Complex dynamics of proton and deuteron transfer in double hydrogen bond of benzoic acid isotopes

This paper deals with spin-lattice relaxation due to classical jumps and incoherent tunnelling of protons and deuterons in hydrogen bonds in solids. An analysis of experimental spin-lattice relaxation data for carboxylic acids suggests that tunnelling does not contribute to spin-lattice relaxation above the temperature at which the thermal energy of molecules and the potential barrier height are equal. It is also shown that contributions to the spin-lattice relaxation rate due to classical motion and incoherent tunnelling in excited vibrational states are negligible for fast proton transfer. However, for deuterons this contribution to spin-lattice relaxation is significant.     

Neutral currents in alternative U3 (W)-gauge models of weak and electromagnetic interactions

Two alternative U₃(W)-gauge models are presented. Both agree with the recent Abbott-Barnett fits to the neutrino-nucleon neutral-current data, and with the SLAC measurement of the asymmetry parameter for longitudinally polarised electrondeuteron inelastic scattering. Results for are also found in agreement with the latest measurements. The models differ in the parameterQ _W(Z, N) characterising parity-violation in heavy atoms for which, however, the experimental situation is still unclear.     

Characterization of Doubly Ionic Hydrogen Bonds in Protic Ionic Liquids by NMR Deuteron Quadrupole Coupling Constants: Differences to H‐bonds in Amides,Peptides, and Proteins

We present the first deuteron quadrupole coupling constants (DQCCs) for selected protic ionic liquids (PILs) measured by solid‐state NMR spectroscopy. The experimental data are supported by dispersion‐corrected density functional theory (DFT‐D3) calculations and molecular dynamics (MD) simulations. The DQCCs of the N−D bond in the triethylammonium cations are the lowest reported for deuterons in PILs, indicating strong hydrogen bonds between ions. The NMR coupling parameters are compared to those in amides, peptides, and proteins. The DQCCs show characteristic behavior with increasing interaction strength of the counterion and variation of the H‐bond motifs. We report the similar presence of the quadrupolar splitting pattern and the narrow liquid line in the NMR spectra over large temperature ranges, indicating the heterogeneous nature of PILs.     

Measurement of PV asymmetry in n＋p→d＋γ and γ＋d→n＋p

The measurement of parity-violating （PV） observables in few-nucleon system can shed light on our current understanding of the weak interaction between nucleons.Theoretical models describe the nucleonnucleon weak interaction at low energies use a series of undetermined parameters.Two parity violating measurements have been considered： the capture of polarized slow neutrons on hydrogen （n ＋ p → d ＋ γ） at Los Alamos National Laboratory for first phase and Oka Ridge National Laboratory for second phase and the helicity dependence of the deuteron photodisintegration cross section using circularly polarized photons （γ ＋ d → n ＋ p） at Shanghai Institute of Applied Physics.The goal of both experiments is to constraint the weak meson-nucleon couplings to a precision of 1 ×10^-8 .The introduction of both experiments is presented.     

An estimate of two-photon exchange effect on deuteron electromagnetic form factors

The effect of the two-photon exchange on the deuteron electromagnetic form factors is estimated based on an effective Lagrangian approach. A numerical estimate calculation of the effect is discussed. In particular, the effect on the polarization observables is analyzed.     

Determination of Deuteron Dipole Moment in Nuclear Quark-Like Model

Using the quark-like model, we have improved the existing deviation between theoretical and experimental values of magnetic dipole moment of deuteron. Based upon Pauli Exclusion Principle, the constituent quarks form a ground state for l = 0. The expectation value of the deuteron magnetic dipole moment operator is determined to be equal to 0.861 597 8μ N in better agreement with the measured value of 0.857 437 6μ N as compared to the shell model calculations.     

Photoproduction of mesons off the deuteron: quasifree and coherent processes

Photoproduction of mesons off the deuteron has been investigated at a tagged photon beam of the Bonn ELSA accelerator with the combined Crystal Barrel - TAPS electromagnetic calorimeter for incident photon energies up to 2.5 GeV. The mesons have been detected in coincidence with recoil protons, neutrons and deuterons. This allow the measurement of meson production reactions off the quasifree nucleons bound in the deutron, as well as the coherent production off the deuteron. The comparison of quasifree proton reactions to free proton reactions can confirm or invalidate possible nuclear effects on the extracted cross section reactions. Furthermore the isospin composition of a resonance can be estimated from the comparison of quasifree proton and neutron reactions. The quasifree photoproduction of the η' and π~°η mesons off nucleons and the coherent photoproduction of π~°η-pairs off the deuteron are discussed.     

不带奇异数的双重子态（英文）

在手征SU（3） 夸克模型下应用共振群方法讨论了三个非奇异的双重子态的性质。计算中的模型参数取自我们以前的工作,拟合核子-核子相互作用散射相移确定下来的。首先,研究了氘核的性质,这是非常重要的,因为氘核是多年来实验上唯一发现的双重子态。氘核属于核子-核子系统,它是自旋为S =1 和同位旋为T =0 的双重子态。我们计算了氘核的结合能、散射长度以及氘核的相对运动波函数,结果表明手征SU（3） 夸克模型可以合理描述氘核的性质并且发现张量力对形成松散束缚态的氘核是重要的。然后,给出了S = 3 和T =0 的ΔΔ双重子态的理论预言结果,这里考虑了分波耦合和隐色道耦合效应,计算了结合能和均方根半径。结果表明,隐色道耦合效应比分波耦合效应大,也就是说隐色道耦合效应在形成（ΔΔ）_ST=30 双重子态中是重要的。我们的理论预言结果在几十个MeV 左右,低于ΔΔ道的阈值但是高于NΔπ的阈值. 出乎意料地,我们的预言结果很接近最近2014 年WASA的实验结果。接着,给出了对S = 0 和T =3 的ΔΔ双重子态性质的最新研究结果,这里在以前的单道计算基础上考虑了隐色道耦合效应。结果表明,隐色道耦合对（ΔΔ）ST=03的结合能也有较大的影响。但是,和（ΔΔ）_ST=30 一样,它的质量低于ΔΔ道的阈值但是高于NΔπ的阈值。最后,对S = 3 以及S = 0 两个不同ΔΔ自旋态,详细比较了两者结构之间的差异。结果表明,σ'介子交换和OGE 交换对自旋S = 0 和S = 1 态提供的吸引作用分别是主要的,从而导致耦合道计算中系统的结合能变大。In the present work we discuss three dibaryons without strangeness in the chiral SU(3) quark model by solving the resonating group method (RGM) equation. In the calculation, the model parameters are taken from our previous work in which the nucleon-nucleon (NN) scattering phase shifts are fitted quite well. Firstly, the structure of deuteron is discussed, which is very important since it is the first dibaryon confirmed by experiment in the past many years. Deuteron belongs to NN system with spin S =1 and isospin T =0, the binding energy, scattering length and the relative wave functions of deuteron are discussed. The results show that the chiral SU(3) quark model describes the properties of deuteron quite well and tensor interaction is important in forming the deuteron loosely bound. Secondly, the predicted results of ΔΔ dibaryon with S =3 and T =0 are shown, the resultant binding energy and size of root-mean-square (RMS) of six quarks are calculated by including the L coupling and hidden color channel (CC) coupling. The results show that the CC coupling effect is much larger than the L mixing effect, which means that CC coupling plays an important role in forming the spin S =3 ΔΔ dibayon state. Our predicted binding energy is several tens MeV, it is lower than the threshold of the ΔΔ channel and higher than the mass of NΔπ. Unexpectedly, our predicted mass is quite close to the recent confirmation by WASA experiments in 2014. Thirdly, we present our new results of ΔΔ dibaryon with S = 0 and T =3, obtained recently by extending the single-channel calculation to including the CC coupling. It is seen that the CC coupling also has a relatively large effect on (ΔΔ)ST=03 state. However, its mass is still lower than the threshold of the ΔΔ channel and higher than the mass of NΔπ, similar as that of (ΔΔ)_ST=30 state. Finally, we further make some comparisons between S = 3 and S = 0 ΔΔ states to show the difference of the two dibaryons. The results show that the attractive interactions from σ' meson and OGE exchanges are dominantly important for S =0 and S =3 states, respectively, so their binding energies all become larger in coupled-channel calculation.     

Radiation effect of neutrons produced by D–D side reactions on a D–3He fusion reactor

One of the most important characteristics in D–³He fusion reactors is neutron production via D–D side reactions. The neutrons can activate structural material, degrading them and ultimately converting them into high-level radioactive waste, while it is really costly and difficult to remove them. The neutrons from a fusion reactor could also be used to make weapons-grade nuclear material, rendering such types of fusion reactors a serious proliferation hazard. A related problem is the presence of radioactive elements such as tritium in D–³He plasma, either as fuel for or as products of the nuclear reactions; substantial quantities of radioactive elements would not only pose a general health risk, but tritium in particular would also be another proliferation hazard. The problems of neutron radiation and radioactive element production are especially interconnected because both would result from the D–D side reaction. Therefore, the presentation approach for reducing neutrons via D–D nuclear side reactions in a D–³He fusion reactor is very important. For doing this research, energy losses and neutron power fraction in D–³He fusion reactors are investigated. Calculations show neutrons produced by the D–D nuclear side reaction could be reduced by changing to a more ³He-rich fuel mixture, but then the bremsstrahlung power loss fraction would increase in the D–³He fusion reactor.     

Study of Charged Pion Photoproduction on Deuteron with Tagged Photons

The reactions γd→π~- pp and γd→npπ~+π~- have been studied in an energy range from 0.8 to 1.1 GeV at the tagged photon facility of Laboratory of Nuclear Science,T ohoku University.Charged pions and protons in the final state were measured by using the Neutral Kaon Spectrometer (NKS2).The analysis of the γd→π~- pp was mainly used to check the acceptance of the NKS2 and to calibrate the tagged photon energy.The photoproduction of the Δ~(++)Δ~- was identified in the γd→npπ~+π~- reaction.Since the data analyses are still in progress,we issue an interim report and preliminary results.