Measurement of the D0, D+ and Ds+ meson lifetimes at √s = 10.58 GeV

We have measured the lifetimes of the D⁰, D⁺ and D_s⁺ mesons with data from the CLEO detector. We find τ_D⁰ = (5.0 ± 0.7 ± 0.4) × 10⁻¹³s, τ_D⁺ = (11.4 ± 1.6 ± 0.7) × 10⁻¹³s and τ_Ds⁺ = (4.7 ± 2.2 ± 0.5) × 10⁻¹³s, giving lifetime ratios τ_D⁺/τ_D⁰ = 2.3 ± 0.5 and τ_Ds⁺/τ_D⁰ = 0.9 ± 0.5.     

New Measurement of the π0 radiative decay width

High precision measurements of the differential cross sections for π0 photoproduction at forward angles for two nuclei, 12C and 208Pb, have been performed for incident photon energies of 4.9-5.5 GeV to extract the π0→γγ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The π0→γγ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current Particle Data Group average of this fundamental quantity, and it is consistent with current theoretical predictions.     

Production properties ofD 0,D +,D *+ andD s + in 230 GeV/cπ − andK −-Cu interactions

We have studied the hadronic production of charmed mesons in the NA 32 experiment at CERN. A special trigger together with a high resolution vertex detector consisting of charge coupled devices and silicon microstrip detectors allowed the selection of very clean samples of charmed mesons. We have collected 852 fully reconstructed decays: 60D _s ⁺ →K ⁺ K ^?π⁺, 543D°→K ^?π⁺ andK ^?π⁺π^?π⁺ as well as 249D ⁺→K ^?π⁺π⁺ (or charge conjugate). 147 mesons out of our \({{D^0 } \mathord{\left/ {\vphantom {{D^0 } {\bar D^0 }}} \right. \kern-0em} {\bar D^0 }}\) sample were produced via chargedD ^* state. For all charmed mesons we determine the total production cross-section and study thex _F andp _t ² distributions.     

TheN\bar N and ππ decay modes of baryonium

A non-relativistic quark model is used to calculate the decay widths of baryonium states to \(N\bar N,N\bar \Delta \) , \(N\bar N,N\bar \Delta \) and \(\Delta \bar \Delta \) . Large widths are found and used to estimate the \(\bar pp\) and \(\bar pn\) elastic cross-sections. The couplings of baryonium states to two identical mesons are also investigated.     

Contributions toΛ c + →πΣ,πΛ andp\bar K^0 from excited states

We consider contributions to _c ⁺ , and from excited states. The calculations are performed within the MIT-bag model and a heavy quark bag model. Because the mass of _c ⁺ is rather big compared to the strange baryons, excited baryon states with mass close to that of _c ⁺ in some cases give significant pole contributions to the decay amplitudes of _c ⁺ .     

Measurement of the f1(1285) → π+π−π0 decay

The isospin symmetry-breaking (ISB) decay f ₁(1285) → π⁺π^?π⁰ has been studied at the VES facility. The branching ratio is measured: $\frac{{BR\left( {f_1 \to \pi ^ + \pi ^ - \pi ^0 } \right)}} {{BR\left( {f_1 \to \eta \pi ^ + \pi ^ - } \right)}} = 0.86 \pm 0.16_{ - 0.20}^{ + 0.70} \%Low-energy resonances in ³¹P(p, α ²⁸Si and ³⁵Cl(p, α)³²S were studied directly in order to gain a better understanding of reaction cycling in the Si-Ar region in novae. New resonance strengths at E _c.m. = 600 and 622 keV in ³¹P(p, α)²⁸Si were measured (ωγ _{p, α} = (2.2#x00B1;0.7) × 10^?2 eV and ωγ _{p, α} = (0.99±0.08) eV, respectively) as well as the E _c.m. = 610 keV resonance in ³⁵Cl(p, α)³²S [ωγ _{p, α} = (1.2±0.2) × 10^?2 eV], the lowest energy that any resonance in this reaction has been observed, directly or indirectly. The strengths of these resonances were found to be lower than previously determined, resulting in even weaker cycling in the Si-Ar region.     

Interplay between the intramolecular hydrogen bonds and cation–π interactions in various complexes of salicylaldehyde,thiosalicylaldehyde and selenosalicylaldehyde with Li+, Na+, K+, Mg2+ and Ca2+ cations

For the first time, the mutual influences of the intramolecular hydrogen bond (IMHB) and cation–π interactions in various complexes of salicylaldehyde, thiosalicylaldehyde and selenosalicylaldehyde with Li⁺, Na⁺, K⁺, Mg²⁺ and Ca²⁺ cations were studied. First, the strength of IMHB and cation–π interactions of the mentioned complexes by energetic, geometrical, spectroscopic, topological and molecular orbital parameters was evaluated and compared with the corresponding results of benzene–cation complexes and salicylaldehyde analogues. The results show that the coexistence of IMHB and cation–π interactions increases the IMHB strength and decreases the cation–π interactions. Second, the significance of π–electron delocalisation (π–ED) within the resonance-assisted hydrogen bond (RAHB) unit and aromaticity of benzene ring in the studied complexes were estimated by using the harmonic oscillator model of aromaticity and compared with the respective amounts of references. The results indicated that the mentioned coupling decreases the π–ED of RAHB unit and aromaticity of the benzene ring. In addition, it was found that variations in the strength of the interactions, π–ED and aromaticity, depend on the charge-to-radius ratio of cations. Finally, the effects of replacement of O by S and Se atoms in both of the mentioned cases were explored.     

Measurement of the decay rate and the parameter αK* of the decay KL → μμγ

The rate of the decay of the neutral K meson into K _L ⁰ → μμγ has been measured with the NA48 detector at the CERN SPS. A total of 59 events has been observed with an estimated background of 14 events. The overall Kaon flux was determined to be 1.2 × 10⁹. This observation corresponds to a branching ratio of (3.4 ± 0.6_stat ± 0.4_sys × 10^-7. Using this branching ratio the parameter α_K* describing the relative strength of the two contributing amplitudes to this decay, through intermediate pseudoscalar or vectorlike mesons, was measured to be α_K* = -0.04+ _-0.21 ^+0.24 .     

Effects of final-state interactions in pure annihilation decay of B s 0 → π+π −

The hadronic decay of B _s ⁰ → π ⁺ π ^? is analyzed by using “QCD factorization” (QCDF) method and final-state interaction (FSI). First, the B _s ⁰ → π ⁺ π ^? decay is calculated via QCDF method and the annihilation graphs only exist in this method. Hence, the FSI must be seriously considered to solve the B _s ⁰ → π ⁺ π ^? decay and the K ^+(*) K ^?(*) and \(K^{0(*)} K^{\bar 0(*)}\) via the exchange of K ^0(*) and K ^?(*) mesons are chosen for the intermediate states. To estimate the intermediate state amplitudes, the QCDF method is again used. These amplitudes are used in the absorptive part of the diagrams. The experimental branching ratio of B _s ⁰ → π ⁺ π ^? decay is less than 1.2 × 10^?6 and our results according to the QCDF method and FSI are 0.68 × 10^?8 and 1.18 × 10^?6, respectively.     

Final state interaction effects in the B + → D + K 0 decay

The exclusive decay of B ⁺ → D ⁺ K ⁰ is calculated by the QCD factorization method (QCDF) and final state interaction (FSI). First, the B ⁺ → D ⁺ K ⁰ decay is calculated via QCDF method. The result that is found by using the QCDF method is less than the experimental result. So FSI is considered to solve the B ⁺ → D ⁺ K ⁰ decay. For this decay, the D _s ⁺ π⁰, D _s ⁺ *ρ⁰, D _s ⁺ *? via the exchange of \(\bar K^0\) , \(\bar K^{0*} \) , D ^?, and D ^?* mesons are chosen for the intermediate states. The above intermediate states are calculated by using the QCDF method. In the FSI effects, the results of our calculations depend on η as the phenomenological parameter. The range of this parameter is selected from 2 to 2.4. It is found that if η = 2.4 is selected, the numbers of the branching ratio are placed in the experimental range. The experimental branching ratio of this decay is less than 2.9 × 10^?6 and our results calculated by QCDF and FSI are (0.16 ± 0.04) × 10^?6 and (2.8 ± 0.09) × 10^?6, respectively.     

Measurement of the CP-violating phase ϕ(s) in the decay B(s)(0) → J/ψϕ

We present a measurement of the time-dependent CP-violating asymmetry in B(s)(0) → J/ψ? decays, using data collected with the LHCb detector at the LHC. The decay time distribution of B(s)(0) → J/ψ? is characterized by the decay widths Γ(H) and Γ(L) of the heavy and light mass eigenstates, respectively, of the B(s)(0) - B(s)(0) system and by a CP-violating phase ?(s). In a sample of about 8500 B(s)(0) → J/ψ? events isolated from 0.37 fb(-1) of pp collisions at sqrt[s] = 7 TeV, we measure ?(s) = 0.15 ± 0.18(stat) ± 0.06(syst) rad. We also find an average B(s)(0) decay width Γ(s) ≡ (Γ(L) + Γ(H))/2 = 0.657 ± 0.009(stat) ± 0.008(syst) ps(-1) and a decay width difference ΔΓ(s) ≡ Γ(L) - Γ(H) = 0.123 ± 0.029(stat) ± 0.011(syst) ps(-1). Our measurement is insensitive to the transformation (?(s),ΔΓ(s)) ? (π - ?(s), -ΔΓ(s)).     

Status of the lattice and τ decay determinations of αs

The two highest precision determinations of α s （M 2 Z ）,that based on the analysis of short-distancesensitive lattice observables,and that based on an analysis of hadronic τ decay data,have,until very recently,given results which are not in good agreement.I review new versions of these analyses which bring the two determinations into excellent agreement,and discuss prospects for additional future improvements.     

Nuclear structure calculation ofβ + β +,β +/EC and EC/EC decay matrix elements

Nuclear matrix elements for double positron emisson ( ^{+ +}), positron emission/electron capture ( ⁺/ EC) and double electron capture (EC/EC) in the 2 decay mode and for ^{+ +} and ⁺/EC decay in the 0 mode are calculated for the experimentally most promising isotopes⁵⁸Ni,⁷⁸Kr,⁹⁶Ru,¹⁰⁶Cd,¹²⁴Xe,¹³⁰Ba and¹³⁶Ce within pn-QRPA. We point out that the matrix element for the 2 ⁺/EC decay differs from the 2 ^{+ +} matrix element, an effect not considered previously. For the neutrino accompanied decays our calculation predicts for the ⁺/EC and the EC/EC mode half lives which are shorter typically by 4–7 orders of magnitude than those for the double positron emission. However, even for the best candidates typical values for 2 ⁺/EC (2 EC/EC) are still in the range of 10²² ((some) 10²¹) years. For 0 decay we have calculated all matrix elements relevant for both, the mass mechanism and the right-handed currents for the first time complete. A detailed discussion of the differences between the 0 ⁺⁺, the 0 ⁺/EC and 0 ^{– –} decay is given.This work is supported in part by a Grant-in-Aid for Scientific Research (05243204) from the Ministry of Education, Science and Culture. One of us (M.H.) would like to thank the Japanese Ministry of Education, Science and Culture (Monbusho) for financial support. He also acknowledges valuable discussions with S.S.     

Study of Exclusive Hadronic Decays for D0→Ks0π+π- and D0→Ks0K+K- and Their Resonant Structures

We report the results of an experimental study of the exclusive hadronic decays for D0→K0 sπ+π - and K 0 sK +K - and their resonant structures using BES-Ⅰ detector at the BEPC Collider. Using the data sample of 22.3 pb -1 collected at the center-of-mass energy s=4.03 GeV, we measured the branching fraction for D 0→K 0π +π - to be (5.32±0.53±0.40)%, the branching fractions for the decays D 0→ K *-π +, D 0→K 0ρ 0 and D 0→K 0(π +π -) non-resonant to be (6.05±0.32±0.49)%, (1.17±0.17±0.13)% and (1.35±0.22±0.17)%, respectively. We measured the branching fractions Br(D 0→f) to be (1.04±0.24± 0.16)% for f=K 0K +K -, (1.12±0.34±0.15)% for f=K0, and (0.27±0.13±0.03)% for f=K 0(K+K-)non-.     

Differential branching fraction and angular analysis of the decay B0 → K*0 μ+ μ-

The angular distributions and the partial branching fraction of the decay B0 → K*0 μ+ μ- are studied by using an integrated luminosity of 0.37 fb(-1) of data collected with the LHCb detector. The forward-backward asymmetry of the muons, A(FB), the fraction of longitudinal polarization, F(L), and the partial branching fraction dB/dq2 are determined as a function of the dimuon invariant mass. The measurements are in good agreement with the standard model predictions and are the most precise to date. In the dimuon invariant mass squared range 1.00-6.00 GeV2/c4, the results are A(FB)=-0.06(-0.14)(+0.13)±0.04, F(L)=0.55±0.10±0.03, and dB/dq2=(0.42±0.06±0.03)×10(-7) c4/GeV2. In each case, the first error is statistical and the second systematic.     

Determination of the CP violating phase γ by a sum over common decay modes toB s and\bar B_s

To help the difficult determination of the angle γ of the unitarity triangle, Aleksan, Dunietz and Kayser have proposed the modes of the typeK ^? D _s ⁺ , common toB _s and $\bar B_s $ . We point out that it is possible to gain in statistics by a sum over all modes with ground state mesons in the final state, i.e.K ^? D _s ⁺ ,K ^*? D _s ⁺ ,K ^? D _s ^*+ ,K ^* D _s ^* . The delicate point is the relative phase of these different contributions to the dilution factorD of the time dependent asymmetry. Each contribution toD is proportional to a product $F^{cb} F^{ub} f_{D_s } f_K $ whereF denotes form factors andf decay constants. Within a definite phase convention (i.e. for example the one defined by the heavy quark symmetry in the limit of heavy quarks), lattice calculations do not show any change in sign when extrapolating to light quarks the form factors and decay constants. Then, we can show that all modes contribute constructively to the dilution factor, except theP-waveK ^* D _s ^*+ , which is small. Quark model arguments based on wave function overlaps also confirm this stability in sign. By summing over all these models we find a gain of a factor 6 in statistics relatively toK ^? D _s ⁺ . The dilution factor for the sumD _tot is remarkably stable for theoretical schemes that are not in very strong conflict with data onB→ψK(K ^*) or extrapolated from semileptonic charm form factors, givingD _tot≥0.6, always close toD(K ^? D _s ⁺ ).