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16 tutorial_MadLoop = """
17 You have entered tutorial mode. This will introduce you to the main
18 syntax options for MadLoop which are mostly similar to the MadGraph5_aMC@NLO one.
19 If you have not done so already, please follow MadGraph5_aMC@NLO tutorial before
20 this one.
21
22 Remember that exactly as in MadGraph5, you can learn more about the different
23 options for any command by typing
24 MG5_aMC> help A_CMD
25 And to see a list of all commands, use
26 MG5_aMC> help
27
28 MadLoop is the part of MadGraph5_aMC@NLO used to generate the code for
29 evaluating the loop diagrams. This tutorial teaches you how to use MadLoop
30 as standalone tool for studying loops within particular processes.
31 Therefore in this mode, you can only consider definite processes, meaning
32 without multiparticle labels.
33
34 This tutorial has three parts:
35 a) How to generate a process.
36 b) How to cross-check / profile an output.
37 c) How to compute the loop matrix element squared for local phase-space points.
38
39 Let's start with the first point, how to generate a process with MadLoop in
40 standalone mode. Keep in mind that this means only the loop and born diagrams
41 are generated.
42
43 MG5_aMC>generate g g > d d~ [virt=QCD]
44
45 Note that a space is mandatory between the particle names and that '[virt=QCD]'
46 specifies that you want to consider QCD NLO corrections. The keyword option
47 'virt' before '=' within the squared brackets precisely specifies you are only
48 interested in the virtual contribution.
49 """
50
51 tutorial = tutorial_MadLoop
52
53 generate = """
54 You have just generated a new process.
55 You can find more information on supported syntax by using:
56 MG5_aMC>help generate
57 To list all defined processes, type
58 MG5_aMC>display processes
59
60 You can display a pictorial representation of the diagrams with
61 MG5_aMC> display diagrams
62 Notice you can add the option 'loop' or 'born' if you only want those diagrams
63 to be displayed.
64
65 If you want to add a second process, you can use the add process command:
66 MG5_aMC>add process e+ e- > d d~ [virt=QCD]
67 But keep in mind that you must still consider only virtual corrections and
68 cannot employ multiparticle labels. Also decay chains are not available for
69 loops.
70
71 At this stage you can export your processes.
72 This is done simply by typing:
73
74 MG5_aMC>output MY_FIRST_MADLOOP_RUN
75
76 Notice that the standalone output mode (implicit in the above) is the only
77 available for MadLoop standalone runs.
78 """
79
80 display_processes = """
81 You have seen a list of the already defined processes.
82
83 At this stage you can export your processes to different formats.
84 To create a MadLoop standalone output for these, simply type:
85
86 MG5_aMC>output MY_FIRST_MADLOOP_RUN
87 """
88
89 display_diagrams = """
90 You have displayed the diagrams.
91 Notice you can add the 'born' or 'loop' option to this command to specify the
92 class of diagrams to be displayed.
93
94 At this stage you can export your processes to different formats.
95 To create a MadLoop standalone output for these, simply type:
96
97 MG5_aMC>output MY_FIRST_MADLOOP_RUN
98 """
99
100 add_process = """
101 You have added a process to your process list.
102
103 At this stage you can export your processes.
104 For this, simply type
105
106 MG5_aMC>output MY_FIRST_MADLOOP_RUN
107 """
108
109 output = """
110 If you are following the tutorial, a directory MY_FIRST_MADLOOP_RUN has
111 been created under your MadGraph5_aMC@NLO installation directory.
112
113 The code for the evaluation of the squared loop matrix element is in
114 'SubProcesses/P0_<shell_proc_name>/'. There, you can compile and edit
115 running parameters from 'MadloopParams.dat' and then run the code with './check'
116 Alternatively, for a simple quick run, type:
117
118 MG5_aMC>launch -f
119
120 This computes the squared matrix element for a given PS points.
121 For the purpose of this tutorial, the option '-f' is added to automatically skip
122 the edition of the cards and phase-space point specification.
123 """
124
125 launch = """
126 You just launched the MadLoop standalone evalutation of the squared loop matrix
127 element for (a/many) specific process(es) for a random Phase-Space point.
128 The two processes proposed in this tutorial were g g > d d~ and e+ e- > d d~.
129 You can check that you get the right double pole normalized with respect to
130 the born*(alpha_s/2*pi), namely -26/3 and -8/3 respectively.
131
132 Now this tutorial will introduce you to two checking functionalities for the
133 evaluation of the contributions of virtual origin.
134 Start by typing:
135
136 MG5_aMC>check g g > d d~ [virt=QCD]
137
138 This will test lorentz and crossing invariance as well as of the gauge
139 invariance check from the ward identity for the initial state gluon.
140 You can add an option after check to specify to perform only one definite check.
141 Notice that the check functionality is only available for MadLoop standalone
142 runs (those with the 'virt=' option).
143 """
144
145 check = """
146 You have seen the results for the various consistency checks performed on the
147 MadGraph5_aMC@NLO loop computation.
148 You can now use the check command to obtain a full profiling of a given process
149 including loop contributions.
150 Simply type:
151
152 MG5_aMC>check profile g g > d d~ [virt=QCD]
153
154 Notice that you can replace 'profile' by 'timing' or 'stability' if
155 you only want timing or stability benchmarks about this process.
156 """
157
158 check_profile = """
159 You have seen detailed information about the stability, timings and code size
160 of a given process including loop.
161 Keep in mind that these check functionalities are only available for MadLoop
162 standalone runs.
163
164 You just learned the basic commands for the MadLoop runs (i.e. with the
165 'virt=' option). You can close this tutorial by typing
166 MG5_aMC>tutorial stop
167 Or exit MG5 with
168 MG5_aMC>exit
169 """
170