Natural left-right symmetry,atomic parity experiments and asymmetries in high energy e+e− collisions in petra and pep regions

The previously proposed left-right-symmetric SU(2)_L × SU(2)_R × U(1) theory permits one of the two neutral gauge particles N₁ and N₂ to be particularly light (<mW⁺_L) compatible with all neutrin-data and the present atomic parity experiments. Distinguishing features of this theory (with the light mass solution) for e^?e⁺ → μ⁺μ^? and π⁺π^? at PETRA and PEP energies as compared to the SU(2) × U(1) predictions are given.     

Phase portrait ofSU(5) model. II intermediate phasesSU(3)×[U(1)]2 and [SU(2)]2×[U(1)]2

The effective potential of the scalar field in theSU(5) model has extrema with symmetry:SU(5),SU(4)×U(1),SU(3)×SU(2)×U(1),SU(3)×[U(1)]², [SU(2)]²×[U(1)]². In our recent paper it was shown that theSU(4)×U(1) phase as well asSU(3)×SU(2)×U(1) phase were stable at the nonzero temperature in a vast region of parameters. In the present paper it is found that the [SU(2)]²×[U(1)]² symmetric vacuum is unstable and theSU(3)×[U(1)]² symmetric vacuum can be metastable in the certain interval of the temperature. Domains of the three phases:SU(4)×U(1),SU(3)×SU(2)×U(1),SU(3)×[U(1)]²-could co-exist in the early. Universe.     

The Skyrme model with a U*(1) gauged Wess‐Zumino term in a noncommutative spacetime

The Skyrme model is generalized for a noncommutative spacetime with the Weyl‐operators of SU(2) matrices and the corresponding star‐product. The unitary condition and the topological current can be extended to star‐exponential matrices. The Wess‐Zumino term which breaks unphysical symmetries of the Skyrme action is gauged with the U_*(1) group to allow for electromagnetic processes in a noncommutative spacetime. Apart from corrections to the anomalous decay γ→π⁰π⁺π^– in commuting spacetime, the additional anomalous process γ→π⁰π⁰π⁰ is found in the U_*(1) gauged Wess‐Zumino action for a noncommutative spacetime.     

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.     

Evidence that absorption in the π+ π− π− system in nuclear matter is stronger in the JP = 0− than in the JP = 1+ state

In the reaction π^? + A → π⁺π^?π^? + A at 15.1 GeV/c the coherently produced 3π mass spectrum has a broad peak around 1.1 GeV which consists mainly of a J^P = 1⁺ state and of a smaller fraction of 0^-. Comparing the observed dependence of the production of these diffractive states on the atomic weight A of the target nuclei with the optical model, we have studied the absorption of the produced states in nuclear matter. We have found the following values of the absorption cross-sections: σ₂(0^-) = 49_?7⁺⁹ mb and σ₂(1⁺) = 15.8_?1.3^+1.5 mb.     

Multicharged dyonic integrable models

We introduce and study new integrable models (IMs) of A_n⁽¹⁾-nonabelian Toda type which admit U(1)⊗U(1) charged topological solitons. They correspond to the symmetry breaking SU(n+1)→SU(2)⊗SU(2)⊗U(1)ⁿ⁻² and are conjectured to describe charged dyonic domain walls of N=1 SU(n+1) SUSY gauge theory in large n limit. It is shown that this family of relativistic IMs corresponds to the first negative grade q=−1 member of a dyonic hierarchy of generalized cKP type. The explicit relation between the 1-soliton solutions (and the conserved charges as well) of the IMs of grades q=−1 and q=2 is found. The properties of the IMs corresponding to more general symmetry breaking SU(n+1)→SU(2)^⊗p⊗U(1)^n−p as well as IM with global SU(2) symmetries are discussed.     

SU3 comparison of line reversed charge exchange and hyperchange exchange reactions

The recent data at 10.1 GeV/c on the hypercharge reactions π⁺p → K⁺Σ⁺ (1385) and the line reversed processes are compared with the SU₃ related charge exchange processes K⁺n → K^op and K⁺p →K^oΔ⁺⁺ and their line reversed partners in order to study the systematics of line reversal breaking. Allowing for a t- independent SU₃ breaking between charge and hypercharge exchange the data follow the SU₃ relations. We conclude that the line reversal breaking in the hypercharge exchange reactions is in agreement with the breaking in exchange degeneracy (in both flip and non-flip amplitudes) which is observed for the charge exchange processes.     

In-beam studies of203, 205Bi and shell-model features of odd-a bismuth isotopes

States in^{203, 205}Bi are populated using the reaction^{203, 205}Tl(³He,3n). Theπi _13/2 single-proton states and all the members of thev(2 ₁ ⁺ )?π h _9/2 quintuplet are identified in both nuclei. The half-lives of the isomericJ ^π=21/2⁺ states in both isotopes are measured and found to be 90±7 ns and 100±6 ns, and from these values suggestions for the half-lives of the previously reportedJ ^π=25/2⁺ isomers are made. The structures of the multiplets of the formv(Pb)?π h _9/2 are calculated in the framework of the shell model and it is shown that the main features can be derived from theπ?v ^?1 effective interaction. The wave functions of the 4 ₁ ⁺ and 4 ₀ ⁺ states in^{202, 204}pb are deduced indirectly from the calculation in^{203, 205}Bi.     

Deformed states of high spin in42Ca

The⁴²Ca levels at 4,715 and 6,633 keV excitation energy have been investigated using the³⁹ K(α,pγ reaction atE _α=14 and 15 MeV. From particle-γ-ray angular correlations the spin assignmentsJ(4,715)=6, 4 andJ(6,633)=8, 6, 4 have been obtained. Lifetime measurements using the Doppler-shift attenuation method yieldedτ (4,715)=120±46 fs andτ(6,633)=52±21 fs. Both levels have positive parity and decay by enhancedE2 transitions. They are interpreted as theJ ^π=6⁺ and 8⁺ members, respectively, of theK ^π=0⁺ rotational band which has theE _x =1,837, 2,423 and 3,250 keV states as further members. The enhancement of inbandE2 transitions is 50 _?16 ⁺³⁵ W.u. (6→4) and 63 W.u. (8→6) respectively. The intrinsic quadrupole moments which have been derived on the basis of the coexistence model, areQ ₀=1.13?0.16/+0.37b(8→6) andQ ₀=1.36±0.25b(6→4), respectively. TheJ ^π=10⁺ member of the rotational band has possibly been observed as a level at 8,856±5 keV excitation energy.     

Isospin violation in the standard model and the decay F+ → π+π0

The decay F⁺ → π⁺π⁰ can proceed via isospin violating mechanisms similarly to $\text{ψ′ →}\text{J}\text{ψπ}{}^0$. I estimate that π⁰-η-′ mixing together with symmetry breaking in the amplitude lead to Γ(F⁺ → π⁺π⁰)/Γ(F⁺ → π⁺η) = (2.2 ± 0.7) × 10^?3 or (1.0 ± 0.3) × 10^?3, if annihilation processes dominate nonleptonic charmed meson decays. These values correspond to different assumptions for two-meson production in F decays.     

Determination of the radiative widths of the η′ and A2 from two-photon exchange production

From the two-photon exchange processes e⁺e^? → e⁺e^?η' (958) → e⁺e^??⁰γ and e⁺e^? → e⁺e^?A₂ (1310) → e⁺e^?π⁺π^?π⁰ observed using the CELLO detector at PETRA the radiative widths of the η' and A₂ have been determined with the results: Γ_γγ(η') = 5.4 ± 1.0[stat.] ± 0.7[syst.] keV; Γ_γγ(A₂) = 0.59 ± 0.14[stat.] _?0.08^+0.31[syst.] keV.     

Spin-parity analysis of the nπ+ system produced in the reaction π+p → π+π+n at 16GeV/c

A spin-parity analysis of the nπ⁺ system produced in the reaction π⁺p → π⁺π⁺n at 16 MeV/c has shown apart from the mass enhancements associated with the known resonances Δ⁺(1238), N¹(1520) and N¹(1688) there is an enhancement peaked at M(nπ⁺) ? 1.35 GeV, ∑0.2 GeV wide. For masses below M(nπ⁺) ? 1.35 GeV this enhancement is predominantly due to $\text{J}{}^{\mathrm{P}}\text{=}\text{1}\text{2}{}^{\mathrm{?}}$ states, predominate. The presence of $\text{J}{}^{\mathrm{P}}\text{=}\text{1}\text{2}{}^{\mathrm{?}}$ states indicates that the rule ΔP = (?1)^ΔJ is strongly violated in the diffractive process N → Nπ, and hence it cannot be considered a specific characteristic of all diffractive processes.     

Analytical potential energy function for the electronic states 2^∏1/2 and 2^∏3/2 of O^x2 （x=＋1, -1）

The splitting of potential energy levels for ground state X^2∏g of O^x2 （x = ＋1,-1） under spin-orbit coupling （SOC） has been calculated by using the spin-orbit （SO） multi-configuration quasi-degenerate perturbation theory （SO-MCQDPT）. Their Murrell-Sorbie （M S） potential functions are gained, and then the spectroscopic constants for electronic states 2^∏1/2 and 2^∏3/2 are derived from the M S function. The vertical excitation energies for O^x2 （x = ＋1,-1） are v[O2＋1^（2∏3/2→X^2∏1/2）] =195.652cm^-1, and v[O2^-1（2^∏1/2 →X^2∏3/2）] =182.568cm^-1, respectively. All the spectroscopic data for electronic states 2^∏1/2 and 2^∏3/2 are given for the first time.     

Backward production of a spin-parity 1+ Kϱ resonance at 1.28 GeV

A (K_ππ)⁺ mass enhancement is observed in the reactions K^?p → Ξ ?K^o+π⁺π^o? when events with a small (K^? → Ξ^?) four momentum transfer squared are selected. The signal is also visible in the reaction K^?p → Ξ^?π⁺+ neutrals. The enhancement, centered at 1.28 GeV, is seen to decay preferentially into K? with spin-parity J^P = 1⁺. The cross section for K^?p→ Ξ^?C⁺(1.28) with C⁺ → K? at 4.15 GeV/c incident K^? momentum is (6.2 ± 0.6) μb.     

Signals of new gauge bosons at futuree + e − colliders

We analyze possible indirect signals of additional neutral gauge bosons at futuree ⁺ e ^? colliders, concentrating onSU(2) _L ×U(1) _y ×U(1) _y , andSU(2) _L ×SU(2) _R ×U(1) effective theories. We develop a simple formalism to describe these effects and make a careful study of radiative corrections, in particular initial state radiation, which will be shown to have important implications. To make realistic estimates of the sensitivity to the new gauge boson effects, we use a model detector fore ⁺ e ^? annihilation at a center of mass energy of 500 GeV. Using a number of selected physical observables we then show that masses considerably higher than the total energy (up to a factor of 6) can be probed and that distinction between various theoretical models is possible.     

A supersymmetricSU(5)×U(1) model with natural gauge hierarchy

We present a supersymmetricSU(5)×U(1) model. This model has the following features. The gauge hierarchy is naturally generated by the quadratically divergent nature of the Fayet-IliopoulosD term. TheSU(5)×U(1) gauge symmetry breaks uniquely intoSU(3) _W ×SU(2) _c ×U(1) _y at an energy scale of 10^17–18GeV. The non-vanishing vacuum expectation value of an auxiliary field component ofU(1) gauge vector multiplet induces the breaking ofSU(2) _W ×U(1) _y . It gives a mass of 10^2–3GeV to scalar quarks and scalar leptons at the tree level. The renormalization group analysis shows that the color fine structure constant α _C (M _W ) becomes somewhat small and the Weinberg angle sin²θ _W (M _W ) somewhat too large in a simple version of the model.     

A measurement of the lifetime of the Λ3 H hypernucleus

The mean lifetime of the hypernucleus _Λ³H has been measured in a helium bubble chamber with the result, τ(_Λ³H)=(2.46_?0.41^+0.62)×10^?10 sec, based on 16 examples of the decay mode _Λ³H→π^?+³He and 24 examples of the decay mode _Λ³H→π^?+p+d. The decay branching ratio R₃ = Γ(_Λ³H → π^?+^{3He)/Γ(_Λ3H → all π? modes}) has been estimated to be 0.30 ± 0.07.     

Two-photon annihilation into pion pair

The first experimental study of the interaction γγ → π⁺π^t- has been carried out in the region of ?(660) through the reaction e⁺e^? → e⁺e^?π⁺π^?. Based on two observed events, the γγ width of ?(660) is obtained to be Γ_?γγ = 9.6_?8.0^+12.3 keV. Applied on this, theory of P.C.D.C. anomaly predicts R_∞ = 5.8_?3.5^+3.2 for the asymptotic value of σ(e⁺e^? → hadrons)/σ(e⁺e^? → μ⁺μ^?).     

Measurement of the KS0 → π+π−γ decay rate

From a study of 70 000 K° decays in the CERN 2m hydrogen bubble chamber, we have estimated the rate for K_S⁰ → π⁺π^?γ for different cuts in the γ momentum. The results are in good agreement with inner bremsstrahlung on K_S⁰ → π⁺π^?. For γ momentum in the K° c.m. greater than 50 MeV/c, we obtain the branching ratio: Γ(K_S → π⁺π^?γ, k>50 MeV/c)/Γ(K_S→π⁺π^?)=(2.8. ± 0.6)×10^?3. This leads to an estimate for the direct γ emission process: Γ(K_S→π⁺π^?γ direct)/Γ(K_S → π⁺π^?)=(0.3 ± 0.6) × 10^?3.