Bug #1766521 “Negative mass particles have width changed to be n...” : Bugs : MadGraph5_aMC@NLO

Revision history for this message

Dan Kreso (dankreso) wrote on 2018-04-24:

#1

234536140.slha Edit (38.3 KiB, text/plain)

Revision history for this message

Olivier Mattelaer (olivier-mattelaer) wrote on 2018-04-24: Re: [Bug 1766521] [NEW] Negative mass particles have width changed to be negative

#2

Hi,

I would naively think that this is a model issue.
But without the model, I can not be sure.

My guess is that the model has an analytical formula for the width, and that such analytical formula does not support negative number for the mass.
Do you have the defaut param_card generated by MG5aMC, this shoudl clearly be written.

If that's the case, we just follow the model instructions which is change the width according to the mass value.

Cheers,

Olivier

> On 24 Apr 2018, at 10:38, Dan Kreso <email address hidden> wrote:
>
> Public bug reported:
>
> Dear MG5 Developers,
>
> In the SLHA card format, some particle masses are given as negative
> values, according to the convention explained in https://arxiv.org/pdf
> /hep-ph/0311123.pdf.
>
> In the generation of p p > n2 n1 events, I noticed that for cards with
> n2 masses given as negative values, no leptons are produced from n2
> decay. Upon closer inspection of the MadGraph output, the program
> changes the width of n2 to a negative value (i.e. "For consistency, the
> width of particle 1000023 (n2) is changed to -2.688724e-13"). This then
> switches off the n2 decay. Unless I am mistaken, the convention for
> negative masses in SLHA files should not influence whether or not a
> particle is decayed.
>
> I have attached an example SLHA card with the mass of n2 set to a
> negative value. I am also happy to provide further details if needed.
>
> Kind regards,
>
> Dan
>
> ** Affects: mg5amcnlo
> Importance: Undecided
> Status: New
>
> ** Attachment added: "234536140.slha"
> https://bugs.launchpad.net/bugs/1766521/+attachment/5126408/+files/234536140.slha
>
> --
> You received this bug notification because you are subscribed to
> MadGraph5_aMC@NLO.
> https://bugs.launchpad.net/bugs/1766521
>
> Title:
> Negative mass particles have width changed to be negative
>
> Status in MadGraph5_aMC@NLO:
> New
>
> Bug description:
> Dear MG5 Developers,
>
> In the SLHA card format, some particle masses are given as negative
> values, according to the convention explained in https://arxiv.org/pdf
> /hep-ph/0311123.pdf.
>
> In the generation of p p > n2 n1 events, I noticed that for cards with
> n2 masses given as negative values, no leptons are produced from n2
> decay. Upon closer inspection of the MadGraph output, the program
> changes the width of n2 to a negative value (i.e. "For consistency,
> the width of particle 1000023 (n2) is changed to -2.688724e-13"). This
> then switches off the n2 decay. Unless I am mistaken, the convention
> for negative masses in SLHA files should not influence whether or not
> a particle is decayed.
>
> I have attached an example SLHA card with the mass of n2 set to a
> negative value. I am also happy to provide further details if needed.
>
> Kind regards,
>
> Dan
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1766521/+subscriptions

Hi,

I would naively think that this is a model issue. 
But without the model, I can not be sure.

My guess is that the model has an analytical formula for the width, and that such analytical formula does not support negative number for the mass.
Do you have the defaut param_card generated by MG5aMC, this shoudl clearly be written.

If that's the case, we just follow the model instructions which is change the width according to the mass value.

Cheers,

Olivier

> On 24 Apr 2018, at 10:38, Dan Kreso <1766521@bugs.launchpad.net> wrote:
> 
> Public bug reported:
> 
> Dear MG5 Developers,
> 
> In the SLHA card format, some particle masses are given as negative
> values, according to the convention explained in https://arxiv.org/pdf
> /hep-ph/0311123.pdf.
> 
> In the generation of p p > n2 n1 events, I noticed that for cards with
> n2 masses given as negative values, no leptons are produced from n2
> decay. Upon closer inspection of the MadGraph output, the program
> changes the width of n2 to a negative value (i.e. "For consistency, the
> width of particle 1000023 (n2) is changed to -2.688724e-13"). This then
> switches off the n2 decay. Unless I am mistaken, the convention for
> negative masses in SLHA files should not influence whether or not a
> particle is decayed.
> 
> I have attached an example SLHA card with the mass of n2 set to a
> negative value. I am also happy to provide further details if needed.
> 
> Kind regards,
> 
> Dan
> 
> ** Affects: mg5amcnlo
>     Importance: Undecided
>         Status: New
> 
> ** Attachment added: "234536140.slha"
>   https://bugs.launchpad.net/bugs/1766521/+attachment/5126408/+files/234536140.slha
> 
> -- 
> You received this bug notification because you are subscribed to
> MadGraph5_aMC@NLO.
> https://bugs.launchpad.net/bugs/1766521
> 
> Title:
>  Negative mass particles have width changed to be negative
> 
> Status in MadGraph5_aMC@NLO:
>  New
> 
> Bug description:
>  Dear MG5 Developers,
> 
>  In the SLHA card format, some particle masses are given as negative
>  values, according to the convention explained in https://arxiv.org/pdf
>  /hep-ph/0311123.pdf.
> 
>  In the generation of p p > n2 n1 events, I noticed that for cards with
>  n2 masses given as negative values, no leptons are produced from n2
>  decay. Upon closer inspection of the MadGraph output, the program
>  changes the width of n2 to a negative value (i.e. "For consistency,
>  the width of particle 1000023 (n2) is changed to -2.688724e-13"). This
>  then switches off the n2 decay. Unless I am mistaken, the convention
>  for negative masses in SLHA files should not influence whether or not
>  a particle is decayed.
> 
>  I have attached an example SLHA card with the mass of n2 set to a
>  negative value. I am also happy to provide further details if needed.
> 
>  Kind regards,
> 
>  Dan
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1766521/+subscriptions

Revision history for this message

Dan Kreso (dankreso) wrote on 2018-04-24:

#3

param_card_default.dat Edit (17.5 KiB, text/plain)

Dear Olivier,

The model is MSSM_SLHA2. I've attached the param_card_default.dat file. Looking at the decays.py file for the MSSM_SLHA2 model, analytic expressions for the partial widths of n2 are given from line 610.

Thanks,

Dan

Revision history for this message

Olivier Mattelaer (olivier-mattelaer) wrote on 2018-04-24: Re: [Bug 1766521] Re: Negative mass particles have width changed to be negative

#4

Download full text (6.3 KiB)

Hi,

I do not actually reproduce your error.
Using your slha file, produces a lot of error/warning since you provide input in the wrong convention.
I would strongly suggest that you use an external converter since our internal one, as stated
is not generic and can in some cases wrongly convert your input.

This being said, I do not reproduce your negative width warning.

(I have tested both in 2.6.1 and in the development version)

Cheers,

Olivier

> Do you want to edit a card (press enter to bypass editing)?
> /------------------------------------------------------------\
> | 1. param : param_card.dat |
> | 2. run : run_card.dat |
> | 3. plot : plot_card.dat |
> \------------------------------------------------------------/
> you can also
> - enter the path to a valid card or banner.
> - use the 'set' command to modify a parameter directly.
> The set option works only for param_card and run_card.
> Type 'help set' for more information on this command.
> - call an external program (ASperGE/MadWidth/...).
> Type 'help' for the list of available command
> [0, done, 1, param, 2, run, 3, plot, enter path][90s to answer]
> >http://bugs.launchpad.net/bugs/1766521/+attachment/5126408/+files/234536140.slha
> INFO: copy http://bugs.launchpad.net/bugs/1766521/+attachment/5126408/+files/234536140.slha as param_card.dat
> Do you want to edit a card (press enter to bypass editing)?
> /------------------------------------------------------------\
> | 1. param : param_card.dat |
> | 2. run : run_card.dat |
> | 3. plot : plot_card.dat |
> \------------------------------------------------------------/
> you can also
> - enter the path to a valid card or banner.
> - use the 'set' command to modify a parameter directly.
> The set option works only for param_card and run_card.
> Type 'help set' for more information on this command.
> - call an external program (ASperGE/MadWidth/...).
> Type 'help' for the list of available command
> [0, done, 1, param, 2, run, 3, plot, enter path]
> >
> INFO: Update the dependent parameter of the param_card.dat
> WARNING: Param card is not complete: Block mse2 is simply missing.
> We will use model default for all missing value! Please cross-check that
> this correspond to your expectation.
> WARNING: Param card is not complete: Block msu2 is simply missing.
> We will use model default for all missing value! Please cross-check that
> this correspond to your expectation.
> WARNING: Param card is not complete: Block msq2 is simply missing.
> We will use model default for all missing value! Please cross-check that
> this correspond to your expectation.
> WARNING: Param card is not complete: Block msl2 is simply missing.
> We will use model default for all missing value! Please cross-check that
> this correspond to your expectation.
> WARNING: ...

Hi,

I do not actually reproduce your error. 
Using your slha file, produces a lot of error/warning since you provide input in the wrong convention.
I would strongly suggest that you use an external converter since our internal one, as stated
is not generic and can in some cases wrongly convert your input.

This being said, I do not reproduce your negative width warning.

(I have tested both in 2.6.1 and in the development version)

Cheers,

Olivier

> Do you want to edit a card (press enter to bypass editing)?
> /------------------------------------------------------------\
> |  1. param : param_card.dat                                 |
> |  2. run   : run_card.dat                                   |
> |  3. plot  : plot_card.dat                                  |
> \------------------------------------------------------------/
>  you can also
>    - enter the path to a valid card or banner.
>    - use the 'set' command to modify a parameter directly.
>      The set option works only for param_card and run_card.
>      Type 'help set' for more information on this command.
>    - call an external program (ASperGE/MadWidth/...).
>      Type 'help' for the list of available command
>  [0, done, 1, param, 2, run, 3, plot, enter path][90s to answer]
> >http://bugs.launchpad.net/bugs/1766521/+attachment/5126408/+files/234536140.slha
> INFO: copy http://bugs.launchpad.net/bugs/1766521/+attachment/5126408/+files/234536140.slha as param_card.dat
> Do you want to edit a card (press enter to bypass editing)?
> /------------------------------------------------------------\
> |  1. param : param_card.dat                                 |
> |  2. run   : run_card.dat                                   |
> |  3. plot  : plot_card.dat                                  |
> \------------------------------------------------------------/
>  you can also
>    - enter the path to a valid card or banner.
>    - use the 'set' command to modify a parameter directly.
>      The set option works only for param_card and run_card.
>      Type 'help set' for more information on this command.
>    - call an external program (ASperGE/MadWidth/...).
>      Type 'help' for the list of available command
>  [0, done, 1, param, 2, run, 3, plot, enter path]
> >
> INFO: Update the dependent parameter of the param_card.dat
> WARNING: Param card is not complete: Block mse2 is simply missing.
>                 We will use model default for all missing value! Please cross-check that
>                 this correspond to your expectation.
> WARNING: Param card is not complete: Block msu2 is simply missing.
>                 We will use model default for all missing value! Please cross-check that
>                 this correspond to your expectation.
> WARNING: Param card is not complete: Block msq2 is simply missing.
>                 We will use model default for all missing value! Please cross-check that
>                 this correspond to your expectation.
> WARNING: Param card is not complete: Block msl2 is simply missing.
>                 We will use model default for all missing value! Please cross-check that
>                 this correspond to your expectation.
> WARNING: Param card is not complete: Block msd2 is simply missing.
>                 We will use model default for all missing value! Please cross-check that
>                 this correspond to your expectation.
> ERROR: Convention for the param_card seems to be wrong. Trying to automatically convert your file to SLHA2 format.
> Please check that the conversion occurs as expected (The converter is not fully general)
> Generating 10000 events with run name run_01
> survey  run_01
> INFO: compile directory
> WARNING: Missing mass in the lhef file (6) . Please fix this (use the "update missing" command if needed)
> ERROR: The width of particle 1000024 is too small for an s-channel resonance (1.464597e-12). If you have this particle in an s-channel, this is likely to create numerical instabilities .
> ERROR: The width of particle 1000023 is too small for an s-channel resonance (2.688724e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
> write compile file for card: /Users/omattelaer/Documents/workspace/2.6.2/PROC_MSSM_SLHA2_0/Cards/param_card.dat
> WARNING: information about "mass [23]" is missing using default value: 91.1876.
> WARNING: information about "mass [15]" is missing using default value: 1.777.
> WARNING: information about "mass [6]" is missing using default value: 175.0.
> WARNING: information about "decay [23]" is missing using default value: 2.411433.
> WARNING: information about "decay [24]" is missing using default value: 2.002822.

> On 24 Apr 2018, at 14:26, Dan Kreso <1766521@bugs.launchpad.net> wrote:
> 
> Dear Olivier,
> 
> The model is MSSM_SLHA2. I've attached the param_card_default.dat file.
> Looking at the decays.py file for the MSSM_SLHA2 model, analytic
> expressions for the partial widths of n2 are given from line 610.
> 
> Thanks,
> 
> Dan
> 
> ** Attachment added: "param_card_default.dat"
>   https://bugs.launchpad.net/mg5amcnlo/+bug/1766521/+attachment/5126512/+files/param_card_default.dat
> 
> -- 
> You received this bug notification because you are subscribed to
> MadGraph5_aMC@NLO.
> https://bugs.launchpad.net/bugs/1766521
> 
> Title:
>  Negative mass particles have width changed to be negative
> 
> Status in MadGraph5_aMC@NLO:
>  New
> 
> Bug description:
>  Dear MG5 Developers,
> 
>  In the SLHA card format, some particle masses are given as negative
>  values, according to the convention explained in https://arxiv.org/pdf
>  /hep-ph/0311123.pdf.
> 
>  In the generation of p p > n2 n1 events, I noticed that for cards with
>  n2 masses given as negative values, no leptons are produced from n2
>  decay. Upon closer inspection of the MadGraph output, the program
>  changes the width of n2 to a negative value (i.e. "For consistency,
>  the width of particle 1000023 (n2) is changed to -2.688724e-13"). This
>  then switches off the n2 decay. Unless I am mistaken, the convention
>  for negative masses in SLHA files should not influence whether or not
>  a particle is decayed.
> 
>  I have attached an example SLHA card with the mass of n2 set to a
>  negative value. I am also happy to provide further details if needed.
> 
>  Kind regards,
> 
>  Dan
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1766521/+subscriptions

Revision history for this message

Dan Kreso (dankreso) wrote on 2018-04-25:

#5

Dear Olivier,

Thanks for checking, I will take a further look.

All the best,

Dan

Olivier Mattelaer (olivier-mattelaer) on 2018-05-03

Changed in mg5amcnlo:
status:	New → Incomplete

Revision history for this message

Olivier Mattelaer (olivier-mattelaer) wrote on 2018-06-08:

#6

Hi,

Is this issue solved? Can I close this bug report? Or can I help you to fix the issue?

Cheers,

Olivier

Revision history for this message

Dan Kreso (dankreso) wrote on 2018-06-11:

#7

Dear Olivier,

You can close the bug report - I have moved on from my project and do not
currently have the time to look at it.

Thank you for your help.

Dan

On 8 June 2018 at 14:38, Olivier Mattelaer <email address hidden>
wrote:

> Hi,
>
> Is this issue solved? Can I close this bug report? Or can I help you to
> fix the issue?
>
> Cheers,
>
> Olivier
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1766521
>
> Title:
> Negative mass particles have width changed to be negative
>
> Status in MadGraph5_aMC@NLO:
> Incomplete
>
> Bug description:
> Dear MG5 Developers,
>
> In the SLHA card format, some particle masses are given as negative
> values, according to the convention explained in https://arxiv.org/pdf
> /hep-ph/0311123.pdf.
>
> In the generation of p p > n2 n1 events, I noticed that for cards with
> n2 masses given as negative values, no leptons are produced from n2
> decay. Upon closer inspection of the MadGraph output, the program
> changes the width of n2 to a negative value (i.e. "For consistency,
> the width of particle 1000023 (n2) is changed to -2.688724e-13"). This
> then switches off the n2 decay. Unless I am mistaken, the convention
> for negative masses in SLHA files should not influence whether or not
> a particle is decayed.
>
> I have attached an example SLHA card with the mass of n2 set to a
> negative value. I am also happy to provide further details if needed.
>
> Kind regards,
>
> Dan
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1766521/+subscriptions
>

Olivier Mattelaer (olivier-mattelaer) on 2018-06-11

Changed in mg5amcnlo:
status:	Incomplete → Invalid

MadGraph5_aMC@NLO

Negative mass particles have width changed to be negative

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