5063164
Partially quenched study of strange baryon with Nf = 2 twisted mass fermions
7 pages, 9 figures, Talk presented at The XXVI International Symposium on Lattice Field Theory, LATTICE 2008, July 14 - 19, 2008, Williamsburg, Virginia, USA
118634793
Lattice study on $\eta_{c2}$ and X(3872)
Properties of 2(-+) charmonium eta(c2) are investigated in quenched lattice QCD. The mass of eta(c2) is determined to be 3.80(3) GeV, which is close to the mass of D-wave charmonium psi(3770) and in agreement with quark model predictions. The transition width of eta(c2) -> gamma J/psi is also obtained with a value of Gamma = 3.8(9) keV. Since the possible 2(-+) assignment to X(3872) has not been ruled out by experiments, our results help to clarify the nature of X(3872). DOI: 10.1103/PhysRevD.87.014501
37916668
Renormalization of bilinear quark operators for overlap fermions
We present nonperturbative renormalization constants of fermionic bilinears on the lattice in the quenched approximation at {beta}=6.1 using an overlap [H. Neuberger, Phys. Lett. B 417, 141 (1998)] fermion action with hypercubic (HYP)-blocked links. We consider the effects of the exact zero modes of the Dirac operator and find they are important in calculating the renormalization constants of the scalar and pseudoscalar density. The results are given in the RI' and MS schemes and compared to perturbative calculations.
18642908
Moments of meson distribution functions with dynamical twisted mass fermions
We present our preliminary results on the lowest moment hxi of quark distribution functions of the pion using two flavor dynamical simulations with Wilson twisted mass fermions at maximal twist. The calculation is done in a range of pion masses from 300 to 500 MeV. A stochastic source method is used to reduce inversions in calculating propagators. Finite volume effects at the lowest quark mass are examined by using two different lattice volumes. Our results show that we achieve statistical errors of only a few percent. We plan to compute renormalization constants non-perturbatively and extend the calculation to two more lattice spacings and to the nucleons.
16381056
Lattice QCD calculation of form factors describing the rare decays $B \to K^* \ell^+ \ell^-$ and $B_s \to \phi \ell^+ \ell^-$
The rare decays $B^0 \to K^{*0} \mu^+ \mu^-$ and $B_s \to \phi \mu^+ \mu^-$ are now being observed with enough precision to test Standard Model predictions. A full understanding of these decays requires accurate determinations of the corresponding hadronic form factors. Here we present results of lattice QCD calculations of the $B \to K^*$ and $B_s \to \phi$ form factors; we also determine the form factors relevant for the tree-level decays $B_s \to K^* \ell \nu$. We use full-QCD configurations including 2+1 flavors of sea quarks using an improved staggered action, and we employ lattice non-relativistic QCD to describe the bottom quark.
118450238
Oscillatory behavior of the domain wall fermions revisited
In the generic domain wall fermion formulation of chiral fermions on the lattice, the zero modes of the four-dimensional Wilson fermion operator with the negative mass parameter -M-5 introduce unphysical massive modes propagating in the four-dimensional spacetime. In the free fermion case, the pole mass of this kind of unphysical modes is given by (E) over bar = ln(1-M-5), which acquires an imaginary part, i pi, when M-5 > 1 and results in an oscillatory behavior of the domain wall fermion propagator in time. The existence of the unphysical modes in the presence of gauge fields is investigated in the mean field approximation, and their physical consequences are discussed. In addition, we also give a semiquantitative criterion for tuning M-5 in the realistic numerical study.
124550490
Study of $J/ψ → ωp\overline{p}$ at BESIII
14335700
Measurement of the topological branching fractions of the τ lepton at LEP
Using data collected with the L3 detector at LEP from 1992 to 1995 on the Z peak, we determine the branching fractions of the $\tau$ lepton into one, three and five charged particles to be: \begin{eqnarray*} & {\cal{B}}(\tau\rightarrow (1-prong)) & = 85.274 \pm 0.105 \pm 0.073 \% , \\ & {\cal{B}}(\tau\rightarrow (3-prong)) & = 14.556 \pm 0.105 \pm 0.076 \%, \\ & {\cal{B}}(\tau\rightarrow (5-prong)) & = \phantom{0} 0.170 \pm 0.022 \pm 0.026 \%. \end{eqnarray*} \noindent The first uncertainties are statistical and the second systematic. The accuracy of these measurements alone is similar to that of the current world avera
209843256
Search for branons at LEP
Abstract We search, in the context of extra-dimension scenarios, for the possible existence of brane fluctuations, called branons . Events with a single photon or a single Z-boson and missing energy and momentum collected with the L3 detector in e + e − collisions at centre-of-mass energies 2 = 189 – 209  GeV are analysed. No excess over the Standard Model expectations is found and a lower limit at 95% confidence level of 103  GeV is derived for the mass of branons, for a scenario with small brane tensions. Alternatively, under the assumption of a light branon, brane tensions below 180 GeV are excluded.
120266426
Inclusive charged hadron production in two photon collisions at LEP
Inclusive charged hadron production, $ m{e}^{+} m{e}^{-} ightarrow m{e}^{+} m{e}^{-}$ h$^{pm}$ X, is studied using 414 pb$^{-1}$ of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 202 GeV. Single particle inclusive differential cross sections are measured as a function of the particle transverse momentum, $p_t$, and pseudo-rapidity, $eta$. For $ p_t le 1.5$ GeV, the data are well described by an exponential, typical of soft hadronic processes. For higher $p_t$, the onset of perturbative QCD processes is observed. The $pi^{pm}$ production cross section for $p_t 5$ GeV is much higher than the NLO QCD predictions.
99260097
Charmonium decay and Charmoniumlike spectroscopy study in experiment