Universal Correlations in Pion-less EFT with the Resonating Group Model: Three and Four Nucleons
Johannes Kirscher, Harald W. Griesshammer, Deepshikha Shukla, Hartmut M. Hofmann
备注：
24 pages revtex4, including 8 figures as .eps files embedded with includegraphicx, leading-order results added, calculations include the LO three-nucleon interaction
explicitly, comment on Wigner bound added, minor modifications
The Effective Field Theory "without pions" at next-to-leading order is used to analyze universal bound state and scattering properties of the 3- and 4-nucleon system. Results of a variety of phase shift equivalent nuclear potentials are presented for bound state properties of 3H and 4He, and for the singlet S-wave 3He-neutron scattering length a_0(3He-n). The calculations are performed with the Refined Resonating Group Method and include a full treatment of the Coulomb interaction and the leading-order 3-nucleon interaction. The results compare favorably with data and values from AV18(+UIX) model calculations. A new correlation between a_0(3He-n) and the 3H binding energy is found. Furthermore, we confirm at next-to-leading order the correlations, already found at leading-order, between the 3H binding energy and the 3H charge radius, and the Tjon line. With the 3H binding energy as input, we get predictions of the Effective Field Theory "without pions" at next-to-leading order for the root mean square charge radius of 3H of (1.6\pm 0.2) fm, for the 4He binding energy of (28\pm 2.5) MeV, and for Re(a_0(3He-n)) of (7.5\pm 0.6)fm. Including the Coulomb interaction, the splitting in binding energy between 3H and 3He is found to be (0.66\pm 0.03) MeV. The discrepancy to data of (0.10\mp 0.03) MeV is model independently attributed to higher order charge independence breaking interactions. We also demonstrate that different results for the same observable stem from higher order effects, and carefully assess that numerical uncertainties are negligible. Our results demonstrate the convergence and usefulness of the pion-less theory at next-to-leading order in the 4He channel. We conclude that no 4-nucleon interaction is needed to renormalize the theory at next-to-leading order in the 4-nucleon sector.
Threshold pion production in proton-proton collisions at NNLO in chiral EFT
反应$NN \to NN π$为手征有效场论在中能区提供了一个很好的实验平台。它挑战了我们对核子-核子散射中第一非弹性通道和强子反应中电荷对称性破缺模式的理解。在我们以前的研究中，我们给出了手征有效场论中包括π介子、核子和$Δ(1232)$自由度在内的s波π介子的π介子产生算符的完整计算.在本文中，我们计算了$pp \to d π^{+}$反应的近阈值截面的基础上现代唯象和手征势核波函数进行卷积的操作。可用的手性$NN$波函数的构造与π介子生产反应中固有的动量传递尺度的截止。因此，动态中程物理学的很大一部分因此被它们切断。另一方面，用唯象波函数评估的NNLO振幅似乎在很大程度上独立于所用的$NN$模型，并对主导的领先阶贡献进行了修正，正如量纲分析所预期的那样。这一结果支持了对π介子产生算符进行分类的计数方案，这是可靠地研究手征抑制中性π介子产生的前提。明确列入的$Δ(1232)$被认为是重要的，但小于预期的，由于取消。
Quantum Algorithms for Simulating Nuclear Effective Field Theories
Joint Center for Quantum Information and Computer Science, NIST/University of Maryland（量子信息与计算联合中心，美国国家标准与技术研究院/马里兰大学）；Department of Computer Science and Institute for Advanced Computer Studies, University of Maryland（马里兰大学计算机科学与高级计算研究所）；Joint Quantum Institute, NIST/University of Maryland（NIST/马里兰大学联合量子研究所）；Department of Physics, Harvard University（哈佛大学物理系）；Department of Physics, University of Maryland（马里兰大学物理系）
Charge and Magnetic Properties of Three-Nucleon Systems in Pionless Effective Field Theory
本文给出了一种在短程相互作用的有效场论（EFT）中计算三体系统非导数耦合外电流形状因子的方法。用该方法计算了无π介子EFT（$\mathrm{EFT}(\not{\!π})$）中${}^3\mathrm{He}$的点电荷半径，并计算了${}^3\mathrm{H}$和${}^3\mathrm{He}$的磁矩和半径.对于${}^3\mathrm{He}$，电荷和磁形状因子库仑相互作用被忽略。${}^3\mathrm{He}$点电荷半径由1.74（4）fm在NNLO下给出。这与1.7753（54）fm的实验${}^3\mathrm{He}$点电荷半径完全一致[Angeli和Marinova，At. Data Nucl. Data Tables 99，69（2013）]。在非线性光学（NLO）下，${}^3\mathrm{H}$（${}^3\mathrm{He}$）的磁矩（以核磁子为单位）为2.92（35）（-2.08（25）），与实验值2.979（-2.127）一致。对于${}^3\mathrm{H}$（${}^3\mathrm{He}$），非线性光学磁半径为1.78（11）fm（1.85（11）fm），与实验值1.840（182）fm（1.965（154）fm）一致[I.生病了，程序员。部分47，245（2001）]。还讨论了等矢量二体磁流的低能常数$L_{1}$的拟合和Wigner…
在建立手征核有效场论（EFT）的一致功率计数的基础上，以重整化群不变性为约束条件，讨论了核子-核子散射单重态通道中的次主导接触相互作用，即反项.我们认为，相当大的截止误差的领先幅度要求O（Q）的EFT扩展是非零的，相反，温伯格的原始功率计数。这一点，再加上扭曲波膨胀中两π介子交换的紫外发散，导致1 S 0反项的增强，并导致单重态通道的无π介子理论般的功率计数。
Renormalization group invariance in pionless effective field theory for the NN system
我们考虑NN相互作用在无π有效场论（EFT）的次-首阶（NNLO）和使用递归减法重整化方案来描述NN散射在1 S 0通道。我们将接触相互作用的强度固定在一个参考尺度上，选择一个为相移提供最佳拟合的尺度，然后通过非相对论性Callan-Symanzik方程来演化减去的Lippmann-Schwinger方程的驱动项，从而滑动重整化尺度。结果表明，这种多重减项的系统重整化方案是完全重整化群不变的。
