Precision measurements of the SLC beam energy Kent, J.; King, M.; Von Zanthier, C. ...
Proceedings of the 1989 IEEE Particle Accelerator Conference, . 'Accelerator Science and Technology,
1989
Conference Proceeding
A method of precisely determining the beam energy in high-energy linear colliders has been developed using dipole spectrometers and synchrotron radiation detectors. The method of measurement ...indirectly observes the deflection of charged beams via the narrow beams of synchrotron radiation they emit. Beam lines implementing this method have been installed on the Stanford Linear Collider (SLC). An absolute energy measurement with an accuracy of better than delta E/E=5*10/sup -4/ can be achieved on a pulse-to-pulse basis. The operation of this system is described.< >
PHASEFIX-correcting the tunes of the SLC arcs Haissinski, J.; Bambade, P.; Brown, K.L. ...
Proceedings of the 1989 IEEE Particle Accelerator Conference, . 'Accelerator Science and Technology,
1989
Conference Proceeding
Odprti dostop
The betatron phase advance tunes are crucial parameters in the SLC (Stanford Linear Collider) arc optics because of the strong cross coupling between the x and y phase spaces, which takes place at ...rolled achromat boundaries. Phase measurements have been performed with an accuracy of about 0.3 degrees /cell and, initially, substantial deviations from the design (108 degrees ) were observed. Corrections on an achromat-by-achromat basis have been performed to reduce the phase errors within less than 1 degrees /cell. They were done by adjusting a current balance between focusing (F) and defocusing (D) magnets and by changing the horizontal relative displacements of F and D magnets using the XMOV magnet movers or with realignment work.< >
This report summarises the results of the four-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the calculation of four-fermion processes in ...electron-positron collisions at LEP-2 centre-of-mass energies are presented, concentrating on predictions for four main reactions: W-pair production, visible photons in four-fermion events, single-W production and Z-pair production. Based on a comparison of results derived within different approaches, theoretical uncertainties on these predictions are established.
Higgs Physics at LEP2 Carena, M; Zerwas, P; Accomando, E ...
02/1996
Journal Article
Odprti dostop
In this report we review the prospects for Higgs physics at LEP2. The
theoretical aspects and the phenomenology of Higgs particles are discussed
within the Standard Model (SM) and the Minimal ...Supersymmetric Standard Model
(MSSM). The experimental search techniques are described and the discovery
limits for Higgs bosons in the LEP2 energy range are summarized. In addition,
opportunities of detecting Higgs particles in non-minimal extensions of the SM
and the MSSM are investigated.
Higgs Physics at LEP2 Carena, M; Zerwas, P; Accomando, E ...
arXiv.org,
02/1996
Paper
Odprti dostop
In this report we review the prospects for Higgs physics at LEP2. The theoretical aspects and the phenomenology of Higgs particles are discussed within the Standard Model (SM) and the Minimal ...Supersymmetric Standard Model (MSSM). The experimental search techniques are described and the discovery limits for Higgs bosons in the LEP2 energy range are summarized. In addition, opportunities of detecting Higgs particles in non-minimal extensions of the SM and the MSSM are investigated.
Phys.Lett. B580 (2004) 108-118 Using recent measurements of the b-quark fragmentation distribution obtained
in $e^+e^- \to b \bar{b}$ events registered at the Z pole, the non-perturbative
QCD ...component of the distribution has been extracted independently of any
hadronic physics modelling. This distribution depends only on the way the
perturbative QCD component has been defined. When the perturbative QCD
component is taken from a parton shower Monte-Carlo, the non-perturbative QCD
component is rather similar with those obtained from the Lund or Bowler models.
When the perturbative QCD component is the result of an analytic NLL
computation, the non-perturbative QCD component has to be extended in a
non-physical region and thus cannot be described by any hadronic modelling. In
the two examples used to characterize these two situations, which are studied
at present, it happens that the extracted non-perturbative QCD distribution has
the same shape, being simply translated to higher-x values in the second
approach, illustrating the ability of the analytic perturbative QCD approach to
account for softer gluon radiation than with a parton shower generator.
Using recent measurements of the b-quark fragmentation distribution obtained in \(e^+e^- \to b \bar{b}\) events registered at the Z pole, the non-perturbative QCD component of the distribution has ...been extracted independently of any hadronic physics modelling. This distribution depends only on the way the perturbative QCD component has been defined. When the perturbative QCD component is taken from a parton shower Monte-Carlo, the non-perturbative QCD component is rather similar with those obtained from the Lund or Bowler models. When the perturbative QCD component is the result of an analytic NLL computation, the non-perturbative QCD component has to be extended in a non-physical region and thus cannot be described by any hadronic modelling. In the two examples used to characterize these two situations, which are studied at present, it happens that the extracted non-perturbative QCD distribution has the same shape, being simply translated to higher-x values in the second approach, illustrating the ability of the analytic perturbative QCD approach to account for softer gluon radiation than with a parton shower generator.
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