19 const ParticleList &in,
const double time,
const int n_frac_photons,
20 const double hadronic_cross_section_input)
22 reac_(bremsstrahlung_reaction_type(in)),
23 number_of_fractional_photons_(n_frac_photons),
24 hadronic_cross_section_(hadronic_cross_section_input) {}
65 for (
const auto &output : outputs) {
66 if (output->is_photon_output()) {
68 output->at_interaction(*
this, 0.0);
78 <<
"Problem in BremsstrahlungAction::generate_final_state().\nThe "
81 <<
" entries. It should however have 1.";
82 throw std::runtime_error(
"");
100 if ((k_max - k_min) < 0.0) {
107 delta_k = (k_max - k_min);
116 double diff_xs_k = diff_xs_pair.first;
117 double diff_xs_theta = diff_xs_pair.second;
120 const double W_theta = diff_xs_theta * (M_PI - 0.0);
121 const double W_k = diff_xs_k * delta_k;
122 weight_ = std::sqrt(W_theta * W_k) /
133 new_particle.set_4position(interaction_point);
134 new_particle.boost_momentum(
149 const double sqrts =
sqrt_s();
150 const double E_ab = sqrts - m_c -
k_;
151 const double pcm =
pCM(sqrts, E_ab, m_c);
152 const double pcm_pions =
pCM(E_ab, m_a, m_b);
159 pcm * phitheta_photon.
threevec() / std::sqrt(pcm * pcm + E_ab * E_ab);
171 double reaction_cross_section) {
172 CollisionBranchPtr dummy_process = make_unique<CollisionBranch>(
179 CollisionBranchList process_list;
203 double xsection_pipi = (*pipi_pipi_opp_interpolation)(sqrts);
204 double xsection_pi0pi0 = (*pipi_pi0pi0_interpolation)(sqrts);
207 xsection_pipi = (xsection_pipi <= 0.0) ?
really_small : xsection_pipi;
208 xsection_pi0pi0 = (xsection_pi0pi0 <= 0.0) ?
really_small : xsection_pi0pi0;
212 CollisionBranchList process_list_pipi;
215 process_list_pipi.push_back(make_unique<CollisionBranch>(
218 process_list_pipi.push_back(make_unique<CollisionBranch>(
219 *pi_z_particle, *pi_z_particle, *photon_particle, xsection_pi0pi0,
223 double total_cross_section = xsection_pipi + xsection_pi0pi0;
225 choose_channel<CollisionBranch>(process_list_pipi, total_cross_section);
227 xsection = proc->
weight();
229 process_list.push_back(make_unique<CollisionBranch>(
239 xsection = (*pipi_pipi_same_interpolation)(sqrts);
242 xsection = (*pipi0_pipi0_interpolation)(sqrts);
248 process_list.push_back(make_unique<CollisionBranch>(
255 xsection = (*pi0pi0_pipi_interpolation)(sqrts);
260 process_list.push_back(make_unique<CollisionBranch>(
261 *pi_p_particle, *pi_m_particle, *photon_particle, xsection,
264 throw std::runtime_error(
"Unknown ReactionType in BremsstrahlungAction.");
272 const double collision_energy =
sqrt_s();
274 double dsigma_dtheta;
280 (*pipi_pipi_opp_dsigma_dk_interpolation)(
k_, collision_energy);
281 dsigma_dtheta = (*pipi_pipi_opp_dsigma_dtheta_interpolation)(
282 theta_, collision_energy);
285 dsigma_dk = (*pipi_pi0pi0_dsigma_dk_interpolation)(
k_, collision_energy);
287 (*pipi_pi0pi0_dsigma_dtheta_interpolation)(
theta_, collision_energy);
291 dsigma_dk = (*pipi_pipi_same_dsigma_dk_interpolation)(
k_, collision_energy);
293 (*pipi_pipi_same_dsigma_dtheta_interpolation)(
theta_, collision_energy);
296 dsigma_dk = (*pipi0_pipi0_dsigma_dk_interpolation)(
k_, collision_energy);
298 (*pipi0_pipi0_dsigma_dtheta_interpolation)(
theta_, collision_energy);
300 dsigma_dk = (*pi0pi0_pipi_dsigma_dk_interpolation)(
k_, collision_energy);
302 (*pi0pi0_pipi_dsigma_dtheta_interpolation)(
theta_, collision_energy);
304 throw std::runtime_error(
305 "Unkown channel when computing differential cross sections for "
306 "bremsstrahlung processes.");
310 dsigma_dk = (dsigma_dk < 0.0) ?
really_small : dsigma_dk;
311 dsigma_dtheta = (dsigma_dtheta < 0.0) ?
really_small : dsigma_dtheta;
314 std::pair<double, double> diff_x_sections = {dsigma_dk, dsigma_dtheta};
316 return diff_x_sections;
322 std::vector<double> photon_momentum =
BREMS_K;
334 std::vector<double> dsigma_dk_pipi_pipi_same =
341 std::vector<double> dsigma_dtheta_pipi_pipi_opp =
343 std::vector<double> dsigma_dtheta_pipi_pipi_same =
345 std::vector<double> dsigma_dtheta_pipi0_pipi0 =
347 std::vector<double> dsigma_dtheta_pipi_pi0pi0 =
349 std::vector<double> dsigma_dtheta_pi0pi0_pipi =
355 make_unique<InterpolateDataLinear<double>>(sqrts, sigma_pipi_pipi_opp);
357 make_unique<InterpolateDataLinear<double>>(sqrts, sigma_pipi_pipi_same);
359 make_unique<InterpolateDataLinear<double>>(sqrts, sigma_pipi0_pipi0);
361 make_unique<InterpolateDataLinear<double>>(sqrts, sigma_pipi_pi0pi0);
363 make_unique<InterpolateDataLinear<double>>(sqrts, sigma_pi0pi0_pipi);
368 photon_momentum, sqrts, dsigma_dk_pipi_pipi_opp);
370 photon_momentum, sqrts, dsigma_dk_pipi_pipi_same);
372 photon_momentum, sqrts, dsigma_dk_pipi0_pipi0);
374 photon_momentum, sqrts, dsigma_dk_pipi_pi0pi0);
376 photon_momentum, sqrts, dsigma_dk_pi0pi0_pipi);
381 make_unique<InterpolateData2DSpline>(photon_angle, sqrts,
382 dsigma_dtheta_pipi_pipi_opp);
384 make_unique<InterpolateData2DSpline>(photon_angle, sqrts,
385 dsigma_dtheta_pipi_pipi_same);
387 make_unique<InterpolateData2DSpline>(photon_angle, sqrts,
388 dsigma_dtheta_pipi0_pipi0);
390 make_unique<InterpolateData2DSpline>(photon_angle, sqrts,
391 dsigma_dtheta_pipi_pi0pi0);
393 make_unique<InterpolateData2DSpline>(photon_angle, sqrts,
394 dsigma_dtheta_pi0pi0_pipi);