| 1 | #!/usr/bin/env python
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| 2 | #################################################################################################
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| 3 | #
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| 4 | # Requires python v2.7
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| 5 | #
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| 6 | # Simple script for generation of a LHE file containing events distributed with a flat (log) e, pt and eta spectrum.
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| 7 | #
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| 8 | # For help type:
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| 9 | # python flatGunLHEventProducer.py -h
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| 10 | #
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| 11 | #################################################################################################
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| 12 | import os, random, math, argparse, sys
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| 13 |
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| 14 | #__________________________________________________________
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| 15 | def print_params(args):
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| 16 |
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| 17 | print 'sqrt(s) : ', args.ecm
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| 18 | print 'pdg codes : ', args.pdg
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| 19 | print 'gun mode : ', args.guntype
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| 20 | print 'pmax : ', args.pmax
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| 21 | print 'pmin : ', args.pmin
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| 22 | print 'etamin : ', args.etamin
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| 23 | print 'etamax : ', args.etamax
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| 24 | print 'nevts : ', args.nevts
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| 25 | print 'Seed : ', args.seed
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| 26 | print 'flat log : ', args.log
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| 27 | print 'output : ', args.output
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| 28 | #__________________________________________________________
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| 29 | def write_init(args):
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| 30 |
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| 31 | ebeam = args.ecm/2.
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| 32 |
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| 33 | out = open(args.output, "a")
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| 34 | out.write('<LesHouchesEvents version="3.0">\n')
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| 35 | out.write('<init>\n')
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| 36 | out.write('2212 2212 {0} {1} 0 0 1 1 -4 1\n'.format(ebeam, ebeam))
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| 37 | out.write('1000. 1. 1000. 1\n')
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| 38 | out.write('</init>\n')
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| 39 | out.close()
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| 40 | #__________________________________________________________
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| 41 | def write_event(args, pt, eta, phi):
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| 42 |
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| 43 | # define particle masses
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| 44 | mass = dict()
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| 45 | mass[1] = 0.
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| 46 | mass[2] = 0.
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| 47 | mass[3] = 0.
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| 48 | mass[4] = 1.29
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| 49 | mass[5] = 4.7
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| 50 | mass[6] = 173.
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| 51 | mass[11] = 0.
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| 52 | mass[12] = 0.
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| 53 | mass[13] = 0.
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| 54 | mass[14] = 0.
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| 55 | mass[15] = 0.
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| 56 | mass[16] = 0.
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| 57 | mass[21] = 0.
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| 58 | mass[22] = 0.
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| 59 | mass[23] = 9.118800e+01
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| 60 | mass[24] = 80.419002
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| 61 | mass[25] = 1.250000e+02
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| 62 |
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| 63 | def alpha_s(q):
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| 64 | return 12*math.pi/((33.-6.)*math.log(q**2/0.3**2))
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| 65 |
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| 66 | # randomly pick a pdg code from supplied list
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| 67 | pdg = random.choice(args.pdg)
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| 68 |
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| 69 | # compute particles 4-vectors: px, py, pz, e
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| 70 |
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| 71 | px = pt*math.cos(phi)
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| 72 | py = pt*math.sin(phi)
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| 73 | pz = pt*math.sinh(eta)
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| 74 | e = math.sqrt(mass[pdg]**2 + px**2 + py**2 + pz**2)
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| 75 |
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| 76 | p1 = [0., 0., e, e]
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| 77 | p2 = [0., 0., -e, e]
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| 78 | p3 = [px, py, pz, e]
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| 79 | p4 = [-px, -py, -pz, e]
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| 80 |
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| 81 | cf_list = []
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| 82 |
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| 83 | # initialize stuff
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| 84 | color = [501, 501, 0, 0]
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| 85 |
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| 86 | out = open(args.output, "a")
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| 87 | out.write('<event>\n')
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| 88 | out.write(' 4 1 +1000. {:.8e} 7.54677100e-03 {:.8e}\n'.format(2*e, alpha_s(e)))
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| 89 |
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| 90 |
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| 91 | ########## g g -> g g ###################
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| 92 |
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| 93 | if pdg == 21:
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| 94 |
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| 95 | cf_list.append([503, 501, 504, 502, 503, 502, 504, 501])
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| 96 | cf_list.append([504, 501, 503, 502, 503, 501, 504, 502])
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| 97 |
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| 98 | color = cf_list[random.randint(0, 1)]
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| 99 |
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| 100 | out.write(' 21 -1 0 0 {} {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 1.0000e+00\n'.format(color[0], color[1], p1[0], p1[1], p1[2], p1[3], 0.))
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| 101 | out.write(' 21 -1 0 0 {} {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 1.0000e+00\n'.format(color[2], color[3], p2[0], p2[1], p2[2], p2[3], 0.))
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| 102 | out.write(' 21 1 1 2 {} {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 1.0000e+00\n'.format(color[4], color[5], p3[0], p3[1], p3[2], p3[3], 0.))
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| 103 | out.write(' 21 1 1 2 {} {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 1.0000e+00\n'.format(color[6], color[7], p4[0], p4[1], p4[2], p4[3], 0.))
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| 104 |
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| 105 | ########## q q -> q' q' ###############
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| 106 |
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| 107 | elif pdg > 0 and pdg < 7:
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| 108 |
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| 109 | cf_list.append([501, 501, 502, 502])
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| 110 | cf_list.append([501, 502, 501, 502])
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| 111 |
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| 112 | color = cf_list[random.randint(0, 1)]
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| 113 |
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| 114 | out.write(' 1 -1 0 0 {} 0 {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 1.0000e+00\n'.format(color[0], p1[0], p1[1], p1[2], p1[3], 0.))
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| 115 | out.write(' -1 -1 0 0 0 {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 -1.0000e+00\n'.format(color[1], p2[0], p2[1], p2[2], p2[3], 0.))
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| 116 | out.write(' {} 1 1 2 {} 0 {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} {:.8e} 1.0000e+00\n'.format(pdg, color[2], p3[0], p3[1], p3[2], p3[3], mass[pdg], 0.))
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| 117 | out.write(' -{} 1 1 2 0 {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} {:.8e} -1.0000e+00\n'.format(pdg, color[3], p4[0], p4[1], p4[2], p4[3], mass[pdg], 0.))
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| 118 |
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| 119 | ########## q q -> l l (l = e, mu, tau, ve, vm , vtau) ###############
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| 120 |
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| 121 |
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| 122 | elif pdg > 10 and pdg < 17:
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| 123 |
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| 124 | out.write(' 1 -1 0 0 {} 0 {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 1.0000e+00\n'.format(color[0], p1[0], p1[1], p1[2], p1[3], 0.))
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| 125 | out.write(' -1 -1 0 0 0 {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 -1.0000e+00\n'.format(color[1], p2[0], p2[1], p2[2], p2[3], 0.))
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| 126 | out.write(' {} 1 1 2 {} 0 {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} {:.8e} -1.0000e+00\n'.format(pdg, color[2], p3[0], p3[1], p3[2], p3[3], mass[pdg], 0.))
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| 127 | out.write(' -{} 1 1 2 0 {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} {:.8e} 1.0000e+00\n'.format(pdg, color[3], p4[0], p4[1], p4[2], p4[3], mass[pdg], 0.))
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| 128 |
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| 129 | ########## q q -> B B (B = gamma, Z, W, H) ###############
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| 130 |
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| 131 | elif pdg > 21 and pdg < 26:
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| 132 |
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| 133 | out.write(' 1 -1 0 0 {} 0 {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 1.0000e+00\n'.format(color[0], p1[0], p1[1], p1[2], p1[3], 0.))
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| 134 | out.write(' -1 -1 0 0 0 {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} 0.0000e+00 -1.0000e+00\n'.format(color[1], p2[0], p2[1], p2[2], p2[3], 0.))
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| 135 | out.write(' {} 1 1 2 {} 0 {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} {:.8e} 0.0000e+00\n'.format(pdg, color[2], p3[0], p3[1], p3[2], p3[3], mass[pdg], 0.))
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| 136 | if pdg == 24:
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| 137 | out.write(' -{} 1 1 2 0 {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} {:.8e} 0.0000e+00\n'.format(pdg, color[3], p4[0], p4[1], p4[2], p4[3], mass[pdg], 0.))
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| 138 | else:
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| 139 | out.write(' {} 1 1 2 0 {} {:+.8e} {:+.8e} {:+.8e} {:.8e} {:.8e} {:.8e} 0.0000e+00\n'.format(pdg, color[3], p4[0], p4[1], p4[2], p4[3], mass[pdg], 0.))
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| 140 |
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| 141 | out.write('</event>\n')
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| 142 |
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| 143 |
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| 144 |
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| 145 |
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| 146 | #__________________________________________________________
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| 147 |
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| 148 | if __name__=="__main__":
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| 149 |
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| 150 | parser = argparse.ArgumentParser()
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| 151 | parser.add_argument("--pdg", nargs='+', type=int)
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| 152 | parser.add_argument('--guntype', dest='guntype', help='pt or e gun. The parameters pmin(max) are then interpreted as ptmin(max) or emin(max) depending on the specified gunmode', default='pt')
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| 153 | parser.add_argument("--pmin", type=float, help="minimum pt/e [GeV] (default: 1.)", default=1.)
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| 154 | parser.add_argument("--pmax", type=float, help="maximum pt/e [GeV] (default: 50000.)", default=50000.)
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| 155 | parser.add_argument("--etamin", type=float, help="minimum eta (default: -2.5)", default=-6.)
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| 156 | parser.add_argument("--etamax", type=float, help="maximum eta (default: 2.5)", default=6.)
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| 157 | parser.add_argument("--ecm,", dest='ecm', type=float, help="center of mass energy (default: 13000)", default=13000)
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| 158 | parser.add_argument("--nevts", type=int, help="number of events to generate (default: 1000)", default=1000)
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| 159 | parser.add_argument("--seed", type=int, help="random seed (default uses cpu time)", default=None)
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| 160 | parser.add_argument('--log', dest='log', help="flat in log pt (default: yes)", action='store_true')
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| 161 | parser.add_argument('--nolog', dest='log', help="flat in pt (default: false)", action='store_false')
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| 162 | parser.set_defaults(log=True)
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| 163 | parser.add_argument("--output", help="output LHE file (default: events.lhe)", default='events.lhe')
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| 164 |
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| 165 | args = parser.parse_args()
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| 166 |
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| 167 | # check if provided pdgCode is allowed
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| 168 | allowed_pdgCodes = [1,2,3,4,5,6,11,12,13,14,15,16,21,22,23,24,25]
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| 169 | for p1 in args.pdg:
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| 170 | if p1 not in allowed_pdgCodes:
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| 171 | print args.pdg ,'Please provide a list of supported pdgCodes : 1, 2, 3, 4, 5 or 21'
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| 172 | sys.exit(0)
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| 173 |
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| 174 | # print user-defined parameters
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| 175 | print_params(args)
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| 176 | print ''
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| 177 |
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| 178 | # intialize file and write LHE file header
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| 179 | out = open(args.output, "w+")
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| 180 | out.close()
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| 181 | write_init(args)
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| 182 |
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| 183 | # initialize random seed
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| 184 | random.seed(args.seed)
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| 185 |
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| 186 | print 'Start event generation ...'
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| 187 |
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| 188 | ebeam = args.ecm/2.
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| 189 | count = 0
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| 190 |
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| 191 | if args.guntype not in ['pt', 'e']:
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| 192 | print 'Please specify either gun mode "pt" or "e".'
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| 193 | sys.exit(0)
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| 194 |
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| 195 | # start event loop
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| 196 | nfail = 0
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| 197 | while count < args.nevts:
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| 198 |
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| 199 | phi = random.uniform(0., math.pi)
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| 200 | eta = random.uniform(args.etamin, args.etamax)
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| 201 |
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| 202 | # flat in e/pt or in log e/pt
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| 203 | if args.log:
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| 204 | gun = math.pow(10, random.uniform(math.log10(args.pmin), math.log10(args.pmax)))
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| 205 | else:
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| 206 | gun = random.uniform(args.pmin, args.pmax)
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| 207 |
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| 208 | # generating "balanced" collision, i.e x1 = x2 = 2*energy/sqrt(s)
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| 209 | if args.guntype == 'pt':
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| 210 | pt = gun
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| 211 | e = pt*math.cosh(eta)
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| 212 | elif args.guntype == 'e':
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| 213 | e = gun
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| 214 | pt = e/math.cosh(eta)
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| 215 |
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| 216 | # write event corresponding to required process
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| 217 | if e <= ebeam:
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| 218 | write_event(args, pt, eta, phi)
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| 219 | count += 1
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| 220 | if (count+1)%500 == 0:
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| 221 | print ' ... processed {} events ...'.format(count+1)
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| 222 | else:
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| 223 | nfail += 1
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| 224 |
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| 225 | if nfail > 10*args.nevts:
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| 226 | print 'Too many events fail phase space requirements. Usually means ptmax is too high given eta cuts.'
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| 227 | print 'To fix this either increase center of mass/ change cuts.'
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| 228 | out.close()
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| 229 | os.system('rm {}'.format(args.output))
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| 230 | sys.exit(0)
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| 231 |
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| 232 | out = open(args.output, "a")
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| 233 | out.write('</LesHouchesEvents>\n')
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| 234 | out.close()
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| 235 |
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| 236 | os.system('gzip {}'.format(args.output))
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| 237 |
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| 238 | print ''
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| 239 | print 'Event generation completed.'
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| 240 | print 'Output file:'
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| 241 | print '{}'.format(os.path.abspath(args.output +'.gz'))
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| 242 |
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