial wave T-matrix in the coupled channel pion-nucleon partial wave analysis
P11介子-核子分波的极结构的审查，重点是1700 MeV的能量域。在π-核子分波分析中，利用耦合道形式消除连续谱模糊性的机制（在别处对π N-> etaN道提出），被应用于π N-> K λ道，目的是澄清物理现实是否不需要（VPI/GWU），（KH 80，CMB，Kent，Pittsburgh/ANL，Giessen），或者可能是1700 MeV范围内的分波T矩阵的两个（Zagreb）极点。论证了第二非弹性通道对解决这一难题的作用。它指出，实验的piN -> K λ和piN -> K σ通道，非常重要的1700 MeV的范围内，是旧的和不确定的，所以迫切需要重新测量该通道强调。
