Changes between Version 2 and Version 3 of TopBSM
 Timestamp:
 04/13/12 08:55:09 (8 years ago)
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TopBSM
v2 v3 3 3 == Model for BSM physics studies in ttbar production ([http://arxiv.org/abs/0712.2355 arxiv:0712.2355]) Version 1.3 == 4 4 5 The {{{ 6 topBSM 7 }}} is a model implemented to study BSM effects in the ttbar invariant mass spectrum. This model includes the following possible resonances in the ttbar spectrum: 5 The 6 {{{ 7 topBSM 8 }}} 9 is a model implemented to study BSM effects in the ttbar invariant mass spectrum. This model includes the following possible resonances in the ttbar spectrum: 8 10 * spin0, color singlet 9 11 * spin0, color octet … … 13 15 * spin2, RS model 14 16 15 Note that this {{{ 16 topBSM 17 }}} model can only be used for ttbar production. Any other final state might lead to inconsistencies in the evaluation of the diagrams. This model uses a special {{{ 18 param_card.dat 19 }}} and {{{ 20 run_card.dat 21 }}} that can be found [attachment:param_card.dat here] and [attachment:run_card.dat here]. 17 Note that this 18 {{{ 19 topBSM 20 }}} 21 model can only be used for ttbar production. Any other final state might lead to inconsistencies in the evaluation of the diagrams. This model uses a special 22 {{{ 23 param_card.dat 24 }}} 25 and 26 {{{ 27 run_card.dat 28 }}} 29 that can be found [attachment:param_card.dat here] and [attachment:run_card.dat here]. 22 30 23 31 === spin0, color singlet === … … 25 33 ([attachment:proc_card.dat proc_card.dat]: topBSM spin0 color singlet proc_card.dat) 26 34 27 The spin0, color singlet particle, in the {{{ 28 topBSM 29 }}} called {{{ 35 The spin0, color singlet particle, in the 36 {{{ 37 topBSM 38 }}} 39 called 40 {{{ 30 41 s0 31 }}} (PDG code: 6000045), is a Higgslike particle that couples only to top quarks. The production of the spin0 is only through a top quark loop by gluon fusion. And its decay is directly to two top quarks with a branching ratio $\textrm{BR}(s0\to t\bar{t})=1$. 32 33 It's coupling strength to the top quark is by default equal to the SM Higgs coupling to top quarks, ''i.e.'', %$im_t/v$%, but this can be changed in the {{{ 34 param_card.dat 35 }}}. In the {{{ 36 param_card.dat 37 }}} there are the following two lines: 42 }}} 43 (PDG code: 6000045), is a Higgslike particle that couples only to top quarks. The production of the spin0 is only through a top quark loop by gluon fusion. And its decay is directly to two top quarks with a branching ratio $\textrm{BR}(s0\to t\bar{t})=1$. 44 45 It's coupling strength to the top quark is by default equal to the SM Higgs coupling to top quarks, ''i.e.'', $im_t/v$, but this can be changed in the 46 {{{ 47 param_card.dat 48 }}} 49 . In the 50 {{{ 51 param_card.dat 52 }}} 53 there are the following two lines: 38 54 {{{ 39 55 1. 1.00000000e+00 # s0scalarf ,spin0 scalar mult.fac. … … 41 57 }}} 42 58 43 These two values correspond to multiplication factors for the coupling strength, ''i.e.'', %$g_{s0tt}=$% {{{ 59 These two values correspond to multiplication factors for the coupling strength, ''i.e.'', $g_{s0tt}=$ 60 {{{ 44 61 s0scalarf 45 }}} %$i\frac{m_t}{v}+$% {{{ 62 }}} 63 $i\frac{m_t}{v}+$ 64 {{{ 46 65 s0axialf 47 }}} $\frac{m_t}{v}\gamma_5$. Hence, the spin0 can be a scalar or a pseudoscalar or a mixed CP state by playing around with these two factors. 48 49 Due to the loop in the production mechanism the coupling strength between the gluons and the {{{ 66 }}} 67 $\frac{m_t}{v}\gamma_5$. Hence, the spin0 can be a scalar or a pseudoscalar or a mixed CP state by playing around with these two factors. 68 69 Due to the loop in the production mechanism the coupling strength between the gluons and the 70 {{{ 50 71 s0 51 }}} depends on its momentum. Therefore it is important to set the flag {{{ 72 }}} 73 depends on its momentum. Therefore it is important to set the flag 74 {{{ 52 75 fixed_couplings 53 }}} to false in the {{{ 54 run_card.dat 55 }}}. (See above for a sample {{{ 56 run_card.dat 57 }}}) 58 59 The width is calculated automatically and is not read from the {{{ 60 param_card.dat 61 }}} (this takes into account the values for {{{ 76 }}} 77 to false in the 78 {{{ 79 run_card.dat 80 }}} 81 . (See above for a sample 82 {{{ 83 run_card.dat 84 }}} 85 ) 86 87 The width is calculated automatically and is not read from the 88 {{{ 89 param_card.dat 90 }}} 91 (this takes into account the values for 92 {{{ 62 93 s0scalarf 63 }}} and {{{ 94 }}} 95 and 96 {{{ 64 97 s0axialf 65 }}}). 98 }}} 99 ). 66 100 67 101 === spin0, color octet === … … 69 103 ([attachment:proc_card_o0.dat proc_card_o0.dat]: topBSM spin0 color octet proc_card.dat) 70 104 71 The spin0, color octet particle, in the {{{ 72 topBSM 73 }}} called {{{ 105 The spin0, color octet particle, in the 106 {{{ 107 topBSM 108 }}} 109 called 110 {{{ 74 111 o0 75 }}} (PDG code: 6000046), is a scalar, colored particle that couples only to top quarks. The production of the spin0 is only through a top quark loop by gluon fusion. And its decay is directly to two top quarks with a branching ratio $\textrm{BR}(s0\to t\bar{t})=1$. 76 77 It's coupling strength to the top quark is by default equal to the SM Higgs coupling to top quarks, ''i.e.'', %$im_t/v$%, but this can be changed in the {{{ 78 param_card.dat 79 }}}. In the {{{ 80 param_card.dat 81 }}} there are the following two lines: 112 }}} 113 (PDG code: 6000046), is a scalar, colored particle that couples only to top quarks. The production of the spin0 is only through a top quark loop by gluon fusion. And its decay is directly to two top quarks with a branching ratio $\textrm{BR}(s0\to t\bar{t})=1$. 114 115 It's coupling strength to the top quark is by default equal to the SM Higgs coupling to top quarks, ''i.e.'', $im_t/v$, but this can be changed in the 116 {{{ 117 param_card.dat 118 }}} 119 . In the 120 {{{ 121 param_card.dat 122 }}} 123 there are the following two lines: 82 124 {{{ 83 125 3. 1.00000000e+00 # o0scalarf ,spin0 scalar mult.fac. … … 85 127 }}} 86 128 87 These two values correspond to multiplication factors for the coupling strength, ''i.e.'', %$g_{o0tt}=$% {{{ 129 These two values correspond to multiplication factors for the coupling strength, ''i.e.'', $g_{o0tt}=$ 130 {{{ 88 131 o0scalarf 89 }}} %$i\frac{m_t}{v}+$% {{{ 132 }}} 133 $i\frac{m_t}{v}+$ 134 {{{ 90 135 o0axialf 91 }}} $\frac{m_t}{v}\gamma_5$. Hence, the spin0 can be a scalar or a pseudoscalar or a mixed CP state by playing around with these two factors. 92 93 Due to the loop in the production mechanism the coupling strength between the gluons and the {{{ 136 }}} 137 $\frac{m_t}{v}\gamma_5$. Hence, the spin0 can be a scalar or a pseudoscalar or a mixed CP state by playing around with these two factors. 138 139 Due to the loop in the production mechanism the coupling strength between the gluons and the 140 {{{ 94 141 o0 95 }}} depends on its momentum. Therefore it is important to set the flag {{{ 142 }}} 143 depends on its momentum. Therefore it is important to set the flag 144 {{{ 96 145 fixed_couplings 97 }}} to false in the {{{ 98 run_card.dat 99 }}}. (See above for a sample {{{ 100 run_card.dat 101 }}}) 102 103 The width is calculated automatically and is not read from the {{{ 104 param_card.dat 105 }}} (this takes into account the values for {{{ 146 }}} 147 to false in the 148 {{{ 149 run_card.dat 150 }}} 151 . (See above for a sample 152 {{{ 153 run_card.dat 154 }}} 155 ) 156 157 The width is calculated automatically and is not read from the 158 {{{ 159 param_card.dat 160 }}} 161 (this takes into account the values for 162 {{{ 106 163 o0scalarf 107 }}} and {{{ 164 }}} 165 and 166 {{{ 108 167 o0axialf 109 }}}). 168 }}} 169 ). 110 170 111 171 === spin1, color singlet === … … 113 173 ([attachment:proc_card_S1.dat proc_card_S1.dat]: topBSM spin1 color singlet proc_card.dat) 114 174 115 The spin1, color singlet particle in the {{{ 116 topBSM 117 }}} is called {{{ 175 The spin1, color singlet particle in the 176 {{{ 177 topBSM 178 }}} 179 is called 180 {{{ 118 181 s1 119 }}} (PDG code: 6000047). This spin1 particle is a similar to the SM Z boson. Its mass and width have to be set in the {{{ 120 param_card.dat 121 }}}. By default it has the same couplings as the SM Z boson (only couplings to fermions are implemented). By changing the multiplication factors in the {{{ 182 }}} 183 (PDG code: 6000047). This spin1 particle is a similar to the SM Z boson. Its mass and width have to be set in the 184 {{{ 185 param_card.dat 186 }}} 187 . By default it has the same couplings as the SM Z boson (only couplings to fermions are implemented). By changing the multiplication factors in the 188 {{{ 122 189 BLOCK MGUSER 123 }}} in the {{{ 124 param_card.dat 125 }}} the coupling strengths can be altered. 190 }}} 191 in the 192 {{{ 193 param_card.dat 194 }}} 195 the coupling strengths can be altered. 126 196 127 197 === spin1, color octet === … … 129 199 ([attachment:proc_card_O1.dat proc_card_O1.dat]: topBSM spin1 color octet proc_card.dat) 130 200 131 The spin1, color octet particle in the {{{ 132 topBSM 133 }}} is called {{{ 201 The spin1, color octet particle in the 202 {{{ 203 topBSM 204 }}} 205 is called 206 {{{ 134 207 o1 135 }}} (PDG code: 6000048). This spin1 particle is a similar to a heavy gluon. Its mass and width have to be set in the {{{ 136 param_card.dat 137 }}}. By default it has the same couplings as the gluon (only couplings to quarks are implemented). By changing the multiplication factors in the {{{ 208 }}} 209 (PDG code: 6000048). This spin1 particle is a similar to a heavy gluon. Its mass and width have to be set in the 210 {{{ 211 param_card.dat 212 }}} 213 . By default it has the same couplings as the gluon (only couplings to quarks are implemented). By changing the multiplication factors in the 214 {{{ 138 215 BLOCK MGUSER 139 }}} in the {{{ 140 param_card.dat 141 }}} the coupling strengths can be altered. 216 }}} 217 in the 218 {{{ 219 param_card.dat 220 }}} 221 the coupling strengths can be altered. 142 222 143 223 === spin2, ADD model === … … 145 225 ([attachment:proc_card_ADD.dat proc_card_ADD.dat]: topBSM spin2 ADD proc_card.dat) 146 226 147 The spin2 graviton particle of the large extra dimensions model (ADD) is called {{{ 227 The spin2 graviton particle of the large extra dimensions model (ADD) is called 228 {{{ 148 229 s2 149 }}} in the {{{ 150 topBSM 151 }}} (PDG code: 6000049). Due to the large extra dimensions, the KK gravitons are almost degenerate in mass. Therefore in this model there is not a single resonance, but a very large number that contribute only together significantly. Effectively the denominator of the graviton propagator is calcelled by the sum over all the KK states. 152 153 There is a cutoff scale {{{ 230 }}} 231 in the 232 {{{ 233 topBSM 234 }}} 235 (PDG code: 6000049). Due to the large extra dimensions, the KK gravitons are almost degenerate in mass. Therefore in this model there is not a single resonance, but a very large number that contribute only together significantly. Effectively the denominator of the graviton propagator is calcelled by the sum over all the KK states. 236 237 There is a cutoff scale 238 {{{ 154 239 mstring 155 }}} that you have to specify in the {{{ 156 param_card.dat 157 }}}, as well as the number of extra dimensions (so far only implemented for 3 extra dimensions). The mass of the {{{ 240 }}} 241 that you have to specify in the 242 {{{ 243 param_card.dat 244 }}} 245 , as well as the number of extra dimensions (so far only implemented for 3 extra dimensions). The mass of the 246 {{{ 158 247 s2 159 }}} should be set equal to the cutoff scale, while the width is not used at all. Note that this cutoff scale is parameter in the model, this is '''not''' a cut on the ttbar invariant mass, and there will be [http://www.essaybank.com/ essay writing] events produced above this cutoff scale. 160 161 For this model it is important that the couplings are calculated on an eventbyevent basis, hence one should set the flag {{{ 248 }}} 249 should be set equal to the cutoff scale, while the width is not used at all. Note that this cutoff scale is parameter in the model, this is '''not''' a cut on the ttbar invariant mass, and there will be [http://www.essaybank.com/ essay writing] events produced above this cutoff scale. 250 251 For this model it is important that the couplings are calculated on an eventbyevent basis, hence one should set the flag 252 {{{ 162 253 fixed_couplings 163 }}} in the {{{ 164 run_card.dat 165 }}} to false. (For an example {{{ 166 run_card.dat 167 }}} see above.) 254 }}} 255 in the 256 {{{ 257 run_card.dat 258 }}} 259 to false. (For an example 260 {{{ 261 run_card.dat 262 }}} 263 see above.) 168 264 169 265 === spin2, RS model === … … 171 267 ([attachment:proc_card_RS.dat proc_card_RS.dat]: topBSM spin2 RS proc_card.dat) 172 268 173 In the RS model there are a number of KK resonances with their mass ratio's given by the zeros of the BesselJ function. The mass of the first resonance has to be given in the {{{ 269 In the RS model there are a number of KK resonances with their mass ratio's given by the zeros of the BesselJ function. The mass of the first resonance has to be given in the 270 {{{ 174 271 param_card 175 }}}, the others are calculated by the MadGraph code. Also the widths are calculated internally. Furthermore the ratio of %$\kappa/\bar{M}_{\textrm{planck}}$% also has to be specified in the {{{ 272 }}} 273 , the others are calculated by the MadGraph code. Also the widths are calculated internally. Furthermore the ratio of $\kappa/\bar{M}_{\textrm{planck}}$ also has to be specified in the 274 {{{ 176 275 BLOCK MGUSER 177 }}} to specify the size of the coupling. Note that the RS gravitons are implemented to couple only to quarks and gluons, but in the calculation of the widths, couplings to all SM particles are taken into account. 178 179 Only the first 10 resonances are implemented, called {{{ 276 }}} 277 to specify the size of the coupling. Note that the RS gravitons are implemented to couple only to quarks and gluons, but in the calculation of the widths, couplings to all SM particles are taken into account. 278 279 Only the first 10 resonances are implemented, called 280 {{{ 180 281 g1 181 }}}, {{{ 282 }}} 283 , 284 {{{ 182 285 g2 183 }}},..., {{{ 286 }}} 287 ,..., 288 {{{ 184 289 g0 185 }}} (PDG codes: 6000050...6000059) so setting the mass of the first resonance small and using a large value for the coupling strength should be used with care, because effects from higher resonances start getting more important in this part of the parameter space. 290 }}} 291 (PDG codes: 6000050...6000059) so setting the mass of the first resonance small and using a large value for the coupling strength should be used with care, because effects from higher resonances start getting more important in this part of the parameter space. 186 292 187 293  Main.RikkertFrederix  09 Dec 2008