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+−.
12420090
Observation and properties of the orbitally excited B_(s2)(*) meson.
We report the direct observation of the excited L=1 state B_(s2)(*) in fully reconstructed decays to B+K-. The mass of the B_(s2)(*) meson is measured to be 5839.6+/-1.1(stat)+/-0.7(syst) MeV/c(2), and its production rate relative to the B+ meson is measured to be [1.15+/-0.23(stat)+/-0.13(syst)]%.
208869198
Measurement of angular correlations of jets at s=1.96 TeV and determination of the strong coupling at high momentum transfers
We present a measurement of the average value of a new observable at hadron colliders that is sensitive to QCD dynamics and to the strong coupling constant, while being only weakly sensitive to parton distribution functions. The observable measures the angular correlations of jets and is defined as the number of neighboring jets above a given transverse momentum threshold which accompany a given jet within a given distance Delta-R in the plane of rapidity and azimuthal angle. The ensemble average over all jets in an inclusive jet sample is measured and the results are presented as a function of transverse momentum of the inclusive jets, in different regions of Delta-R and for different transverse momentum requirements for the neighboring jets. The measurement is based on a data set corresponding to an integrated luminosity of 0.7 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider in pp-bar collisions at sqrt(s)=1.96 The results are well described by a perturbative QCD calculation in next-to-leading order in the strong coupling constant, corrected for non-perturbative effects. From these results, we extract the strong coupling and test the QCD predictions for its running over a range of momentum transfers of 50-400 GeV.
195944
Precision measurement of the top quark mass in lepton + jets final States.
We measure the mass of the top quark in lepton+jets final states using the full sample of pp collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at sqrt[s] = 1.96 TeV, corresponding to 9.7 fb(-1) of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from tt production or background. The overall jet energy scale is constrained in situ by the mass of the W boson. We measure m(t) = 174.98 ± 0.76 GeV. This constitutes the most precise single measurement of the top-quark mass.
12834301
Jet energy scale determination in the D0 experiment
The calibration of jet energy measured in the DO detector is presented, based on p (p) over bar collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider, jet energies are measured using a sampling calorimeter composed of uranium and liquid argon as the passive and active media, respectively. This paper describes the energy calibration of jets performed with gamma+jet, Z+jet and dilet events, with jet transverse momentum p(T) > 6 GeV and pseudorapidity range vertical bar eta vertical bar < 3.6, The corrections are measured separately for data and simulation, achieving a precision of 1.4-1.8% for jets in the central part of the calorimeter ancl up to 3.5% for the jets with pseudorapidity vertical bar eta vertical bar = 3.0. Specific corrections are extracted to enhance the description of jet energy in simulation and in particular of the effects due to the flavor of the parton originating the jet, correcting biases up to 3-4% in jets with low PT originating from gluons and up to 6-8% in jets from b quarks. Published by Elsevier B.V.
15350493
Search for long-lived particles decaying into electron or photon pairs with the D0 detector.
In this Letter we report on a search for long-lived particles that decay into final states with two electrons or photons. Such long-lived particles arise in a variety of theoretical models, such as hidden valleys and supersymmetry with gauge-mediated breaking. By precisely reconstructing the direction of the electromagnetic shower we are able to probe much longer lifetimes than previously explored. We see no evidence of the existence of such long-lived particles and interpret this search as a quasi model-independent limit on their production cross section, as well as a limit on a long-lived fourth generation quark.
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.
15639610
SU(3)-Equivariant Quiver Gauge Theories and Nonabelian Vortices
We consider SU(3)-equivariant dimensional reduction of Yang-Mills theory on Kahler manifolds of the form M × SU(3)/H, with H = SU(2) × U(1) or H = U(1) × U(1). The induced rank two quiver gauge theories on M are worked out in detail for representations of H which descend from a generic irreducible SU(3)-representation. The reduction of the Donaldson-Uhlenbeck-Yau equations on these spaces induces nonabelian quiver vortex equations on M, which we write down explicitly. When M is a noncommutative deformation of the space d, we construct explicit BPS and non-BPS solutions of finite energy for all cases. We compute their topological charges in three different ways and propose a novel interpretation of the configurations as states of D-branes. Our methods and results generalize from SU(3) to any compact Lie group.
2313047
The Topological B-model on a Mini-Supertwistor Space and Supersymmetric Bogomolny Monopole Equations
In the recent paper [1], it was argued that the open topological B-model whose target space is a complex (2|4)-dimensional mini-supertwistor space with D3- and D1-branes added corresponds to a super Yang-Mills theory in three dimensions. Without the D1-branes, this topological B-model is equivalent to a dimensionally reduced holomorphic Chern-Simons theory. Identifying the latter with a holomorphic BF-type theory, we describe a twistor correspondence between this theory and a supersymmetric Bogomolny model on 3. The connecting link in this correspondence is a partially holomorphic Chern-Simons theory on a Cauchy-Riemann supermanifold which is a real one-dimensional fibration over the mini-supertwistor space. Along the way of proving this twistor correspondence, we review the necessary basic geometric notions and construct action functionals for the involved theories. Furthermore, we discuss the geometric aspect of a recently proposed deformation of the mini-supertwistor space, which gives rise to mass terms in the supersymmetric Bogomolny equations. Eventually, we present solution generating techniques based on the developed twistorial description together with some examples and comment briefly on a twistor correspondence for super Yang-Mills theory in three dimensions.
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).
18586470
Hidden Symmetries and Integrable Hierarchy of the N = 4 Supersymmetric Yang-Mills Equations
We describe an infinite-dimensional algebra of hidden symmetries of N = 4 supersymmetric Yang-Mills (SYM) theory. Our derivation is based on a generalization of the supertwistor correspondence. Using the latter, we construct an infinite sequence of flows on the solution space of the N = 4 SYM equations. The dependence of the SYM fields on the parameters along the flows can be recovered by solving the equations of the hierarchy. We embed the N = 4 SYM equations in the infinite system of the hierarchy equations and show that this SYM hierarchy is associated with an infinite set of graded symmetries recursively generated from supertranslations. Presumably, the existence of such nonlocal symmetries underlies the observed integrable structures in quantum N = 4 SYM theory. On leave from Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna, Russia. Address after October 1st, 2006: Theoretical Physics Group, The Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom.