Physics program of open charm and heavy cc states at the BES-Ⅲ experiment

We present the physics program of the open charm and heavy cc states above the DD production energy threshold, which will be studied with the BES-Ⅲ detector at the BEPC- Ⅱ collider in the coming years. Based on some full Monte Carlo simulations with the BES-Ⅲ detector, we predict the accuracy levels on measuring some physical quantities related to D^0, D^＋ and Ds^＋ decays as well as some non-charmed decays of the heavy cc states.     

D0-(D-)0 mixing and other charm decays at Belle

The D0-D-0 mixing at Belle in different modes with corresponding methods is reported in this paper,there is a clear evidence for non-zero y D0 mixing parameter,and the measurement of D0 mixing parameter x is still a challenge.CP violation in the decays is not observed.Branching fractions of other charm decays are presented.     

Recent results from NA48/2

Recent results on radiative K^± decays from the NA48/2 experiment are reported. From the full NA48/2 data set, about a million K^±→π^±π^γ decays were reconstructed. Based on this sample, the first measurement of the interference between direct photon emission and inner bremsstrahlung in K^±→π^±π^γ decays was performed. Stringent limits on CP violation in this decay were also set. In addition, a precise measurement of the branching fraction of K^±→π^±γγ is presented. This measurement was based on a data sample of more than 1000 event candidates. Also the related decay K^±→π^±e^＋e^-γ has first been observed. Results of the measurement of the decay rate and the decay parameter 5 are summarized.     

B~0-B~0 Mixing in Local Gauged Baryon and Lepton Numbers

Using the effective Hamiltonian method, we analyze the B0-B0 mixing in the extension of the standard model （SM） where baryon number and lepton number are local gauge symmetries. The numerical results indicate the correction from the extra particles to the mass difference ArnB is significant. There is a 60% enhancement compared to the SM prediction for AraB at most, which agrees with the current experimental result.     

Measurement of D0-D0 mixing parameters in D0 --> Ks pi+ pi- decays

We report a measurement of D0-D(0) mixing parameters in D(0) --> K(s)(0) pi(+) pi(-) decays using a time-dependent Dalitz-plot analysis. We first assume CP conservation and subsequently allow for CP violation. The results are based on 540 fb(-1) of data accumulated with the Belle detector at the KEKB e(+)e(-) collider. Assuming negligible CP violation, we measure the mixing parameters x = (0.80 +/- 0.29(-0.07-0.14)(+0.09+0.10))% and y = (0.33+/-0.24(-0.12-0.08)(+0.08+0.06))%, where the errors are statistical, experimental systematic, and systematic due to the Dalitz decay model, respectively. Allowing for CP violation, we obtain the CP-violating parameters |q / p| = 0.86(-0.29-0.03)(+0.30+0.06) +/- 0.08 and arg(q/p) = (-14(-18-3-4)(+16+5+2)) degrees .     

A test of CPT symmetry in K^0 vs K^0→π^＋π^-π^0 decays

I show that the CP-violating asymmetry in K^0 vs K^0→π^＋π^-π^0 decays differs from that in KL→π^＋π^-, KL →π^0π^0 or the semileptonic KL transitions, if there exists CPT violation in K^0-K^0 mixing. A delicate measurement of this difference at a super flavor factory （e.g., the φ factory） will provide us with a robust test of CPT symmetry in the neutral kaon system.     

D^0D^0 mixing and other recent charm results from BABAR

Studies in which BABAR data have shown evidence for mixing in the neutral charm meson system are presented. A new measurement of the lifetime difference parameter ycp = （1.16±0.22±0.18）% is described. Results are also presented from a systematic study of DK and D＊K invariant mass distributions from a 470 fb^-1 sample of asymmetric e^＋e^- interactions recorded by the BABAR detector at the PEP-Ⅱ storage rings. A new charmed-strange meson has been observed with mass [3044 ± 8stat （-5^＋30 ）syst] MeV/c^2 and width [239± 35stat （-42^＋46）syst]MeV/c^2.     

Study ao（980）-f0（980） mixing in charmonium decays

In this proceeding, we propose to directly measure the a0^0（980）-f0 （980） mixing in J/ψ→φf0（980）→φa0^0（980） and Xc1→π^0a0^0（980） →π^0f0（980） with the upgraded Beijing Electron Positron Collider（BEPCII） with BESIII detector. We show that a narrow peak of about 8 MeV will be produced by the a0^0（980）-f0（980） mixing, and the predominant feature makes it standing out from the background contributions. The predicted branching ratios for these two reactions are both expected to be about O（10^-6）, which is unambiguously accessible with 10^9 J/ψ and 3 × 10^8 Xc1 at BESⅢ.     

Study on Bd → φKs Decay in EDQS Model

We study Bd → φKs decay in extra down-type quarks （EDQS） model with a non-universal Z boson associated with flavor changing neutral currents （FCNCs） at the tree level. With the up-to-date experimental data of Br（Bd → φKs）, SCKs, and ACKs, we derive the bounds on the Z-b-s coupling parameter ｜Ubs ｜ and the new weak phase φ, using the constrained parameter spaces, we finally give predictions for Bd → φφ decay, which could be tested at the Fermilab Tevatron and the LHC-b experiments.     

QCD Approach to B →Dπ Decays and CP Violation

The branching ratios and CP violations of the B →Dπ decays, including both the color-allowed and the color-suppressed modes, are investigated in detail within QCD framework by considering all diagrams that lead to three effective currents of two quarks. An intrinsic mass scale as a dynamical gluon mass is introduced to treat the infrared divergence caused by the soft collinear approximation in the endpoint regions, and the Cutkosky rule is adopted to deal with a physical-region singularity of the on mass-shell quark propagators. When the dynamical gluon mass μg is regarded as a universal sca/e, it is extracted to be around μg = 440 MeV from one of the well-measured B →Dπ decay modes. The resulting predictions for all branching ratios are in agreement with the current experimental measurements. As these decays have no penguin contributions, there are no direct CP asymmetries. Due to interference between the Cabibbo-suppressed and the Cabibbo-favored amplitudes, mixing-induced CP violations are predicted in the B →D^±π^±↓ decays to be consistent with the experimental data at 1-σ level. More precise measurements will be helpful to extracting weak angle 2β＋γ.     

Deviations of the lepton mapping matrix from the Harrison-Perkins- Scott form

We propose a simple set of hypotheses governing the deviations of the leptonic mapping matrix from the Harrison-Perkins-Scott （HPS） form. These deviations are supposed to arise entirely from a perturbation of the mass matrix in the charged lepton sector. The perturbing matrix is assumed to be purely imaginary （thus maximally T-violating） and to have a strength in energy scale no greater （but perhaps smaller） than the muon mass. As we shall show, it then follows that the absolute value of the mapping matrix elements pertaining to the tau lepton deviate by no more than O（（mμ/mτ）^2） ≈ 3.5 ×10^-3 from their HPS values. Assuming that （mμ/mτ）^2 can be neglected, we derive two simple constraints on the four parameters θ12,θ23, θ31, and δ of the mapping matrix. These constraints are independent of the details of the imaginary T-violating perturbation of the charged lepton mass matrix. We also show that the e and μ parts of the mapping matrix have a definite form governed by two parameters α and β; any deviation of order mμ/mτ can be accommodated by adjusting these two parameters.     

Study of scalar meson a0（980） from B → a0（980）π decays

In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B^0 → a0^0（980）π^0, a0^＋ （980）π^-, a0^-（980）π^＋ and B^- → a0^0 （980）π^-, a0^- （980）π^0 by employing the perturbative QCD （pQCD） factorization approach at the leading order. We found that （a） the pQCD predictions for the branching ratios are around （0.4-2.8） × 10^-6, consistent with currently available experimental upper limits; （b） the CP asymmetries of B^0→ a0^0（980）π^0 and B^- → a0^- （980）π^0 decays can be large, about （70-80）% for α= 100°.     

Measurements of CP-violating asymmetries in the decay B0-->K+K-K0

We analyze the decay B0-->K+K-K0 using 383 x 10(6) BB events collected by the BABAR detector at SLAC to extract CP violation parameter values over the Dalitz plot. Combining all K+K-K0 events, we find ACP=-0.015+/-0.077+/-0.053 and beta eff = 0.352+/-0.076+/-0.026 rad, corresponding to a CP violation significance of 4.8 sigma. A second solution near pi/2-beta eff is disfavored with a significance of 4.5 sigma. We also report ACP and beta eff separately for decays to phi(1020)K0, f0(980)K0, and K+K-K0 with mK+K- > 1.1 GeV/c2.     

Image reconstruction from few views by l_0-norm optimization

In the medical computer tomography(CT) field, total variation(TV), which is the ?1-norm of the discrete gradient transform(DGT), is widely used as regularization based on the compressive sensing(CS) theory. To overcome the TV model’s disadvantageous tendency of uniformly penalizing the image gradient and over smoothing the low-contrast structures, an iterative algorithm based on the ?0-norm optimization of the DGT is proposed. In order to rise to the challenges introduced by the ?0-norm DGT, the algorithm uses a pseudo-inverse transform of DGT and adapts an iterative hard thresholding(IHT) algorithm, whose convergence and effective efficiency have been theoretically proven. The simulation demonstrates our conclusions and indicates that the algorithm proposed in this paper can obviously improve the reconstruction quality.     

Search for narrow NNπ resonances in exclusive pp→ppππ measurements

Narrow structures in the range of a few MeV have been searched for in ppπ⁺ and ppπ⁻ invariant mass spectra (M_ppπ⁺ and M_ppπ⁻) obtained from exclusive measurements of the pp→ppπ⁺π⁻ reaction at T_p=725,750 and 775 MeV using the PROMICE/WASA detector at CELSIUS. The selected reaction is particularly well suited for the search for dibaryon resonances decoupled from NN and/or NΔ. In the mass range 2020 MeV/c²<m_dibaryon<2085 MeV/c² no narrow structures could be identified on the 3σ level of statistical significance neither in M_ppπ⁻ nor in M_ppπ⁺ giving an upper limit (95% C.L.) for dibaryon production in this reaction of σ<20 nb.     

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

Based on the effective Hamiltonian with the generalized factorization approach, we calculate the branching ratios and CP asymmetries of B→VV decays in the Topcolor-assisted Technicolor (TC2) model. Within the considered parameter space we find that: (a) for the penguin-dominated B→K^*+φ and K^*0φ decays, the new physics enhancements to the branching ratios are around 40%; (b) the measured branching ratios of B→K^*+φ and K^*0φ decays prefer the range of 3≤N_c^eff≤5; (c) the SM and TC2 model predictions for the branching ratio B(B⁺→ρ⁺ρ⁰) are only about half of 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 m_π and N_c^eff.     

Measurements of the branching fraction and CP-violation asymmetries in B0-->f0(980)K0S

We present measurements of the branching fraction and CP-violating asymmetries in the decay B0-->f0(980)K0S. The results are obtained from a data sample of 123 x 10(6) Upsilon(4S)-->BB decays. From a time-dependent maximum likelihood fit, we measure the branching fraction B(B0-->f0(980)(-->pi+pi-)K0)=(6.0+/-0.9+/-0.6+/-1.2)x10(-6), the mixing-induced CP violation parameter S=-1.62(+0.56)(-0.51)+/-0.09+/-0.04, and the direct CP violation parameter C=0.27+/-0.36+/-0.10+/-0.07, where the first errors are statistical, the second systematic, and the third due to model uncertainties. We measure the f0(980) mass and width to be mf0(980)=(980.6+/-4.1+/-0.5+/-4.0) MeV/c2 and Gammaf0(980)=(43(+12)(-9)+/-3+/-9) MeV/c2, respectively.     

D0(D-)0 mixing and other recent charm results from BABAR

Studies in which BABAR data have shown evidence for mixing in the neutral charm meson system are presented.A new measurement of the lifetime difference parameter yCP=(1.16±0.22±0.18)% is described.Results are also presented from a systematic study of DK and D*K invariant mass distributions from a 470 fb-1sample of asymmetric e+e-interactions recorded by the BABAR detector at the PEP-Ⅱ storage rings.A new charmed-strange meson has been observed with mass[3044±8stat(+30-5)syst]MeV/c2 and width[239±35stat(+46-42)syst]MeV/c2.     

Energy loss of charm quarks from J/ψ production in cold nuclear matter

J/ψ suppression in p-A collisions is studied by considering the nuclear effects on parton distribution,energy loss of beam proton and the finial state energy loss of color octet cc. The leading-order computations for J/ψproduction cross-section ratios RW/Be(x F) are presented and compared with the selected E866 experimental data with the cc remaining colored on its entire path in the medium. It is shown that the combination of the different nuclear effects accounts quite well for the observed J/ψ suppression in the experimental data. It is found that the J/ψ suppression on RW/Be(x F) from the initial state nuclear effects is more important than that induced by the energy loss of color octet cc in the large x F region. Whether the cc pair energy loss is linear or quadratic with the path length is not determined. The obtained cc pair energy loss per unit path length α = 2.78±0.81 Ge V/fm, which indicates that the heavy quark in cold nuclear matter can lose more energy compared to the outgoing light quark.