Issue faced in SModels

[hdeka1]

Dear developers of SModels,

I am writing to you regarding one of the issues I face in SModels. I generated the lhe file in MG-3.5.5 for the channel:
generate p p > bp bp~, (bp > hp2~ u, hp2~ > e- ne), (bp~ > hp2 u~, hp2 > e+ ~ne)

But, when I test the signal via ./runModels, I face the following error:

(base) hrishikesh@hrishikesh-OptiPlex-3000:~/Downloads/smodels-3.1.1$ ./runSModelS.py -f inputFiles/lhe/test.lhe -p parameters.ini -o results
INFO in databaseObj.loadBinaryFile() in 562: loading binary db file /home/hrishikesh/.cache/smodels/official311.pcl format version 214
INFO in databaseObj.loadBinaryFile() in 569: Loaded database from /home/hrishikesh/.cache/smodels/official311.pcl in 1.1 secs.
INFO in modelTester.testPoints() in 354: Running SModelS for a single file
Traceback (most recent call last):
File "/home/hrishikesh/Downloads/smodels-3.1.1/smodels/base/model.py", line 208, in getModelDataFrom
res = pyslha.readSLHAFile(inputFile)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/hrishikesh/anaconda3/lib/python3.11/site-packages/pyslha.py", line 1560, in readSLHAFile
return readSLHA(_read(spcfile), **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/hrishikesh/anaconda3/lib/python3.11/site-packages/pyslha.py", line 790, in readSLHA
sys.stderr.write("Ignoring unknown section type: %s\n" % line.split()[0])
^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'write'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/hrishikesh/Downloads/smodels-3.1.1/smodels/matching/modelTester.py", line 255, in runSingleFile
res = testPoint(inputFile, outputDir, parser, database)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/hrishikesh/Downloads/smodels-3.1.1/smodels/matching/modelTester.py", line 126, in testPoint
model.updateParticles(inputFile=inputFile,
File "/home/hrishikesh/Downloads/smodels-3.1.1/smodels/base/model.py", line 418, in updateParticles
massDict, decaysDict, xsections = self.getModelDataFrom(inputFile)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/hrishikesh/Downloads/smodels-3.1.1/smodels/base/model.py", line 220, in getModelDataFrom
massDict, decaysDict = lheReader.getDictionariesFrom(inputFile)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/hrishikesh/Downloads/smodels-3.1.1/smodels/base/lheReader.py", line 248, in getDictionariesFrom
eventMass,eventDecays = getDictionariesFromEvent(event)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/hrishikesh/Downloads/smodels-3.1.1/smodels/base/lheReader.py", line 355, in getDictionariesFromEvent
raise SModelSError("More than one parent particle found")
smodels.base.exceptions.SModelSBaseError: 'More than one parent particle found'

---

Will you please help me out how to resolve this issue?

[WolfgangWaltenberger]

Hi Hrishikesh, would you mind posting the lhe file here, so I can try and reproduce the error? Also, what version of pyslha are you using, and could you try with the latest version if you are using an older version?

Cheers

Wolfgang

[hdeka1]

test.zip

Hi, first of all, thank you for your quick response.
Here, I am attaching the .lhe file with 100 events. And in my system, i have pyslha version 3.2.6. I also tried with v-3.3.2. But the issue remains.

[WolfgangWaltenberger]

Right, I am seeing that in your lhe file, there is a <generator> tag within this <init> block. We were not aware that the LHE format allows this. Also, the mother indices for the daughter particles seem to be duplicated now (e.g. "3 3"), while we are expecting the second to be zero (e.g. "3 0"). I will clarify that this is indeed the syntax of mg5-generated LHE files (maybe this is even version dependent? will investigate), and fix accordingly. But these seem to be the culprits. Will keep you posted Wolfgang

…

On Tue, Mar 17, 2026 at 10:58 AM hrishideka ***@***.***> wrote: *hrishideka* left a comment (SModelS/smodels#54) <#54 (comment)> test.zip <https://github.com/user-attachments/files/26049357/test.zip> Hi, fist of all, thank you for ypur quick response. Here is the .lhe file with 100 events. And in my system, i have pyslha version 3.2.6 — Reply to this email directly, view it on GitHub <#54 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABLSE44CAWHYEDAFVNW75K34REOT3AVCNFSM6AAAAACWUF7PKSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DANZTG4YDSMRVHA> . You are receiving this because you commented.Message ID: ***@***.***>

[hdeka1]

Thank you for your reply.. I checked with another model (IDM) also. I generated the events with MG-3.5.5 (p p > H+ H-, H+ >H0 j j , H- > H0 j j). But the same error exists like the previous one. Currently, I am using SModelS v-3.1.1.

[WolfgangWaltenberger]

Right. Once the above issues are fixed, it seems we will run into the problem that your model is not within the set of models we already have "model files" for, see:

https://github.com/SModelS/smodels/tree/main/smodels/share/models

What kind of model is this, what are these eg 600000x particles?

Cheers

Wolfgang

[WolfgangWaltenberger]

Update, I google it, it is an alternative left-right symmetric model. Is there a way we can have a typical slha file for this model?

[hdeka1]

Yes, you are right. It is an alternative left right model. But, the SLHA file is not generated yet . However, for the mass spectrum generation and BR, we use SPheno. Now, how to add those info plus the xsection to the slha file, i am not aware of it..

[WolfgangWaltenberger]

Would you have one of the spheno output files for us? that would be sufficient i believe

[hdeka1]

SPheno.spc.zip
Here it is. I am attaching the SPheno output file. It contains all the mass spectrum, BR etc. (but, not the cross section, as spheno doesnot calculate it).

[WolfgangWaltenberger]

Alright, I think the develop branch of smodels has fixed this now.
Except we are not getting any results for your case,
as your xsecs are tiny (10**-33 pb).
Is there a way for you to try running the develop branch of smodels? If that's not easy I could
upload a version to testpypi that you can install via

pip install -i https://test.pypi.org/simple/

Wolfgang

[hdeka1]

Thank you very much .. The develop version does not have that previous issue. This seems running well.

In my case, final state is : 2OS lepton + 2j+ MET. But, for this final state, SMOdels reports that "no matching experimental results". I am attaching the results and the lhe file as well. Please look into this.

test2.lhe.py

test2.zip

[andlessa]

Indeed I do not think we have results for this specific topology, you can check the full list of topologies here
Note that your topology is not simply 2 OS leptons + 2j + MET, but a cascade decay with a lepton and then a jet being emitted in subsequent decays.

[WolfgangWaltenberger]

So given that we do not have results for that specific topology, are your issues resolved now, @hrishideka ?

[hdeka1]

Yes. Issues are resolved. Thanks again for your efforts..