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.     

AnSO(10) model withSU(3)⊗SU(2) L ⊗SU(2) R ⊗U(1) B-L ⊗D intermediate symmetry

We construct aSO(10) model with intermediate symmetry $$SU(3) \otimes SU(2)_L \otimes SU(2)_R \otimes U(1)_{B - L} \otimes D$$ and baryon and lepton number conserved between the two highest scales. The experimental values of sin²θ _w and α _s are consistent with the lower bound on τp→e ⁺+π⁰ and with a mass value forv _τ around 1 eV.     

Family unification inSU(6) L ⊗U(1) Y

Electroweak and horizontal interactions are unified with the groupSU(6) _L U(1) _Y for three generations. The horizontal gauge group suggested from low energy phenomenology isSU(2) _H . This model does not contain exotic quarks, but exotic leptons are needed in order to make it anomaly-free. The breaking of the symmetry gives, in a natural way, heavy masses for exotic leptons and a BCS mass matrix for the up quarks, which implies that at tree level only the top quark gets a mass of orderM _W . The see-saw mechanism generates tiny masses for the three known neutrinos. The remaining of the known fermion masses are light, because they can be generated only as radiative corrections.     

Green function renormalization in SU(2)L ⊗ U(1) four-fermion model

Using the Dyson-Schwinger equation, the four-fermion Green functions in one-loop approximation to the SU(2)_L U(1) four-fermion model are found, as well as corrections to them. An expression is obtained for the collective field propagator in the one-loop approximation, and its regularization is performed. In the model under consideration, collective excitations are identified with a massless Goldstone field and a massive scalar field. It is shown that as a result of the reconstruction of the vacuum, one fermion (the analog of the neutrino) is massless, while the other (the analog of the electron), massive.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 19–23, January, 1984.     

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.     

Manifestation of a singlet heavy up-type quark in the branching ratios of rare decays K → πν \bar \nu , B → πν \bar \nu , and B → Kν \bar \nu

The implications of the model with a SU(2)-singlet up-type quark, heavy enough not to be produced at the LHC, namely, the contribution of the new quark to the branching ratios of the K → πν $ \bar \nu $ , B → πν $ \bar \nu $ , and B → Kν $ \bar \nu $ decays are investigated. It is shown that the deviation from the Standard Model can be up to 10% in the case of a 5-TeV quark. Precise measurements of these branching ratios in future experiments will allow for the observation of the contributions of the new quark or to impose stronger constraints on its mass.     

Tests for heavier gauge bosons in theSP(6) L ⊗U(1) Y model

Small deviations from the standard model may exist in the hadronic and leptonic cross sections at KEK. We explore the possibility that these may be accounted for by the extra gauge bosonsZ andW in theSP(6) _L U(1) _Y model, with its parameters constrained by the LEP data.     

Pion and kaon electromagnetic form factors in a SUL(3) ⊗ SUR(3) effective Lagrangian

A SU(2) effective Lagrangian is extended to a SU _L(3) ⊗SU _R(3) by including the vector and axial vector meson. With this effective Lagrangian, electromagnetic form factors of charged pion and kaon are calculated in both time- and space-like regions. The pseudoscalar meson loops are taken into account. Good agreement with experimental data is obtained for those form factors and charged pseudoscalar meson radii. Decay widths of ρ→ππ and φ→K ⁺ K ^- are also calculated and shown to agree with experimental data very well. Received: 20 December 1999 / Accepted: 12 October 2000     

Line Positions and Intensities in the 2nu(2)/nu(4) Vibrational System of (14)NH(3) near 5-7 µm

Line positions and intensities belonging to the vibrational system 2nu(2)/nu(4) of ammonia (14)NH(3) are measured and analyzed between 1200 and 2200 cm(-1) in order to improve the molecular database. For this, laboratory spectra are obtained at 0.006 and 0.011 cm(-1) unapodized resolution and with 4% precisions for the intensities using Fourier transform spectrometers located at the Kitt Peak National Observatory and the Jet Propulsion Laboratory. The observed data contain transitions of the nu(4) fundamental band near 1626.276(1) and 1627.375(2) cm(-1) (for s and a inversion upper states, respectively) and the 2nu(2) overtone band near 1597.470(3) and 1882.179(5) cm(-1) (for s and a inversion states, respectively). A total of 2345 lines with J' 相似文献   

Search for Θ+(1540) in exclusive proton-induced reaction p + C(N) \to \Theta ^ + \bar \kappa ^0 + C(N) at the energy of 70 GeV

A search for narrow Θ⁺(1540), a candidate for a pentaquark baryon with positive strangeness, has been performed in an exclusive proton-induced reaction $p + C(N) \to \Theta ^ + \bar \kappa ^0 + C(N)$ on carbon nuclei or quasifree nucleons at $E_{beam} = 70GeV(\sqrt s = 11.5GeV)$ studying nK ⁺, pK _S ⁰ , and pK _L ⁰ decay channels of Θ⁺(1540) in four different final states of the $\Theta ^ + \bar K^0 $ system. In order to assess the quality of the identification of the final states with neutron or K _L ⁰ , we reconstructed Λ(1520) → nK _S ⁰ and ? → K _L ⁰ K _S ⁰ decays in the calibration reactions p + C(N) → Λ (1520)K ⁺+C(N) and p+C(N) → p?+C(N). We found no evidence for a narrow pentaquark peak in any of the studied final states and decay channels. Assuming that the production characteristics of the $\Theta ^ + \bar K^0 $ system are not drastically different from those of the Λ(1520)K ⁺ and p? systems, we established upper limits on the cross-section ratios $\sigma (\Theta ^ + \bar K^0 )/\sigma (\Lambda (1520)K^ + ) < 0.02$ and $\sigma (\Theta ^ + \bar K^0 )/\sigma (p\phi ) < 0.15$ at 90% C.L. and a preliminary upper limit for the forward-hemisphere cross section $\sigma (\Theta ^ + \bar K^0 )$ nb/nucleon.     

Inclusion of fermions in the locally SU(2) ⊗ U(1)-invariant model with dynamical symmetry breaking

It is shown that dynamic symmetry breaking in the locally SU(2) U(1)-invariant model with mixed inclusion of fermions in a four-fermion interaction leads to a situation in which one collective scalar field, representing the sum of all generations of fermion-antifermion pairs, acts as the total (one-loop) effective Lagrangian. Mass formulas are found for the scalar field and gauge vector fields. The effective Lagrangian obtained coincides in form with the standard Lagrangian in the Glashow-Weinberg-Salam theory of electroweak interactions.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 41–45, July, 1991.     

Line intensity measurements of methane’s \nu _3-band using a cw-OPO

We report on absolute line strength measurements of P(1), R(0) and R(1) singlet lines in the \(3.3\,\upmu\hbox {m}\,\nu _{3}\) (C–H stretching) band of methane \(^{12}\hbox {CH}_4\) at reference temperature \(T=296\)  K. Line strength measurements are performed at low pressure \((P \le 1\hbox { Torr})\) using direct absorption spectroscopy technique based on a widely tunable continuous-wave singly resonant optical parametric oscillator. The \(1\sigma \) overall accuracy in line strength determinations ranges between 7 and 8 % mostly limited by pressure and frequency measurements. A comparison with previous reported values is made. Our results show good agreement with the HITRAN 2012 database.     

Atomic and Electronic Structure of 3C-SiC(111)-( $$2\sqrt 3 \times 2\sqrt 3 $$ 2 3 × 2 3 )-R30° Surface

Physics of the Solid State - The theoretical studies and ab initio calculations have been carried out for the first time for atomic and electronic structure of four variants of 3C-SiC(111)-(...     

Excited strange mesons and their decays in a chiral U(3)×U(3) Lagrangian

We bosonize the Nambu-Jona-Lasinio quark model with separable nonlocal interactions in order to derive a chiral U(3)×U(3) Lagrangian, containing, besides the usual meson fields, their first radial excitations. The spontaneous breaking of chiral symmetry is governed by the Nambu-Jona-Lasinio gap equation. The first radial excitations of the kaon, K*, and ? are described with the help of two form factors. The decays K*′ → ρK, K*′ → K*π, K*′ → Kπ, ?′ → K*K, ?′ → $\bar KK$ K, K′ → Kρ, K′ → K*π, and K′ → K2π are considered, and a qualitative agreement of our results with the experimental data is found.     

Bicovariant differential calculi on Sμ U(2)

Bicovariant, differential calculi on S U(2) are investigated and the nonexistence of three-dimensional calculus and the uniqueness of 4D_± calculi are proved. Formulae for the external product, external derivative, and classical limit are presented.     

U(1) gauge theory for charged bosonic fields onR×S 3 topology

A model for U(1) gauge theories over a compact Lie group is described usingR×S ³ as background space. A comparison with other results is given. Electrodynamics equations are obtained. Finally, some considerations and observations about gravity onR×S ³ space are presented.     

Eu-Gd区域的破缺U(3)限U(6/12)模型

本文从超对称性破缺的角度讨论了位于典型U(3)限区域的奇A核₆₃Eu^₁₅₃, 在能谱和B(E2)方面得到了一些定量符合的结果.     

A theoretical study of the non-adiabatic charge transfer process Ar2+ (3 P) + He(1 S) → Ar+(2 P) + He+(2 S)

CI calculation with a large basis have been used to calculate the two lowest ³Π adiabatic potential energy curves for the title reaction. These potentials have been transformed to diabatic potentials by employing a recipe based on the CI coefficients. Quantum mechanical close coupling calculations in the diabatic basis have produced total and differential cross sections which are in good agreement with experimental data. Full quantum mechanical and Landau-Zener calculations of the total cross section are in fair agreement with recent experimental measures and by small changes to the diabatic potentials can be brought into essentially exact agreement.