36892867
Perturbative QCD predictions for the fragmentation functions of the P- wave mesons with two heavy quarks.
The fragmentation functions for the heavy mesons of [ital S] and [ital P] waves are calculated in the framework of perturbative QCD and the nonrelativistic quark model. The results are manifestly process independent. As applications, the production ratios for [ital P]-wave [ital [bar b]c] mesons to the [ital b[bar b]] production at high energy colliders are predicted. The spin dependence of the fragmentation functions for various states is discussed and the predicted results for the [ital D] ([ital D][sup *]) mesons are consistent with the recent experimental data.
119107781
QCD corrections to single slepton production at hadron colliders
We evaluate the cross section for single slepton production at hadron colliders in supersymmetric theories with R-parity violating interactions to the next-to-leading order in QCD. We obtain fully differential cross section by using the phase space slicing lethod. We also perform soft-gluon resummation to all order in alpha(s) of leading logarithm to obtain a complete transverse momentum spectrum of the slepton. We find that the full transverse momentum spectrum is peaked at a few GeV, consistent with the early results for Drell-Yan production of lepton pairs. We also consider the contribution from gluon fusion via quark-triangle loop diagrams dominated by the b-quark loop. The cross section of this process is significantly smaller than that of the tree-level process induced by the initial b (b) over bar annihilation.
120782930
On the reparameterization invariance in heavy quark effective theory
Abstract The reparameterization invariance in Heavy Quark Effective Theory is reconsidered. Starting from an effective Lagrangian derived from QCD full theory, a consistent transformation law for the heavy quark effective field under the variation of the parameter v is obtained and the reparameterization invariance in the effective Lagrangian is shown.
124674675
EXPERIMENTAL STUDY OF J/PSI RADIATIVE DECAY TO PI 0PI 0
9063079
The Physics of the B Factories
This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C.
120909739
Relativistic corrections to heavy quark fragmentation to S-wave heavy mesons
The relativistic corrections of order v{sup 2} to the fragmentation functions for the heavy quark to S-wave heavy quarkonia are calculated in the framework of the nonrelativistic quantum chromodynamics factorization formula. We derive the fragmentation functions by using the Collins-Soper definition in both the Feynman gauge and the axial gauge. We also extract them through the process Z{sup 0}{yields}Hqq in the limit M{sub Z}/m{yields}{infinity}. We find that all results obtained by these two different methods and in different gauges are the same. We estimate the relative size of the relativistic corrections to the fragmentation functions.
40500552
Measurement of the bottom-quark production cross section in 800 GeV/c proton-gold collisions.
Using a silicon-microstrip detector array to identify secondary vertices, we have observed {ital b}{r_arrow}{ital J}/{psi}{r_arrow}{mu}{sup +}{mu}{sup {minus}} decays in 800 GeV/{ital c} proton-gold interactions. The doubly differential cross section for {ital J}/{psi} mesons originating from {ital b}-quark decays, assuming linear dependence on nucleon number, is {ital d}{sup 2}{sigma}/{ital dx}{sub {ital Fdp}}{sup 2}{sub {ital T}}=107{plus_minus}28{plus_minus}19/nucleon at {ital x}{sub {ital F}}=0.05 and {ital p}{sub {ital T}}=1GeV/{ital c}. This measurement is compared to next-to-leading-order QCD predictions. The integrated {ital b}-quark production cross section, obtained by extrapolation over all {ital x}{sub {ital F}} and {ital p}{sub {ital T}}, is {sigma}({ital pN}{r_arrow}{ital bb}{ovr bar}+{ital X})=5.7{plus_minus}1.5{plus_minus}1.3 nb/nucleon.
18727634
Mott transition in an anyon gas.
We introduce and analyze a lattice model of anyons in a periodic potential and an external magnetic field, which exhibits a transition from a Mott insulator to a quantum Hall fluid. The transition is characterized by the anyon statistics [alpha], which can vary between fermions, [alpha]=0, and bosons, [alpha]=1. For bosons the transition is in the universality class of the classical three-dimensional [ital XY] model. Near the fermion limit, the transition is described by a massless 2+1 Dirac theory coupled to a Chern-Simons gauge field. Analytic calculations perturbative in [alpha], and also a large-[ital N] expansion, show that due to gauge fluctuations, the critical properties of the transition are dependent on the anyon statistics. Comparison with previous calculations at and near the boson limit, strongly suggest that our lattice model exhibits a fixed line of critical points, with universal critical properties that vary continuously and monotonically as one passes from fermions to bosons. Possible relevance to experiments on the transitions between plateaus in the fractional quantum Hall effect and the magnetic-field-tuned superconductor-insulator transition are briefly discussed.
43134745
Free heterotic string field theory.
A gauge-fixed action is constructed for the free heterotic string based on the bosonic string and the Neveu-Schwarz-Ramond (NSR) superstring by the Becchi-Rouet-Stora-Tyutin approach. The field theory gives a balance condition; it replaces the Gliozzi-Scherk-Olive projector in the NS sector to eliminate the tachyons and to ensure that the states have the correct spin statistics. At the massless level we get a ten-dimensional linearized supergravity, a ten-dimensional linearized super-Yang-Mills field with the gauge group E/sub 8/ x E/sub 8/ or Spin(32)/Z/sub 2/, a dilaton, an interesting dilatonlike Majorana-Weyl spinor, and so on.
42992975
Study of the strong coupling constant using W+jet processes.
The ratio of the number of W + 1 jet to W + 0 jet events is measured with the D0 detector using data from, the 1992--93 Tevatron Collider run. For the W {yields} e{nu} channel with a minimum jet E{sub T} cutoff of 25 GeV, the experimental ratio is 0.065 {+-} 0.003(stat) {+-} 0.007(sys). Next-to-Leading order QCD predictions for various parton distributions agree well with each other and are all over one standard deviation below the measurement. Varying the strong coupling constant {alpha}{sub s} in both the parton distributions and the partonic cross sections simultaneously does not remove this discrepancy.
43756291
Top quark search with the D0 1992-1993 data sample.
We present results on the search for the top quark in {ital p{bar p}} collisions at {radical}{ital s} =1.8 TeV with an integrated luminosity of 13.5{plus_minus}1.6 pb{sup {minus}1}. We have considered {ital t{bar t}} production in the standard model using electron and muon dilepton decay channels ({ital t{bar t}}{r_arrow}{ital e}{mu}+jets, {ital ee}+jets, and {mu}{mu}+jets) and single-lepton decay channels ({ital t{bar t}}{r_arrow}{ital e}+jets and {mu}+jets) with and without tagging of {ital b} quark jets. An analysis of these data optimized for top quark masses below 140 GeV/{ital c}{sup 2} gives a lower top quark mass limit of 128 GeV/{ital c}{sup 2}. An analysis optimized for higher top quark masses yields 9 events with an expected background of 3.8{plus_minus}0.9. If we assume that the excess is due to {ital t{bar t}} production, and assuming a top quark mass of 180 GeV/{ital c}{sup 2}, we obtain a cross section of 8.2{plus_minus}5.1 pb.