122657028
Three jet production in neutral current deep inelastic scattering with ZEUS at HERA
i
117840720
Top Quark Production at the Tevatron Collider
Top quark physics has been a rich testing ground for the standard model since the top quark discovery in 1995. The large mass of top quark suggests that it could play a special role in searches for new phenomena. In this paper I provide an overview of recent top quark production cross section measurements from both CDF and D0 collaborations and also some new physics searches done in the top quark sector.
125836359
Test of QCD using multijets in neutral current DIS at HERA
119221579
Observation of Single Top Quark Production at D0
This paper presents the observation of the electroweak production of single top quarks in the D0 detector at the Fermilab Tevatron pp Collider at a center‐of‐mass energy of 1.96 TeV. Events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks are used to measure a cross section for single top‐quark production of σ(pp→tb+X,tqb+X) = 3.94±0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5×10−7, corresponding to a 5.0 standard deviation significance.
16864354
Evidence for single top quark production at D0
We present evidence for the production of single top quarks at the Fermilab Tevatron p collider. Using a 0.9 fb-1 dataset collected with D0 detector, the analysis is performed in the electron+jets and muon+jets decay modes, taking special care in modeling the large backgrounds, applying a new powerful b-quark tagging algorithm and using three multivariate techniques to extract the small signal. The combined measured production cross section is σ(p tb + X, tqb + X) = 4.7 ± 1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. We use the cross section measurement to directly determine the CKM matrix element that describes the Wtb coupling and find 0.68 < |Vtb|≤ 1 at 95% C.L. within the standard model.
119793175
Studies of dijet and trijet production in ep interactions at HERA
Measurements of dijet and trijet production in photoproduction, deep inelastic scattering and in the transition region between them, performed with the H1 and ZEUS detector at HERA are presented. The predictions of next-to-leading-order perturbative QCD are compared to the measured cross sections and found to be compatible with the data over a wide kinematic range.PACS: 12.38.Qk Experimental test – 13.60.Hb Total and inclusive cross sections
122970197
Multijet production in neutral current deep inelastic scattering at HERA and determination of alpha(s)
Multijet production rates in neutral current deep inelastic scattering (DIS) have been measured in the range of exchanged boson virtualities 10<Q2<5000 GeV2. The data were taken at the ep collider HERA with centre-of-mass energy using the ZEUS detector and correspond to an integrated luminosity of 82.2 pb-1. Jets were identified in the Breit frame using the kT cluster algorithm in the longitudinally invariant inclusive mode. Measurements of differential multijet cross sections are presented as functions of jet transverse energy , pseudorapidity and Q2 with and . Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant αs(MZ), determined from the ratio of the trijet to dijet cross sections, is .
119108763
Magnetic field effect on the phase transition in AdS soliton spacetime
We investigate the scalar perturbations in an anti-de Sitter soliton background coupled to a Maxwell field via marginally stable modes. In the probe limit, we study the magnetic field effect on the holographic insulator/superconductor phase transition numerically and analytically. The condensate will be localized in a finite circular region for any finite constant magnetic field. Near the critical point, we find that there exists a simple relation among the critical chemical potential, magnetic field, the charge, and mass of the scalar field. This relation indicates that the presence of the magnetic field causes the transition from insulator to superconductor to be difficult.
125066933
FIELD MEASUREMENT OF SPEAR3 MAGNETS AT IHEP
The SPEAR3 storage ring comprises a total of 292 magnets which has four types and eight different effective magnetic lengths. The magnetic measurements of all the production magnets including 40 gradient dipoles, 102 quadrupoles with quadrupole modulation system (QMS) coils, 76 sextupoles with skew quadrupole trim coils and 74 dipole correctors combined H/V function, and their prototypes as well have been completed at IHEP successfully by the end of April, 2002. This paper covers the development of the measurement systems as well as the results of the magnetic measurements for SPEAR3 magnets at IHEP.
197491146
Structure and evolution of low-mass W UMa type systems -- II. with angular momentum loss