Rare kaon decay $$K^ + \to \pi ^ + \nu \bar \nu $$ in S U(3)C ⊗ S U(3)L ⊗ U(1)N models

The rare kaon decay \(K^ + \to \pi ^ + \nu \bar \nu \) is considered in the framework of models based on the SU(3) _C ? SU(3) _L ? U(1) _N (3-3-1) gauge group. In the 3-3-1 model with right-handed neutrinos, the lower bound of the Z’ mass is derived at 3 TeV, and that in the minimal version, at 1.7 TeV.     

C (2) N+1 Ruijsenaars–Schneider Models

We define the notion of C ⁽²⁾ _N+1Ruijsenaars–Schneider models and construct their Lax formulation. They are obtained by a particular folding of the A _2N+1 systems. Their commuting Hamiltonians are linear combinations of Koornwinder–van Diejen external fields Ruijsenaars–Schneider models, for specific values of the exponential one-body couplings but with the most general two double-poles structure as opposed to the formerly studied BC _N case. Extensions to the elliptic potentials are briefly discussed.     

Experimental test of the PCAC hypothesis in the reactionsv μ p→ μ− pπ+ and \bar v_\mu p \to \mu ^ + p\pi ^ - in theΔ(1232) region

Data on the reactionsv _μ p→ μ^? pπ⁺ and \( \bar v_\mu p \to \mu ^ + p\pi ^ - \) in the Δ(1232) region are presented and a test of the PCAC hypothesis, using a modified version of the Adler model, is performed. The analysis is based on 1081 events in the neutrino and on 180 events in the antineutrino reaction, obtained in a bubble chamber experiment with BEBC at CERN. The experimental cross-sections for an invariant hadronic massW<1.4 GeV and an (anti-)neutrino energyE _v ^L >10 GeV are determined to be (0.628±0.059)·10^?38 cm² for the neutrino and (0.168±0.023)·10^?38 cm² for the antineutrino reaction. TheQ ² andW distributions, the density matrix elements of the Δ resonance, and moments of the pion angular distribution are discussed. The data are found to be in good agreement with the Adler model in theQ ² region below 1 GeV². A maximum likelihood fit for the axial massm _A in the axial-vector form factor yields a value ofm _A =1.31±0.12 GeV. At lowQ ² the data confirm the PCAC hypothesis and the discrepancy, formerly observed between the experimental and theoretical cross-sections forv _μ p→ μ^? pπ⁺ at low momentum transfers (Q ²?0.2 GeV²), is understood as being due to inadequate pion ‘off-mass-shell’ corrections.     

Predictions for $$\Xi _b^- \rightarrow \pi ^- (D_s^- ) \ \Xi _c^0 (2790) \left( \Xi _c^0 (2815) \right) $$ and $$\Xi _b^- \rightarrow \bar{\nu }_l l \ \Xi _c^0 (2790) \left( \Xi _c^0 (2815) \right) $$Ξb-→ν¯llΞc0(2790)Ξc0(2815)

We have performed calculations for the nonleptonic \(\Xi _b^- \rightarrow \pi ^- \ \Xi _c^0 (2790) \left( J=\frac{1}{2}\right) \) and \(\Xi _b^- \rightarrow \pi ^- \ \Xi _c^0 (2815) \left( J=\frac{3}{2}\right) \) decays and the same reactions replacing the \(\pi ^-\) by a \(D_s^-\). At the same time we have also evaluated the semileptonic rates for \(\Xi _b^- \rightarrow \bar{\nu }_l l \ \Xi _c^0 (2790)\) and \(\Xi _b^- \rightarrow \bar{\nu }_l l \ \Xi _c^0 (2815)\). We look at the reactions from the perspective that the \(\Xi _c^0 (2790)\) and \(\Xi _c^0 (2815)\) resonances are dynamically generated from the pseudoscalar–baryon and vector–baryon interactions. We evaluate ratios of the rates of these reactions and make predictions that can be tested in future experiments. We also find that the results are rather sensitive to the coupling of the \(\Xi _c^*\) resonances to the \(D^* \Sigma \) and \(D^* \Lambda \) components.     

Analysis of the vertexes \Xi_{Q}^{*}′QV , \Sigma_{Q}^{*} \Sigma_{Q}^{}V and radiative decays \Xi_{Q}^{*} \rightarrow ′Q \gamma , \Sigma_{Q}^{*} \rightarrow \Sigma_{Q}^{} \gamma

In this article, we study the vertexes $ \Xi_{Q}^{*}$ ′_Q V and $ \Sigma_{Q}^{*}$ $ \Sigma_{Q}^{}$ V with the light-cone QCD sum rules, then assume the vector meson dominance of the intermediate $ \phi$ (1020) , $ \rho$ (770) and $ \omega$ (782) , and calculate the radiative decays $ \Xi_{Q}^{*}$ $ \rightarrow$ ′_Q $ \gamma$ and $ \Sigma_{Q}^{*}$ $ \rightarrow$ $ \Sigma_{Q}^{}$ $ \gamma$ .     

$$\Lambda _b \rightarrow \pi ^- (D_s^-) \Lambda _c(2595),~\pi ^- (D_s^-) \Lambda _c(2625)$$ decays and $$DN,~D^*N$$DN,D∗N molecular components

From the perspective that \(\Lambda _c(2595)\) and \(\Lambda _c(2625)\) are dynamically generated resonances from the \(DN,~D^*N\) interaction and coupled channels, we have evaluated the rates for \(\Lambda _b \rightarrow \pi ^- \Lambda _c(2595)\) and \(\Lambda _b \rightarrow \pi ^- \Lambda _c(2625)\) up to a global unknown factor that allows us to calculate the ratio of rates and compare with experiment, where good agreement is found. Similarly, we can also make predictions for the ratio of rates of the, yet unknown, decays of \(\Lambda _b \rightarrow D_s^- \Lambda _c(2595)\) and \(\Lambda _b \rightarrow D_s^- \Lambda _c(2625)\) and make estimates for their individual branching fractions.     

Energy dependence of e + e − → 6π and e + e − → N\bar N cross sections near N\bar N the threshold

Using recent BABAR, CMD-3 and SND data, the sum of e ⁺ e ^? → 3(π⁺π^?), 2(π⁺π^?π⁰), \(p\bar p\) , \(n\bar n\) cross sections is obtained. Unlike e ⁺ e ^? 3(π⁺π^?) and e ⁺ e ^? → 2(π⁺π^?π⁰) processes, no structures in total cross section are found near the \(N\bar N\) threshold within the limits of measurement errors.     

$$f_0(500)$$, $$f_0(980)$$f0(980), and $$a_0(980)$$a0(980) production in the $$\chi _{c1} \rightarrow \eta \pi ^+\pi ^-$$χc1→ηπ+π- reaction

We study the \(\chi _{c1} \rightarrow \eta \pi ^+ \pi ^-\) decay, paying attention to the production of \(f_0(500)\), \(f_0(980)\), and \(a_0(980)\) from the final state interaction of pairs of mesons that can lead to these three mesons in the final state, which is implemented using the chiral unitary approach. Very clean and strong signals are obtained for the \(a_0(980)\) excitation in the \(\eta \pi \) invariant mass distribution and for the \(f_0(500)\) in the \(\pi ^+ \pi ^-\) mass distribution. A smaller, but also clear signal for the \(f_0(980)\) excitation is obtained. The results are contrasted with experimental data and the agreement found is good, providing yet one more test in support of the picture where these resonances are dynamically generated from the meson–meson interaction.     

~(12)C+~(159)Tb,~(12)C+~(165)Ho熔合截面的测量

我们测量了库仑位垒附近~(12)C+~(159)Tb、~(12)C+~(165)Ho反应的熔合截面.实验中用Si(Li)X射线谱仪离线测量了蒸发余核的特征K-x射线能谱,从而得到了蒸发余核的半寿命及其蒸发余核生成分支比.最后获得了熔合截面,并与理论计算值进行了比较.     

三种N湮没势和+~(12)C非弹性散射

在Glauber多重散射理论框架下 ,使用跃迁密度方法和 3种 NN湮没势 ,计算了入射动量为6 0 0MeV c的反质子在12 C上的非弹性散射微分截面 .理论曲线与实验数据符合得甚好     

One-pot synthesis of $$\upgamma $$-spiroiminolactones and $$\upgamma $$-dispiroiminolactones using $$\textit{N}{,}{} \textit{N}^{\prime }$$N,N′-disubstituted parabanic acid and thioparabanic acid derivatives

A direct entry and simple process for the synthesis of \(\upgamma \)-spiroiminolactones present in a large number of natural products has been developed. In the first step, the synthesis of parabanic acid derivatives was commenced from the reaction of \(\textit{N}{,}{} \textit{N}^{\prime }\)-disubstituted urea and thiourea with oxalyl chloride, then a three-component reaction was carried out with isocyanides, acetylenic esters, and \(\textit{N}{,}{} \textit{N}^{\prime }\)-disubstituted parabanic acid derivatives. The method allows the construction of a variety of \(\upgamma \)-spiroiminolactone structures in good to high yields starting from readily available precursors. It was found that in the case of \(\textit{N}{,}{} \textit{N}^{\prime }\)-diphenyl thioparabanic acid, additional products of \(\upgamma \)-dispiroiminolactones have been formed due to the higher electrophilicity of \(\upalpha \)-dicarbonyl groups. The structures were fully established using spectroscopic analysis NMR, IR, and Mass spectrometry. The crystal structure of \(\upgamma \)-dispiroiminolactone was confirmed from single-crystal X-ray diffraction study.     

The twisted SU(N) group. On the C *-algebra C(S μ U(N))

It is proved that C(S U(N)) is a type I C ^*-algebra.     

A fresh look at η 2(1645), η 2(1870), η 2(2030) and f 2(1910) in \bar{p}p \to \eta \pi ^{0}\pi ^{0}\pi ^{0}

There is a large discrepancy between results of Crystal Barrel and WA102 for the branching ratio R=BR[η ₂(1870)→a ₂(1320)π]/BR[η ₂(1870)→f ₂(1270)η]. An extensive re-analysis of the Crystal Barrel data redetermines branching ratios for decays of η ₂(1870), η ₂(1645), η ₂(2030) and f ₂(1910). This re-analysis confirms a small value for R of 1.60±0.39, inconsistent with the value 20.4±6.6 of WA102. The likely origin of the discrepancy is that the WA102 data contain a strong f ₂(1910)→a ₂ π signal as well as η ₂(1870). There is strong evidence that the η ₂(1870) has resonant phase variation. A peak in f ₂(1270)a ₀(980) confirms closely the parameters of the a ₂(2255) resonance observed previously. A peak in η ₂(2030)π is interpreted naturally in terms of π ₂(2245) with reduced errors for mass and width M=2285±20(stat)±25(syst) MeV, Γ=250±20(stat)±25(syst) MeV.     

Ξ Resonances in Ξ− Be interactions II. Properties of Ξ(1820) and Ξ(1960) in the\Lambda \bar K^0 and\Sigma ^0 \bar K^0 channels

In an experiment at the CERN-SPS charged hyperon beam, we have investigated the inclusive \(\Lambda \bar K^0 \) and \(\Sigma ^0 \bar K^0 \) final states formed in Ξ^? Be interactions. In the \(\Lambda \bar K^0 \) channel, we observe a signal at 1826 MeV/c² which can be identified with the known Ξ(1820) resonance. We determine its mass and width to be:M=1826±4 MeV/c², Г=12±14 MeV/c². A moment analysis is consistent with a spin of 3/2 and indicates a negative parity for this spin assignment. Also in the \(\Lambda \bar K^0 \) channel, we observe a 3.6σ signal with the following parameters:M=1963±5 MeV/c², Г=25±15 MeV/c². This state, which we call Ξ(1960), is not observed in the \(\Sigma ^0 \bar K^0 \) channel, leading to an upper limit on the ratio of partial widths \(\Sigma \bar K/\Lambda \bar K\) of 2.3 (90% confidence level). A moment analysis of the \(\Lambda \bar K^0 \) final state indicates a spin of 5/2 or greater in the natural spin-parity series 5/2⁺, 7/2^?, etc.     

Extracting angular correlations from the rare decay \bar Bd \to \bar K*^0 μ + μ − at LHCb

$ \bar Bd \to \bar K*^0 $ μ ⁺ μ ^? is a rare flavor-changing neutral-current decay. It proceeds via a b → s quark transition and is sensitive to many classes of new physics model. In this article the theoretical framework relevant to making a measurement at LHCb, the precision flavor experiment at the Large Hadron Collider, will be introduced. Progress made towards using a full angular analysis to extract A _FB, the forward-backward asymmetry of the μ pair, will be covered and its implications for the precision of the A _FB zero-crossing-point measurement discussed.     

Lepton-flavor-violating pion decay π+→μ−νμ e + e + and SU(3)C ⊗ SU(3)L ⊗ U(1)N model

Within the minimal SU(3)_C ? SU(3)_L ? U(1)_N model, the lepton-flavor-violating decay π⁺→μ^?ν_μ e ⁺ e ⁺ is calculated without directly invoking lepton mixing. The branching ratio for this rare pion-decay mode is found to be much smaller than the current experimental upper limit. If the anomalous interactions are discarded, this result coincides with the result of the previous calculation.     

Experimental determination of the branching ratiosp\bar p \to 2\pi ^0 ,\pi ^0 \gamma,and 2γ at rest

The branching ratios of \(p\bar p\) annihilations into the neutral final states 2π⁰, π⁰γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are \(B_{2\pi ^0 } = \left( {2.06 \pm 0.14} \right) \times 10^{ - 4} \) , \(B_{\pi ^0 \gamma } = \left( {1.74 \pm 0.22} \right) \times 10^{ - 5} \) , andB _γγ<1.7×10^?6 (95% c.l.).     

Symplectic three-algebra and \mathcal{N}=6, Sp(2N)×U(1) superconformal Chern–Simons-matter theory

We introduce an antisymmetric metric into a 3-algebra and call it a symplectic 3-algebra. The $\mathcal{N}=6$ , Sp(2N)×U(1) superconformal Chern–Simons-matter theory with SU(4) R-symmetry in three dimensions is constructed by specifying the 3-brackets in a symplectic 3-algebra. We also demonstrate that the $\mathcal{N}=6$ , U(M)×U(N) theory can be recast into this symplectic 3-algebraic framework.     

Determination of the ~(12)C(p, γ)~(13)N reaction rates fromthe ~(12)C(~7Li,~6He)~(13)N reaction

The angular distribution of the 12C(7Li,6He)13N reaction at E(7Li) = 44.0 MeV was measured at the HI-13 tandem accelerator of Beijing, China. The asymptotic normalization coefficient (ANC) of 13N → 12C + p was derived to be (1.64 ± 0.11) fm-1/2 through the distorted wave Born approximation (DWBA) analysis. The ANC was then used to deduce the astrophysical S (E) factors and reaction rates for the 12C(p,γ)13N direct capture reaction at energies of astrophysical relevance.