Search results for "Elementary Particle"
showing 10 items of 659 documents
Measurement of the lifetime of tau-lepton
1996
The tau lepton lifetime is measured with the L3 detector at LEP using the complete data taken at centre-of-mass energies around the Z pole resulting in tau_tau = 293.2 +/- 2.0 (stat) +/- 1.5 (syst) fs. The comparison of this result with the muon lifetime supports lepton universality of the weak charged current at the level of six per mille. Assuming lepton universality, the value of the strong coupling constant, alpha_s is found to be alpha_s(m_tau^2) = 0.319 +/- 0.015(exp.) +/- 0.014 (theory). The tau lepton lifetime is measured with the L3 detector at LEP using the complete data taken at centre-of-mass energies around the Z pole resulting in τ τ =293.2 ± 2.0 (stat) ± 1.5 (syst) fs . The c…
Charged particle multiplicity distributions in restricted rapidity intervals in Z0 hadronic decays.
1991
The multiplicity distributions of charged particles in restricted rapidity intervals in Z0 hadronic decays measured by the DELPHI detector are presented. The data reveal a shoulder structure, best visible for intervals of intermediate size, i.e. for rapidity limits around ±1.5. The whole set of distributions including the shoulder structure is reproduced by the Lund Parton Shower model. The structure is found to be due to important contributions from 3-and 4-jet events with a hard gluon jet. A different model, based on the concept of independently produced groups of particles, "clans", fluctuating both in number per event and particle content per clan, has also been used to analyse the pres…
Anomalous non-leptonic kaon decays
1992
8 páginas, 1 figura.
HAWK 2.0: A Monte Carlo program for Higgs production in vector-boson fusion and Higgs strahlung at hadron colliders
2019
Abstract The Monte Carlo integrator HAWK provides precision predictions for Higgs production at hadron colliders in vector-boson fusion and Higgs strahlung, i.e. in production processes where the Higgs boson is Attached to WeaK bosons. The fully differential predictions include the full QCD and electroweak next-to-leading-order corrections. Results are computed as integrated cross sections and as binned distributions for important hadron-collider observables. Title of program: HAWK, version 2.0 Catalogue Id: AEWT_v1_0 Nature of problem Precision calculation of cross sections and differential distributions for Higgs-boson production in vector-boson fusion and Higgs strahlung at the LHC as de…
A new method for computing one-loop integrals
2019
Abstract We present a new program package for calculating one-loop Feynman integrals, based on a new method avoiding Feynman parametrization and the contraction due to Passarino and Veltman. The package is calculating one-, two- and three-point functions both algebraically and numerically to all tensor cases. This program is written as a package for Maple. An additional Mathematica version is planned later. Title of program: ONELOOP.MA Catalogue Id: ACVW_v1_0 Nature of problem The theoretical determination of cross sections in particle processes requires the calculation of radiative corrections. The most important contribution comes from the level of one-loop Feynman diagrams which arise fr…
oneloop 2.0 — A program package calculating one-loop integrals
2019
Abstract We present an improved version of our program package oneloop which — written as a package for MAPLE (Char, Geddes, Gonnet, Leong, Monagan, Watt, MAPLE V Language and Library Reference Manuals) — solves one-loop Feynman integrals. The package is calculating one-, two- and three-point functions both algebraically and numerically to any tensor rank. In addition to the original version, oneloop 2.0 also calculates infrared divergent integrals. Higher powers of propagator terms and the O(ε) parts... Title of program: oneloop.ma, version 2.0 Catalogue Id: ACVW_v2_0 [ADGT] Nature of problem The theoretical determination of cross sections in particle processes requires the calculation of …
QQ-onia package: a numerical solution to the Schrödinger radial equation for heavy quarkonium
2019
Abstract This paper presents the basics of the QQ-onia package, a software based upon the Numerov O (h^6 ) method which can be used to solve the Schrödinger radial equation using a suitable potential V (r) for the heavy quarkonium system. This package also allows the analysis of relevant properties of those resonances such as the square of the wave functions at the origin, their corresponding derivatives for l ≠ 0 states, typical heavy-quark velocities, and mean square radii. Besides, it includes a to... Title of program: QQ-onia package Catalogue Id: AECQ_v1_0 Nature of problem Software to solve the Schrödinger radial equation using a suitable potential V (r) for the heavy quarkonium syste…
anQCD: Fortran programs for couplings at complex momenta in various analytic QCD models
2019
Abstract We provide three Fortran programs which evaluate the QCD analytic (holomorphic) couplings _(Aν)(^(Q2)) for complex or real squared momenta ^(Q2). These couplings are holomorphic analogs of the powers a(^(Q2))ν of the underlying perturbative QCD (pQCD) coupling a(^(Q2))≡_(αs)(^(Q2))/π, in three analytic QCD models (anQCD): Fractional Analytic Perturbation Theory (FAPT), Two-delta analytic QCD (2δanQCD), and Massive Perturbation Theory (MPT). The index ν can be noninteger. The pro... Title of program: AanQCDext Catalogue Id: AEYK_v1_0 Nature of problem Calculation of values of the running analytic couplings A ν (Q 2 ;N f ) for general complex squared momenta Q 2 === -q 2 , in three a…
FlexibleSUSY—A spectrum generator generator for supersymmetric models
2019
This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract We introduce FlexibleSUSY, a Mathematica and C++ package, which generates a fast, precise C++ spectrum generator for any SUSY model specified by the user. The generated code is designed with both speed and modularity in mind, making it easy to adapt and extend with new features. The model is specified by supplying the superpotential, gauge structure and particle content in a SARAH model file; specific boundary conditions e.g. at the GUT, weak or intermediate scales are defined in a separate F... Title of program: FlexibleSUSY Catalogue Id: AEVI_v1_0 Nature of problem Determini…
Vbfnlo: A parton level Monte Carlo for processes with electroweak bosons
2019
This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract Vbfnlo is a fully flexible parton level Monte Carlo program for the simulation of vector boson fusion, double and triple vector boson production in hadronic collisions at next-to-leading order in the strong coupling constant. Vbfnlo includes Higgs and vector boson decays with full spin correlations and all off-shell effects. In addition, Vbfnlo implements CP-even and CP-odd Higgs boson via gluon fusion, associated with two jets, at the leading-order one-loop level with the full top- a... Title of program: VBFNLO Catalogue Id: AEDO_v1_0 Nature of problem To resolve the large sc…