QCD average hadronic multiplicity in the ψ(1S) decay

The average hadronic multiplicity in the ψ(1S) decay, via the mode ψ→ggg, is studied in the framework of Quantum Chromodynamics. We test the predictions of perturbative QCD working to \(O(\sqrt {\alpha _s } )\) in the coupling constant.     

Pseudoscalar mixing in J/ψ and ψ(2S)decay

Based on the branching fractions of J/ψ(ψ(2S))→ VP from different collaborations, pseudoscalar mixing is extensively discussed with a well established phenomenological model. The mixing angle is determined to be -14° by fitting to the new world average if only quark content is considered. After taking into account the gluonic content in η and η' simultaneously, the investigation shows that η favors only consisting of light quarks, while the gluonic content of η' is Z2η', = 0.30±0.24.     

The CP violation of theB→Kϕ decay at γ(4s) in the non-standard models

The CP violating asymmetry in theB→K? decay is studied in both supersymmetric model and three Higgs doublets model. The absorptive part of the penguin amplitude leads to the CP violating asymmetry in theB _u ^+- →K ^±? decays, which is at most 3% due to the GIM mechanism in the standard model. However, the asymmetry could be relatively large if there exists a new source of the imaginary component in the decay amplitude. In the supersymmetric model, the contributions of the imaginary part of the super-penguin and the super-box processes rather suppress the magnitude of the asymmetry, whereas in the three Higgs doublets model, that of the charged Higgs-penguin process could significantly enhance it.     

Measurement of Integrated Luminosity at ψ(2S) by Wide-Angle Bhabha Scattering

A method for measuring the integrated luminosity of the e⁺ e^－ colliding experiment by using the wide-angle Bhabha events at the center of mass energy of the ψ(2S) resonance is presented. The determination of the integrated luminosity for the ψ(2S) data collected by the BES detector at the BEPC collider shows the feasibility of the method.     

Abnormal Suppression of Vector-Tensor Decays of ψ(2S)

The hadronic decays ψ(2S)→ρα₂ and K^*0K₂^*0+c.c. have been studied in a sample of 3.6×10⁶ ψ(2S) events.Measurements of their branching fractions are presented.Both channels violate the “15% rule” predicted by perturbative QCD compared with the corresponding J/ψ decays.These results serve as new examples of abnormal suppression of ψ(2S) decays into vector-tensor final states that was first observed in ψ(2S)→ωf₂     

Determination of the number of ψ(3686)events at BESⅢ

The numbers of ψ(3686) events accumulated by the BESⅢ detector for the data taken during 2009 and2012 are determined to be(107.0±0.8)×10~6 and(341.1±2.1)×10~6, respectively, by counting inclusive hadronic events,where the uncertainties are systematic and the statistical uncertainties are negligible. The number of events for the sample taken in 2009 is consistent with that of the previous measurement. The total number of ψ(3686) events for the two data taking periods is(448.1±2.9)×10~6.     

Radiative pion decay: Determination of FA(0) from τ-lepton decay data

The form factor F_A(0) in π→eνγ is calculated, at the soft pion point, directly from data on the semileptonic τ-lepton decays τ→ν_τ + nπ, which determine the relevant vector and axial-vector hadronic spectral functions. The reliability of this calculation is assessed by using these fitted spectral functions to check the saturation of the first two Weinberg sum rules. The results are: F_A(0)=0.017±0.004, and γ(0)F_A(0)/F_V(0)=0.67±0.04±0.16.     

A study on the decay of ^72As

The excited states of the ⁷²Ge nucleus were investigated in radioactive decay of ⁷²As. Three new transitions with 1996.58, 2125.59 and 2255.49keV have been found for the first time. One γ-ray with 912.09keV has been placed in the decay scheme for the first time, and the placement of 1938.88, 2116.79, 2785.59, 2833.03, 2950.69 and 3338.00keV γ-rays are confirmed again in the present work. One new level at 2027.72keV excitation energy is proposed. The level scheme was established and for a number of levels spin-parity assignments are suggested on the basis of logft values and γ-branching ratios.     

Search for CP violation in the decays D(0)→K(S)(0)P(0)

We have searched for CP violation in the decays D(0)→K(S)(0)P(0) where P(0) denotes a neutral pseudoscalar meson that is either a π(0), η, or η' using KEKB asymmetric-energy e(+)e(-) collision data corresponding to an integrated luminosity of 791 fb(-1) collected with the Belle detector. No evidence of significant CP violation is observed. We report the most precise CP asymmetry measurement in the decay D(0)→K(S)(0)π(0) to date: A(CP)(D(0)→K(S)(0)π(0))=(-0.28±0.19±0.10)%. We also report the first measurements of CP asymmetries in the decays D(0)→K(S)(0)η and D(0)→K(S)(0)η': A(CP)(D(0)→K(S)(0)η)=(+0.54±0.51±0.16)% and A(CP)(D(0)→K(S)(0)η')=(+0.98±0.67±0.14)%, respectively.     

Measurement of the forward-backward asymmetry in the B→K*μ(+)μ(-) decay and first observation of the B(s)0→ϕμ(+)μ(-) decay

We reconstruct the rare decays B(+)→K(+)μ(+0μ(-0, B90)→K*(892)(0)μ(+)μ(-), and B(s)(0)→?(1020)μ(+)μ(-) in a data sample corresponding to 4.4 fb(-1) collected in pp collisions at √[s]=1.96 TeV by the CDF II detector at the Tevatron Collider. Using 121±16 B(+)→K(+)μ(+)μ(-) and 101±12 B(0)→K(*0)μ(+)μ(-) decays we report the branching ratios. In addition, we report the differential branching ratio and the muon forward-backward asymmetry in the B(+) and B(0) decay modes, and the K(*0) longitudinal polarization fraction in the B(0) decay mode with respect to the squared dimuon mass. These are consistent with the predictions, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the B(s)(0)→?μ(+)μ(-) decay and measure its branching ratio BR(B(s)(0)→?μ(+)μ(-))=[1.44±0.33±0.46]×10(-6) using 27±6 signal events. This is currently the most rare B(s)(0) decay observed.     

New Suppression Mode of the ψ(2S) Hadronic Decay

The hadronic decays ,and ωf2(1270) have been studied in a sample of 1.27 million produced.Measurements of their branching fractions are presented. While obeys the "14% rule" predicted by theory, →ωf2 (1270) is suppressed comparing with the corresponding decay. As a vector-tensor pair combination, the ωf2 mode is the first example of a non-vector-pseudoscalar decay of charmonium which violates the above mentioned rule.     

A phenomenological study of bottom-quark fragmentation in top-quark decay

Top-quark physics is one of the main fields of investigation at the Tevatron accelerator and, ultimately, at the LHC. We perform a phenomenological analysis of $t\bar{t}$ events at hadron colliders, with a focus on observables relying on bottom-quark fragmentation in top-quark decay. In particular, we investigate the B-lepton invariant-mass distribution in the dilepton channel and give an estimate of the contribution of bottom fragmentation to the Monte Carlo uncertainty on the top-quark mass reconstruction.     

Fast Reconstruction of ψ(2S) Data and Corresponding Quality Supervision

A data quality monitoring system for fast reconstructed event is depicted in detail for ψ(2S)data taking during 2001-2002 years' running at Beijing Spectrometer(BES Ⅱ) . In parallel with fast reconstruction of raw data, the performance and stability of BES Ⅱ subdetector can be inspected from various intuitive distributions of fast reconstructed and selected events. The system,with operation simplicity,function completeness and extension flexibility,has played and will play an important role in the quality monitoring of BES data taking.     

CP asymmetry from the resonance effect of the B meson decay process with π and K final states

We present the novel V→K⁺K^-(V=φ,ρ,ω) resonance,which generates a strong phase associated with vector meson resonances,leading to significant CP asymmetry in the interference region.The φ→K⁺K^-,ρ→K⁺K^-,and ω→K⁺K^-resonances arise from the mixing of the vector mesons φ,ρ,and ω.We calculate the CP asymmetry from the decay mode of B→ KKπ(K).Meanwhile,the localized CP asymmetries are presented and a detailed analysis...     

Search for CP violation in τ±→K(S)0π±ντ decays at Belle

We report on a search for CP violation in τ(±)→K(S)(0)π(±)ν(τ) decays using a data sample of 699 fb(-1) collected by the Belle experiment at the KEKB electron-positron asymmetric-energy collider. The CP asymmetry is measured in four bins of the invariant mass of the K(S)(0)π(±) system and found to be compatible with zero with a precision of O(10(-3)) in each mass bin. Limits for the CP violation parameter Im(η(S)) are given at the 90% confidence level. These limits are |Im(η(S))| < 0.026 or better, depending on the parametrization used to describe the hadronic form factors, and improve upon previous limits by 1 order of magnitude.     

Evidence for CP violation in time-integrated D0→h(-)h(+) decay rates

A search for time-integrated CP violation in D(0)→h(-)h(+) (h=K, π) decays is presented using 0.62 fb(-1) of data collected by LHCb in 2011. The flavor of the charm meson is determined by the charge of the slow pion in the D(*+)→D(0)π(+) and D(*-)→D[over ˉ](0)π(-) decay chains. The difference in CP asymmetry between D(0)→K(-)K(+) and D(0)→π(-)π(+), ΔA(CP)≡A(CP)(K(-)K(+))-A(CP)(π(-)π(+)), is measured to be [-0.82±0.21(stat)±0.11(syst)]%. This differs from the hypothesis of CP conservation by 3.5 standard deviations.     

Pseudoscalar mixing in J/ψ and ψ（2S）decay

Based on the branching fractions of J/ψ（ψ（2S））→ VP from different collaborations, pseudoscalar mixing is extensively discussed with a well established phenomenological model. The mixing angle is determined to be -14° by fitting to the new world average if only quark content is considered. After taking into account the gluonic content in η and η＇ simultaneously, the investigation shows that η favors only consisting of light quarks, while the gluonic content of η＇ is Z2η＇, = 0.30±0.24.     

Study on Production of Exotic 0 Meson D*sJ(2317) in Decays of ψ(4415)

The newly observed D*sJ family containing D*sJ(2317), DsJ(2460), and DsJ(2632) attracts great interests.Determining their structures may be an important task for both theorists and experimentalists. In this work we use a non-relativistic model (the harmonic oscillator model) to evaluate the production rate of D*sJ (2317) from the decays of ψ(4415). For a comparison, we also employ the widely adopted heavy quark effective theory to repeat the calculation.We find that the rate is sizable and may be observed at BES Ⅲ and CLEO, if it is a p-wave excited state of Ds (1968).Unfortunately, the other two members of the family cannot be observed through decays of charmonia, because of the constraints from the final state phase space.     

A study of the production of high-p t π0 at the CERN intersecting storage rings

The inclusive cross-section for π⁰ production near 90° inpp collisions at the CERN Intersecting Storage Rings has been studied for thep _T range 3<p _T <16GeV/c at four different centre-of-mass energies ( \(\sqrt s = 30.6\) , 44.8, 52.7, and 62.8 GeV). In this experiment the two photons from the π⁰→yy decay were resolved and measured separately forp _T values up to 10 GeV/c. Results indicate an agreement with thep _T ^?8 behaviour for the lower values ofp _T and a slower decrease of the cross-section for the higher values ofp _T . The high-p _T data deviate from the scaling expressionp _T ^?n F(x _T ), which holds for the lowerp _T values (p _T <8GeV/c).