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capitalize Monte Carlo
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5 changed files with 15 additions and 15 deletions
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@ -2,7 +2,7 @@
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The analytical cross section for the parton-level \(\qqgg\) diphoton
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process is calculated. With the application to this in mind, some
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monte carlo integration and sampling methods are studied, implemented
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Monte Carlo integration and sampling methods are studied, implemented
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and compared. Proton-Proton scattering is simulated on the partonic
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level through the use of parton density functions. Throughout,
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obtained results are verified through comparison with the \sherpa\
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Der analytische wirkungsquerschnitt fuer den \(\qqgg\) diphoton prozess
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wird berechnet. Mit hinblick auf die Anwendung auf diesen Prozess
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werden monte carlo Methoden untersucht, implementiert und
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werden Monte Carlo Methoden untersucht, implementiert und
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verglichen. Proton-Proton Streuung wird auf der partonischen ebene
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mithilfe von parton-density Funktionen simuliert. Gewonnene resultate
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werden durchweg mit dem \sherpa\ event generator verifiziert. Zuletzt
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Monte carlo methods have been and still are one of the most important
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tools for theoretical calculations in particle physics. Be it for
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validating the well established standard model or for making
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predictions about new theories, monte carlo simulations are the
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predictions about new theories, Monte Carlo simulations are the
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crucial interface of theory and experimental data, making them
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directly comparable. Furthermore horizontal scaling is almost trivial
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to implement in monte carlo algorithms, making them well adapted to
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modern parallel computing. In this the thesis, the use of monte carlo
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to implement in Monte Carlo algorithms, making them well adapted to
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modern parallel computing. In this the thesis, the use of Monte Carlo
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methods will be traced through from simple integration to the
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simulation of proton-proton scattering.
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@ -22,11 +22,11 @@ scope of this thesis. The differential and total cross section of this
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process is being calculated in leading order in \cref{chap:qqgg} and
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the obtained result is compared to the total cross section obtained
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with the \sherpa~\cite{Gleisberg:2008ta} event generator, used as
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matrix element integrator. In \cref{chap:mc} some simple monte carlo
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matrix element integrator. In \cref{chap:mc} some simple Monte Carlo
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methods are discussed, implemented and their results compared. First
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monte carlo integration is studies and the \vegas\
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Monte Carlo integration is studies and the \vegas\
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algorithm~\cite{Lepage:19781an} is implemented and
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evaluated. Subsequently monte carlo sampling methods are explored and
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evaluated. Subsequently Monte Carlo sampling methods are explored and
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the output of \vegas\ is used to improve the sampling
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efficiency. Histograms of observables are generated and compared to
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histograms from \sherpa using the \rivet~\cite{Bierlich:2019rhm}
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@ -9,7 +9,7 @@ probability density on
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with a \(1\) in the fashion of \cref{eq:baseintegral}, the Integral
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of \(f\) over \(\Omega\) can be interpreted as the expected value
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\(\EX{F/\Rho}\) of the random variable \(F/\Rho\) under the
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distribution \(\rho\). This is the key to most monte carlo methods.
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distribution \(\rho\). This is the key to most Monte Carlo methods.
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\begin{equation}
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\label{eq:baseintegral}
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@ -77,9 +77,9 @@ The convergence of \cref{eq:approxexp} is not dependent on the
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dimensionality of the integration volume as opposed to many other
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numerical integration algorithms (trapezoid rule, Simpsons rule) that
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usually converge like \(N^{-\frac{k}{n}}\) with \(k\in\mathbb{N}\) as
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opposed to \(N^{-\frac{k}{n}}\) with monte carlo. Because integrals in
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particle physics usually have a high dimensionality, monte carlo
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integration is suitable there. When implementing monte carlo methods,
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opposed to \(N^{-\frac{k}{n}}\) with Monte Carlo. Because integrals in
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particle physics usually have a high dimensionality, Monte Carlo
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integration is suitable there. When implementing Monte Carlo methods,
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the random samples can be obtained through hardware or software random
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number generators (RNGs). Most implementations utilize software RNGs
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because supply pseudo-random numbers in a reproducible way, which
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@ -97,7 +97,7 @@ stratified sampling (as discussed in \cref{sec:stratsamp-real}) and
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the hit-or-miss method. Because the stratified sampling requires very
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accurate upper bounds, they have been overestimated by
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\result{xs/python/pdf/overesimate}, which lowers the efficiency
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slightly but reduces bias. The monte carlo integrator was used to
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slightly but reduces bias. The Monte Carlo integrator was used to
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estimate the location of the maximum in each hypercube and then this
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estimate was improved by gradient ascend\footnote{Which becomes
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problematic, when performed close to a cut.}.
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@ -2,7 +2,7 @@
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\label{sec:compsher}
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The result obtained in \cref{sec:qqggcalc} shall now be verified by the
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monte carlo event generator \sherpa{}~\cite{Gleisberg:2008ta}. To
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Monte Carlo event generator \sherpa{}~\cite{Gleisberg:2008ta}. To
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facilitate this, an expression for the total cross section for a range
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of \(\theta\) or \(\eta\) has to be obtained. Using the golden rule
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for \(2\rightarrow 2\) processes and observing that the initial and
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@ -86,7 +86,7 @@ an interval of \([-\eta, \eta]\), is dominated by the linear
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contributions in \cref{eq:total-crossec} and would result in an
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infinity if no cut on \(\eta\) would be made. Choosing
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\(\eta\in [-2.5,2.5]\) and \(\ecm=\SI{100}{\giga\electronvolt}\) the
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process was monte carlo integrated in \sherpa\ using the runcard
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process was Monte Carlo integrated in \sherpa\ using the runcard
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in \cref{sec:qqggruncard}. This runcard describes the exact same (first
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order) process as the calculated cross section.
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