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JetScapeConstants.h
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1 /*******************************************************************************
2  * Copyright (c) The JETSCAPE Collaboration, 2018
3  *
4  * Modular, task-based framework for simulating all aspects of heavy-ion collisions
5  *
6  * For the list of contributors see AUTHORS.
7  *
8  * Report issues at https://github.com/JETSCAPE/JETSCAPE/issues
9  *
10  * or via email to bugs.jetscape@gmail.com
11  *
12  * Distributed under the GNU General Public License 3.0 (GPLv3 or later).
13  * See COPYING for details.
14  ******************************************************************************/
15 
16 #ifndef JETSCAPECONSTANTS_H
17 #define JETSCAPECONSTANTS_H
18 
19 namespace Jetscape {
20 
21 // define the usual constants
22 static double pi = 3.141592653589793;
23 
24 static double nf = 3.0;
25 
26 static double Cf = 4.0 / 3.0;
27 
28 static double Tf = 0.5;
29 
30 static double Ca = 3.0;
31 
32 static double Nc = 3.0;
33 
34 static double Lambda_QCD = 0.2;
35 // 0.4 is the value chosen in JETSET
36 
37 static const double hbarC = 0.197327053;
38 
39 static const double fmToGeVinv = 1.0 / hbarC;
40 
41 static double zeta3 = 1.20206;
42 
43 static double mu = 0.722;
44 
45 /* When the code becomes really accurate, a more accurate value for this can be used */
46 
47 /* the following is the maximum value from the standard C++ random number generator */
48 static double maxN = double(pow(2.0, 31.0) - 1.0);
49 
50 static double a_very_large_number = maxN;
51 
52 /* the following 2 lines control the error in the analytical part of the calculation. */
53 /* Note analytical approximation, cannot be rectified by more statistics */
54 /* However, more accurate analytical calculation will require less statistics to obtain smooth distributions */
55 /* the value is something for the user to choose based on his/her computing resources */
56 
57 static double error = 0.02;
58 
59 static double approx = 0.02;
60 
61 static double s_error = 0.01;
62 static double s_approx = 0.01;
63 
64 static double E_minimum = 1.0;
65 
66 static double rounding_error = 1e-6; // slightly more than float precision
67 
68 /**************************************************************************************/
69 
70 /* the standard PDG particle id codes for the gluon and the d quark */
71 static int gid = 21;
72 
73 static int qid = 1;
74 
75 static int uid = 2;
76 
77 static int did = 1;
78 
79 static int sid = 3;
80 
81 static int cid = 4;
82 
83 static int bid = 5;
84 
85 static int photonid = 22;
86 
87 static int Zid = 23;
88 
89 static int Wid = 24; // refers to W+, use -24 for W-
90 /*******************************************************************/
91 
92 }; // namespace Jetscape
93 #endif // JETSCAPECONSTANTS_H