decay chain syntax.

Hi,

You mix up with the parenthesis.
I guess that the correct definition is this one:

> p p > HG, (HG > E2 E2~, (E2 > SUT Y1~, SUT > NR j , (Y1 > W- D1, W- > j j, (D1 > XU1 e-, XU1 > j e+))))

let me explain:
in a parenthesis you should always have a valid process.
if I look at your definition:
level by level from the deepest one to the higher one (and defining shortcut for those)
> (XU1 > j e+)
this is valid
> (W- > j j, D1 > XU1 e-, (XU1 > j e+) )

Here this is not valid since you have a core process W- > j j and two associate decay D1 > XU1 e- and XU1 > j e+ but neither D1 or XU1 or define in W- > j j

I guess that the correct definition for the second decay is
(D1 > XU1 e-, (XU1 > j e+) )
or equivalently
(D1 > XU1 e-, XU1 > j e+ )

if we go one level up, we have
> Y1 > W- D1
with two associate decay
> W- > j j,
and
(D1 > XU1 e-, XU1 > j e+ )

therefore the correct syntax is
(Y1 > W- D1, DECAY1, DECAY2)
i.e.
> (Y1 > W- D1, W- > j j, (D1 > XU1 e-, XU1 > j e+))

and so on.

> I try with more simple process like p p > HG, (HG > E2 E2~, (E2 > SUT Y1~, (Y1 > W- D1))) but the same error appears.

The problem here is different, you have
> (E2 > SUT Y1~, (Y1 > W- D1))
the problem is that Y1 is not in your production, since you only have Y1~
the correct syntax should be ( I guess)
> (E2 > SUT Y1~, (Y1~ > W+ D1~))
or
> (E2 > SUT Y1~, Y1~ > W+ D1~)

Cheers,

Olivier

On 17 Jul 2015, at 18:46, daniel camargo <email address hidden> wrote:

> New question #269353 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/269353
>
> Dear experts,
>
> I have a large decay chain for a particular process. I am trying to follow the MG syntax in order to have all the decays on-shell, but MG show me some error messages.
> "Decay without corresponding particle in core process found.
> Decay information for particle(s) xu1,d1 is discarded". ....and the same message for the other intermediaries particles...Y1, SUT, XU1, D1
>
> The decay chain that I want is the following:
>
> p p > HG, (HG > E2 E2~, (E2 > SUT Y1~,(Y1 > W- D1, SUT > NR j,(W- > j j, D1 > XU1 e-,(XU1 > j e+)))))
>
> the decays in two particles are:
>
> HG > E2 E2~
>
> E2 > SUT Y1~
>
> Y1 > W- D1
>
> SUT > NR j
>
> D1 > XU1 e-
>
> XU1 > j e+
>
> Then, I want to produce the pair E2 E2~ through HG (pp > HG) until have NR, leptons and jets as a final state.
>
> I try with more simple process like p p > HG, (HG > E2 E2~, (E2 > SUT Y1~, (Y1 > W- D1))) but the same error appears.
>
> some hint!
>
> Thanks in advance.
>
> Daniel.
>
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