Exotic vector charmonium and its leptonic decay width

We propose a novel type of interpolating field operator, which manifests the hybrid-like configuration that the charm quark-antiquark pair recoils against gluonie degrees of freedom. A heavy vector charmonium-like state with a mass of 4.33（2） GeV is disentangled from the conventional charmonium states in the quenched approximation. This state has affinity for the hybrid-like operators but couples less to the relevant quark bilinear operator. We also try to extract its leptonic decay constant and give a tentative upper limit that it is less than one tenth of that of J/ψ, which corresponds to a leptonic decay width about dozens of eV. The connection of this state with X（4260） is also discussed.

Light meson spectrum and their leptonic decay widths in the frame work of constituent quark models

The phenomenological non-relativistic quark model has been employed to obtain the ground state masses of light vector mesons and their radially excited states and their decay widths.The full hamiltonian used in the investigation has kinetic energy,the confinement potential and the one-gluon-exchange potential.A good agreement is obtained with the experimental masses and their leptonic decay widths.

Leptonic Decays of Heavy Vector and Pseudoscalar Mesons

Pure leptonic decays of D~*0)(B_^(*s),B_d~*)→l^+l^- and D^(±*)(D_s~*,B^(*+),B_c~*)→lν_l are investigated.The hadronic contributions such as D^0→D^(*0)γ→μ^+μ^- are also explored.We then obtain the updated branching fractions of the pseudoscalar mesons to lepton pairs are modified by a factor of few percentages.Specifically,the Br(B+→e^+ν_e)is reduced by a factor 13%.

Factorization of radiative leptonic D-meson decay with sub-leading power corrections

In this work,we calculate the sub-leading power contributions to radiative leptonic D→γνdecay.For the first time,we provide the analytic expressions of next-to-leading power contributions and the error estimation associated with the power expansion of O(∧_(QCD)/m_(c)).In our calculation,we adopt two different models of the D-meson distribution amplitudesφ^(+)_(D,Ⅰ)andφ^(+)_(DⅡ).Within the framework of QCD factorization as well as the dispersion relation,we evaluate the soft contribution up to the next-to-leading logarithmic accuracy and also consider the higher-twist contribution from the two-particle and three-particle distribution amplitudes.Finally,we find that all the sub-leading power contributions are significant atλd(μ0)354 MeV,and the next-to-leading power contributions lead to 143%inφ^(+)_(D,Ⅰ)and 120%inφ^(+)_(DⅡ)corrections to leading power vector form factors with Eγ=0.5 GeV.As the corrections from the higher-twist and local sub-leading power contributions are enhanced with increasing inverse moment,it is difficult to extract an appropriate inverse moment of the D-meson distribution amplitude.The predicted branching fractions are(1.88^(+0.36)_(0.29))×10^(-5)forφ^(+)_(D,Ⅰ)and(2.31^(+0.65)_(-0.54))×10^(-5)forφ^(+)_(DⅡ).

B_(s,d)→μ^+μ_- decays in a flavor changing Z′ model

We study the pure leptonic decays Bs,d → μ^μ^- in a Flavor Changing ZI Model. From the recent measurements of the branching ratios B（Bs,d → μ^μ^-）, we have derived the bounds on the effective μ-μ-Z＇ lepton coupling Bμμ^L. We find that, （i） if neglecting the contribution from the right-handed lepton coupling R L Bμμ^R, we obtain 1.32 〈 Bμμ^L 〈 3.32; （ii） if considering the contribution from the right-handed lepton coupling Bμμ^R and setting Bμμ^R and setting Bμμ^L= Bμμ^R, we obtain 0.99 〈 Bμμ^L 〈 2.19. Our results could be useful for researching Z＇ effects.

Decay properties of D and D_s mesons in coulomb plus power potential (CPP_ν)

The decay properties of the D and D s mesons are computed in a nonrelativistic phenomenological quark-antiquark potential of the type V （r） =-4 /3 α s /r＋ Ar ν with different choices of ν.Numerical method to solve the Schrdinger equation has been used to obtain the spectroscopy of qQ mesons.The numerically obtained radial solutions are employed to obtain the decay constant and leptonic decay widths.It has been observed that predictions of the ground state masses and the decay widths are consistent with other model predictions as well as with the known experimental values.

Revisiting the heavy vector quarkonium leptonic widths

We revisit the heavy quarkonium leptonic decays ψ(nS)→■^+■^- and Υ(nS)→■^+■^- using the Bethe-Salpeter method.The emphasis is on the relativistic corrections.For the ψ(1S-5S)decays,the relativistic effects are 22-2^+3%,34-2^+5%,41-6^+6%,52-13^+11% and 62-12^+14%,respectively.For the Υ(1S-5S) decays,the relativistic effects are 14-2^+1%,23-3^+0%,20-2^+8%,21-7^+6% and 28-7^+2%,respectively.Thus,the relativistic corrections are large and important in heavy quarkonium leptonic decays,especially for the highly excited charmonium.Our results forΥ(nS)→■^+■^- are consistent with the experimental data.

Panda X-III： Searching for neutrinoless double beta decay with high pressure ^(136)Xe gas time projection chambers

Searching for the neutrinoless double beta decay(NLDBD)is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments.Panda X-III(particle and astrophysical xenon experiment III)will search for the NLDBD of136Xe at the China Jin Ping Underground Laboratory(CJPL).In the first phase of the experiment,a high pressure gas Time Projection Chamber(TPC)will contain 200 kg,90%136Xe enriched gas operated at10 bar.Fine pitch micro-pattern gas detector(Microbulk Micromegas)will be used at both ends of the TPC for the charge readout with a cathode in the middle.Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution.The detector will be immersed in a large water tank to ensure～5 m of water shielding in all directions.The second phase,a ton-scale experiment,will consist of five TPCs in the same water tank,with improved energy resolution and better control over backgrounds.

The Lepton Flavor Violating Decays of AHin the Littlest Higgs Model with T-Parity Violation

The T-parity in the littlest Higgs model can be broken by the anomalous Wess-Zumin-Witten term, which leads that the lightest T-odd gauge boson AH decays into the SM particles. First, we examine some lepton flavor violating decays of AH, namely AH → τ±μ±, AH→ τ±e±, and AH→ τ±e±. We find that the branching ratios can reach 10-7 for AH → τ±μ±, 10-s for AH → τ±μ±, and 10-s for AH → τ±e± Then, we study the lepton flavor violating plus jets signatures of the heavy charged gauge boson and mirror quarks at the LHC, and find that it is possible to be detected for pp jets, and hardly to be detected for pp → τ±e± （μ±e±） ＋ 4 jets and p p → W H W H → τ±μ±（ τ±e±,μ±e±） ＋ 6 jets.

LEPTON MIXING-RIGHT SYMMETRY ELECTROWEAK GAUGE THEORY AND v_3 NEUTRINO DECAY

In this paper, we introduce four models for the discrete horizontal symmetry in the gauge theory of electroweak interactions with left-right symmetry （i. e., the SU（2）L × SU（2）R × U（1） model） to obtain four sets of the mixing angles among the different generations of leptons separately. In light of the corresponding mass relations obtained and the preliminary result for mv1 and mv2, we estimate the possible value of mv3 and discuss the various physical effects arising from the lepton mixing and non-vanishing mass of neutrinos in these four models, such as their influences on the determination of quark mixing angle and the representation of the μ-e universality, the neutrino oscillations and their applications in astrophysics and so on, with special emphasis on the life-time and various possible decay modes of v3 （its mass is about 2×102 Mev in Model B） so as to give a clue to experimental detection of v3.

A possible signature of new physics at BES-Ⅲ

The recent observations of the purely leptonic decay Ds＋→μ＋νμ and τ＋ντ at CLEO-c and B factory may allow a possible contribution from a charged Higgs boson. One such measurement of the decay constant fD. differs from the most precise unquenched lattice QCD calculation by a level of 4 σ. Meanwhile, the measured ratio, BR（Ds＋→μ＋νμ）/BR（D＋→μ＋νμ）, is larger than the standard model prediction at a 2.0σ level. We discuss that the precise measurement of the ratio BR（Ds＋→μ＋νμ）/BR（D＋→μ＋νμ） at BES-Ⅲ will shed light on the presence of new intermediate particles by comparing the data with the theoretical predictions, especially, the predictions of high precise unquenched lattice QCD calculations.

Anatomy of the ρ resonance from lattice QCD at the physical point

We propose a strategy to access the qq component of the p resonance in lattice QCD. Through a mixed action formalism（overlap valence on domain wall sea）, the energy of the qq component is derived at different valence quark masses, and shows a linear dependence on mπ^2. The slope is determined to be c1 =0.505（3）GeV^-1, from which the valence πρ sigma term is extracted to be σ（πρ）^val= 9.82（6） MeV using the Feynman-Hellman theorem. At the physical pion mass, the mass of the qq component is interpolated to be mρ = 775.9±6.0±1.8 MeV, which is close to the p resonance mass. We also obtain the leptonic decay constant of the qq component to be fρ-=208.5±5.5±0.9 MeV, which can be compared with the experimental value fρ^exp≈221 MeV through the relation fρ^exp=（1/2）Zfρ±, with Zρ≈1.13 being the on-shell wavefunction renormalization of p owing to the ρ-π interaction. We emphasize that mρand fρ of the qq component, which are obtained for the first time from QCD, can be taken as the input parameters of p in effective field theory studies where p acts as a fundamental degree of freedom.

Searching for new physics in D^0→μ^+ μ^-,e^+e^-,μ~±e~■ at BES and/or the super charm-tau factory

In contrast with B0-ˉB0, Bs-ˉBs mixing where the standard model（SM） contributions overwhelm that of the new physics beyond standard model（BSM）, a measured relatively large D0-ˉD0mixing where the SM contribution is negligible, definitely implies the existence of the new physics BSM. It is natural to consider that the rare decays of D meson might be more sensitive to new physics, and the decay mode D0→μ＋μ-could be an ideal area to search for new physics because it is a flavor changing process. In this work we look for a trace of the new physics BSM in the leptonic decays of D0. Concretely we discuss the contributions of unparticle or an extra gauge boson Z while imposing the constraints set by fitting the D0-ˉD0mixing data. We find that the long-distance SM effects for D0→lˉl still exceed those contributions of the BSM under consideration, but for a double-flavor changing process such as D0→μ±e, the new physics contribution would be significant.

Implications of the RK and R_(K*) anomalies

We discuss the implications of the recently reported R_K and R_（K＊） anomalies, the lepton flavor nonuniversality in the B → Kl~＋l^-and B → K~＊l~＋~l- decay channels. Using two sets of hadronic inputs of form factors, we perform a fit of new physics to the R_K and R_（K＊） data, and significant new physics contributions are found. We suggest the study of lepton flavor universality in a number of related rare B,Bs,Bc and Λb decay channels, and in particular we give predictions for the μ-to-e ratios of decay widths with different polarizations of the final state particles, and of the b → dl~＋l^- processes, which are presumably more sensitive to the structure of the underlying new physics. With the new physics contributions embedded in the Wilson coefficients, we present theoretical predictions for lepton flavor non-universality in these processes.