Higgs Diphoton Decay

[JPEllis]

Hi,

In my implementation of the Standard Model (as a sanity check to make sure things work), I see the following two blocks for Higgs decays:

Code: Select all

DECAY        25     3.09400148E-03   # H0re
#    BR                NDA      ID1      ID2
     2.44448482E-03    2           22         22   # BR(H0re -> VEMBoson VEMBoson )
     9.15138854E-02    2           21         21   # BR(H0re -> VSU3CBoson VSU3CBoson )
     6.71831333E-03    2           23         23   # BR(H0re -> VZBoson VZBoson )
     8.87881220E-02    2           24        -24   # BR(H0re -> VWBoson^* VWBoson_virt )
     7.26622024E-07    2           -1          1   # BR(H0re -> Fd_1^* Fd_1 )
     2.61359525E-04    2           -3          3   # BR(H0re -> Fd_2^* Fd_2 )
     6.99716529E-01    2           -5          5   # BR(H0re -> Fd_3^* Fd_3 )
     5.98727155E-09    2          -11         11   # BR(H0re -> Fe_1^* Fe_1 )
     2.67463346E-04    2          -13         13   # BR(H0re -> Fe_2^* Fe_2 )
     7.71883763E-02    2          -15         15   # BR(H0re -> Fe_3^* Fe_3 )
     1.39354180E-07    2           -2          2   # BR(H0re -> Fu_1^* Fu_1 )
     3.31005941E-02    2           -4          4   # BR(H0re -> Fu_2^* Fu_2 )
DECAY1L        25     4.26656053E-04   # H0re
#    BR                NDA      ID1      ID2
     5.84736783E-01    2          -15         15   # BR(H0re -> Fe_3^* Fe_3 )
     3.39716991E-02    2           22         22   # BR(H0re -> VEMBoson VEMBoson )
     3.81291518E-01    2           21         21   # BR(H0re -> VSU3CBoson VSU3CBoson )

I presume that DECAY are for tree level decays only, and DECAY1L are for one-loop decay. (If not, then my question is a misunderstanding).

So why is it that the DECAY block contains a decay to diphotons, given that is a strictly NLO process? I'm guessing that at some point, SPheno calculate an effective Higgs-diphoton vertex, but then might there be an issue with double counting?

Josh

[FStaub]

See sec. 4.4 of 1703.09237

[JPEllis]

Thanks, that clarifies it! I was searching the wiki for this but couldn't find the relevant information.