10189692
Combination of the top-quark mass measurements from the Tevatron collider
We thank the Fermilab staff and technical staffs of the 
participating institutions for their vital contributions and 
acknowledge support from the DOE and NSF (USA), ARC 
(Australia), CNPq, FAPERJ, FAPESP, and FUNDUNESP 
(Brazil), NSERC (Canada), NSC, CAS, and CNSF 
(China), Colciencias (Colombia), MSMT and GACR 
(Czech Republic), the Academy of Finland, CEA, and 
CNRS/IN2P3 (France), BMBF and DFG (Germany), 
DAE and DST (India), SFI (Ireland), INFN (Italy), 
MEXT (Japan), the Korean World Class University 
Program and NRF (Korea), CONACyT (Mexico), FOM 
(Netherlands), MON, NRC KI, and RFBR (Russia), the 
Slovak R&D Agency, the Ministerio de Ciencia e 
Innovacio´n, and Programa Consolider-Ingenio 2010 
(Spain), The Swedish Research Council (Sweden), SNSF 
(Switzerland), STFC and the Royal Society (United 
Kingdom), and the A. P. Sloan Foundation (USA).
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.
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.
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.
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)]%.
16559244
Noncommutative solitons in open N=2 string theory
Coincident D2-branes in open N = 2 fermionic string theory with a B-field background yield an integrable modified U(n) sigma model on noncommutative 2,1. This model provides a showcase for an established method (the `dressing approach') to generate solutions for integrable field equations, even in the noncommutative case. We demonstrate the technique by constructing moving U(1) and U(2) solitons and by computing their energies. It is outlined how to derive multi-soliton configurations with arbitrary relative motion; they correspond to D0-branes moving inside the D2-branes.
15740394
Seiberg–Witten monopole equations on noncommutative R4
It is well known that, due to vanishing theorems, there are no nontrivial finite action solutions to the Abelian Seiberg–Witten (SW) monopole equations on Euclidean four-dimensional space R4. We show that this is no longer true for the noncommutative version of these equations, i.e., on a noncommutative deformation Rθ4 of R4 there exist smooth solutions to the SW equations having nonzero topological charge. We introduce action functionals for the noncommutative SW equations and construct explicit regular solutions. All our solutions have finite energy. We also suggest a possible interpretation of the obtained solutions as codimension four vortex-like solitons representing D(p−4)- and D(p−4)¯-branes in a Dp-Dp¯ brane system in type II superstring theory.
14570856
Quiver Gauge Theory and Noncommutative Vortices
We construct explicit BPS and non-BPS solutions of the Yang-Mills equations on noncommutative spaces R 2n � × G/H which are manifestly G-symmetric. Given a G-representation, by twisting with a particular bundle over G/H, we obtain a Gequivariant U(k) bundle with a G-equivariant connection over R 2n � × G/H. The U(k)
115387889
On spontaneous compactification of superstrings with torsion
We consider the spontaneous compactification of the field-theory limit of superstrings with a nonvanishing antisymmetric tensor H/sub M//sub N//sub P/. The existence of a class of solutions with internal spaces of constant negative curvature and vanishing cosmological constant is proved. Compactification to Ricci-flat spaces (in particular, to Calabi--Yau manifolds) is realized in the limit H/sub M//sub N//sub P/..-->..0.
121257668
FOCK BUNDLES AND QUANTIZATION OF SYSTEMS WITH FIRST CLASS CONSTRAINTS
The flat phase space (R2n, ω) with a symmetry group G generated by quadratic first class constraints is considered. We analyze the quantization of this constrained system in terms of the Fock bundle , where S=Sp(2n, R)/U(n) is the space of positive translationally invariant complex structures J on (R2n, ω) and fibers HJ are the Hilbert spaces of quantization associated with the space (R2n, ω, J).