# Generate onshell and offshell intermediate bosons

Dear MG experts,

I am trying to generate the process: H > h h, h > b b~, h > z z > 4l , where H and h are heavy BSM and light SM higgs respectively. I am using 2HDM-typeI generated by SARAH.

As mass of h ~ 125GeV & mass of Z ~ 91.3GeV, so the decay of h is: h > Z Z*, where Z is onshell with mass ~ 91.3 GeV and Z* is offshell with mass < 91.3 so both gives the invariant mass of h around 125 GeV.

My question is, is it possible to generate such a decay with both onshell and offshell Z bosons? and if so could you kindly tell me the proper syntax for doing so?

Aya

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Olivier Mattelaer
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 Revision history for this message Olivier Mattelaer (olivier-mattelaer) said on 2021-09-06: #1

Hi,

Your syntax includes both onshell and offshell Z.
So you seem to use the syntax that you are looking for.

Cheers,

Olivier

PS:
> h > z z > 4l
is actually the same as
> h > z > 4l

Since repeating multiple times the request of "at least one s-channel" will not have any impact

> On 5 Sep 2021, at 01:01, Aya Ismail Beshr <email address hidden> wrote:
>
> New question #698636 on MadGraph5_aMC@NLO:
>
> Dear MG experts,
>
>
> I am trying to generate the process: H > h h, h > b b~, h > z z > 4l , where H and h are heavy BSM and light SM higgs respectively. I am using 2HDM-typeI generated by SARAH.
>
> As mass of h ~ 125GeV & mass of Z ~ 91.3GeV, so the decay of h is: h > Z Z*, where Z is onshell with mass ~ 91.3 GeV and Z* is offshell with mass < 91.3 so both gives the invariant mass of h around 125 GeV.
>
> My question is, is it possible to generate such a decay with both onshell and offshell Z bosons? and if so could you kindly tell me the proper syntax for doing so?
>
>
>
> Aya
>
> --

 Revision history for this message Aya Ismail Beshr (ayabeshr) said on 2021-09-13: #2

Dear Olivier,

Thanks a lot! and sorry for my late reply, I had an issue with my account

I have tried the syntax h > z > 4l as you suggested, however I got diagrams
from other contributions rather than Z, so in order to get rid of them and
keep only that with Z, I did:

g g > h2 > h1 h1, h1 > b b~, (h1 > z > mu+ mu- mu+ mu- /ah2 mu+ mu-)

is there an issue here?

I also tried another syntax with the same result;

g g > h2 > h1 h1, h1 > b b~, (h1 > z mu+ mu- \$z /ah2 mu+ mu-, z > mu+ mu-)

is this true?

Thanks a lot!
Aya

On Mon, Sep 6, 2021 at 9:30 AM Olivier Mattelaer <

>
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
> Your syntax includes both onshell and offshell Z.
> So you seem to use the syntax that you are looking for.
>
> Cheers,
>
> Olivier
>
> PS:
> > h > z z > 4l
> is actually the same as
> > h > z > 4l
>
> Since repeating multiple times the request of "at least one s-channel"
> will not have any impact
>
>
> > On 5 Sep 2021, at 01:01, Aya Ismail Beshr <
> >
> > New question #698636 on MadGraph5_aMC@NLO:
> >
> > Dear MG experts,
> >
> >
> > I am trying to generate the process: H > h h, h > b b~, h > z z > 4l ,
> where H and h are heavy BSM and light SM higgs respectively. I am using
> 2HDM-typeI generated by SARAH.
> >
> > As mass of h ~ 125GeV & mass of Z ~ 91.3GeV, so the decay of h is: h > Z
> Z*, where Z is onshell with mass ~ 91.3 GeV and Z* is offshell with mass <
> 91.3 so both gives the invariant mass of h around 125 GeV.
> >
> > My question is, is it possible to generate such a decay with both
> onshell and offshell Z bosons? and if so could you kindly tell me the
> proper syntax for doing so?
> >
> >
> >
> > Thanks for your time!
> > Aya
> >
> > --
>
> --
> know that it is solved:
>
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
>
>

 Revision history for this message Olivier Mattelaer (olivier-mattelaer) said on 2021-09-13: #3

Hi,

Just the usual potential issue that you can arrive to a set of non gauge invariant set of Feynman Diagram when removing Feynman Diagram.

The second syntax is also something that I'm worried about since you artificially break the symmetry between the muon which can lead to a wrong symmetry factor in some part of the phase-space.

Cheers,

Olivier

 Revision history for this message Aya Ismail Beshr (ayabeshr) said on 2021-09-13: #4

Hi,

Thanks for the clarification!

Aya

On Mon, Sep 13, 2021 at 1:25 PM Olivier Mattelaer <

>
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
> Just the usual potential issue that you can arrive to a set of non gauge
> invariant set of Feynman Diagram when removing Feynman Diagram.
>
> The second syntax is also something that I'm worried about since you
> artificially break the symmetry between the muon which can lead to a
> wrong symmetry factor in some part of the phase-space.
>
> Cheers,
>
> Olivier
>
> --
> know that it is solved:
>
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback: