771 research outputs found
Model of CMS Tracker
No full textA full scale CMS tracker mock-up exposed temporarily in the hall of building 40. The purpose of the mock-up is to study the routing of services, assembly and installation. The people in front are only a small fraction of the CMS tracker collaboration. Left to right : M. Atac, R. Castaldi, H. Breuker, D. Pandoulas,P. Petagna, A. Caner, A. Carraro, H. Postema, M. Oriunno, S. da Mota Silva, L. Van Lancker, W. Glessing, G. Benefice, A. Onnela, M. Gaspar, G. M. Bile
Measurement of inclusive production in two-photon collisions at LEP
No full textInclusive production of mesons in two-photon collisions was measured by the L3 experiment at LEP. The data were collected at a centre-of-mass energy GeV with an integrated luminosity of . Differential cross sections of the process are determined as functions of the transverse momentum and pseudorapidity of the mesons in the kinematic region GeV GeV and . The cross section integrated over this phase space domain is measured to be pb. The differential cross sections are compared with next-to-leading order perturbative QCD calculations.Inclusive production of D ∗± mesons in two-photon collisions was measured by the L3 experiment at LEP. The data were collected at a centre-of-mass energy s =189 GeV with an integrated luminosity of 176.4 pb −1 . Differential cross sections of the process e + e − → e + e − D ∗± X are determined as functions of the transverse momentum and pseudorapidity of the D ∗± mesons in the kinematic region 1 GeVInclusive production of mesons in two-photon collisions was measured by the L3 experiment at LEP. The data were collected at a centre-of-mass energy GeV with an integrated luminosity of . Differential cross sections of the process are determined as functions of the transverse momentum and pseudorapidity of the mesons in the kinematic region 1 GeV < p_{T}^{\mathrm{D^*}} < 5 GeV and \mathrm{|\eta^{D^*}|} < 1.4. The cross section integrated over this phase space domain is measured to be pb. The differential cross sections are compared with next-to-leading order perturbative QCD calculations
Measurement of the B-d(0)-(B)over-bar(d)(0) oscillation frequency RID C-4549-2008 RID C-5719-2008
No full textTime-dependent B-0-(B) over bar(0) mixing is studied using about two million hadronic Z decays registered by L3 in 1994 and 1995. For this study three techniques are used. Tagging of the b-quark charge at decay time is performed by identifying leptons from semileptonic B decays. The flavour of the b quark at production time is determined from the charge of the lepton in the opposite hemisphere or by using a jet-charge technique. The proper time of the B-particle decay is obtained by reconstructing the production and decay vertices or by a measurement of the lepton impact parameter. The combined result for the frequency of B-d(0) meson oscillations is Delta m(d) = 0.444 +/- 0.040 ps(-1)
The rejection of QCD jet background to the process pp --> HX(H --> ) using a finely segmented crystal calorimeter
No full textHiggs-detection in the decay-channel H --> at the proposed experiment L3P at the future pp-collider LHC
No full textD*+- PRODUCTION BY E+ E- ANNIHILATION NEAR 34.4-GEV center-of-mass ENERGY
No full textD*± production via e+e-→D*±X has been measured at an average CM energy of 34.4 GeV. The D*± energy spectrum is hard, with a maximum near χ = 0.6. The size of the D* cross section, RD* = σ(e+e- → D*X) σμμ = 2.50 ± 0.64 ± 0.88 (assuming RD*0 = RD*+) indicates that a large fraction of charm quark production yields D* mesons. The D*± angular distribution exhibits a forward-backward asymmetry, A = -0.28 ± 0.13. This is consistent with that expected in the standard theory for weak neutral currents and leads to |gAc| = 0.89 ± 0.44 for the axial vector coupling of the charm quark. © 1983
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