121273996
A study of double tagged two-photon reactions at spear☆
Abstract We have identified 262 doubly tagged two-photon events. A subset of the data shows an enhancement of 21 events in the inclusive two-photon mass squared distribution between 0.8 and 2.2 GeV 2 . If these events result from spin 2 resonance production then Γ γγ = 9.5 ± 3.9 ± 2.4 keV (statistical and systematic). From another subset of 58 events in which the final state could be classified we determine the two-photon hadron to muon cross section ratio R γγ = 1.1 ± 0.3 ± 0.3.
122233998
Comparison and summary of tau topological branching fractions
After nearly two decades of work on topological branching fractions, it appears that an experimental consensus is forming. The new world average is 14.54 ± 0.20.
118236755
Recent Results in Charmless Hadronic B Decays from BABAR
We report results from five analyses based on data taken with the BABAR detector at the PEP-II asymmetric e{sup +}e{sup -} collider. Included are branching fraction measurements for many B-meson decays involving {eta}, {eta}{prime}, {omega}, {phi} or a{sub 0} mesons and the final state K{sub s}{sup 0}{pi}{sup +}{pi}{sup -}, and a full angular analysis of the decay B{sup 0} {yields} {phi}K*{sup 0}.
14586426
Review of New Rare Hadronic B-decay Results
We present a new result from Belle and many new results from BABAR for rare hadronic B decays. These include measurements of decays involving baryons, a Dalitz plot analysis of the three-charged-kaon system, many new results for B decays to eta'X and omegaX, and a limit for the decay B-> a_1 rho. Measurements of the vector-vector decays B->rhoKstar and B->omegaKstar are helping to understand the value of the longitudinal polarization fraction for these B->VV decays.
15188676
Calibration and performance of the MARK II drift chamber vertex detector
We have calibrated and studied the performance of the MARK II drift chamber vertex detector with cosmic ray tracks collected with the chamber inside the MARK II detector at the SLC. The chamber achieves 30 {mu}m impact parameter resolution and 500 {mu}m track-pair resolution using CO{sub 2}/C{sub 2}H{sub 6}H{sub 6}(92/8) at 2 atmospheres pressure. The chamber has successfully recorded Z{sup 0} decays at the SLC, and resolved tracks in dense hadronic jets with good efficiency and high accuracy. 5 refs., 13 figs.
120135663
Studies of tau decay modes with K0 mesons from CLEO
We examine five final states involving K 0 mesons, presenting branching fractions for the decays τ → K 0 πν τ , τ → K 0 ππ 0 ν τ , τ → K 0 Kν τ , τ → K 0 Kπ 0 ν τ , and τ → K s K s hν τ . The mass spectra provide evidence for the dominant role of K * in Kπ decays and K 1 in Kππ modes. We find evidence for a significant K * K contribution to the KKπ decays.
119473292
J/Psi and Psi' Polarizations in Polarized Proton-Proton Collisions at the RHIC
We study inclusive heavy quarkonium production with definite polarizations in polarized proton-proton collisions using the non-relativistic QCD color-octet mechanism. We present results for rapidity distributions of cross sections and spin asymmetries for the production of J/psi and psi' with specific polarizations in polarized p-p collisions at \sqrt s = 200 GeV and 500 GeV at the RHIC within the PHENIX detector acceptance range.
16345343
NLO distributions for Higgs production at the LHC
We report on results for the NLO corrected differential distributions dσdpT and dσdy for the process p + p → H +′ X ′, where pT and y are the transverse momentum and rapidity of the Higgs-boson H respectively and X denotes the inclusive hadronic state. All QCD partonic subprocesses have been included. The computation is carried out in the limit that the top-quark mass mt → ∞. Our calculations reveal that the dominant subprocess is given by g + g → H +′ X′ but the reaction g + q(q) → H +′ X′ is not negligible. Also the K-factor representing the ratio between the next-to-leading order and leading order differential distributions varies from 1.4 to 1.7 depending on the kinematic region and choice of parton densities.
119484471
The difference between n-dimensional regularization and n-dimensional reduction in QCD
Abstract.We discuss the difference between n-dimensional regularization and n-dimensional reduction for processes in QCD which have an additional mass scale. Examples are heavy flavor production in hadron-hadron collisions or on-shell photon-hadron collisions where the scale is represented by the mass m. Another example is electroproduction of heavy flavors where we have two mass scales given by m and the virtuality of the photon $\smash[b]{Q = \sqrt{-q^2}}$. Finally we study the Drell-Yan process where the additional scale is represented by the virtuality $\smash[t]{Q = \sqrt{q^2}}$ of the vector boson ($\gamma^*, W, Z$). The difference between the two schemes is not accounted for by the usual oversubtractions. There are extra counter terms which multiply the mass scale dependent parts of the Born cross sections. In the case of the Drell-Yan process it turns out that the off-shell mass regularization agrees with n-dimensional regularization.
119411437
Comparison between variable flavor number schemes for charm quark electroproduction
A comparison is made between two variable flavor number schemes which describe charm quark production in deep inelastic electron-proton scattering. In these schemes the coefficient functions are derived from mass factorization of the heavy quark coefficient functions presented in a fixed flavor number scheme. Since the coefficient functions in the variable flavornumber schemes have to be finite in the limit m → 0 we have defined a prescription for those processes where the virtual photon is attached to a light quark. Furthermore one has to construct a parton density set with four active flavors (u,d,s,c) out of a set which only contains three light flavors (u,d,s). In order � 2 the two sets are discontinuous at µ = mc which follows from mass factorization of the heavy quark coefficient functions. The charm component ofthe structure function F2,c is insensitive to the different variable flavor number schemes. In particular in the threshold region they both agree with the description in fixed order perturbation theory presented in a three flavor scheme. However one version does not lead to a correct description of the threshold behavior of the longitudinal structure function FL,c. This happens when one requires a non-vanishing zeroth order longitudinal coefficient function.
121445609
All-order resummation of soft gluon contributions to heavy quark production in hadron-hadron collisions
Abstract We investigate the all-order resummation of soft collinear gluon emission from initial quarks and gluons participating in heavy quark inclusive production. A resummation formula is used to calculate both the cross section and the inclusive transverse momentum distribution of the heavy (anti)-quark. Results are given for a top quark in mass range 100 GeV ⩽ m ⩽ 200 GeV to be explored in p p experiments at the Fermilab Tevatron.