386 research outputs found
TAUOLA as tau Monte Carlo for future applications
The status of the Monte Carlo programs for the simulation of tau-lepton
production and decay in high-energy accelerator experiments is reviewed. In
particular, the status of the following packages is discussed: (i) TAUOLA for
tau-lepton decay, (ii) PHOTOS for radiative corrections in decays, (iii)
MC-TESTER packages for various types of semi-automatic tests, and (iv)
universal interface of TAUOLA for the decay of tau leptons produced by `any'
generator. Emphasis is put on recent developments for high-precision tests and
extensions of PHOTOS. Some considerations for the software organization
necessary in future applications for Belle and BaBar will be given; examples of
TAUOLA universal interface use will only be listed at the end of the review.Comment: 7 pages, 2 figure, Presented at International workshop on Tau Lepton
Physics, TAU04 Nara, Japan September 14-17,200
Next to Leading Logarithms and the PHOTOS Monte Carlo
With the approaching start-up of the experiments at LHC, the urgency to
quantify systematic uncertainties of the generators, used in the interpretation
of the data, is becoming pressing. The PHOTOS Monte Carlo program is often used
for the simulationof experimental, selection-sensitive, QED radiative
corrections in decays of Z bosons and other heavy resonances and particles.
Thanks to its complete phase-space coverage it is possible, with no
approximations for any decay channel, to implement the matrix-element. The
present paper will be devoted to those parts of the next-to-leading order
corrections for Z decays which are normally missing in PHOTOS. The analytical
form of the exact and truncated (standard) kernel used in PHOTOS will be
explicitly given. The correction, being the ratio of the exact to the
approximate kernel, can be activated as an optional contribution to the
internal weight of PHOTOS.
To calculate the weight, the information on the effective Born-level Z/gamma*
couplings and even directions of the incoming beams, is needed. A universal
implementation would have made the PHOTOS solution less modular and less
convenient for the users. That is why, for the time being, we will keep the
correcting weight as an extra option, available for special tests only.
We will quantify the numerical effect of the approximation with the help of a
multitude of distributions. The numerical size of the effect is in general
below 0.1%; however, in some corners of the phase-space (well defined and
contributing less than 0.5% to the total rate), it may reach up to about 20% of
their relative size.Comment: 23+1 pages 6 groups of figure
MC-TESTER v. 1.23: a universal tool for comparisons of Monte Carlo predictions for particle decays in high energy physics
Theoretical predictions in high energy physics are routinely provided in the
form of Monte Carlo generators. Comparisons of predictions from different
programs and/or different initialization set-ups are often necessary. MC-TESTER
can be used for such tests of decays of intermediate states (particles or
resonances) in a semi-automated way.
Since 2002 new functionalities were introduced into the package. In
particular, it now works with the HepMC event record, the standard for C++
programs. The complete set-up for benchmarking the interfaces, such as
interface between tau-lepton production and decay, including QED bremsstrahlung
effects is shown. The example is chosen to illustrate the new options
introduced into the program. From the technical perspective, our paper
documents software updates and supplements previous documentation.
As in the past, our test consists of two steps. Distinct Monte Carlo programs
are run separately; events with decays of a chosen particle are searched, and
information is stored by MC-TESTER. Then, at the analysis step, information
from a pair of runs may be compared and represented in the form of tables and
plots.
Updates introduced in the progam up to version 1.24.3 are also documented. In
particular, new configuration scripts or script to combine results from
multitude of runs into single information file to be used in analysis step are
explained.Comment: 27 pages 4 figure
MC-TESTER: a universal tool for comparisons of Monte Carlo predictions for particle decays in high energy physics
Theoretical predictions in high energy physics are routinely provided in the
form of Monte Carlo generators. Comparisons of predictions from different
programs and/or different initialization set-ups are often necessary. MC-TESTER
can be used for such tests of decays of intermediate states (particles or
resonances) in a semi-automated way. Our test consists of two steps. Different
Monte Carlo programs are run; events with decays of a chosen particle are
searched, decay trees are analysed and appropriate information is stored. Then,
at the analysis step, a list of all found decay modes is defined and branching
ratios are calculated for both runs. Histograms of all scalar Lorentz-invariant
masses constructed from the decay products are plotted and compared for each
decay mode found in both runs. For each plot a measure of the difference of the
distributions is calculated and its maximal value over all histograms for each
decay channel is printed in a summary table. As an example of MC-TESTER
application, we include a test with the tau lepton decay Monte Carlo
generators, TAUOLA and PYTHIA. The HEPEVT (or LUJETS) common block is used as
exclusive source of information on the generated events.Comment: Version as published in Computer Physics Communications, 157(2004) 1,
pp 39-6
PHOTOS Monte Carlo for precision simulation of QED in decays - History and properties of the project
Because of properties of QED, the bremsstrahlung corrections to decays of
particles or resonances can be calculated, with a good precision, separately
from other effects. Thanks to the widespread use of event records such
calculations can be embodied into a separate module of Monte Carlo simulation
chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo
program is used for this purpose since nearly 20 years now. In the following
talk let us review the main ideas and constraints which shaped the program
version of today and enabled it widespread use. We will concentrate specially
on conflicting requirements originating from the properties of QED matrix
elements on one side and degrading (evolving) with time standards of event
record(s). These issues, quite common in other modular software applications,
become more and more difficult to handle as precision requirements become
higher.Comment: Prepared for XI International Workshop on Advanced Computing and
Analysis Techniques in Physics Research, Amsterdam, the Netherlands, April 23
200
The tauola-photos_F environment for versioning the TAUOLA and PHOTOS packages
We present the system for versioning two packages: the TAUOLA of tau lepton
decay and PHOTOS for radiative corrections in decays. The following features
can be chosen in automatic or semi-automatic way: (1) format of the common
block HEPEVT; (2) version of the physics input (for TAUOLA): as published, as
initialized by CLEO collaboration, as initialized by ALEPH collaboration (it is
suggested to use this version only with the help of the collaboration advice);
(3) type of application: stand-alone, universal interface through HEPEVT,
interface for KKMC Monte Carlo; (4) random number generators; (5) compiler
options.Comment: nine pages, late
PHOTOS Monte Carlo and its theoretical accuracy
Because of properties of QED, the bremsstrahlung corrections to decays of
particles or resonances can be calculated, with a good precision, separately
from other effects. Thanks to the widespread use of event records such
calculations can be embodied into a separate module of Monte Carlo simulation
chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo
program is used for this purpose since nearly 20 years now. In the following
talk let us review the main ideas and constraints which shaped the program
version of today and enabled it widespread use. Finally, we will underline
importance of aspects related to reliability of program results: event record
contents and implementation of channel specific matrix elements.Comment: Presented by Z. Was, April 08 2008, International Workshop on e+e-
collisions from Phi to Ps
PHOTOS Monte Carlo for precision simulation of QED in decays
Because of properties of QED, the bremsstrahlung corrections to decays of particles or resonances can be calculated, with a good precision, separately from other effects. Thanks to the widespread use of event records such calculations can be embodied into a separate module of Monte Carlo simulation chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo program is used for this purpose since nearly 20 years now. In the following talk let us review the main ideas and constraints which shaped the program version of today and enabled it widespread use. We will concentrate specially on conflicting requirements originating from the properties of QED matrix elements on one side and degrading (evolving) with time standards of event record(s). These issues, quite common in other modular software applications, become more and more difficult to handle as precision requirements become higher
AUTOMATING THE CONFIGURATION OF THE CONTROLS SYSTEMS OF THE LHC EXPERIMENTS
The supervisory layer of the Large Hadron Collider (LHC) experiments is based on the Prozeßvisualisierungs- und Steuerungsystem (PVSS) [1] and the Joint COntrols Project (JCOP) Framework (FW) [2]. This controls framework includes a Finite State Machine (FSM) toolkit, which allows to operate the control systems according to a well-defined set of states and commands. During the FSM transitions of the detectors, it is required to re-configure parts of the control systems. All configuration parameters of the devices integrated into the control system are stored in the so-called configuration database. In this paper the JCOP FW FSM-Configuration database tool is presented. This tool ensures the availability of all required configuration data, for a given type of run of the experiment, in the PVSS sub-detector control applications. The chosen implementation strategy is discussed in the paper. The approach enables the standalone operation of different partitions of the detectors simultaneously while ensuring independent data handling
Automating the configuration of the controls systems of the LHC experiments
The supervisory layer of the Large Hadron Collider (LHC) experiments is based on the Prozeßvisualisierungs- und Steuerungsystem (PVSS) [1] and the Joint COntrols Project (JCOP) Framework (FW) [2]. This controls framework includes a Finite State Machine (FSM) toolkit, which allows to operate the control systems according to a well-defined set of states and commands. During the FSM transitions of the detectors, it is required to re-configure parts of the control systems. All configuration parameters of the devices integrated into the control system are stored in the so-called configuration database. In this paper the JCOP FW FSM-Configuration database tool is presented. This tool ensures the availability of all required configuration data, for a given type of run of the experiment, in the PVSS sub-detector control applications. The chosen implementation strategy is discussed in the paper. The approach enables the standalone operation of different partitions of the detectors simultaneously while ensuring independent data handling
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