Search for the standard model Higgs boson in the H→WW→lνq'q decay channel

We present a search for the standard model Higgs boson (H) in pp collisions at sqrt(s)=1.96 TeV in events containing a charged lepton (?), missing transverse energy, and at least two jets, using 5.4 fb(-1) of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. This analysis is sensitive primarily to Higgs bosons produced through the fusion of two gluons or two electroweak bosons, with subsequent decay H→WW→?νq'q, where ? is an electron or muon. The search is also sensitive to contributions from other production channels, such as WH→?νbb. In the absence of a signal, we set limits at the 95% C.L. on the cross section for H production σ(pp→H+X) in these final states. For a mass of M(H)=160 GeV, the limit is a factor of 3.9 larger than the cross section in the standard model and consistent with an a priori expected sensitivity of 5.0.     

Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV

Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.     

Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV

We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.     

Precision measurement of the ratio B(t→Wb)/B(t→Wq) and extraction of V(tb)

We present a measurement of the ratio of top quark branching fractions R=B(t→Wb)/B(t→Wq), where q can be a d, s, or b quark, in the lepton+jets and dilepton tt final states. The measurement uses data from 5.4 fb(-1) of pp collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure R=0.90±0.04, and we extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |V(tb)| as |V(tb)|=0.95±0.02, assuming unitarity of the 3×3 CKM matrix.     

Ozone photolysis: determination of the O(3P) quantum yield at 266 nm

Direct production of O(³P) from the photodissociation of O₃ at 266 nm has been observed by time-resolved resonance fluorescence following laser flash photolysis. The quantum yield for O(³P) production was determined to be 0.12 = 0.02 at this wavelength. This result confirms the qualitative observations of two previous photofragment studies and establishes an absolute value of Φ(O¹D)) = 0.88. This value has been used as a basis for normalizing relative quantum yields in the falloff region, and interpreting O(¹D) kinetics studies.     

An intuitionistic formula hierarchy based on high‐school identities

We revisit the notion of intuitionistic equivalence and formal proof representations by adopting the view of formulas as exponential polynomials. After observing that most of the invertible proof rules of intuitionistic (minimal) propositional sequent calculi are formula (i.e., sequent) isomorphisms corresponding to the high‐school identities, we show that one can obtain a more compact variant of a proof system, consisting of non‐invertible proof rules only, and where the invertible proof rules have been replaced by a formula normalization procedure. Moreover, for certain proof systems such as the G4ip sequent calculus of Vorob'ev, Hudelmaier, and Dyckhoff, it is even possible to see all of the non‐invertible proof rules as strict inequalities between exponential polynomials; a careful combinatorial treatment is given in order to establish this fact. Finally, we extend the exponential polynomial analogy to the first‐order quantifiers, showing that it gives rise to an intuitionistic hierarchy of formulas, resembling the classical arithmetical hierarchy, and the first one that classifies formulas while preserving isomorphism.