B→ηK and B→φKs Decays in the Two Higgs Doublet Model Ⅲ

Using the QCD factorization approach, we investigate the large branching ratios of B→ηK^＊ decays and the SCKs anomaly of B→φKs decay in the two Higgs doublet model Ⅲ. With the contributions of flavour-changing neutral current mediated by the neutral Higgs bosons H^0, h^0 and A^0 at the tree level, we provide a coherent resolution to these anomalies within the constrained parameter spaces, which are 120 〈｜λbs λss｜ 〈136. This will be really interesting in searching for the signs of new physics.     

Radiative Corrections to e~+e~-→ Zh at Future Higgs Factory in the Minimal Dilaton Model

The minimal dilaton model(MDM) extends the Standard Model by one singlet scalar called dilaton and one top quark partner called t. In this work we investigate the t-induced radiative correction to the Higgs-strahlung production process e+e-→ Zh at future Higgs factory. We first present the analytical calculations in detail and show how to handle the ultraviolet divergence. Then we calculate the correction numerically by considering the constraints from precision electroweak data. We find that, for sin θL= 0.2 and mt = 1200 Ge V, the correction is 0.26% and 2.1% for (se+e)~(1/2)-= 240 Ge V, 1 Te V respectively, and a larger value can be achieved as sin θLincreases.     

Effects of the littlest Higgs model on the process e~+ e~- → μ~+ μ~- at a Z~0-factory

We investigate the possibilities of finding the effects of the littlest Higgs (LH) model on the process e + e - →μ + μ - at the leadingorder at a possible Z 0-factory.We study the impacts of the LH model on the observables,such as,the total cross section,the distribution of the transverse momentum of μ-,and the forward-backward charge asymmetry of μin polarized and unpolarized electron-positron collision modes.Besides,we analyze the relations between the observables and the LH model parameters,and discuss the observables of process e + e→μ + μ-in different incoming electron-positron polarization modes.We conclude that one could observe the effects contributed by the LH model on the process e + e-→μ + μin a reasonable parameter space,or might put more stringent constraints on the LH parameters in the future experiments at the possible Z 0-factory.     

Z′particles and e~+ e~- → τ~+ μ~-

We analyze the cross section of e + e-→τ + μ-within the frameworks of SM and its Z extension.The theoretical prediction of the SM on the total cross section is suppressed by the tiny neutrino masses.On the other hand,the contributions from Z to the cross section are enhanced drastically because of the tree level FCNC couplings among Z and leptons.     

Interference effects on Higgs mass measurement in e~+e~-→H(γγ)Z at CEPC

A high luminosity Circular Electron Positron Collider(CEPC) as a Higgs Factory will be helpful for precision measurements of the Higgs mass. The signal-background interference effect is carefully studied for the Higgs diphoton decay mode in associated Z boson production at future e~+e~-colliders at energy 246 GeV. The mass shifts go up from about 20 MeV to 50 MeV for the experimental mass resolution ranging from 0.8 GeV to 2 GeV.     

e~+e~- →charm cross sections via ISR

We discuss recent measurements of exclusive e+e-cross sections for charmed hadron final states near threshold performed by Belle and BABAR.The results are based on a study of events with initial-state-radiation photons in a large data sample collected with the Belle and BABAR detectors at the Υ(4S) resonance and nearby continuum.     

Experimental review of e~+e~-→ππh_c

We review the recent BESIII measurement of e~+e~-→ππh_c in which its line shape is studied between the center-of-mass energies of 3.9 to 4.42 Ge V and an iso-vector charmonium-like state Z_c(4020) is observed in the invariant mass of πhc at the BESIII experiment. The charged Z_c(4020)~± is the second observed Z_c state following Z_c(3900), while the Z_c(4020)~0 is the first observed neutral Z_c state. The line shape of σ(e~+e~-→ππh_c) is also reanalyzed in view of searching for the Y state and the existence of the Y(4220) state is confirmed and compared with the previous work of the BESIII experiment.     

Study of the rare decay J/ψ→e~+e~-φ

We study the decay process of J/ψ→e~+e~-φ where the relatively clean electromagnetic(EM) transitions appear at leading order at tree level while the hadronic contributions only emerge via hadronic loop transitions. We include the low-lying scalar f_0(980) and pseudoscalar η/η as the dominant contributions in the evaluation of the hadronic loop contributions. It is found that the hadronic effects are negligible compared with the EM contributions.The decay width of J/ψ→e~+e~-φ is determined to be about 2.12 × 10~(-6) ke V if there is no other leading mechanism contributing. This result will be tested by the BESIII experiment with a large J/ψ data sample.     

Probing HZγ and Hγγ anomalous couplings in the process e~+e~-→ Hγ

We propose to measure the HZγ and Hγγ anomalous couplings in the process e+e-→Hγ with the sequential decay of H→bˉb. The discovery potential of observing the anomalous couplings are explored in detail.Our study shows that future electron–positron colliders have great potential to test the HZγ and Hγγ couplings.Conservative bounds on the two anomalous couplings are also derived when no new physics signal is detected on top of the SM backgrounds.     

Top—Higgs and the Process e^＋e^— → vvtt

We discuss the contributions of the top-Higgs ht^0 proedicted by topcolor-assisted technicolor (TC2) models to the process e^ e^-→vvtt.We find that the contributions are very large.For mht=400 GeV and ε=0.01,the production cross section of this process can reach 11.2fb,which may be detected in the future high energy e^ e^- collider experiments.The process e^ e^-→vvtt can be used to test experimentally the signal of TC2 models.     

B → Kμ+μ-: Light Higgs and fourth generation

We examine the current limit on the branching ratio for B → Kμ⁺μ^- and the theoretical predictions for B → KH → Kμ⁺μ^- in three- and four-generation models. It is shown that for a heavy top quark m_t≳60 GeV a light Higgs, m_H ⩽3.5 GeV, is disfavoured in a three-generation model. We also find that the existence of a light Higgs constrains the four-generation model quite strongly through the above process.     

Determination of the Spin–Spin Coupling Constant in Hydrogen Deuteride HD and Estimates of the Manifestation of Axion-Like Particles

An experimental value of the spin–spin coupling constant in deuterated molecular hydrogen HD has been obtained, J _pd = (43.112 ± 0.005) Hz (300 K), while investigating two gaseous samples at pressures of 95 and 155 atm. The experimental result does not coincide with Jpd = (43.31 ± 0.05) Hz that was calculated theoretically by Helkager et al. The observed discrepancy ΔJ _pd ≈ (0.20 ± 0.05 Hz) may point to a manifestation of the involvement of light pseudo-scalar (axion-like) bosons with a mass m _a ≈ 1 keV/c² in the spin–spin coupling of the HD proton and deuteron.     

Study of the η'→Ve~+e~- decay with hidden local symmetry model

Within the hidden local symmetry framework, the Dalitz decay η→Ve+e-is studied with the vector meson dominance model. It is found that the partial width Γ(η→ωe+e-)≈40 e V and branching ratio B(η→ωe+e-)≈2×10-4, and Γ(η→ρe+e-)≈10Γ(η→ωe+e-) and B(η→ρe+e-)≈10B(η→ωe+e-). The maximum position of the dilepton distribution is m e+e-≈1.33 Me V. These decays are measurable with the advent of high statistic ηexperiments.     

J／φ→γBB Decays and the Quark—pair Creation Model

We generalize the quark-pair creation model to a study of the radiative decays J/φ→γBB by assuming that the u.d,or s quark pairs are created with the same interaction strength,From the calculation of the ratio of the decay widths （J/φ→γpp)/Γ（J/φ→pp),we extract the quark-pari creation strength gI=15.40GeV,Based on the SU(6)spin-flavour basis and the “uds” basis,the radiative decay branching ratios cotaining strange baryons are evaluated.Measurements for these decay widths from the BESII data are suggested.     

Study of the η’→Ve~+e~- decay with hidden local symmetry model

Within the hidden local symmetry framework, the Dalitz decay η→Ve+e-is studied with the vector meson dominance model. It is found that the partial width Γ(η→ωe+e-)≈40 e V and branching ratio B(η→ωe+e-)≈2×10-4, and Γ(η→ρe+e-)≈10Γ(η→ωe+e-) and B(η→ρe+e-)≈10B(η→ωe+e-). The maximum position of the dilepton distribution is m e+e-≈1.33 Me V. These decays are measurable with the advent of high statistic ηexperiments.     

Observation of e~+e~-→D_s~+■~((*)0)K~- and study of the P-wave D_s mesons

Studies of e~+e~→D_s~+■~((*)0)K~-and the P-wave charmed-strange mesons are performed based on an e~+e~-collision data sample corresponding to an integrated luminosity of 567 pb~(-1) collected with the BESIII detector at s~(1/2)=4.600 GeV. The processes of e~+e~-→D_s~+■~(*0)K~- and D_s~+■~0K~- are observed for the first time and are found to be dominated by the modes D_s~+D_(s1)(2536)~-and D_s~+D_(s2)~*(2573)~-, respectively. The Born cross sections are measured to be σ~B(e~+e~-→D_s~+■~(*0)K~-) =(10.1±2.3±0.8) pb and σ~B(e~+e~-→D_s~+■~0K~-) =(19.4±2.3± 1.6) pb, and the products of Born cross section and the decay branching fraction are measured to be σ~B(e~+e~-→D_s~+D_(s1)(2536)~-+c.c.)·B(D_(s1)(2536)~-→■~(*0)K~-)=(7.5±1.8±0.7) pb and σ~B(e~+e~-→D_s~+D_(s2)~*(2573)~-+ c.c.)·B(D_(s2)~*(2573)~-→■~0 K~-)=(19.7 ± 2.9 ±2.0) pb. For the D_(s1)(2536)~-and D_(s2)~*(2573)~-mesons, the masses and widths are measured to be M(D_(s1)(2536)~-)=(2537.7±0.5 ±3.1) MeV/c2, Γ(D_(s1)(2536)~-) =(1.7 ±1.2 ±0.6)MeV, and M(D_(s2)~*(2573)~-)=(2570.7±2.0 ±1.7) MeV/c~2, Γ(D_(s2)~*(2573)~-)=(17.2 ±3.6 ±1.1) MeV. The spin-parity of the D_(s2)~*(2573)~-meson is determined to be J~p= 2~+. In addition, the processes e~+e~-→D_s~+■~((*)0)K~-are searched for using the data samples taken at four(two) center-of-mass energies between 4.416(4.527) and 4.575 GeV, and upper limits at the 90% confidence level on the cross sections are determined.     

Charmless Hadronic Decays B→VV in the Topcolor-Assisted Technicolor Model

Based. On the effective Hamiltonian with the generalized factorization approach, we calculate the branchingratios and CP asymmetries of B → VV decays in the Topcolor-assisted Technicolor (TC2) model. Within the consideredparameter space we find that: (a) for the penguin-dominated B → K* φ and K*0 φ decays, the new physics enhancementsto the branching ratios are around 40%; (b) the measured branching ratios of B →K* φ and K*0φ decays prefer therange of 3 Neffc 5; (c) the SM and TC2 model predictions for the branching ratio B(B →ρ ρ0) are only about halfof the Belle‘s measurement; and (d) for most B → VV decays, the new physics corrections on their CP asymmetries are generally small or moderate in magnitude and insensitive to the variation of mπ and Neffc.     

MINDO/3 CI Study of NCO Spectrum and the Chemiluminescent Reaction N + CO → NCO + h

Abstract

The mechanism of chemiluminescence in the reaction N + CO → NCO (1) and the electronic spectrum of NCO radical have been investigated by means of MINDO/3 CI method. The potential energy curves for the ground and some excited doublet and quartet states have been built along the linear and nonlinear (angle NCO is equal to 150°) reaction coordinates. The reaction channels N(⁴S) + CO(¹σ⁺), N(²D) + CO(¹°⁺) and N(²P) + CO(¹σ⁺) have been discussed in detail. The spin-orbit coupling (SOC) constants for ²π states and nonadiabatic SOC matrix elements <⁴σ^?|;H_SOC|X²π> have been calculated.     

Evidence for resonant structures in e~+e~-→π~+π~-h_c

The cross sections of e+e-→π+π-hc at center-of-mass energies from 3.90 to 4.42 GeV were measured by the BES and the CLEO-c experiments. Resonant structures are evident in the e+e-→π+π-hc line shape. The fit to the line shape results in a narrow structure at a mass of(4216±18) MeV/c2and a width of(39±32) MeV, and a possible wide structure of mass(4293±9) MeV/c2and width(222±67) MeV. Here, the errors are combined statistical and systematic errors. This may indicate that the Y(4260) state observed in e+e-→π+π-J/ψ has a fine structure in it.     

A discussion on vacuum polarization correction to the cross-section of e~+e~-→γ~*/ψ →μ~+μ~-

Vacuum polarization is a part of the initial-state radiative correction for the cross-section of e~+e~- annihilation processes. In the energy region in the vicinity of narrow resonances J/ψ and ψ(3686), the vacuum polarization contribution from the resonant component has a significant effect on the line-shape of the lepton pair production cross-section. This paper discusses some basic concepts and describes an analytical calculation of the cross-section of e~+e~-→γ*/ψ→μ+μ-considering the single and double vacuum polarization effect of the virtual photon propagator. Moreover, it presents some numerical comparisons with the traditional treatments.