27068281
Measurement of the near-threshold e+e- --> D(*)+/-D(*)-/+ cross section using initial-state radiation.
We report a measurement of the exclusive e+e- -->D(*)+/-D*-/+ cross section as a function of center-of-mass energy near the D(*)+/-D*-/+ threshold with initial-state radiation. A partial reconstruction technique is used to increase the efficiency and to suppress background. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of 547.8 fb(-1).
100409752
Observation of B0 ---> a+-(1) (1260) pi-+
40146055
Measurement of forward-backward asymmetry and Wilson coefficients in B --> K*l+l-.
We report the first measurement of the forward-backward asymmetry and the ratios of Wilson coefficients and in A9/A7 and A10/A7 in B --> K*l+l-, where l represents an electron or a muon. We find evidence for the forward-backward asymmetry with a significance of 3.4sigma. The results are obtained from a data sample containing 386 x 10(6) BB pairs that were collected on the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.
207845948
Improved measurement of Anti-B0 ---> D(s)- D+ and search for anti-B0 ---> D(s)+ D(s)- at BELLE
180004720
Observation of B ---> phi phi K Decays
44272712
Improved evidence for direct CP violation in B0-->pi+pi- decays and model-independent constraints on phi2.
We present a new measurement of the time-dependent CP-violating parameters in B(0)--> pi(+)pi(-) decays with 275 x 10(6) BB pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating at the Gamma(4S) resonance. We find 666 +/- 43 B(0) --> pi(+)pi(-) events and measure the CP-violating parameters: S(pipi) = -0.67 +/- 0.16(stat) +/- 0.06(syst) and A(pipi) = +0.56 +/- 0.12(stat) +/- 0.06(syst). We find evidence for large direct CP violation with a significance greater than 4 standard deviations for any S(pipi) value. Using isospin relations, we obtain 95.4% confidence intervals for the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi(2) of 0 degree < phiv(2) < 19 degrees and 71 degrees < phi(2) < 180 degrees.
14423824
Properties of color singlet chain states in e+ e- annihilation
We use the method of the color effective Hamiltonian to study the structure of color singlet chain states in ${N}_{c}=3$ and in the large ${N}_{c}$ limit. In order to obtain their total fraction when ${N}_{c}$ is finite, we illustrate how to orthogonalize these nonorthogonal states. We give numerical results for the fraction of orthogonalized states in ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}q\overline{q}\mathrm{gg}.$ With the help of a diagram technique, we derive their fraction up to ${O(1/N}_{c}^{2})$ for the general multigluon process. For large ${N}_{c}$ the singlet chain states correspond to well-defined color topologies. Therefore we may expect that the fraction of non-color-singlet-chain states is an estimate of the fraction of events where color reconnection is possible. In the case of soft gluon bremsstrahlung, we give an explicit form for the color effective Hamiltonian which leads to the dipole cascade formulation for parton showering in leading order in ${N}_{c}.$ The next-to-leading order corrections are also given for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}q\overline{q}{g}_{1}{g}_{2}$ and ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}q\overline{q}{g}_{1}{g}_{2}{g}_{3}.$
115989990
Contribution of color singlet process upsilon ---> J / psi + c anti-c g to upsilon ---> J / psi + X
We show that the colour-singlet process $\Upsilon \to J/\Psi + c\bar{c}g$ significantly contributes to the inclusive process $\Upsilon \to J/\Psi + X$. We calculate the partial width and the momentum distribution of the produced $J/\Psi$ in this channel. The obtained width is comparable to the experimental data. The momentum distribution is fairly soft, which is in contrast to the results from the colour-octet processes discussed earlier in literature but is consistent with the CLEO measurements. Further experiments to check this contribution are suggested.
125751010
Energy and centrality dependence of the contribution from leading particles to charged-particle pseudorapidity distribution
121542763
Lowest-order contribution of soft gluon rescattering for large rapidity gap events in DIS
Using a powerful PQCD technique developed by Luo, Qiu and Sterman, we derive the diffractive structure functions at the lowest order. The procedure leading to these results is straightforward. More importantly, in this approach, we find that, effectively, there are no double hard scatterings of gluons responsible for the diffractive process at lowest order. The dominant scattering process must involve a soft gluon. This soft gluon contributes to the process only by adding two colour vertex terms to the cross section without affecting the kinematic state, thus the kinematics is the same as that of the PGF process. Our approach displays the important role played by the soft gluon in LRG events exactly.
119452619
Charged-particle rapidity density in Au+Au collisions in a quark combination model
Rapidity/pseudorapidity densities for charged particles and their centrality, rapidity, and energy dependence in Au+Au collisions at the Relativistic Heavy Ion Collider are studied in a quark combination model. Using a Gaussian-type rapidity distribution for constituent quarks as a result of Landau hydrodynamic evolution, the data at {radical}(s{sub NN})=130,200 GeV at various centralities in full pseudorapidity range are well described, and the charged-particle multiplicities are reproduced as functions of the number of participants. The energy dependence of the shape of the dN{sub ch}/d{eta} distribution is also described at various collision energies {radical}(s{sub NN})=200,130,62.4 GeV in central collisions with same value of parameters except 19.6 GeV. The calculated rapidity distributions and yields for the charged pions and kaons in central Au+Au collisions at {radical}(s{sub NN})=200 GeV are compared with experimental data of the BRAHMS Collaboration.