120112297
Fundamental chiral strings
The problem of the non-uniqueness of the string theory in the space Rd-1,1 with d ≤ 10 and the procedure of the compactification and the deompactification are discussed. We consider a compact bosonic string defined as a closed string moving in the Lorentizian torus T25,1 and introduce fundamental chiral bosonic string (FCBS) as a universal cover of a compact string. It is shown that the Fock spaces of any standard strings are embedded into the Fock space of FCBS.
122917668
Dimensional reduction method and meson mass spectrum in unified multidimensional field theory
A new method is suggested for dimensional reduction of a langrangian defined in a 4+N-dimensional spacetime fiber bundle into a four-dimensional “effective” langrangian. The method is considered for the particular case of N=4. Mass formulas are obtained for mesons with charge, isospin etc., mass splitting of meson multiplets neglected. Taking the mass of the pion as an input, other mesons' masses are computed. The masses predicted are in good agreement with the experiment (Δm/m<0.04).
14915418
On nonperturbative solutions of superstring field theory
Abstract Nonperturbative solutions to the nonlinear field equations in the NS sector of cubic as well as nonpolynomial superstring field theory can be obtained from a linear equation which includes a “spectral” parameter λ and a coboundary operator Q ( λ ). We borrow a simple ansatz from the dressing method (for generating solitons in integrable field theories) and show that classical superstring fields can be constructed from any string field  T subject merely to Q ( λ ) T =0. Following the decay of the non-BPS D9 brane in IIA theory and shifting the background to the tachyon vacuum, we repeat the arguments in vacuum superstring field theory and outline how to compute classical solutions explicitly.
121020880
Vortices, strings, and pseudoinstantons
15445916
Noncommutative 't Hooft instantons
We employ the twistor approach to the construction of U(2) multi-instantons a la 't Hooft on non-commutative 4. The non-commutative deformation of the Corrigan-Fairlie-'t Hooft-Wilczek ansatz is derived. However, naively substituting into it the 't Hooft-type solution is unsatisfactory because the resulting gauge field fails to be self-dual on a finite-dimensional subspace of the Fock space. We repair this deficiency by a suitable Murray-von Neumann transformation after a specific projection of the gauge potential. The proper non-commutative 't Hooft multi-instanton field strength is given explicitly, in a singular as well as in a regular gauge.
121271402
Meron-type solutions of the Yang-Mills equations in 4n dimensions
The Yang-Mills theory in d = 4n with an arbitrary gauge group G is considered. Using the generalization of the Corrigan-Fairlie-'t Hooft-Wilczek ansatz, we reduce the Yang-Mills equation in 4n dimensions to simpler equations. As an example, for G = SU(2) we write out the explicit form of some solutions that are 4n-dimensional analogues of the d = 4 meron solutions.
120672843
Exotic meson production in BNL experiment E852
The status of spin-exotic mesons is reviewed. There is now compelling evidence for at least three π1 states between one and two GeV. Preliminary results from the reaction π−p → π+π+π−π−π0p show structure in the exotic waves corresponding to IGJPC = 0−2+−.
118241188
Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron
The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.
14338627
Evidence for production of single top quarks
We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p (p) over bar collider. The standard model predicts that the electroweak interaction c ...
118282787
A Partial wave analysis of the pi- pi- pi+ and pi- pi0 pi0 systems and the search for a J**PC = 1-+ meson
A partial wave analysis (PWA) of the $\pi^- \pi^- \pi^+$ and $\pi^- \pi^0 \pi^0$ systems produced in the reaction $\pi^- p \to (3\pi)^-p$ at 18 GeV/$c$ was carried out using an \emph{isobar} model assumption. This analysis is based on 3.0M $\pi^- \pi^0 \pi^0$ events and 2.6M $\pi^- \pi^-\pi^+$ events and shows production of the $a_1(1260)$, $a_2(1320)$, $\pi_2(1670)$ and $a_4(2040)$ resonances. Results of detailed studies of the stability of partial wave fits are presented. An earlier analysis of 250K $\pi^- \pi^- \pi^+$ events from the same experiment showed possible evidence for a $J^{PC}=1^{-+}$ exotic meson with a mass of $\sim$1.6 GeV/$c^2$ decaying into $\rho \pi$. In this analysis of a higher statistics sample of the $(3\pi)^-$ system in two charged modes we find no evidence of an exotic meson.
1147194
Experimental discrimination between charge 2e/3 top quark and charge 4e/3 exotic quark production scenarios.
We present the first experimental discrimination between the 2e/3 and 4e/3 top quark electric charge scenarios, using top quark pairs (tt) produced in pp collisions at (square root) s = 1.96 TeV by the Fermilab Tevatron Collider. We use 370 pb;{-1} of data collected by the D0 experiment and select events with at least one high transverse momentum electron or muon, high transverse energy imbalance, and four or more jets. We discriminate between b- and b-quark jets by using the charge and momenta of tracks within the jet cones. The data are consistent with the expected electric charge, |q|=2e/3. We exclude, at the 92% C.L., that the sample is solely due to the production of exotic quark pairs QQ with |q|=4e/3. We place an upper limit on the fraction of QQ pairs rho<0.80 at the 90% C.L.