when I calculate the process chi chi~ > e+ e- for the effective operator " Gf chibarchi fbarf" , when I set the dark matter mass to 100MeV, the result of maddm is: ___________________________________________________________________________________________________________________ ################################################ # MadDM v. 3.2 # ################################################ ################################################ # Relic Density # ################################################ Omegah2 = 6.57e+00 Omegah_Planck = 1.20e-01 xsi = 1.00e+00 # xsi = (Omega/Omega_Planck) x_f = 1.00e+01 sigmav_xf = 3.71e-28 # cm^3 s^-1 # % of the relic density channels %_xchixchix_ssx = 0.00 % %_xchixchix_emep = 100.00 % %_xchixchix_uux = 0.00 % %_xchixchix_vtvtx = 0.00 % %_xchixchix_ccx = 0.00 % %_xchixchix_ttx = 0.00 % %_xchixchix_mummup = 0.00 % %_xchixchix_vevex = 0.00 % %_xchixchix_ddx = 0.00 % %_xchixchix_bbx = 0.00 % %_xchixchix_vmvmx = 0.00 % %_xchixchix_tamtap = 0.00 % ################################################ # Indirect Detection # ################################################ # Results in brackets display [prediction, upper limit] # Annihilation cross section computed with the method: madevent # [cm^3 s^-1] of continuum spectrum final states and Fermi dSph limits (if available, else -1) xchixchix_ddx = [0.00e+00,-1.00e+00] xchixchix_ttx = [0.00e+00,-1.00e+00] xchixchix_vlvl = [0.00e+00,-1.00e+00] xchixchix_ll = [3.21e-36,-1.00e+00] xchixchix_bbx = [0.00e+00,-1.00e+00] xchixchix_ccx = [0.00e+00,-1.00e+00] xchixchix_ssx = [0.00e+00,-1.00e+00] xchixchix_tamtap = [0.00e+00,-1.00e+00] xchixchix_uux = [0.00e+00,-1.00e+00] # Global Fermi dSph Limit computed with pythia8 spectra Total_xsec = [3.21e-36,-1.00e+00] Fermi_Likelihood = -1.76e+01 Fermi_pvalue = 0.00e+00 ################################################# # CR Flux at Earth [particles cm^-2 s^-1 sr^-1) # ################################################# # Fluxes calculated using the spectra from dragon Flux_neutrinos_e = nan Flux_neutrinos_mu = nan Flux_neutrinos_tau = nan Flux_gammas = nan _____________________________________________________________________________________________________________________ It can be seen that there is a problem with the output energy spectrum, showing "nan". At the same time, madevent also shows an error： __________________________________________________________________________________________________________ # Number of Events : 100000 # Integrated weight (pb) : 69.298 # Number of Events : 100000 # Integrated weight (pb) : 3.0968e-06 52 52 5.000000e+02 5.000000e+02 0 0 0 0 -4 1 3.096800e-06 1.325700e-09 3.096800e-06 1995 please cite 1405.0301 4 1995 +3.0968000e-06 2.00000000e-01 7.81860800e-03 nan 9100001 -1 0 0 0 0 +0.0000000000e+00 +0.0000000000e+00 +1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00 -9100001 -1 0 0 0 0 -0.0000000000e+00 -0.0000000000e+00 -1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00 11 1 1 2 0 0 -8.5974541474e-02 +2.8951572333e-02 -4.2073562742e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 1.0000e+00 -11 1 1 2 0 0 +8.5974541474e-02 -2.8951572333e-02 +4.2073562742e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 1.0000e+00 4 1995 +3.0968000e-06 2.00000000e-01 7.81860800e-03 nan 9100001 -1 0 0 0 0 +0.0000000000e+00 +0.0000000000e+00 +1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00 -9100001 -1 0 0 0 0 -0.0000000000e+00 -0.0000000000e+00 -1.9999991286e-06 1.0000000002e-01 1.0000000000e-01 0.0000e+00 -1.0000e+00 11 1 1 2 0 0 -8.7280464371e-02 +3.3613981069e-02 +3.5386732257e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 -1.0000e+00 -11 1 1 2 0 0 +8.7280464371e-02 -3.3613981069e-02 -3.5386732257e-02 1.0000000002e-01 0.0000000000e+00 0.0000e+00 -1.0000e+00 ...... ___________________________________________________________________________________________________________________ You can see that "nan" appears in the event. So of course pythia8 will also get errors: —————————————————————————————————————————————————————————— *------- PYTHIA Error and Warning Messages Statistics ----------------------------------------------------------* | | | times message | | | | 10 Abort from Pythia::next: reached end of Les Houches Events File | | 1 Info from SLHAinterface::initSLHA: No MODSEL found, keeping internal SUSY switched off | | 1 Info from SLHAinterface::initSLHA: importing MASS entries | | 1 Warning in SLHAinterface::initSLHA: ignoring DECAY tables | | 1 Warning in SLHAinterface::initSLHA: ignoring MASS entries | | 1 Warning in SLHAinterface::initSLHA: ignoring empty DECAY tables | | 1 Warning in SLHAinterface::initSLHA: massless particle forced stable | | | *------- End PYTHIA Error and Warning Messages Statistics ------------------------------------------------------* Histogram not shown since it is empty Histogram not shown since it is empty Histogram not shown since it is empty Histogram not shown since it is empty Histogram not shown since it is empty Histogram not shown since it is empty Histogram not shown since it is empty ____________________________________________________________________________________________________________________ I would like to know how to solve this problem, or whether MadDM is suitable for sub-GeV dark matter mass calculations.

When	Who	Action	New State
2023-11-21	Olivier Mattelaer	Answer	Answered
2023-12-30	ZH Cheng	Confirm	Solved

MadDM

History of question #708484