Avraham Gal, Daniel Gazda
Charge symmetry breaking (CSB) is particularly strong in the A=4 mirror hypernuclei $_Λ^4$H--$_Λ^4$He. Recent four-body no-core shell model calculations that confront this CSB by introducing $Λ$-$Σ^0$ mixing to leading-order chiral effective field theory hyperon-nucleon potentials are reviewed, and a shell-model approach to CSB in p-shell $Λ$ hypernuclei is outlined.
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Ongoing progress in understanding and evaluating charge symmetry breaking in $Λ$ hypernuclei is discussed in connection to recent measurements of the $_Λ^{4}{\rm H}(0^+_{\rm g.s.})$ binding energy at MAMI [A1 Collaboration: PRL 114 (2015) 232501] and of the $_Λ^{4}{\rm He}(1^+_{\rm exc})$ excitation energy at J-PARC [E13 Collaboration: PRL 115 (2015) 222501].
The large charge symmetry breaking (CSB) implied by the $Λ$ binding energy difference $ΔB^{4}_Λ(0^+_{\rm g.s.})\equiv B_Λ(_Λ^4$He)$-$$B_Λ(_Λ^4$H) = 0.35$\pm$0.06 MeV of the $A=4$ mirror hypernuclei ground states, determined from emulsion studies, has defied theoretical attempts to reproduce it in terms of CSB in hyperon masses and in hyperon-nucleon interactions, including one pion exchange arising from $Λ-Σ^0$ mixing. Using a schematic strong-interaction $ΛN\leftrightarrowΣN$ coupling model developed by Akaishi and collaborators for $s$-shell $Λ$ hypernuclei, we revisit the evaluation of CSB …
Charge symmetry breaking (CSB) in the $Λ$-nucleon strong interaction generates a charge dependence of $Λ$ separation energies in mirror hypernuclei, which in the case of the $A=4$ mirror hypernuclei $0^+$ ground states is sizable, $ΔB^{J=0}_Λ\equiv B^{J=0}_Λ (_Λ^4{\rm He}) -B^{J=0}_Λ(_Λ^4{\rm H})=230\pm 90$ keV, and of opposite sign to that induced by the Coulomb repulsion in light hypernuclei. Recent ab-initio calculations of the ($_Λ^4{\rm H},{_Λ^4{\rm He}}$) mirror hypernuclei $0^+_{\rm g.s.}$ and $1^+_{\rm exc}$ levels have demonstrated that a $Λ- Σ^0$ mixing CSB model due to Dalitz and vo…
We report on ab-initio NCSM calculations of the A=4 mirror Lambda hypernuclei Lambda-4H and Lambda-4He, using the Bonn-Juelich LO chiral EFT YN potentials plus a CSB Lambda0--Sigma0 mixing vertex. In addition to reproducing rather well the 0+ (g.s.) and 1+ (exc.) binding energies, these four-body calculations demonstrate for the first time that the observed CSB splitting of mirror levels, reaching hundreds of keV for 0+ (g.s.), can be reproduced using realistic theoretical interaction models, although with a non-negligible momentum cutoff dependence. Our results are discussed in relation to re…
The $Λ$ separation energies in the mirror hypernuclei ${_Λ^4}{\rm H}-{_Λ^4}{\rm He}$ exhibit large charge symmetry breaking (CSB). Analyzing this CSB within pionless effective field theory while using partially conserved baryon-baryon SU(3) flavor symmetry, we deduce a $Λ-Σ^0$ induced in-medium admixture amplitude ${\cal A}_{I=1}\approx 1.5\%$ in the dominantly isospin $I=0$ $Λ$ hyperon. Our results confirm the free-space value ${\cal A}^{(0)}_{I=1}$ inferred directly within the SU(3) baryon octet by Dalitz and von-Hippel in 1964 and reaffirmed in a recent QCD+QED lattice calculation. Furtherm…
Charge symmetry breaking effect in mirror Λ hypernuclei with Skyrme-Hartree-Fock model
本研究利用形变Skyrme-Hartree-Fock+BCS模型研究镜像Λ超核的电荷对称性破缺效应，模型成功解释A=7~16的观测数据，并发现形变对A=8和A=9超核的结合能差异有显著影响。
Charge symmetry breaking in hypernuclei within RMF model
该研究在引入NN与ΛN相互作用的RMF模型中，通过拟合强度参数重现¹²_ΛB和¹²_ΛC的结合能差，计算A=7~48镜像超核的CSB能量反常，预测A=40及A=48超核的结合能相关特性，探究超核中的电荷对称性破缺效应。
Recent experiments have presented more accurate data on the $ΛΛ$-binding energies of a few $ΛΛ$- hypernuclei. This is important as the $ΛΛ$- bond energies ($ΔB_{ΛΛ}$) of double-$Λ$ hypernuclei provide a measure of the in-medium strength of the $ΛΛ$ interaction. A mass formula, optimized with the newly available $ΛΛ$ binding energy data, is used to estimate the binding energy and bond energy over a wide range of hypernuclei. The $ΔB_{ΛΛ}$ values calculated with this mass formula are in good agreement with the experimental data, predictions of the quark mean-field (QMF) model and the relativisti…
We include the leading charge symmetry breaking contributions into the hyperon-nucleon interactions derived within chiral effective field theory up to next-to-leading order. Two low energy constants are determined using the experimentally known differences of Lambda separation energies of 4-Lambda-He and 4-Lambda-H. This allows one to predict the Lambda-neutron scattering lengths for the first time based on data. Various sources of uncertainty are discussed.
We propose a novel method for producing very-neutron-rich hypernuclei and corresponding resonance states by employing charge-exchange reactions via pp($^{12}$C, $^{12}$N $K^+$)n$Λ$ with single-charge-exchange and ppp($^{9}$Be, $^{9}$C $K^+$)nn$Λ$ with double-charge-exchange, both of which produce $ΛK^+$ in a target nucleus. The feasibility of producing very-neutron-rich hypernuclei using the proposed method was analysed by applying an ultra-relativistic quantum molecular dynamics model to a $^6$Li+$^{12}$C reaction at 2 $A$ GeV. The yields of very-neutron-rich hypernuclei, signal-to-background…
Generalized mass formula for non-strange and hyper nuclei with SU(6) symmetry breaking
由自旋味SU（6）对称性破缺启发的单一质量公式提供了对非奇异核和超核的同时描述。用这个公式计算了λ超核、双λ超核、Sigma超核、Cascade超核和Theta超核的超子结合能。结果被发现是在良好的协议与现有的实验数据的“束缚”核和相对论以及夸克平均场计算。这个质量公式对于估算包括轻质量核在内的大范围质量的结合能是有用的。它不适用于排斥势。
We utilize the experimentally known difference of the $Λ$ separation energies of the mirror hypernuclei ${^4_Λ\rm He}$ and ${^4_Λ\rm H}$ to constrain the $Λ$-neutron interaction. We include the leading charge-symmetry breaking (CSB) interaction into our hyperon-nucleon interaction derived within chiral effective field theory at next-to-leading order. In particular, we determine the strength of the two arising CSB contact terms by a fit to the differences of the separation energies of these hypernuclei in the $0^+$ and $1^+$ states, respectively. By construction, the resulting interaction descr…
The separation energies of the isospin triplet $^7_Λ\mathrm{He}$, $^7_Λ\mathrm{Li^{*}}$, $^7_Λ$Be, and the $T=1/2$ doublet $^8_Λ$Li, $^8_Λ$Be are investigated within the no-core shell model. Calculations are performed based on a hyperon-nucleon potential derived from chiral effective field theory at next-to-leading order. The potential includes the leading charge-symmetry breaking (CSB) interaction in the $Λ$N channel, whose strength has been fixed to the experimentally known difference of the $Λ$ separation energies of the mirror hypernuclei $^4_Λ\mathrm{He}$ and $^4_Λ\mathrm{H}$. It turns ou…
Measurement of energy-level splitting from Charge-Symmetry Breaking in $A$ = 4 mirror hypernuclei
利用STAR实验在Au+Au碰撞中精确测量$A$=4镜像超核$\rm ^4_{\Lambda}H$和$\rm ^4_{\Lambda}He$的$\Lambda$结合能，发现基态和激发态电荷对称性破缺大小相当但符号相反。
The study of hypernuclei in the quark mean-field model are extended from single-$Λ$ hypernuclei to double-$Λ$ hypernuclei as well as $Ξ$ hypernuclei (double strangeness nuclei), with a broken SU(3) symmetry for the quark confinement potential. The strength of the potential for $u,d$ quarks is constrained by the properties of finite nuclei, while the one for $s$ quark is fixed by the single $Λ$-nucleus potential at the nuclear saturation density, which has a slightly different value. Compared to our previous work, we find that the introduction of such symmetry breaking improves efficiently the …
A data-driven idea is presented to test if light nuclei and hypernuclei obey the coalescence-inspired sum rule, i.e., to test if the flow of a light nucleus or hypernucleus is the summed flow of each of its constituents. Here, the mass difference and charge difference among the constituents of light nuclei and hypernuclei are treated appropriately. The idea is applied to the available data for $\sqrt{s_{NN}} = 3$ GeV fixed-target Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC), published by the STAR collaboration. It is found that the sum rule for light nuclei is approximately v…
The production of light nuclei and hypernuclei together with heavy baryons, both hyperons and $Δ$-baryons, in low density matter as found in stellar environments such as supernova or binary mergers is studied within relativistic mean-field models. Five light nuclei were considered together with three light hypernuclei. The presence of both hyperons and $Δ$-baryons shift the dissolution of clusters to larger densities and increase the abundance of clusters. This effect is larger the smaller the charge fraction and the higher the temperature. The couplings of the $Δ$-baryons were chosen imposing…
Constraints on $ΛN$ Effective Interactions from Mirror Hypernuclei in a Deformed Relativistic Hartree-Bogoliubov Model
该研究在形变相对论 Hartree-Bogoliubov 框架下计算四对镜像超核，利用八种 $ΛN$ 有效相互作用揭示分离能、电荷半径及对称性破缺关联，并提出约束超子–核子相互作用的关键测量体系。
Structure of neutron-rich He $Λ$ hypernuclei using the cluster orbital shell model
本研究采用团簇轨道壳模型计算A=6–9丰中子He Λ超核能谱，验证已知核基态并预测新核能级，提出J-PARC的实验产生方案。
The structure of the T=1 iso-triplet hypernuclei, $^7_Λ$He, $^7_Λ$Li and $^7_Λ$Be within the framework of an $α+Λ+N+N$ four-body cluster model is studied. Interactions between the constituent subunits are determined so as to reproduce reasonably well the observed low-energy properties of the $αN$, $αΛ$, $αNN$ and $αΛN$ subsystems. Furthermore, the two-body $ΛN$ interaction is adjusted so as to reproduce the $0^+$-$1^+$ splitting of $^4_Λ$H. Also a phenomenological $ΛN$ charge symmetry breaking(CSB) interaction is introduced. The $Λ$ binding energy of the ground state in $^7_Λ$He is predicted t…
Study of Light Lambda- and Lambda Lambda-Hypernuclei with the Stochastic Variational Method and Effective Lambda N Potentials
我们首先确定了λ-N S波相移，从而重现了实验上A=3，4的λ-超核的λ-分离能，然后构造了三个具有不同中心排斥力的相位等价的λ-N势.本文用关联高斯基随机变分法对A=6以下的超核进行了广泛的从头算计算。超核的结合能和大小与相等效的N势的类型无关。我们使用两种不同的Lambda-Lambda电位，它们都相当好地再现了6 He_{Lambda Lambda}的Δ B_{Lambda Lambda}。这些Lambda-N势和Lambda-Lambda势的任何组合都预测了迄今为止尚未发现的粒子稳定的束缚态，4 H_{Lambda Lambda}，5 H_{Lambda Lambda}和5 He_{Lambda Lambda}：预测值B_{Lambda Lambda}分别约为0.4，5.5和6.3 MeV。4 H_{Lambda Lambda}的结合能非常小，其可能性主要取决于λ-λ相互作用的强度。与实验相比，计算的5 He_λ和6 He_{Lambda Lambda}的结合能都是强烈超束缚的。在这个众所周知的异常，我们研究的夸克子结构的$N$和Lambda对它们的结合能的影响。如果包含三个夸克的重子的尺寸小于0.6 fm，这种效应可以忽略不计，但是如果尺寸大到0.7 fm，这种效应就变得明显了，特别是在6 He_{Lambda Lambda}中。我们讨论了在何种程度上的核子子系统的超核的…
A quantitative understanding of charge-symmetry breaking is an increasingly important ingredient for the extraction of the nucleon's strange vector form factors. We review the theoretical understanding of the charge-symmetry-breaking form factors, both for single nucleons and for Helium-4.
Nucleon Charge Symmetry Breaking and Parity Violating Electron-Proton Scattering
研究了上夸克和下夸克质量差的电荷对称性破缺效应和电磁效应对寻找宇称破坏电子与质子散射中奇异形状因子的影响。必要的形式主义，以确定和计算相关的可观的发展分离的哈密顿量成电荷对称性守恒和破缺条款。利用一组SU（6）非相对论性夸克模型，考虑了电荷对称破缺哈密顿量对实验相关动量转移值的影响，发现其影响小于1%。电荷对称性破缺修正Bjorken求和规则也进行了研究，并示出消失在一阶微扰理论。
The effects of charge symmetry breaking in nucleon electromagnetic form factors on parity- violating elastic electron-12C scattering is studied, and found to be much smaller than other known effects. The analysis of a planned experiment is discussed.
A formalism for the study of charge symmetry breaking (CSB) effects is discussed and used to analyze the effects of charge symmetry breaking on neutron beta decay. The effect of including CSB reduces the beta decay matrix element by an amount on the order of $10^{-4}$, a value much larger than the previous estimate. A much smaller contribution due to proton recoil is treated as well, which is found to be on the order of $10^{-6}$. The current uncertainty in the value of $V_{ud}$ is also of order $10^{-4}$. An improvement of that uncertainty by an order of magnitude would require that charge sy…
Charge Symmetry Breaking in Pion-Nucleon Coupling Constants Induced by Axial Anomaly
在QCD真空的瞬子模型下，计算了轴反常对π-核子耦合常数电荷对称性破缺的贡献。它已被证明，贡献是大的，并允许解释诺伦-希弗异常。
Charge symmetry breaking contributions to the proton's neutral weak form factors must be understood in order for future measurements of parity violating electron-proton scattering to be definitively interpreted as evidence of proton strangeness. We calculate these charge symmetry breaking form factor contributions using chiral perturbation theory with resonance saturation estimates for unknown low-energy constants. The uncertainty of the leading-order resonance saturation estimates is reduced by incorporating nuclear physics constraints. Higher-order contributions are investigated through phen…
Charge Symmetry Breaking and QCD
在强相互作用中，由于上夸克和下夸克的质量不同，会发生电荷对称性破缺。有效场论的使用使我们能够在强子和核系统中追踪禁闭夸克的这种影响。本文综述了CSB的观测和认识进展，特别是最近在涉及单个中性π介子产生的测量中对CSB的成功观测以及相关的理论进展。
The basic facts of charge symmetry breaking (CSB) phenomena are reviewed. The relevance of CSB to parity-violating electron-proton scattering experiments that seek to extract strange elastic form factors is discussed. Experimentalists have stated and written that the current uncertainty in our knowledge of CSB limits the ability to push further on the strange form factors. I discuss recent calculations using relativistic chiral perturbation theory and realistic values of strong coupling constants which show that the uncertainties due to lack of knowledge of CSB are at least ten times smaller t…
$K^- d\rightarrow πΛN$ reaction for studying charge symmetry breaking in the $ΛN$ interaction
提出利用停止 K 介子引发的两个同位旋对称 $K^-d$ 反应，通过微分截面比值研究低能 ΛN 相互作用中的电荷对称性破缺。
Charge symmetry breaking in mirror nuclei from quarks
用夸克-介子耦合模型计算了镜像核$^{15}$ O - $^{15}$ N，$^{17}$ F - $^{17}$ O，$^{39}$ Ca -$^{39}$ K和$^{41}$ Sc - $^{41}$ Ca的价质子和中子的结合能差.计算中明确地考虑了原子核结构和壳层效应。结果表明，几百keV的结合能差异产生的强相互作用，即使减去所有的电磁修正。这些差异的来源可能是由于电荷对称性破缺效应通过u和d流夸克质量差而设置在强相互作用中。
Matter induced charge symmetry breaking and pion form factor in nuclear medium
在非对称核物质中，评价了π介子形状因子的介质修正。结果表明，在$ω$-$ρ$混合的情况下，致密非对称核物质中的π介子形状因子的形状和极位都不同于真空中的π介子.这是由于依赖于密度和不对称性的$ρ$ - $ω$混合，其甚至可以在物质中超过其真空对应物。介质中π因子对实验观测量{ \it e.g.}的影响，证明了轻子对的质量分布不变。
Charge Symmetry Breaking in the Valence Quark Distributions of the Nucleon
利用夸克模型研究了电荷对称性破缺对核子价夸克分布的影响。由于夸克质量差和库仑相互作用的带电夸克的影响进行了计算，并在最近的索赔相比，发现是小的。此外，我们还研究了电荷对称性破缺在约束相互作用中的作用，以及在将夸克模型分布与实验联系起来的微扰演化方程中的作用。我们发现，这两种影响都很小，并在标量约束相互作用中包含的强电荷对称性破缺效应可能是从夸克质量差产生的区别。
Possible inconsistency between phenomenological and theoretical determinations of charge symmetry breaking in nuclear energy density functionals
本文总结了核能量密度泛函中电荷对称破缺项的最新确定进展，指出理论确定强度显著小于现象学确定强度，该不一致性仍是未解问题。
We study the interplay between charge symmetry breaking and renormalization in the NN system for s-waves. We find a set of universality relations which disentangle explicitly the known long distance dynamics from low energy parameters and extend them to the Coulomb case. We analyze within such an approach the One-Boson-Exchange potential and the theoretical conditions which allow to relate the proton-neutron, proton-proton and neutron-neutron scattering observables without the introduction of extra new parameters and providing good phenomenological success.
Recent experimental results for neutron-neutron scattering length are reanalyzed from the point of view of three-nucleon force contribution. We found that the limiting value of $a_{nn}=- 15.8\pm 0.5$~fm must be free of any implicit three-body force contribution. We have also shown that the difference between the above experimental value of $a_{nn}$ and the well established value of neutron-proton scattering length $a_{np}$ can be explained by differences in the one-pion exchange potentials.
Isospin-symmetry breaking in kaon production: the role of charge-symmetry
本文探讨了电荷对称性在同位旋精确极限下对产生等量带电与中性K介子的作用，以解释NA61/SHINE合作组报告的带电K介子相对中性的超出。
Isospin Breaking in the Nucleon Isovector Axial Charge from QCD Sum Rules
用外场QCD求和规则方法计算了核子轴向等矢量荷$g_A^3$中的同位旋破缺。由于上下流夸克质量和上下流夸克凝聚的不同而引起的同位旋破坏也包括在内，电磁效应不考虑。我们找到了$δg^3_A/g^3_A \approx (0.5-1.0)\times 10^{-2}$，其中$δg^3_A = (g^3_A)_p + (g^3_A)_n$和$ g^3_A = [(g^3_A)_p - (g^3_A)_n]/2$。利用Goldberger-Treiman关系，我们还得到了π-核子耦合常数$(g_{ppπ_0}-g_{nnπ_0})/g_{NNπ} \approx (2-7) \times 10^{-3}$中同位旋破缺的估计.
We investigate the effects of charge independence and charge symmetry breaking in neutron-rich matter. We consider neutron and proton properties in isospin-asymmetric matter at normal densities as well as the high-density neutron matter equation of state and the bulk properties of neutron stars. We find charge symmetry and charge independence breaking effects to be very small.
Charge-Symmetry-Breaking Potentials from Isospin-Violating Meson-Baryon Coupling Constants
我们考虑了由介子-重子耦合常数的同位旋破坏引起的核子-核子力中的电荷对称性破坏。矢量介子被假定为耦合到核子的电磁流，我们分解成等夸克和等矢量夸克分量。我们计算这些电流的上下文中的组成夸克模型。介子-重子耦合中的同位旋破坏是由上下夸克质量的差异引起的。我们发现，IV类电荷对称性破缺电位产生的$ω$和$ρ$交换贡献的$NN$力。这些贡献的大小是一致的，在183兆电子伏的弹性$\vec{n}-\vec{p}$散射的$n$和$p$分析功率的测量差异所需的现象。
Charge independence breaking and charge symmetry breaking in the nucleon-nucleon interaction from effective field theory
用有效场论方法讨论了少核子系统的电荷对称性和电荷独立性破缺。在理论中，我们系统地介绍了强同位旋破坏算符和电磁算符。在核子-核子散射长度中观察到的电荷依赖性是由于一个π介子交换和一个电磁四核子接触项。这给出了相应的有效射程的电荷依赖性的无参数表达式，这与相当小的和不确定的经验测定是一致的。我们还比较了$nn$和$np$系统的低能相移。
We perform a complete calculation of charge symmetry breaking effects for the reaction pn -> d pi0 at leading order in chiral perturbation theory. A new leading-order operator is included. From our analysis we extract δm_N^{str}, the strong contribution to the neutron-proton mass difference. The value obtained, δm_N^{str} = 1.5 \pm 0.8 (exp.) \pm 0.5 (th.) MeV, is consistent with the result based on the Cottingham sum rule. This agreement provides a non-trivial test of our current understanding of the chiral structure of QCD.
Rho-Omega Mixing Off Shell and Charge Symmetry Breaking In the N-N Potential
讨论了电荷对称性破缺核子-核子势中$ρ-ω$混合的离壳依赖性的作用。结果表明，描述$ρ-ω$混合的离壳层依赖性的模型不足以确定电荷对称性破缺核子-核子势。
Charge-Symmetry Breaking and the Two-Pion-Exchange Two-Nucleon Interaction
在有效场论中，利用基于幂次参数的同位旋破坏相互作用分类，研究了核子-核子力中的电荷对称性破缺。讨论了功率计数中前两级对应的电荷对称性破缺相互作用及其对~ 3 He-~ 3 H结合能差的影响。利用手征微扰理论构造了与核子质量差成线性关系的静态电荷对称性破缺势。给出了动量空间和位形空间的显式公式。本文的工作是对前人研究成果的补充。
I review the effects of charge symmetry breaking CSB on electromagnetic form factors and how that influences extraction of information regarding nucleon strangeness content and the weak mixing angle. It seems that CSB effects are very modest and should not impact the analysis of experiments.
We present a determination, from lattice QCD, of charge symmetry violation in the spin- independent and spin-dependent parton distribution functions of the nucleon. This is done by chirally extrapolating recent QCDSF/UKQCD Collaboration lattice simulations of the first several Mellin moments of the parton distribution functions of octet baryons to the physical point. We find small chiral corrections for the polarized moments, while the corrections are quantitatively significant in the unpolarized case.
Charge-Symmetry-Breaking Three-Nucleon Forces
用手征微扰理论计算了违反同位旋对称性的首阶三核子力。利用Faddeev方法研究了三核子系统中电荷对称性破缺的三核子力的作用。我们发现，这个力的贡献的3 He-3 H结合能差约为5 keV。
We show that using parameters consistent with the charge symmetry violating difference between the strong nn and pp scattering lengths provides significant constraints on the amplitude for the dd -> alpha pi0 reaction.
Breaking of Charge Independence of Nucleon-Nucleon Interaction and Bulk Properties of Nuclear Matter
研究了核子-核子相互作用的电荷无关破缺对核物质体性质的影响。我们的研究结果表明，在高密度下，核子-核子势中包含的电荷依赖性影响了核物质的整体性质。然而，在低密度下，这种影响并不显著。可以看出，由于电荷独立性的破坏，我们的核物质计算结果的变化随着密度的增加而增加。结果表明，考虑核子-核子相互作用中的电荷依赖性，$^1S_0$沟道的能量贡献是敏感的。结果表明，电荷无关性破缺对计算的核物质物态方程的影响是可以忽略的。
Effective field theory contribution to charge symmetry breaking NN scattering
利用有效场论，在低能弹性NN散射中考虑了同位旋破缺π介子s波再散射的影响。虽然这种机制在np -> d π 0中对电荷对称性破缺有很大贡献，但在pp与nn散射参数和3 H-3 He结合能差中的影响相当小。这种小是由于上下夸克质量差贡献的大抵消和电磁效应对np质量差的影响。
Charge symmetry breaking and the d d -> alpha pi0 reaction -- recent theoretical developments
将介绍计算电荷对称性破缺π介子产生反应的理论工作的现状。主要重点将放在d d -> α π 0反应，特别是与最近的IUCF实验。对今后的理论和实验工作提出了建议。
Charge Symmetry Breaking in 500 MeV Nucleon-Trinucleon Scattering
本文研究了核子与~ 3 He和~ 3 H镜像核的弹性散射，作为电荷对称性破坏的检验。微分截面计算在500 MeV使用microsopic，动量空间光学势，包括两个自旋1/2粒子的完全耦合和精确的治疗的库仑力。研究的电荷对称性破缺效应来自于原子核结构内的破坏，来自于p核的库仑力，以及来自于电荷对称态的质量差。可能揭示可靠信息的测量结果被记录下来。
Charge-Independence Breaking in the Two-Pion-Exchange Nucleon-Nucleon Force
研究了（手征）双π交换核子-核子力中由于π-质量差引起的电荷无关破缺。一个一般的论点对称性的基础上提出的，涉及到的电荷对称的一部分，该部队的质子质子的情况下。作为一个明确的例子，利用费曼图计算出了质量差为线性的静电势，证实了一般的论点。
The asymmetry in the angular distribution of n p --> d pi^0 due to Charge Symmetry Breaking is calculated using Heavy Baryon Chiral Perturbation Theory. Recent developments in power counting have proven successful in describing total cross sections, and we apply them to the asymmetry calculation. Reducibility in one of the leading order diagrams is examined. We compare the updated theory with experimental results for a range of physically reasonable parameters and find over-prediction for the entire range.
Effects of charge symmetry breaking associated with the $u$ and $d$ quark mass difference in the elastic form factors of the pion and kaon are presented. We use a confining version of the Nambu--Jona-Lasinio model. The pion and kaon are described as a dressed quark and antiquark bound states governed by the Bethe-Salpeter equation, and exhibit the properties of Goldstone bosons, with the pion mass difference given by $m_{π^{+}}^2 - m_{π^{0}}^2 \propto (m_u -m_d)^2$ as demanded by dynamical chiral symmetry breaking. We found significant charge symmetry breaking effects for realistic current qua…
The Charge-Symmetry-Breaking (CSB) character of the nucleon-nucleon interaction is well established. This work presents two different ways of introducing such effects into a nuclear Energy Density Functional (EDF). CSB terms are either coming from the effective theory expansion or are derived from electromagnetic mixing of $ρ^0$ and $ω$ mesons. These terms are then introduced to Skyrme and Quark-Meson-Coupling EDFs, respectively.
We propose a new approach to determine the strength of the charge symmetry breaking (CSB) term in the framework of nuclear density functional theory. It is shown that once ab initio calculations are available including accurate description of isospin symmetry breaking terms in medium and heavy nuclei, the mass difference of mirror nuclei as well as the neutron-skin thickness of doubly-closed-shell nuclei can be used to constrain the strength of the CSB interaction with an uncertainty less than $ 6 \, \% $, separately from other isospin symmetry breaking forces. This method opens a new vista of…
We revisit the charge symmetry breaking $(CSB)$ in nucleon-nucleon $(NN)$ interaction caused by $π$-$η$ mixing in nuclear matter $(NM)$ employing one boson exchange $(OBE)$ model. The medium effect on $CSB$ is incorporated through the in-medium $π$ and $η$ propagators. In addition, the medium modification to the nucleon mass is also taken into account to construct the $CSB$ class $III$ potential considering off-shell $π$-$η$ mixing amplitude and large contribution of in-medium meson propagators to $CSB$ potential is found for the pseudoscalar $(PS)$ interaction compared to that of pseudovector…
$ΔI=1$ axial-vector mixing and charge symmetry breaking
表现出手征对称性（破缺）和同位旋破坏的唯象拉格朗日量表明具有$\mbox{\boldmath $ σ $}_1 \!\cdot\!\mbox{\boldmath $ σ $}_2$结构的短程电荷对称性破缺（CSB）核子-核子势。这种结构可以通过轴矢量（$1^+$）介子在单介子交换图中的混合来实现。$ΔI_{z}=1$电荷对称性破缺的Coleman-Schmidt how方案应用于介子和重子$SU(2)$质量分裂，给出了一个普适的标度.这个尺度可以扩展到大小为$-0.005$ GeV的$^2$的$ΔI=1$非奇异CSB跃迁$\langle a_1^\circ|H_{em}|f_1\rangle$。由此产生的核子-核子轴向矢量介子交换CSB势，然后预测$ΔI=1$的影响是小的。
$q^2$-Dependence of Meson Mixing in Few-Body Charge Symmetry Breaking: $π^o-η$ Mixing to One Loop in Chiral Perturbation Theory
指出通常被认为是引起少体电荷对称性破缺的主要原因的介子混合矩阵元在QCD中是自然地依赖于$q^2$的。对于$π^o-η$混合，使用赝标量场的通常表示，可以使用手征微扰理论明确地计算主导的$q^2$依赖于一个循环，结果是在从类时到类空值的$q^2$的矩阵元素的幅度显着减少。由于它是后者的范围内的$q^2$是相关的NN散射和少体束缚态，这一结果调用到严重的问题的标准处理与$π^o-η$和$ρ-ω$混合少体电荷对称性破缺的贡献。
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